Poor Image Quality at Infinity with 35mm Typical?

[bluenoser1993]

Maybe a crazy question, but I sold a 35L a couple years ago because I found it a little soft when focus was at infinity, even when stopped down. It was amazing for closer work, I assumed it was just the copy I had.

Now I'm experiencing it worse with a 35 f/2 IS, albeit wide open. Using it on the sideline of volleyball I find I get sharp results on the near side when AF keeps up, but on the far side of the court the subject distance is in the range where infinite focus kicks in. When focused on subjects that are more than 5 meters away (Lightroom plugin info), the next court adjacent to the one I'm working appears better focused than the subject. This is for indoor gyms, so ISO 1600-3200 is typical.

Do I have a lens that requires repair, or is this a typical problem? I'd post examples, but I'm reluctant as they images are of a lot of people's children under 16.

 

[BeenThere]

Try selecting just the center focus point (thereby disabling the other possible focus points) and placing that on a player of interest when you click the shutter. If this gives better results, it means that in out of focus images the camera was previously using focus points that were not on your primary subject.

 

[Mt Spokane Photography]

Are you manually turning the focus ring as far as it goes ? The focus ring goes beyond infinity by design to accommodate for temperature variation, so you will get a poor image if you set it that way.