70-200 F2.8 L IS II, focusing, advise, comments needed

[davet4]

Hi All

Everyone know the reputation of the 70-200mm F2.8 as being one of the sharpest lens around but i seem to be having a problem getting pin sharp results, and i do not know if i am expecting to much from the lens, i am doing something wrong or is it the lens?. See the pictures of the duck, you can see i focused near the eye, but when you zoom in the picture is not clear. I am "pixel Peeping" or is there a problem? I was using a 5D MKIII, set at 1/1250, F2.8, ISO 100. Also note, i have run a test using Focal, which stated an adjustment of -3, but i havent see any improvement. Any comments or advice would be appreciated......

 

[Sven_22]

Is your IS on when yours shooting the duck? I've left mine on accidentally, the IS will fight against your tracking movement if you are trying to follow the duck, resulting in blurry photos

 

[davet4]

Sven

thanks for the reply

I will try with IS switched off to see if i get better results....

 

[Kristofgss]

Can you compare your shots with live view autofocus? If those are sharper, then there is an issue with your phase-detection autofocus system.

 

[Northstar]

Can you compare your shots with live view autofocus? If those are sharper, then there is an issue with your phase-detection autofocus system.

this is good advice. take some photos with live view AF, then take some using your regular AF and compare the results. use a tripod and shoot at something flat like a wall...with good light...tape a section of newspaper to the wall. view results at 100%

google search this topic and you will find detailed instructions for performing this test.

 

[Luds34]

Can you compare your shots with live view autofocus? If those are sharper, then there is an issue with your phase-detection autofocus system.

this is good advice. take some photos with live view AF, then take some using your regular AF and compare the results. use a tripod and shoot at something flat like a wall...with good light...tape a section of newspaper to the wall. view results at 100%

google search this topic and you will find detailed instructions for performing this test.

+1

Tripod and live view will make sure you nailed focus and therefore will see the very best of what any lens has to offer. And obviously comparing that to regular PDAF will let you know if your focus is off.

 

[rgk]

Is it possible for focusing points to be mis-aligned on Canon cameras? What I'm wondering is if the focus point indicator squares are not in sync with the focusing mechanism.

I shoot a lot of business head shots with this lens and the markIII, usually at 135mm. I often focus on the eyeball, but I find the nose is sharp and the eye not as sharp, indicating front focus. I'm using single-point AF squarely on the eyre and I have calibrated the system with LensCal, which a decent tool. Normally shooting around ƒ 5.6 2/3.

I'm trying to come up with a practical test for this possible flaw.

This may not be in play with the duck photos, but at 2.8 it might.

 

[bluemoon]

try it on a non moving target with a tripod. this way you'll eliminate the movement (yours and target's) as the source of the problem.

pierre

 

[Kristofgss]

Is it possible for focusing points to be mis-aligned on Canon cameras? What I'm wondering is if the focus point indicator squares are not in sync with the focusing mechanism.

I'm trying to come up with a practical test for this possible flaw.

This may not be in play with the duck photos, but at 2.8 it might.

If it would be mis-aligned, you could try taking photos of a ball. If you try to take pictures of the top, bottom, left and right. And the mis-alignment would (for example) be to the right, then it would frontfocus if you take a picture from the left side, but backfocus if you take a picture from the right side (as the focus to the right would see a point further away from you). If all picures frontfocus, the focus location would be correctly aligned, but not correctly calibrated.

 

[pwp]

Yes it's a stellar lens no question, and my most used. I don't always expect perfection shooting at f/2.8, though it does happen. You're shooting AI Focus right? Did you shoot single frame or continuous? If you're shooting continuous, you get the benefit of Canon's predictive focus. In a set of shots squeezed off in an action sequence, I wouldn't necessarily rely on the first frame to be pin sharp, the second usually good, the third mostly good and so on provided your AF point is kept in the right place and your shutter speed is appropriately high. Your 5D3 should track a swimming duck with ease.

Solutions? Shooting ducks is far from a reliable tech test of lens sharpness. Northstars suggestions are worth following. Tests should be done in strict, technical conditions if you're going to get any value out of them. You may need further AFMA testing and adjustment. FWIW I wouldn't turn IS off. Sven_22's comment is a new one on me. IS will deliver more keepers than fails.

-pw

 

[Sven_22]

FWIW I wouldn't turn IS off. Sven_22's comment is a new one on me. IS will deliver more keepers than fails.

-pw

One reason I brought up IS is that some people don't have a full understanding of what IS is for. Mode 1 for static subjects and mode 2 is for panning with the subject, I am not sure which mode he was in because it wasn't stated in the post, but I assume it was mode 1, and mode 1 is for static subjects/reducing handshake. And yes this can affect sharpness if your moving with the subject. Another reason was different advice than 'tripod af/liveview/MFA' post that usually follow the 'my lens isnt sharp' post

Obviously the duck is moving, not terribly fast, but it's not static by no means. And at 1/1250 shutter speed, your way beyond the reciprocal rule, and IS is not needed. read more here http://www.bhphotovideo.com/explora/photography/tips-and-solutions/image-stabilization-when-use-it-and-when-turn-it

It's a great lens. But there are many factors when shooting that can affect the sharpness, way to many to list here. And I agree with pwp about f/2.8, that's a very shallow depth of field, you'll benefit from a higher f/stop when shooting birds/wildlife

 

[StudentOfLight]

Something I'm not clear on...

Are you using AI servo or AI focus. I might be wrong, but I think if AI focus is used then the camera will guess whether your subject is moving or stationary. And so if you are slowly panning then the camera might consider the subject static and stop attempts at acquiring focus and just take a shot even though the subject might have drifted closer or further away from the plane of sharp focus.

Most action/sports/wildlife photography trainers who I've encountered advocate to use either single shot or AI servo and to avoid AI focus due to the possible unpredictability of results.

 

[davet4]

Thanks everyone for your comments and suggestions, it has given me a few more things to look at and try....I will keep you posted on if I see any improvements

 

[Ozarker]

For what it's worth: I have found that bird shots over water happen to be extremely difficult for me to get great focus... and the further away from the bird the worse the problem is. This is a huge frustration of mine personally. I chalk it up to large amounts of reflection off the water and then the dappling of those reflections on the bird. A circular polariser has helped me a lot in the past. I do not have the same problems with birds that are not floating in a pond. I just have a very difficult time with what I believe to be the reflections bouncing all over the place and seemingly interfering with the focus system. I shoot with a 70D and the same lens you do.