rthompson10

Hello,
Lately I've been having problems focusing with canon 70D and tamron 70-200 2.8
I'm shooting sports and using back button focus. Lots of shots are out of focus lately. Some of it is operator error as I have a bad right hand but it seems the problem is getting worse lately.

Any known issues with this equipment? Any pointers would also help. Shooting various high school sports
RT

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

I have same camera and lens and although don't use that combo real often, have not noticed anything unusual about focusing.

Now that you've brought it up, I'm going to slap the Tamron 70-200 on my 70D and shot a bunch of pictures to see if any unusual focusing issues come up.

My 70D currently has EF 24-105L mounted and there's been no issues with that combo.

orrie smith Loc: Kansas

have you double checked to make sure you are on continuous focus as opposed to single focus? if you are on continuous focus and are still having the problem, you need to first mount your gear on a tripod and try the shots with a moving target. if you continue to have the problem with this setup, try to disable your back button focus and use the half press on your shutter release, I know this is not preferable but it is just a test to check your back button focus, if none of the above corrects your situation, you may need to contact canon to see if they have a solution.

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

In addition you might try faster shutter sppeds to see if it is camera shake

PaulR01 Loc: West Texas

Clean your contacts on both the camera and the lens with an eraser. I was starting to get some inconsistencies last week on my 7Dii. And cleaning the contacts made a world of difference.

ceh1024 Loc: Lutz, FL

I have had the same problem with my 18-270. Sent to Tamron 1st time and they had to upgrade the firmware.

I just sent it back again 2 days ago with the same problem (soft to very soft focus). Tamron has always been good with their turn-around and warranty service (normally 3 day turn around) I'm expecting it back end of next week.

I never had a problem with the lens on my old t3i. Problems only started with my 70D.

Jim Bob

Sit the camera on a tripod or other stable surface to reduce user error. Take a photo of a stationary subject. Analyze.

rthompson10

Thanks for the input
After doing some analysis I think a lot of it is due to operator error.
Things I've tried: Shot a lacrosse game last night- for one quarter I left it on shutter/focus vs using back focus- that worked fine
Took pix at home using stationary objects- that seemed to work ok.
In looking at fotos I took last night my focus was off. I'm using center point so I was on the mark a few times or I was just off- example the focus point was on the white uniform and not on numbers or a "break point" to get focus- therefore focus was off a bit.
Maybe with my bad right hand I should skip back button focus- Maybe my keep rate will improve
Frustrating- Thanks again

jeep_daddy Loc: Prescott AZ

Try using a tripod. People with physical problems should always use a tripod, and people with little or no photography experience should use a tripod at first. Hand holding takes practice and experience. Often, you must use different settings when hand holding to keep pictures from getting motion blur. Try a tripod first and see if the blurring goes away.

amfoto1 Loc: San Jose, Calif. USA

You might need to Micro Adjust the lens to your particular camera. 70D has the more advanced form of MFA that allows two adjustments with a zoom: on at the shortest focal length and the other at the longest.

If you have a "protection" filter on the lens, remove it and try without it. Some lenses just don't work well with filters.... it either messes with overall sharpness or with effects auto focus.

Does your camera have AI Servo focus priority versus shutter release priority setting? If so, be sure it's set to focus accuracy priority. There may be two different settings.... one for 1st image in a burst... the other for 2nd and subsequent images in the burst.

Does that lens have Tamron's USD focus drive? If so, it should be fast, like Canon's USM. If not, it is a micro motor that might not keep up with moving subjects.

I agree that you should confirm that you're using AI Servo... not One Shot (and definitely not AI Focus, which really isn't a focus mode at all). There are two reasons for this. First, if your subject moves, AI Focus constantly updates so as to track the movement. In contrast, One Shot achieves focus, then stops and locks. If the subject or you or both move and the distance between you changes, that will cause focus errors in One Shot mode. (Note: Some people don't like it, but I leave the Focus Confirmation "beep" turned on in my camera. That only works in One Shot mode... so it effectively alerts me audibly if I've got my camera set to the wrong mode for sports/action shots.)

AI Focus is supposed to decide for you whether the subject is moving or not, then switch to use the appropriate mode: AI Servo or One Shot. It might work fine sometimes. Or it might not. I tried it years ago on the cameras I used then, but soon stopped using it at all because I got too many missed focus shots with it. AI Focus seemed to have a short delay and sometimes just used the wrong focus mode. Today's cameras might do AI Focus better... I don't know because I simply never use it. (It might be a bit of a hint that the most pro-oriented 1D-series cameras don't even have AI Focus mode... they only have One Shot and AI Servo.)

