In the previous post of this series I explained what happens in a digital camera – how a batch of photons is converted into a digital file. This post will cover how to use that file to create an image which can be displayed electronically or printed. This activity is called post-processing, because the initial processing of the image is done by software within the camera.
For wildlife photography, I believe the aim of post-processing is to produce a final image that replicates what you saw as closely as possible. And by “what you saw” I mean what you saw with your eyes through your binoculars, and not what the camera thinks you saw. Modern cameras are extremely capable, but their abilities are vastly inferior to those of the eye, especially the eye aided by precision optics. Occasionally the camera will manage to capture an image exactly the way you wanted it, but most of the time, especially in wildlife photography, the raw material produced by the camera will need some help.
The above images show the out-of-the-box version (Dusky Antbird 1) and the final version after post-processing (Dusky Antbird 2). Which would you prefer?
This article was also published in The Blue Bill, the Quarterly Journal of the Kingston Field Naturalists, Volume 67, No 2, June 2020.
I started this article intending to talk about post- processing – the business of editing your wildlife images. But I rapidly realized that it is too big a subject to deal with at once, so I’m going to break it into manageable chunks.
How the Camera Creates an Image
The first stage of the journey requires us to look at what happens when you snap the shutter. In the days of film cameras it was relatively straightforward – light passed through the lens and onto a film of celluloid or plastic. Light-sensitive chemicals on the film reacted to the exposure, producing a negative or a slide.
Digital cameras use a different process to capture an image. As photographers we need to have a basic understanding of how this works so we can understand how the different image file formats work.
In very simple terms, in a digital camera the light is focused on a sensor, which is a grid made up of very small photosites. Each photosite contains a diode that converts light into digital information. In simplistic terms the diode counts the number of photons that fall onto it while the shutter is open, and the circuitry in the photosite coverts that information into a numerical value.
In order to provide a digital image that matches the level of detail and colour that the eye can see, a camera sensor needs to contain millions of these photosites. This density of information allows a digital image to be at least as good as an image from a film camera. But it also explains why digital image files tend to be very large. Each of those millions of photosites generates a numerical value expressed as a byte of between 12 and 24 bits. To give you an idea of how that adds up, with my current camera set to the highest resolution the information stored by those photosites totals 62 million bytes of data for a single image.
The camera’s onboard processors convert those digital values into an image file. There are two main formats for an image file – JPEG and Raw. These formats take very different approaches to the challenge of storing all this data. In simple terms, JPEG transforms data within the camera to produce a finished image, while Raw stores all the information and the user then processes the information at a workstation. Each approach has its the pros and cons. I want to briefly illustrate the difference so you can make an informed choice about which format to use.
JPEG (Joint Photographic Experts Group) has emerged as the standard format for most photography tasks. For virtually all digital cameras JPEG is the default format, so if you have not been experimenting with the settings menu you are almost certainly shooting JPEG.
The JPEG format was developed to allow onboard compression of digital images. If you recall that figure of 62 million bytes you will see why for many applications there is a need to compress digital images.
Large files are problematic for several reasons:
They demand large storage capacity on your camera’s memory card
They take more time to write to the memory card, which can limit the number of images you can take in quick succession
They take up a lot of room on the storage drives of your PC, laptop, or mobile device
They require a lot of bandwidth to transmit, so websites will be slow to load and sharing is tedious
To avoid these problems the JPEG format compresses the raw information gathered by your camera sensor and then transforms it into a finished image. This image is stored on your camera’s memory card.
For many uses JPEG format is ideal:
JPEG images are small enough to be easily viewable and shareable.*
Virtually all devices and software are compatible with JPEG files.
The simple image editing software available on your cell phone, tablet or computer is designed to use JPEG images.
JPEG is supported by HTML, the language used in creating web pages.
*Note: JPEG files can be created using different compression levels. Lower compression levels lead to better quality but also larger file size. JPEG Fine files are the least compressed (4:1) but therefore the largest. At about 10MB each in the Large size they are not easily shareable.
However, there are limitations to JPEG that you should consider. Most of these limitations result from the way the JPEG algorithm compresses the image file size.
The process by which JPEG compresses a file is highly technical bordering on incomprehensible, but in the simplest possible terms it reduces the size of the file by calculating average values for 8×8 blocks of photosites (thus each block replaces 64 sets of information with one). It then reduces the level of information about colour. Based on the understanding that humans have difficulty discerning small variations of colour, JPEG looks for areas that have similar hues and replaces these small variations with a single average colour.
This process can result in a much smaller image file, but the key thing to remember about the JPEG conversion process is that once the image is created any information that the conversion algorithm considered unnecessary is lost and unrecoverable.
This is why JPEG is classified as a “lossy” format. As noted, a certain amount of information is discarded when the image is originally created. Moreover, each time you recompress the image, by making a change and then re-saving it, some additional information is irrecoverably lost. And if you crop an image – for example to provide a close-up view – the parts of the image that you cropped out are lost forever.
A further implication of JPEG is that, because it produces a final image, the camera settings in use when the image was taken are “baked in”. If you realize afterwards that you had the wrong white balance or picture control settings for example it may not be possible to correct the image.
Raw is a generic term for a file that saves all of the information from an image, with only minimal processing. This information needs to be converted and edited at a workstation before an image is produced.
Raw format is not available on all cameras. All modern digital single lens reflex cameras (DSLRs) and mirrorless cameras can shoot Raw, but only a minority of bridge cameras have the capability and point-and-shoot cameras generally do not.
There are several disadvantages to shooting in Raw:
Raw files are big. With the camera set-up I currently use, each image file is about 29MB. So a 64GB card will hold about 1,300 Raw files instead of 13,000 JPEGs.
