A ton of missed focus on 70-200 2.8 and 300 2.8 lenses today... what?

I am borrowing these lenses for the weekend to try out on my XSi. I've rented a 70-200 2.8 before and never had any missed focus issues on the close to 5 or 600 shots at a swim meet with lots of action in overcast weather. This is the first time using the 300 2.8, however. I also had a 1.4x and 2x extender, I'm not sure which version but they look like early ones.

I was outside all day today in the bright sun and the first lens to go on was the 70-200 2.8. I started snapping photos in Av mode at 2.8 and was getting 90% OOF shots that looked almost blurry like I was shooting at 1/50, when I was getting speeds of 1/1000+. Weird. I switched to manual mode at 1/640 and continued shooting with it, and continued having the problems, even when I bumped it up to 1/800 and 1/1000 (just to make 110% sure this isn't motion blur somehow, though I've never had problems at 1/640 when just randomly shooting people and things outside). I slapped on the 1.4x just for giggles and started seeing some pretty bad back-focus. More weird.

I put the 300 2.8 and was using it handheld at 1/640 with some of the same focus issues, but now it seems more shots were in focus than before, though still very low keeper rate. 1 out of 2 or 3 would come out properly focused, the rest were either OOF or back-focused.

I asked the person I am borrowing these from if they've ever had such issues and they say no. So, I'm wondering what's going on. AI Servo with back button focus was used the whole time and was held down the entire time for series of shots you'll see below.

Below are some samples of what's going on. Click for full size. Screenshots include AF point and shot info.

At 70mm OOF

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300 2.8 back focus

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I have had similar results happen to me and found that using CENTER focus pretty much solved the problem. When I used multi focus settings and ANYTHING was moving the lens would never settle completely and my shots would be terribly OOF. The DOF in long range shots sometimes causes this it seems to me.

Maybe I am completely wrong here but using centered focus is what worked for me.

I am sure more seasoned members will chime in and give better explanations and advice than this.

Hillbille

All those shots were center focus.

what are all the focus modes (AI Servo) etc.. and how do you have the shutter button set up to fire?

I'd have to go through this all again, but I have the * button on all my cameras set up to run the AF in AI Servo, center point and the shutter button sets exposure and fires the shutter. If, for example, the shutter button is locking the AF or the AF is in the non-ai servo mode and with f/2.8 and narrow depth of field and a moving subject, you would get OOF shots.

Some of the softness can be due to handholding especially with the 300. The 1/focal length rule is a guideline and bare minimum anyhow. Whenever I shoot with my 300 (f/4 version) it is always with good support and mostly with a monopod.

Finally, it could be that the lenses need to be microadjusted to your camera which probably isn't possible with that model (I don't know).

Anyhow, it's impossible to tell from these small images but those are the likely culprits.

J.

Not sure why you are shooting with such a narrow f/2.8 DoF? Most of the shots are in focus, just not where your center focus is. The majority of the shots has something in focus, so the lenses are either forward focusing or backwards focusing. You might need to do some MA to fix this or shoot stopped down a bit like f/8.

Take Care,
Cheers, Patrick

Saint728 wrote in post #12324970
Not sure why you are shooting with such a narrow f/2.8 DoF? Most of the shots are in focus, just not where your center focus is. The majority of the shots has something in focus, so the lenses are either forward focusing or backwards focusing. You might need to do some MA to fix this or shoot stopped down a bit like f/8.

Take Care,
Cheers, Patrick

Or the focus is being locked and the subject moves and it's not in AI Servo.

J.

JohnJ80 wrote in post #12324924
what are all the focus modes (AI Servo) etc.. and how do you have the shutter button set up to fire?

I'd have to go through this all again, but I have the * button on all my cameras set up to run the AF in AI Servo, center point and the shutter button sets exposure and fires the shutter. If, for example, the shutter button is locking the AF or the AF is in the non-ai servo mode and with f/2.8 and narrow depth of field and a moving subject, you would get OOF shots.

Some of the softness can be due to handholding especially with the 300. The 1/focal length rule is a guideline and bare minimum anyhow. Whenever I shoot with my 300 (f/4 version) it is always with good support and mostly with a monopod.

Finally, it could be that the lenses need to be microadjusted to your camera which probably isn't possible with that model (I don't know).

Anyhow, it's impossible to tell from these small images but those are the likely culprits.

J.

In my first post I stated that all of these are AI Servo with back-button focus just as you explained. Focus button was held down the entire time the shots were taken. I know the 1/focal length rule, but it's hard to believe it applies here when all shots are 1/640+ and the first shot being 1/1250 and it's still very OOF on a stationary object.

The images are small because they are thumbnails. In my original post you will see that you have to click on them to see the full size screenshot. I thought the screenshots captured all of the information nicely into one image, but I can post some original images if you want to see some particular ones.

Saint728 wrote in post #12324970
Not sure why you are shooting with such a narrow f/2.8 DoF? Most of the shots are in focus, just not where your center focus is. The majority of the shots has something in focus, so the lenses are either forward focusing or backwards focusing. You might need to do some MA to fix this or shoot stopped down a bit like f/8.

