Inadequate Sharpness

 

I use a Nikon D80 with a Sigma APO 70–300mm f/4-5.6 lens for photographing birds. However, I do not get the desired sharpness even when I use shutterspeeds like 1/800sec and 1/1000sec. Is there a problem with the optics? Please guide me on how I can overcome this issue.
Sagane Prasad, via email

The problem could be a combination of optics and incorrect shooting technique. The Sigma APO 70–300mm f/4-5.6 is a budget lens, so it might not give you optimum sharpness. Budget telephoto lenses have a tendency of being slightly soft at the extreme telephoto end, and also when used at the widest aperture.

Also, you need to be extremely careful while focusing. When using autofocus, use the single-point AF mode, and ensure that you have focused on the bird’s eye. If the bird is in flight, you will need to use the Continuous Autofocus (AF-C) mode, letting the camera refocus every time the bird moves across the frame. For the most accurate focus, try to keep the bird within the grid of AF points in the frame.

Tags: Birds, Lens, Question of the Day, inadequate sharpness, shuterspeed, focus