You need to process your Raw files at home in order to generate finished images. This is time-consuming compared to the instant image generated by JPEG.
To process the files you need specialized image editing software (though note that you can download free editing software from your camera manufacturer – all the major camera brands provide this).
Each camera manufacturer has its own a proprietary standard, so a for example a CRW file from a Canon camera is not compatible with a NEF file a Nikon generates.
For Raw files to be printed, shared on a mobile device or posted on the internet you need to create and export a JPEG image.
So why do most professional wildlife photographers shoot in Raw?
Lossless. Raw files are lossless. All the information your camera gathered is available to you. Nothing is averaged out or approximated. As an example, an 8-bit JPEG image is limited to about 16.8 million colours, whereas a 12-bit Raw image can show up to 68.7 billion. What this means in the real world is that you will get more even transition between colours, without the possibility of the pixilation that sometime happens with JPEG (remember that JPEG averages out colours into larger blocks).
Non-destructive. The adjustments you make in post-processing do not change the original file. All changes are saved in a separate hidden file called a sidecar. So regardless of how much you crop and adjust an image, you always have the original file available. With JPEG every significant change degrades the image, and things that are cropped out cannot be recovered.
Settings are not baked in. With Raw you have complete ability to adjust most of the camera settings during post-processing, including exposure, white balance, sharpening, colour gamut, picture control, and contrast.
Greater dynamic range. Raw files are typically created in 12 or 14-bit format, compared to 8-bit for JPEG. This may not seem like a big numerical difference, but remember we are looking at a file made up of millions of bytes. The math is somewhat beyond my ken, but the impact is that in each stop of a camera’s dynamic range there is far more information space available in a Raw file. At the bottom end of the dynamic range – areas of deep shadow in a photograph – there are 65 times as many gradations in a Raw file as in a JPEG.
This has important implications for wildlife photographers. We often find ourselves trying to capture images in areas where there is both bright light and deep shadow. Using JPEG, those shadows will tend to be featureless dark blobs, whereas with Raw we will be able to see the same details that our eyes would see.
Moreover, the greater ability of Raw to capture detail in shadow allows us to apply shadow reduction – a very useful capability that I will talk about in future articles on post-processing.
But perhaps the most striking advantage comes when we shoot images at incorrect exposures. The perfect photographer would never do this, but for the rest of us there will be numerous situations were we have the camera set up for bright daylight only to have a momentary glimpse of a bird – and typically it’s a good one – peeping out of a dark corner.
The higher dynamic range of the Raw format means we can correct a badly underexposed shot in post-processing and end up with a good image.
Consider this example. I deliberately underexposed this shot of an American Goldfinch in my garden. I did this as an experiment, so please ignore the uninteresting composition. The camera took two simultaneous images – one in Raw and one in JPEG Fine.
The images were very dark – I had to increase exposure by about four stops. But the results are clear. The quality of the Raw image is pretty good: there is full feather detail and the colours look right . The JPEG image on the other hand is dreadful. The colour is over-saturated, green blobs have appeared in the breast and belly plumage, and the whole bird looks flat and dull.
If you have read this far, you have probably realized that I am a fan of the Raw format. I believe that in wildlife photography the aim is should be to produce an image that replicates as closely as possible how the creature (bird/animal/plant/butterfly/reptile) looked in the wild. I have found that using Raw format and carefully post-processing the image gives me the best chance of doing that. And there is an element of craftsmanship involved that I find appealing – I prefer to make my own choices rather than having the camera make decisions on my behalf. I am also not worried about file size given that hard drive storage capacity has become increasingly inexpensive.
So is there an argument for using JPEG? The fact remains that some very good images have been created using JPEG. You may well decide that you prefer the simplicity and efficiency of JPEG. If so, I would recommend that you use the lowest compression setting: JPEG Fine. This setting creates a 4:1 compression, so the files are still fairly large, but at 4:1 you will not see any of the artifacts or errors that can creep in at higher compression ratios.
After thoroughly sampling the full Amazonia experience, our next key target in the 2020 Colombia expedition was the Llanos – a huge grassland plain that stretches over eastern Colombia and Venezuela. About 500km of driving lay ahead of us from Bogotá. Obviously we had to look for Eastern Andes endemic birds along the way, so several days were to pass before we reached our jumping-off point in Paz de Ariporo.
We spent some time working the forests near Santa María, Boyacá, and then another couple of days climbing up into the foothills near Monterrey. I will just mention a few highlights from these stops before we get to the main event.
This is a small town (less than 5,000 inhabitants) in an out-of-the-way corner of the Andes. It had a short period of growth during the construction of the La Esmaralda dam and power plant, but has now lapsed back into small-scale agriculture and torpor, enlivened by a bit of eco-tourism. It seems that Santa María is a hotbed for arachnid species, though we did not encounter any spider tourism groups during our stay.
Development is not permitted in the forested hills surrounding the reservoir, so they are home to a large variety of birds. We managed to add three new entries to the birds-whose-names-start-with ant category, the smart-looking Golden-headed Manakin, Rufous-and-White Wren, Crested Spinetail and the enigmatic and highly prized Spotted Nightingale-Thrush. A evening of owling was quite productive. And I also saw more Cerulean Warblers in three days than I have seen in ten years in their breeding range. Photos of the more cooperative species are below.
This is the second part of a trip report on our recent visit to Mitú. Part 1 is here.
Note: if are reading this on a cell phone you are getting the light version, and the images and video may be a bit wonky. If you are connected to WiFi or have a robust data plan I suggest you click on the title, which should connect you to the actual website.