Take Care,
Cheers, Patrick

Patrick,

I'm shooting at 2.8 because that's the reason I got the lens. I'm certainly not going to shoot f/8 on a 300 2.8. That defeats the whole purpose of this lens and I can do that on my $200 EF-S 55-250. It should have no problems locking focus on a moving object at f/2.8, which is the reason it's one of the most beloved sports lenses.

MA could be an issue but the original owner hasn't stated his need to do that on them. I will ask, though.

These shots look like they are bright day light. What is the specific reason that you are taking photos at F2.8 in this light condition? Is it to get higher shutter speeds to arrest motion? What is is your ISO? Have you tried a higher ISO (400, 800) and a smaller aperture? I have read that most sports photographers use 400 or 800 ISO to get sharp images..

http://photo.tutsplus.​com …sports-photos-like-a-pro/

for one...

I missed that that you were using AI Servo and back button. You might want to check the actual settings that pertain to the function of the shutter button however. This looks suspiciously like the focus was not tracking with the subject or was, in fact, not in AI Servo. But, I could be wrong.

The 1/fl rule at being 2X the speed is not at all a hard and fast rule. For example, consider if you are aiming at a subject a long ways away and you have hand shake of 0.5 degree during the time the shutter is open. That 0.5 degree at long distance sweeps through a large arc blurring detail. Now consider it close up, it sweeps through a much smaller arc with respect to your image and blurs less detail. If you have images that are OOF, one of the first things to try is making sure you are totally stable (i.e. tripod) to eliminate that variable - had that happened here, we wouldn't even be talking about it (for example). Do that and rule that out. It's also a simple matter when that is done to then test the lens for front and back focus on some target - like this:

shankarhokie wrote in post #12325082
These shots look like they are bright day light. What is the specific reason that you are taking photos at F2.8 in this light condition? Is it to get higher shutter speeds to arrest motion? What is is your ISO? Have you tried a higher ISO (400, 800) and a smaller aperture? I have read that most sports photographers use 400 or 800 ISO to get sharp images..

http://photo.tutsplus.​com …sports-photos-like-a-pro/

for one...

The specific reason for shooting at 2.8 in broad daylight is for subject isolation. There was no need to use anything higher than 100 ISO as I was getting proper exposure at 1/640 and 1/800. I did shot some iso 400 shots as well but they are also blurry and didn't provide good comparative examples like the ones I linked above. Also, the 70-200 shots with the 1.4x of the dog were shot at f/4. If I was simply missing due to DoF, f/4 would show at least some sort of improvement, which it doesn't appear to.

I have had no problem shooting sports action or fast moving subjects prior to this. I shot a 70-200 2.8 a couple months ago and had no problems nailing focus with it at any point. The same goes for the 70-200 f/4 I used at another swim meet and a 85 1.8 I used at an indoor gymnastics meet. If this were simply a matter of me not knowing how to focus on and track action, I would be the first to throw that out there. However, I've never had remotely close to such focus problems before.

JohnJ80 wrote in post #12325088
I missed that that you were using AI Servo and back button. You might want to check the actual settings that pertain to the function of the shutter button however. This looks suspiciously like the focus was not tracking with the subject or was, in fact, not in AI Servo. But, I could be wrong.

The 1/fl rule at being 2X the speed is not at all a hard and fast rule. For example, consider if you are aiming at a subject a long ways away and you have hand shake of 0.5 degree during the time the shutter is open. That 0.5 degree at long distance sweeps through a large arc blurring detail. Now consider it close up, it sweeps through a much smaller arc with respect to your image and blurs less detail. If you have images that are OOF, one of the first things to try is making sure you are totally stable (i.e. tripod) to eliminate that variable - had that happened here, we wouldn't even be talking about it (for example). Do that and rule that out. It's also a simple matter when that is done to then test the lens for front and back focus on some target - like this:

This was a Tamron zoom lens that I had to exchange because it didn't focus properly - big front focus (focus point was on middle radio). That said, this could have been probably trimmed out with MA in today's cameras but this lens got returned. Also, this was the only lens (of many) I have owned that was not in spec. Spec, by the way, is +/- one half of the DOF. Cameras are not as high precision as we think they are.

It's likely that this is primarily user error, the cameras are much more repeatable than we are. I'd suggest going through this systematically and isolating possible causes as above.

J.

The settings for the back-button focus are to focus on the * button and AE on the shutter button press. It was in AI Servo the whole time. My camera never leaves AI Servo and I checked it several times as I was incredulous about the shots being OOF.

I would absolutely agree that if I had to make a guess for why the 300 2.8 was missing focus as it would be probably due to the lack of a monopod. But, when I apply that theory to the 70-200 2.8, it just doesn't make sense why focus missed so heavily at such short ranges. There is no reason (that I can think of) focus should be missing so badly at 200mm with 1/640+. The first picture linked is a completely missed focus on a stationary object at 1/1250 ss, how does one explain that?

It's just conjecture unless you do the testing and eliminate variables. Can't help you anymore unless you go down that path.

J.

It looks like the Focus Mode Switch on the lens was set to Manual. In fact I'm willing to bet that it is the cause of the problem.

I'd advise going into your camera's menu and doing a complete reset of settings and Custom Functions. Then make sure the Focus Mode Switch on the lens is set to AF and not MF; then try a few sample images again.