Whooping cranes are the tallest bird in North America, with over 7 feet of wing span. There are still around 500 individuals (506 in 2020 according to US Fish and Wild Life services) living in the wild, so they are also one of the rarest. Yet there are not too difficult to see in their wintering ground, in the Rockport-Port Aransas area of Texas.
The whooping cranes are present in Texas from mid-September to late-March, which is also the time when the weather is most pleasant for outside activities in the state.
The same wintering ground is shared with many other birds, notably the Sand Hill Cranes. Although much more common than the whooping cranes (about 100,000 individual in the wild), the Sand Hill cranes are very impressive birds in their own rights.
More common birds, like the rosate spoon bill are also usually present.
For the pictures included in this post, I used a Sony A7R III, 100-400 telephoto lens f/4.5-5.6 and a focal doubler, on a tripod most of the time.
Focal length and Aperture:
The cranes were always far away (100 to 200m), and almost all the pictures were taken at 800mm of focal length and f/11 aperture (the widest I could open at that focal length). f/11 is pretty slow since the animals do move and any unsteadiness of the photographer, at 800mm of focal is unforgiving.
Common wisdom for shutter speed handheld, with Image Stabilization on, is to match the denominator of the shutter speed to the focal lens: that is at 400mm of focal length, shoot faster than 1/400, at 800mm of focal shoot faster than 1/800, etc… With the very high definition of the A7S, and with the IS problems described below, I found I had to considerably exceed the above speed requirements (ie, shoot at least twice as fast).
I ended up boosting the ISO significantly (at or above 2500 ISO) to maintain a speed above 1/500 for tripod and above 1/2000 for hand held. This high ISO makes for slightly grainy pictures (even with modern low noise sensors like the A7R III) but this can be tackled later with the high performance denoise algorithms available in Pixinsight. At all cost grainy is better than motion blurred.
Optical stabilization & shooting mode:
I used optical stabilization Mode 1 exclusively (mode 1 stabilizes both axis, mode 2 would be stabilization in a single axis to allow things like panning). I did experience IS induce blur, and a lot of it: at very high focal length, even on a tripod, a very tiny shake is magnified and the Image Stabilization may run out of room, causing blur. There are 2 possible fixes, which I should have implemented: take bursts of multiple shots to help overcome temporary IS-induced blur, or when on a stable tripod, disable IS, provided the shutter speed is high enough and a remote trigger is used. So a note for the future: use burst mode in all cases, and pay very close attention to the performance of IS. This problem, I think, was the major technical hurdle of the trip, and I ended up trashing a lot of frames on it.
Autofocusing did not cause major problems, except when there were some weeds in the foreground. In those cases it may be useful to decouple focus and shot trigger. I never manually focused, as it did not prove necessary. Having IS on helps focusing.
Another helpful item would have been to have a laptop handy to go back to the car, after each session, and review in details the pictures and settings, to improve on the next session. The next level would be to rent a professional length for the trip, like the 600mm f4 with the x1.4 or x2 teleconverter.
Finally I did some video (modern still cameras are also remarkable video cameras), which will need some work when time allows.
Last, I probably should have spent more time training for the trip on easier targets, like those little guys…