Mitú Day 4 – Pueblo Nuevo
Even by birding standards it was a painfully early start, but we had a long, bumpy road to traverse on our way to Pueblo Nuevo. So after a quick coffee we were on the road at 0500. The sun came up as we rolled into the village and linked up with Florencio, a native guide from the local area. Like Miguel he is a crack bird-finder, and with the two of them working in tandem we were looking for an epic day.
Pueblo Nuevo, BTW, is remote enough to make Mitú appear cosmopolitan. Landlines and cellular signals are non-existent, though electrical power is available courtesy of a nearby hydro power plant . But between their gardens, free-range chickens and small agricultural plots cleared in the forest the people seemed to be well fed and healthy.
So we plunged off down a narrow forest trail and immediately started clocking new birds. The area is rich in ant specialists and over the course of a long morning we found four species of antshrike, two of antwrens and nine(!) antbird species. And Black Bushbird, a close relative which for some reason doesn’t have a name starting with ant.
More Antbird Photos!
On the non-ant side of the ledger, we startled a pair of Marbled Wood-Quail – a very tough bird to spot but we clocked them as they sped off at high speed. We also managed a quick glimpse of a skulking Pectoral Sparrow. A good assortment of toucans, jacamars, parakeets and woodpeckers were spotted, with a background soundtrack provided by the aptly-named Screaming Piha. So with 72 species in the bag it had to rate as a great morning of rain forest birding.
It was after 1330 when we got back to the village so lunch and a snooze were in order. We crashed in the village hall for an hour and then headed back out. Did I mention that Pueblo Nuevo does not have a Starbucks? At that point it seemed like a serious oversight. So we forged on, coffeeless.
It was a sultry afternoon – one of the hottest of the trip. The birds were a bit sluggish and so were we. We did end up tracking down a few new species for the trip list, including a nice male Blue-crowned Manakin, but we eventually called off the hunt and bumped our way back to Mitú, arriving late and hungry but happy.
Day 4 life birds: 26
Day 5 – The Jungle has its Revenge
Our fifth day started very early again as we needed to go beyond Pueblo Nuevo to the end of the road. We picked up Florencio enroute and arrived at the right bridge at the right time.
Fiery Topaz is a highly desirable and hard-to-find hummingbird, but those in the know knew that they often rested below a certain bridge at dawn before zipping off for the day. So there we were and there, eventually, it was too. But the idea that we might get a decent shot of a perched bird was not to be. The male spent ten minutes or so swooping around in the gloom before speeding away.
Photographing fast-moving birds in the half-light is… something other than fun. Even with good equipment there is always a trade-off involved. Set a wide-open aperture, engage super-high ISO, choose the slowest shutter speed you can get away with, and then try to achieve and hold focus. It’s a recipe for frustration.
However in a highly improbable combination of good luck and good camera management I did manage to snap the bird at the moment when it stopped to hover. The resulting photo has not resulted in a call from the National Geographic, but I am somewhat pleased all the same.
We then set off down a narrow forest trail. Interesting birds were calling and needed to be tracked down. But other winged denizens of the forest were also out foraging…
It had crossed our minds that the Amazon rain forest might have a few pesky insects, so we came prepared with the full arsenal of chemical defences. However the effect of tropical temperatures and high humidity was that even the best bug repellent was rapidly sweated off. And birding involves a lot of standing motionless. Not a good combination. There had been some mosquito and sweat fly action on the previous days, but on Day 5 we paid the full price. Our tormentors were:
Mosquitoes. There seemed to be at least two sizes: small nimble ones that left a typical somewhat itchy bite, and a larger type – perhaps an African killer mosquito or a mutant developed by the CIA – that left a large, very itchy and long-lasting welt. This type was our constant companion that morning.
No-see-ums. These were not exactly like the scarce Ontario bug of the same name, but more akin to small Black Flies. Their bite is like a needle stick, but doesn’t do any lasting damage.
Sweat flies. A variety of small flies that swarm around your face trying to drink your sweat. Harmless, but their persistence makes them supremely irritating.
Horse fly relatives. I have been unable to identify these beasts, but picture an extra large, red fly with the malevolent intent and near-indestructability of a Tsetse Fly. Whack these things and they just shake their heads and resume trying to bite. The locals hate them so much they catch them out of the air, pull off one wing and drop them on the ground. Harsh, but understandable.
Chiggers. The worst of all. I was emotionally scarred by my first, 400-bite experience of chiggers. If I had known they were in the area I would have taken extreme precautions. At the time of writing all but two of my 14 or so chigger bites have stopped itching. The bites were two months ago. Grrr.
So anyway we got bitten pretty thoroughly that day. But the birding was good, so it was a fair trade-off.
… and Birds
In the murky and bug-infested forest we spotted a couple of highly desirable skulkers. Musician Wren is one of those heard-but-not-seen birds that proliferate in the rain forest but after half an hour of standing motionless like a mosquito smorgasbord we spotted the beast peering out of the darkest tangle of scrub available. Photography was not an option but we had decent views .
The same patch of woods also housed a lovely Rufous-capped Antthrush. This particular individual’s superpower was ensuring that there was always a branch or leaf between camera and bird, but eventually it showed itself briefly and deigned to be photographed.
A few woodcreepers, our first Green Oropendola, Curve-billed Scythebill and some White-fronted Nunbirds rounded out the list, and we left the trail of insect perdition and headed for our lunch spot.
The road to nowhere actually ends at a good-sized hydro power plant on the Vaupés River. We had lunch at the cafeteria for the plant workers, and then while my compañeros snoozed I wandered down to the river and spied on a large roost of herons and egrets.
Stalking the Cock-of-the-Rock
Our mission for the afternoon was to try and find a Guianan Cock of the Rock. These beasts are one of the most colourful and bizarre of neotropical birds, close cousins of the Andean Cock-of-the-Rock we saw in Jardin last year. They are mostly found in Venezuela, Guyana and Suriname but extreme western end of their range overlaps the Colombian border. So it was a necessary bird to see.
