eddy.fioretti
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 p.2 #8 · focusing troubles with 40D + 70-200 f2.8 IS | |
Pete Klinger wrote:
msalvetti wrote:
eddy,
I think you're on the right track. At this point, you might just need to keep practicing. I don't know if you've cropped the first photos you posted, but even if you haven't, the skiier is pretty small compared to the overall scene. So I can imagine that it is difficult to keep the center point on the subject, and therefore easy to grab focus on the ocean behind.
I still think the center point only is the way to go. If you were to use all the points, I don't think they are close enough together and you might still lose lock on your subject.
Mark
Shooting with all points can "confuse" the camera, it also takes longer to acquire a focus. The IS can take some time to settle, which means I shoot on a monopod with IS off, AIServo and sometimes use only the center bottom focus point. Sometimes only the center point, and if I'm leading a car, going left to right for example, the lower right point, to get the camera focusing ahead of a 180mph car!
I never calculated the shutter lag or focus lag when panning with something moving that fast. Just something I try when the nose of the car is going to be leading, where the lower focus point can read it.
Try the lower center focus point and see if that helps. A white board against the deep blue sea, works fine, and the subject is still centered. This will also bring the focus a little ahead of the subject, if you are having a problem with back focusing.
If you are panning, you can get some sharp images at 400 or 500th, and gain depth of field. Faster shutter speed, you start to give up DoF. Most I go with the 40D is iso 200, but I've seen people do fine at higher numbers.
Point is, every item you change to make one factor improve, will degrade something else. You don't need to shoot at 1000th to stop action, unless you want every water droplet frozen. Sometimes motion blur makes the image more alive.
TV - ISO 200, 500th, the aperture will be around f/8 depending on the brightness of the subject. Take it from there and fine tune for your desired results.
Oh yes, I throw away at least 1/3rd of my action photos because the first one in a burst, the camera is still focusing, the second it's usually on, the third is hit or miss, the 4th is in focus again? I often start shooting and let the subject move into the shot I want, then when I'm editing, I toss the first or first and second shots, which are not filling the frame enough.
uff - a lot of stuff thanks !!!!
some comments to your questions
- no crop, if the kiter is small, that's due to the fact that he is too far from me (no money to buy a longer zoom anyway)
- all made with center point only, AI one shot, 200 ISO usually, Av f4 to increase shutter speed and lower DoF (depth of field, correct?) - never thought that all focusing points active are useful for this kind of shooting: too many white waves and other high contrast object that disturbs the core
- I've tried some time th lower or right/left focus point... doesn't work fine for me... the kiter moves usually in a determined direction before the trick, but the trick is up (he jumps out the water) and for this I prefer the central point, with eventually a crop in PP (if he was near enough)
"TV - ISO 200, 500th, the aperture will be around f/8 depending on the brightness of the subject. Take it from there and fine tune for your desired results." - good thought I would try next time... I have to oblige myself to think in terms of Tv and not Av sometimes (not used to)
thanks guys very helpful
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