1. Focal length
Canon’s 300 mm f/4, 400 mm f/5.6 and Nikon’s 300 mm f/4 are probably sharpers. But I’ll go for that extra focal length and stabilisation.
Update, September 2017: Canon’s 100-400 mm L IS II is one of the sharpest “affordable” wildlife lenses out there. I prefer to carry just this one lens over combinations of the 70-200mm, 300mm, and macro lenses (because of it’s close focusing distance).
I set my Autofocus Area to ‘Single Point’. I like to compose using the rule of thirds and align a focus point with the subject’s eye.
If I’m photographing birds in flight, for example, then I might use Dynamic AF Area (please refer to Autofocus Area and Autofocus Mode in your camera manual).
I ensure that:
- The shutter speed is no slower than 1/500th of a second for stationary and slow moving subjects, and 1/1,000, sometimes even 1/2000th of a second for birds in flight
- The focus point is accurately aligned
- The lens is stopped down (say 2/3 rd to 1 stop) if possible
- Stabilisation is ON, unless the lens is mounted on a sturdy tripod
I like the shutter speed no slower than 1/500th of a second, even at the cost of high ISO sensitivity. Slower shutter speeds have often resulted in unsharp photographs, and ruined the whole experience.
Stabilisation technology helps ensure sharpness at slower shutter speeds. But with focal lengths larger than 200 mm, I still want to be at 1/500th of a second and faster with stabilisation ON.
Please make a note that if you’re using a sturdy tripod, stabilisation must be switched OFF.
I switch OFF stabilisation before switching OFF my camera. I will switch it back ON only after the camera is ON.
The edge to edge sharpness of a lens, especially a zoom lens can deteriorate at its widest aperture. I like to step down a lens by a least 1/3 rd stop.
To spell it out, I’ll set the aperture of the Nikon 200-500 mm f/5.6 lens to f/6.3 or f/7.1 (f/6.3 is 1/3 rd of a stop down and f/7.1 is 2/3 rd of a stop down from the widest Av, f/5.6).
If I’m photographing a larger animal, say an elephant or rhino, than I’ll often set my aperture to f/8, f/11 even so that I the entire animal is in focus.
There must not be a compromise on shutter speed. This means higher ISO sensitivity.
On a bright morning and evening, I always get by with ISO 800 or less.
Portraits of birds and animals, even human beings, look more lively when there is a catchlight in at least one eye.
I’m always looking for catchlight. If I see a catchlight, I click, not otherwise. There are always exceptions though, for example, when I’m using 3/4 backlighting.