One male bird had been observed recently along a forest path, but we square-searched the area to no avail. So the remaining option was a long, hot scramble up a rock massif.
After checking every crevasse and valley we eventually found the charismatic orange bird in its lurking area. Then we rested on our laurels for a while at the top of the rock, with a view towards the hills that mark the border with Brazil.
A good variety of avians passed by, including a couple of needed-for-the-trip birds like Red-fan Parrot and Lemon-throated Barbet and our best view of a Scarlet Macaw. Eventually and with some regret we clambered down, bade farewell to Florencio, and headed back to town for our last night in Mitú.
Day 5 life birds: 16
Day 6 – Adiós Mitú
We had a plane to catch in the afternoon, but an excruciatingly early start allowed us to get another five hours of birding in. At that point we had seen most of our target birds but we did manage to find a couple of new additions , as well as practice some birds-in-flight photography on low-flying vultures. Then back to town for lunch, the usual excess formalities at the airport and we were on our way back to Bogotá.
So that’s the story of our great Amazon adventure. Five days and a bit, 133 life birds, a bit of beautiful scenery and a look into a remote and fascinating part of the world. If you’re interested in neotropical birds you may someday find yourself drawn to Mitú, so I hope this has given you a flavour of what’s in store.
If you would like to see more (and better!) images of the birds mentioned here, you can enter the species name under the Explore Species tab in E-Bird. But note that this is an American site so they use American spelling rules. So for “grey” you have to use the inelegant spelling “gray”. 😉
In January and February of this year I took (yet) another birding trip to Colombia. Ken Edwards and I linked up with Daniel Uribe Restrepo for an extended foray that took us to Amazonia, the Llanos and the eastern foothills of the Andes. Rather than writing a 5,000 word tome on the whole trip I’m going to break it into parts, starting with the wonderful world of Mitú.
Note: if are reading this on a cell phone you are getting the light version, and the images and video may be a bit wonky. If you are connected to WiFi or have a robust data plan I suggest you click on the title, which should connect you to the actual website.
…is a small city in the Amazonia region. It’s in the deep eastern part of Colombia, near the border with Brazil, and thus about 250km beyond the end of the road network. To get there you can either fly from Bogotá with SATENA, or… not go to Mitú. But if you’re a birder you would want to go, for its remote location in the midst of a vast, trackless and undeveloped rain forest makes it one of the few viable places to access the wild and eccentric avian life of the Amazon basin.
So off we went aboard a shiny-new Embraer 170, which looked a bit out of place as it rolled into the grandly-named but rather rustic Aeropuerto Fabio Alberto León Bentley. After some tedious formalities where we had to provide our full particulars to both the tourism agency and the police, we checked into the hotel and headed off for a quick exploratory visit to the village of Urania.
Or at least that was the plan. But as soon as we hit outskirts of the town great birds started to pop up. A short roadside stop yielded ten species – not too big a number but six of them were life birds for me, including the highly desirable Paradise Jacamar, Cobalt-winged Parakeet, Yellow-browed Sparrow and Chestnut-bellied Seed-Finch. This was going to be good!
We managed to tear ourselves away and eventually reached Urania, but to get to the village we had to cross a covered bridge. And the bushes and trees on both sides of the bridge were alive with good birds: Moustached Antwren, Cherrie’s Antwren, White-browed Purpletuft, Swainson’s Flycatcher, Bronzy Jacamar and a host of others. One of my most wanted birds for the trip was the Swallow-winged Puffbird, and there were lots of them perched on telephone wires in full view. Hummingbirds zipped by while Yellow-headed Vultures (Lesser and Greater) soared overhead.
The upshot of this cornucopia of creatures is that we didn’t actually get to Urania. We spent almost two hours on the covered bridge without even reaching the halfway point, before the sun set and we had to head back to town. So Urania would have to wait for another day, but after collecting 27 lifers in an afternoon one was… contented. 😊
Day 2 – Cachivera
The Amazon rain forest is a vast area with a few tracks and trails radiating out from towns and villages. Birding the area involves walking these trails, accompanied by a member of the first nations that collectively own the land. We were very fortunate to have Miguel as our guide – or rather we were fortunate that Daniel knows who the best guides are and made sure that we got Miguel. Aside from having uncannily good hearing and an amazing ability to spot small, far-away birds, Miguel is a really pleasant person and very determined to ensure that every member of the group has a good look at all the birds.
The mission for Day 2 was to walk a long trail that leads into the terra firme forest. Terra firme refers to a relatively small percentage of the Amazon basin rain forest that does not experience seasonal flooding. As a result the trees are much taller than in seasonally-flooded (varzea) forest and there is greater biodiversity. More biodiversity translates into greater bird diversity, so we were hoping to spot some bird species that are endemic to the white sand terra firme forests around Mitú.
So off we went for a short drive at the crack of dawn, and as the sun rose we were walking through a village, across another bird-infested bridge and on into the forest.
The Birding Experience in Mitú
The program for the day, and for most of the days at Mitú,
was to slowly walk along a track scanning for sounds and movement in the
treetops and deep in the forest, and then try and zero in on any birds that we
found. While not truly strenuous, it was hard work in birding terms. Bird
sounds were everywhere but catching sight of the pesky beasts took time and
patience. Most species were either high up in the canopy or skulking in dark tangles
This made photography particularly challenging: I have lots
of dodgy, highly-cropped photographs of far-away birds. Fortunately the Nikon
D500 has outstanding capability in low light, but I had to master the changes
needed to rapidly switch between bird-on-top-of-a
tree-in-bright-tropical-sunlight and bird
Moreover, like every day we spent in the area, the sun was beating down, the daytime high was in the mid thirties, and the humidity felt like about 99%. There were also a reasonable number of pesky insects, but more about them later.
