R7 with 28-70 f2.0, focus issues

[BK5524]

As noted in the title, I am shooting an R7 with the 28-70 f2.0 lens. I am an amateur with a kid in the UF Gator Marching Band. I have been photographing marching bands for several years. This lens is fairly new to me. I also shoot using an EF 70-200mm f/2.8 L lens with an adapter as well. I seem to have much better results when using the longer lens in regards to clarity. I have taken some very crisp shots using the 28-70 lens, but much fewer photos are as crisp as I feel they could/should be. I'm at a loss as to whether this is due to a lens issue, the ability of the camera to accurately auto-focus, my settings, or if it's just me. I have considered, but not tested, removing the UV filter, but I really don't think that could be the issue. I want to really love this lens, but with these kinds of results, I'm not sure what to do. I have considered sending the lens back to Canon for  evaluation, but I thought I would reach out here first. I am open to suggestions, tips, hints, or any other help you might offer. 

[deebatman316]

I would drop the UV filter it’s not needed for digital cameras. Digital cameras have an IR filter on them already. Yes it can also affect focus. Some lenses such as the EF 100-400mm lens lineup doesn’t play nicely with filters. 

[BK5524]

Thanks. I will experiment with it and see what happens. 

[p4pictures]

What AF settings are you using on the EOS R7?

• Subject to detect, auto, people?
• AF area?
• One shot / servo

For a subject further away there is greater depth of field than for a closer subject. So a distant subject with the 70-200 might appear sharper than a close subject on the 28-70mm.

I have the RF 28-70mm F2 and also an EF 70-200mm f/2.8L IS II USM, and on the EOS R10, EOS R6 and EOS R6 Mark II, I have no issues with sharpness using the RF 28-70mm. 

[BK5524]

I have it set to detect people, but I currently have subject tracking off. I tried it "on" with some other changes and I had a LOT of issues getting good shots. I'm sure that has more to do with the user than the camera, but I decided to stick with what I was used to rather than lose great photos. AF area is spot and set for one shot. Servo was one of the settings I had turned on when I had poor results- again, probably more user related than equipment, but I'm still pretty new to this stuff.

[p4pictures]

This is what I found with camera settings.

• Use an AF area that is big enough to fit your subject in. Doesn't need to be too small. So for a group of people the AF area should be suitable that it only covers one person. 
• Leave whole area tracking on, and also subject tracking set to people. This means that the AF point will follow the subject even if them move once you have initially focused.
• Set the camera to servo AF, with the settings above you can "target" a specific subject with the AF point, half-press the shutter and hold it there to start focusing and tracking, then recompose the frame if needed and the AF point will stay on the original subject. 
• I would also check the setting for Preview AF, it is best to set this to disable.

For example I often shoot motocross racing, and I use one of the zone AF areas to target the specific rider in the group of competitors. I have vehicle tracking with spot (helmet) detection enabled and this means I choose who the camera focuses on. 

One of the issues with one shot AF is that once the focus locks if the subject moves - even a little - it will be slightly out of focus, and this is more noticeable at wide apertures and close distance.

For people photos, if there is more than one person in the frame I use the same approach as motorsport, but set the subject to detect to people. If there is only a single person in the frame I use whole area AF and let the camera find the face and eye to focus on.

[BK5524]

Your suggestions about Servo and AF sound similar to what I tried, but I don't think I fully understood how it should work. Maybe having the UV filter on had some effect as well as the previous contributor suggested. I just had it there for protection really. I can try again when I have an event that I want to photograph and play around with it some more. I may even just take the camera to random events just to practice. It certainly wouldn't hurt. 

[p4pictures]

Practice events with less pressure to deliver the results are a great way to hone your skills and learn how to get the best from your camera. Think of them as training, much like an athlete does training before the big race.

The UV filter is not likely to make much difference unless you have a lot of sidelight causing flare from the extra glass. 

[BK5524]

Will do. Thanks again!