 Scott McCord |
Tips for Canon 70-200/2.8 Anybody got any advice on shooting wide open or close to wide open with the Canon 70-200mm f/2.8l lens? I can only seem to get 1 in 10 shots in focus, even with shutter speeds of 1/1000th of a second. I know it's me, not the lens. Even when I really pay attention to centering my autofocus point on my subject's eyes, I still get out of focus subjects - with extremely fast shutter speeds. It's obviously due to depth of field, not shutter speed or camera shake. BTW, I'm using centerpoint autofocus. Should I be activating more of the points?
|
|
|
|
||
|
Jon Close |
(1) Which camera? Some EOS models have standard precision AF that is accurate to just within the depth of focus at f/2.8. This is close enough for printing up to 8"x10", but if you're examining the images on a monitor at 100% (effectively 36" x 54"), then you're going to see focus may be a bit off. Higher level models have high precision AF when used with f/2.8 and faster lenses and will get focus to within 1/3 of the depth of focus. (2) If you are relatively close and using center focus - recompose - then shoot method, then that introduces focus error. See http://visual-vacations.com/Photography/focus-recompose_sucks.htm. More accurate is to frame the scene as you want it and use the focus sensor closest to your subject rather than the one at the center. (3) The AF sensors are a bit larger than the marks in the viewfinder, so may be focusing on larger area than intended. (4) If you nearly always get misfocus and it is consistently in front of (or behind) the intended subject, then the camera and/or lens may be out of spec. They can be returned to Canon for adjustment (for a charge, but I think this is free if within warranty period).
|
|
|
|
||
|
Scott McCord |
Thanks for the info. The camera is a 30D. Have the same problems with my 20D as well. That's mainly why I think it's me. Guess it could be the lens though. However, I do focus and recompose. That is, lock focus on the eyes, for instance, then recompose my frame to the way I'd like it. And I'm not getting images that are a little soft. We're talking subjects so out of focus that it would be obvious printed in wallet format. I noticed last night that focus seemed to be behind the subject. I'm going to set this lens on my tripod and do some testing to see if it's me or the lens.
|
|
|
|
||
|
Scott McCord |
Jon, After reading that article you suggested, I've realized that it almost has to be my style of shooting that's causing this focus problem. In 10+ years of shooting I've never heard about this problem with the shoot and recompose technique, but it makes sense. Since I mainly use a 24-70 lens set to at least f/8 most of the time, I've only noticed it on the longer lens. Looks like I'm really going to have to work to change a 13-year habit. Thanks
|
|
|
|
||
|
This old forum is now archived. Use improved Forum here
Report this Thread |
||