By the way lest this be interpreted as whining, I want to be clear that I was in Mitú at my own request, and we had a fabulous time. But for those might want to go birding in the remote Amazon I thought I would give you an idea of what to expect.
Back to Day 2
After a few hours, despite having seen some great birds we were starting to feel a mite fatigued. But then our fearless leader’s wisdom in telling us to bring a bathing suit was revealed. Cachivera translates as “pool”, but in local usage it refers rapids in a river or stream. But these particular rapids ended in a pleasant-looking pool, so in we went.
Lolling around in the cool water was refreshing indeed, and reinvigorated we pressed on. Shortly thereafter we came upon a mixed flock high up in the canopy and managed to clock a few highly desirable species including Flame-crested, Paradise, Fulvous-crested and Turquoise Tanagers.
In the end we covered about nine km in six and a half hours that morning before retreating to town for lunch. Later on, after a much-needed siesta, we went for a stroll down the old pipeline trail, adding the much-wanted Thrush-like Antpitta, Coraya Wren, Green-backed Trogon and Yellow-billed Jacamar to our tally.
Life birds on Day 2: 37
Day 3 – A festival of Antcreatures
One of the reasons birders flock to Amazonia (groan!) is to gorge (metaphorically) on the huge variety of “antcreatures”: Antbirds, Antshrikes, and Antwrens. No, gentle reader, these birds don’t eat ants. But their favourite feeding strategy is to follow an army ant swarm, feasting on invertebrates as they try to flee the advancing ants.
These bird species are the kind of thing that hard-core birders really like: hard to find, hard to get a good look at, hard to tell apart and of course, hard to photograph. Antbirds and antshrikes are particularly cryptic: a range of small grey birds with semi-distinctive differences in the small white spots on their wings and back.
As we walked the new pipeline trail that morning we lucked upon an ant swarm with its accompanying suite of birds. Of course the ants don’t waltz down the middle of the road. They were in the forest and we needed to get ahead of them to catch the birds. This meant crossing the swarm.
I had somehow imagined army ants as large fearsome beasts, but the ones we saw that day looked like ordinary, medium-sized black ants. In vast numbers. And fast-moving too – if we stopped for even a moment we would find 40 or 50 ants racing up our legs with mayhem in mind. But it was worth the risk because when antbirds are near a swarm they are absolutely focused on feeding and you can get fairly good views without startling them.
So the ants generously provided us with a number of additions to the morning’s list, including Mouse-coloured Antshrike, and Dusky, Grey, Black-faced, White-cheeked, Chestnut-crested, Spot-backed and Scale-backed Antbirds. Or if you prefer, a bunch of LGJs (little grey jobs).
After lunch we returned to Urania/Mitusueño, and this time made it across the bridge and through the village. We piled up a good list in short order, starring Black-headed and Orange-cheeked Parrots, Yellow-tufted Woodpecker, a handful of flycatcher species and Azure-naped Jay. But the star bird was Blackish Nightjar. Nightjars and their kin are hard birds to see as they hide motionless during the day and only come out to hunt after dark. They breed in the area of Urania so we hoped to catch a bird or two flying over in the last moments before nightfall.
What I did not expect is to have one creep out of the bushes so close to us that I had to back away to get it in focus! We marched back to the pick-up point that evening with another 23 bird species added to my life list. A celebration was called for, and achieved after a thorough search of the town turned up a friendly ice cream vendor.
So that’s the story of our first three days in Mitú . Stay tuned for the next installment.
Servicio Aéreo a Territorios Nacionales, a national airline operated by the Colombian Air Force, with the mission of connecting remote communities that commercial airlines decline to serve.
This article was also published in The Blue Bill, the Quarterly Journal of the Kingston Field Naturalists, Volume 67, No 1, March 2020.
If I had to pick a single technique that made a dramatic improvement to my capability as a wildlife photographer, I would choose Back-button Focus. It’s a technique used by professional wildlife and sports photographers, and can help you take your photography to a higher level.
It starts with the recognition that crisp focus is perhaps
the single most important quality of a good photograph.
Because focus is so central to photography, camera manufacturers have developed ways to make it easier to get an in-focus image. Any camera produced in the last 20 years has the ability to focus automatically – indeed autofocus is the default option, and may have to be turned off if you wish to focus manually.
Autofocus is engaged when you press down on the shutter release. This happens so quickly some beginning photographers don’t even realize it is happening, but with practise most people learn that if they depress the shutter release halfway they can focus the camera without taking a picture.
For most types of photography having the autofocus engage when you press the shutter release makes life easier – a single action both focuses the image and releases the shutter. Wildlife photography, though, has its own requirements and many wildlife photographers find that the simple shutter release/autofocus approach actually creates problems.
Instead they use back-button focus, where the autofocus function is disconnected from the shutter release and assigned to a different button.
I am not going to explain how to do this. Each camera system has its own way of assigning buttons, and you will need to consult your manual to learn how to make the change on your camera. Instead, I am going to explain why you might want to make this change.
Targets obscured by foliage
If you have spent any time trying to photograph birds in the wild I am sure you will have had this experience. You are trying to capture an image of a bird roosting in a tree within a tangle of branches, twigs and leaves. You can see the bird clearly, but frustration creeps in because each time you take a shot the camera focuses on a different one of the surrounding twigs and only occasionally on the bird.
For all the capabilities of modern autofocus systems, remember that they are not actually intelligent – they try to guess what you want to focus on but they are frequently wrong.
