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55-250mm Telephoto Zoom Lens help

tina1138
Contributor

I can not get a sharp image with this lens no matter what I do.

please can someone help me.

I tried taking pictures of some birds this morning and they are not sharp at all.

I used a tripod too.

thanks.Tina

10 REPLIES 10

ScottyP
Authority
There are 3 main possible causes of un-sharp images:
1.) Bad focus (which T. Campbell just did a good job of explaining), or
2.). Camera shake blur (from your hands), or
3.). Subject motion blur (from the shutter speed not being fast enough to freeze a moving subject).

You say you used a tripod so camera shake is not likely the problem. In any event a shutter speed as fast as the reciprocal of your focal length will generally eliminate camera shake. Zoomed in to 100 mm, you want a shutter speed of at least 1/100th. Zoomed in to 200 mm, you want a faster shutter, 1/200th. However, your camera is a crop sensor model, so it magnifies your zoom X 1.6, so you have to multiply your shutter speed accordingly. If your lens is at 100mm, you need a shutter of 1/100th x 1.6, so you need 1/160th of a second or faster. If your lens has Image Stabilization, as yours does, you can break these rules to some extent, as the lens compensates for some camera shake.

Subject motion could be it, as birds move pretty fast, even when they are just standing still because they are twitchy. The fix is a high shutter speed. If you can get enough light to pull it off, you probably want at least 1/400 th of a second. Faster would be better (1/500th? 1/640th? 1/1000th?).

Bad focus is the other likely culprit. See if Tim's advice fixes it. It could be both motion blur and bad focus at the same time, of course.

Photography physics are just a series of trade offs though. For example: A narrow aperture (f/16 or f//22) does give a nicely forgiving deep depth of field, but it blocks out a lot of your light. But you need a lot of light to get a fast shutter you want to freeze action. So you are forced to find a compromise between the fastest shutter and the narrowest aperture.

Good luck!
Scott

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?
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