Second, if that lens is varifocal... i.e., if it's not a parfocal zoom... that means it doesn't hold focus when it's zoomed. (I don't know which type the Tamron 70-200 is, but many modern zooms are varifocal as a cost saving design.) If varifocal and using One Shot mode, you have to release the button and redo focus after any change in focal length. But, if using AI Servo it will automatically correct focus immediately, regardless whether the lens is vairfocal or parfocal.

So, for both these reasons, be sure you're using AI Servo.

What focus pattern are you using? Single Point/Manually Selected is the most accurate... but you have to do your part by keeping the AF point right where you want the camera to focus. All Points/Auto Selection leaves it up to the camera to decide where to focus and it will usually choose whatever is closest and covered by one of the 19 AF points. If that doesn't happen to be not your subject the camera decides to focus upon, then you'll have a focus error. Zone Focus is similar to All Points, just on a slightly smaller scale.

Zone or All Points might work fine in some cases... such as shooting birds in flight against a plain background such as the sky. But they are less reliable if used in situations where there are "distractions" for the AF between you and the subject or even in the background behind it.

And, are you in the habit of using f2.8 aperture a lot? If so, you might try stopping down a bit. The f2.8 lens helps AF perform better, regardless of what aperture you use to take the shot (since the lens doesn't actually stop down until the very instant of exposure). But a large aperture used unnecessarily will tend to render shallow depth of field that can accentuate an otherwise minor focus error. Additional DoF rendered by a smaller aperture gives more forgiveness of any minor error... plus most lenses tend to be a little sharper a stop or two down from their maximum aperture.

Yes, you also should watch your shutter speeds... both to prevent "camera shake blur" and "subject movement blur", both of which can be mistaken for focus issues. For most field sports, anything below 1/500 is risky... and even that might not freeze faster moving parts such as a pitcher's arm or a runner's feet or batter's bat tip. Of course, some subject blur might be good... may capture a better indication of the fast action. But if you want tghe fastest acrion more completely frozen, you may need to use 1/1000 or even faster.

Someone mentions cleaning the electronic contacts between the lens and the camera and I agree. However, DO NOT use a pencil eraser to do so. More often than not, the problem is oils on those electronic contacts interfering with the low voltages used for the lens and camera to communicate. They might be finder oils or lubricating oils that were used in the camera or lens. The problem with using pencil erasers is that they're made with vegetable oil, so they are not effective at removing oils.

Instead, dampen a clean, lint free cloth with a couple drops of isopropyl alcohol and use that to carefully wipe the contacts on the rear of the lens. Plain old, cheap "rubbing alcohol" that you can buy at almost any pharmacy or grocery store works fine... it doesn't need to be the high purity stuff for this purpose.

Also inspect the corresponding "pins" just inside the bayonet mount of the camera body. Those are spring-loaded to insure good connection to the contacts of the lens. Lightly press each of them with a fingernail or the flat side of a miniature screwdriver and watch that the pins snap sharply back in place and none stick. Be very gentle, though... both the pins in the camera and the contacts on the lens are gold plated to prevent oxidization and insure good electrical conductivity.

You mention a "bad right hand" and that may be the culprit. I don't know that it would necessarily make a difference where you use BBF or shutter-linked AF... Only you can say and if you are new to it, may need to practice with BBF for a while to get good using it. A tripod might help, but is rather cumbersome when shooting sports... can even be dangerous to players if you're using it right on the sidelines. Maybe a monopod would be helpful, yet easier to move around with.

Some might tell you to turn off image stabilization, if your lens has it. I disagree and usually leave it on when shooting sports. To me, it seems to help AF performance by stabilizing the image that the AF is trying to lock onto (with Canon gear... I know Nikon shooters will disagree and have some reason to believe the opposite is true with VR... that it might slow AF performance a little). Since it's a third party lens on a Canon camera, I really don't know so I'd experiment both ways... with and without VC turned on, if the lens has it.

CraigFair Loc: Santa Maria, CA.

For Sports & Wildlife Shooting and using the back button focusing.
I always push and hold the button so the camera is in Continuous Focus.
Craig