Using back-button focus can solve this problem. You centre your camera on the bird and engage the focus. You may have to do this a number of times until the focus point is actually on the bird. In cases where there is a lot of background clutter you may even have to use manual focus. But the key point is this: once you are focused on the right point you can shoot as many images as you want without the camera trying to refocus each time. As long as you stay at approximately the same distance from the bird it will remain in focus. The camera will not be able to “help” by randomly changing the focus point.
And even if you have to move slightly to get a better angle, if you engage autofocus again it will most likely zero in on the bird because it will be the closest object to the focus point.
I think you will find that once you try this technique you will be reluctant to go back to shutter release focus. Time that you might have wasted in focusing and refocusing can be spent on adjusting ISO and shutter speed and choosing the right moment to shoot.
Focus and reframe
Wildlife photographers often find that they want the focus point of an image to be off-centre. There are two main situations where this occurs:
Large or close-in target
Say you have a chance to see a Moose at fairly close range. You want to capture the whole beast in an image, without cutting off its tail or legs. But you also want your focus point to be on the eye, as tends to create the most compelling image. And not surprisingly, the Moose’s eye is at one side of the image.
You have a bird in your sights but you want to frame the
image so that the bird is off-centre. You might want to better show its within
its habitat, or to give it some open space in front of it, or just because
people are more attracted to images where the main points of interest are
In these situations back-button focus is your friend. It
allows you to focus on the desired point, and then without changing focus
reframe the image by moving the camera until you get the result you want.
Note that landscape and portrait photographers deal with this need by manually adjusting the camera’s focus point. In principle this would also work for wildlife photographers, but in my experience the focus and reframe method is much more intuitive and much faster to use. For subjects that tend to move suddenly and unpredictably I think it provides better results. Moreover it allows you to set your camera adjusted to centre point focus, which is the most accurate autofocus mode.
For moving targets, such as a bird in flight, holding down the back button allows you to keep it continuously in focus while you wait the right moment to shoot – such as when it banks to show its upper wings. You can also hold focus on a stationary target, and you will be in focus when it pounces, takes off, or otherwise moves suddenly. Without holding focus the camera will need to refocus at the critical moment, with unpredictable results.
In principle you could also accomplish this by holding the
shutter release halfway down, but in the real world of wildlife photography,
where you will often be wearing gloves and your hands may be stiff from the
cold, using a separate button removes the need for such fine motor control.
Of course you could just “spray and pray”, firing off twenty
images at high speed and hoping one of them works. As long as you don’t mind
everyone nearby assuming that you are clueless. 😊
Back-button focus – further advantages
While the above points are the key reasons for adopting
back-button focus, there are a few minor advantages as well:
If you are using manual focus, you won’t then risk spoiling your
own efforts when it’s time to press the shutter release.
Use of back-button focus reduces battery drain somewhat. Unlike
shutter release focus it doesn’t automatically engage the lens’s image
stabilization/vibration reduction motors.
Back-button focus is possible on most DSLRs and mirrorless
cameras, but it may not be possible if you are using a bridge or superzoom
camera. Check your manual to see if you can use this function.
And if you ask someone to take a picture using your camera, don’t expect great results. You can explain carefully the need to press the focus button and then press the shutter release, but I find that most people don’t “get” this and the images tend to be out of focus.
Originally published in The Blue Bill, the journal of the Kingston Field Naturalists, Volume 66, No. 4, December 2019
Freezing the Action – Shutter Speed and Shutter Priority Mode
One of the major challenges of wildlife photography (and sports photography for that matter) is the need to choose a sufficiently fast shutter speed. Like all photographers we need to balance available light, depth of field, metering modes and focus points. But unlike, say, landscape or portrait photographers our subject matter tends to move quickly in unpredictable ways.
If our camera’s shutter speed is fast enough we will be able to “freeze” the action of fast-moving subjects and get a crisp image. So in principle the solution is to always use a fast shutter speed. And there are some circumstances where this approach will work. But much more often we will be engaged in a balancing act, adjusting variables such as shutter speed, aperture, and film speed (ISO) to get a correct exposure.
The Basics of Exposure
In very simple terms the image your camera produces is governed by the amount of light that falls on the sensor. A correctly exposed wildlife image will show the creature or plant in natural light with no areas that are too dark (underexposed) or too bright (overexposed), and will be crisp with no motion-induced blurring. Photo 1 shows an American Pipit, and to my eye the exposure is good – all detail is visible and the bird’s foot is frozen in mid-stride.
Exposure is controlled by three settings: aperture (the amount of light that the lens allows to reach the sensor); shutter speed (the length of time that the sensor is exposed to the light); and film speed or ISO (the sensitivity of the sensor).
Each of these variables has implications that the photographer needs to understand:
As noted above, the primary way to get a crisp exposure of a moving animal (or a plant blowing in the wind) is to use a fast shutter speed. The downside of fast shutter speeds is that less light reaches your camera’s sensor. Shutter speed is expressed in fractions of a second. Each step up in shutter speed (e.g. from 1/250 to 1/500) halves the amount of light available. So except in very bright, sunny conditions faster shutter speeds can lead to underexposed images. To an extent you may be able to fix underexposure in post-processing, but artificially adjusting the exposure by more than a small amount adversely affects the quality of the image.
For stationary subjects you can use a slower than normal shutter speed and hope for the best, but typically the creature will move just as you snap the shutter. Photo 2 is a Coatimundi seen just after dawn. I had to use a slow shutter speed and a high film speed to get the shot. If you look closely you will see that the face is slightly blurry as it moves its head to the side.
So if shutter speed isn’t the whole solution, what else can you do to increase your chances of getting a crisp image?
Wide apertures allow more light in, so in the low-light conditions we are often dealing with a wide aperture seems like a good choice. The more light that passes through the lens, the faster your shutter speed can be. But as you might guess there are no easy solutions here. First, telephoto lenses capable of wide apertures are ruinously expensive. For example the Nikon NIKKOR 300MM ƒ2.8G ED lens, a favourite of professional wildlife photographers, will set you back a cool $6899.99 plus HST. So most of us will be using lenses with narrower apertures, and thus will have less light to play with.
Moreover, the wider the aperture, the shallower the depth of field. For the wildlife photographer, this creates a problem: the image may be correctly exposed but parts of the creature are not in focus. Photo 3, a Pearl Crescent, is correctly exposed. But even at ƒ7.1, a middle of the range aperture, the depth of field is shallow enough that the wing closest to the viewer is not in focus. The tails of birds can also fall prey to depth of field issues. In photo 4 the tail of the Canada Jay is a bit soft-edged, as it was beyond the optimal depth of field.
Film Speed (ISO)
Before the advent of digital cameras, photographers adjusted for low-light or fast-moving subjects by using faster film. So instead of ISO 64 or 100 film they might switch in a roll of ISO 200. This involved a big trade-off in image quality, as faster films producing grainer images. ISO 400 was about the maximum usable speed.
Now we have digital cameras capable of ISO equivalents of up to 51,000 so is the problem solved? Yes and no. Good quality digital cameras can produce very good images at higher ISO ratings, but only to a point. Just as fast film was prone to graininess, digital camera sensors can generate “noise” at higher speeds.
With my camera I can get excellent images at ISO 800, and very good ones up to ISO 1000. Speeds faster than that can work reasonably well depending on what you want the image for. Photo 2, for example, was shot at ISO 2000. The image is reasonably crisp and good enough for a record shot, but if you look above and to the right of the creature’s haunches you will see that the image becomes fuzzy (“noisy”) with some random colour blobs.
So what does it all mean? Simply that there is no single recipe for achieving crisp, properly exposed images of wildlife. While we are in the field we have to make continuous judgments about shutter speed, aperture and film speed to enable us to get the images we want.
Shutter Priority Mode
If you spend too much time thinking about these variables you may end up missing some of the action you went out to photograph. So most wildlife photographers use their camera’s mode system to automate part of this work.
All DSLRs and most bridge cameras have four basic operating modes: Manual, Shutter Priority, Aperture Priority and Program. I want to explain Shutter Priority mode here because I think it is the most useful option for wildlife photographers.
Your camera will have an easily accessible way of selecting this mode – most often by a rotating dial on the upper right side (Photo 5). For most DSLRs rotating the dial to S puts you in shutter priority mode. Eccentrically, Canon and Pentax call it “Tv” for time value, but the effect is the same.
When you are operating in this mode, you can select the film speed and shutter speed you desire and the camera will automatically adjust the aperture within its limits to ensure a correct exposure. If there is not enough light to get a correct exposure at maximum aperture the camera will warn you somehow, often by inactivating the shutter release. Check your manual to see how your own camera works and what adjustments you can make.
You can actually go a step further and automate your choice of film speed as well. Somewhere in the menu system of your camera there will be an option to select “auto ISO”. This is a tempting option for wildlife photography, as it minimizes the chance of a missed shot. However beware of the fact that cameras left to their own devices tend to bump up the film speed to fairly high levels, so if you use this function check your manual to see if you can set an upper limit on auto ISO.
Recommended Shutter Speeds
So the final piece of the shutter speed puzzle is: how fast is fast enough?
In principle, unless forced to by low light I would recommend a minimum shutter speed of 1/500 for wildlife. Birds and mammals, even if they appear stationary, are often flicking their ears or looking around, so it’s best to err on the safe side. I did a quick check of the wildlife photos I am most proud of and almost all were shot at 1/500 or 1/640. There are exceptions, such as the Chestnut-naped Antpitta at photo 6 (1/00 at ƒ5.6) but I was fortunate that the bird held still for a moment.
For frogs, turtles, and perched butterflies and odonates you can often get by with a slower speed, as they can sit still for lengthy periods. But the Snapping Turtle at photo 7 was being aggressive so I needed 1/500 to freeze her.
Birds in Flight
There is a simple rule of thumb here: the fastest shutter speed you can manage is the one to choose. But you can cheat to some extent based on the type of bird and its activity. The Trumpeter Swan has fairly slow wingbeats, so in photo 8 even 1/250 was enough to get a crisp image. The gliding Red-tailed Hawk in photo 9 was shot in bright daylight so I was able to go to 1/3200 and ensure that the image was crisp.
The Greater Prairie Chickens at a lek in photo 10 were tricky. We were shooting at dawn so there was very little light available, and the birds were actively jousting. I found through trial and error that a shutter speed of 1/2000 was enough to freeze the action. To make that work I had to bump the ISO up to 8000. The resulting image is reasonably good.
By the way, don’t even think about trying to photograph butterflies in flight. That way lies madness.
Hummingbird wingbeats are so fast that it is difficult to get a crisp image even in optimal light. Shutter speeds of at least 1/3200 will be needed. And because their wings move in strange ways to allow them to hover, even if you do get a crisp image it will often look rather odd. So unless you can find a perched bird, I find the best approach is to intentionally allow a bit of blur in the wings, which gives the impression of movement. The Western Emerald in photo 11 was shot at 1/320 while hovering. This is about right for the wings, but as you can see the tail is a bit blurred, so a slightly faster speed would have resulted in a better image.
So that’s the bluffers’ guide to shutter speed. if you have mastered the basic operation of your camera and want to dip your toe into more advanced options why not try experimenting with shutter priority?
I am not an expert photographer and this post is not intended for experts. I became interested in wildlife photography when I was planning a trip to Tanzania in 2015. It was likely to be a once-in-a-lifetime trip and I wanted to come back with some good wildlife photos. So I obtained a decent camera and lens and took a short photography course before we left. The results were encouraging, and I could see that with more knowledge and experience I ought to be able to capture even better images.
In a way photography is like birding: the is an infinite amount of information, so there is always something new to learn. And like birding, photography rewards both study and practice. Through trial and error I have learned a fair amount about the craft of photography over the last few years. This post is intended to share things I have learned on my journey that may be of use to other aspiring photographers.
Understanding Exposure Compensation
In this first installment I want to talk about exposure compensation. It’s a camera function that many amateur nature photographers I have met seem unaware of, but in certain situations it is a really important tool to ensure you get the image you want.
I won’t get into a long explanation of how camera light metering systems work. Suffice it to say that most of the time they work very well. But there are a few situations in wildlife photography where left to its own devices the camera will make the wrong decision. Knowledge of how to compensate for this will help you get the right exposure and avoid disappointment. Those situations are:
Wetness and Whiteness
Let’s start with a common situation: birds up in the treetops, or in the case, a bird on a wire. You see a Mourning Dove; your camera sees a mostly light background with one dark object. So it averages out the exposure and you are left with something like the image in photo 1 – a dark blob. After I took the first image I adjusted the exposure compensation two steps to the left (to -0.7) and photo 2 was the result. The bird is correctly exposed and all its plumage details are visible (e.g. the thin blue eye ring).
Of course I could have adjusted the exposure
of photo 1 in post-processing, but the best-looking images start with a file
that is correctly exposed in the first place. This is particularly important
if, like most photographers, you shoot in a lossy format such as JPEG. Each
time you edit a JPEG file more data is lost, so the closer you get to correct
exposure in the first place, the better your final image will look.
Metering systems also struggle to correctly
expose objects in shadow. Photo 3 shows a pair of Hadada Ibis from that trip to
Tanzania. The birds are underexposed because they are in shadow and there is
bright sunlight on the right side of the image. The metering system tried to
average out the exposure, which left the birds in the dark. In this case
positive exposure compensation – moving the exposure one or two steps to the
right – would have produced a better image (photo 4).
Wetness and Whiteness
Bright spots also cause trouble for the metering system. In wildlife photography this often shows up when photographing in bright sunlight. Anything white or wet can end up being overexposed even if the rest of the exposure is good. So gulls, terns and white pelicans are a problem, and so too are turtles and frogs when the sun is shining on their shells or skin.
In the case of bright spots, the issue is that the image may look properly exposed, but on closer examination the highlights are blown out. Blowing out, also known as clipping, happens where the intensity of light in a certain area exceeds the camera’s ability to capture information. So a blown highlight may look white, but if you look closely you will see that there is no detail in that part of the image.
Consider photo 5 – a Ring-billed Gull in
sunlight. The image looks properly exposed, but if you zoom in (photo 6) you
will see that there is no feather detail – it’s just a blank field of white.
Sadly, blown highlights are on thing that cannot be corrected in
post-processing, as there is no data to work with.
Here again, exposure compensation comes to the rescue. In photo 7 I deliberately underexposed the image by adjusting exposure compensation two steps to the left (-0.7). In post-processing I was able to increase the exposure so the gull is properly exposed, but as a blow-up shows (photo 8) the plumage details in the white area are fully visible.
Using Exposure Compensation
If you want to experiment with exposure compensation, the first step is to find how to adjust exposures on your camera. I recommend reading the relevant section of the manual, which will show you where the adjustments are made. On most DSLR camera bodies you will find a button that looks like photo 9. On bridge cameras, it is more likely to be a multi-function button. Typically you will need to hold down this button while moving one of the rotating dials or switches to adjust exposure up or down. In either case you will be able to see your adjustments on the exposure compensation slider, which is usually visible in your camera viewfinder.
Three Important Tips
1. The monitor (LCD
viewscreen) on the back of your camera allows you to test and adjust. So when
you come across your quarry and the lighting may be problematic (backlit,
shadow, wet or white) take a photo to start off, then if the bird or beast
stays around, look at your monitor to see if the exposure is good. If not, try
an adjustment of two steps, reshoot, and check the monitor. Continue testing
and adjusting until you either get the perfect exposure, or more likely, the
bird of beast absconds.
2. Most cameras
have a function that will show blown highlights in the monitor. For Nikon
cameras it is cunningly named Highlight Display. Again, check your camera
manual to see how to activate this function. When activated, if you take an
image and look at the monitor you will see flashing lights (photographers call
these “blinkies”) in areas where there are blown highlights. This quick check
will let you know whether you need to adjust the exposure. Note that for
backlit objects, if the object itself is correctly exposed there will probably
be blown highlights in the sky behind it. This is not really a problem other
than the fact that the sky tends to end up white rather than blue.
3. In most cases
your camera will not automatically default back to the zero position once you
have taken an image. I won’t tell you how many times I have forgotten to take
account of this and taken a quick snap of a rapidly-departing bird only to find
that exposure compensation was set for shadows and the image was mostly blown
out. It seems that the rarer the bird, the more likely it is that this happens! So you will want to keep exposure
compensation in mind as part of your mental checklist.
 Wikipedia has a good
article on JPEG. See the section entitled Typical Usage at https://en.wikipedia.org/wiki/JPEG
OK, so I haven’t been posting much lately for a variety of reasons. This is just to advise my vast readership 😉 that I have put up a number of new pages, grouped under the Creatures tab. They include photo galleries of Arizona Wildlife, Birds of Cuba and Butterflies. I’m pestering you with this post because when I create a new page the system does not advise subscribers like it does when I post something. And of course you have been waiting with bated breath for more animal photos to brighten up your day!