7d Poor Focus

[steve_byland]

<p>I am really stumped. I have had my 7d for over a year and love it. Today, I was taking post-storm photos through an open window (birds on feeders) in slightly low light and couldn't get a sharp shot to save my life. I was shooting on a heavy tripod and tried 3 or 4 lens combinations, but no luck. I even tried focusing on large tree trunks with mirror lock-up and photo after photo were far too soft to use. No fog on the lens. I started with a 300mm f/2.8, then 500mm f/4. I was using single shot and center focus point, although I played around with that too - only made things worse.<br>

I finally switched to an old 100-400 and got much better results - even hand held. I'm used to tack sharp bird shots with all of my lenses. Micro adjusting didn't help at all.</p>

 

[chip_degrace]

<p>no fog on sensor either, i imagine</p>

[michael_young3]

<p>That's a real bummer. I'm wondering if it's possible for the mirror to get knocked out of alignment, or jarred loose somehow. I assume you've tried disabling all micro-focus settings (but I don't see how they can go wonky all at once). I can't think of anything else you didn't already mention.</p>

[railphotog]

<p>Way back when I was new to photography, I'd often bring my camera gear to work with me. My office was overlooking the local harbor, so during lunch time I'd sometimes take photos out of an opened window. In the winter time I had trouble focusing (manually then) until I figured it out - the warm air from inside my office was going out the opened window, and disturbing the air in front of my camera lens. Perhaps this is what happened to you? Shooting from a warm interior through a window open to the cold? </p>

[steve_byland]

<p>@bob - that is a VERY interesting thought. I had a portable heater running hard in the small room (a bathroom). Perhaps with the hand held lens, I think that I was much closer to the open window. On the tripod, the lens was about 2 feet from the open window. Maybe either heat shimmer distorting the shots or messing with the AF. I'll bet you are right. Many thanks!</p>

[geoffs1]

<p>I'll bet Bob is right too!<br>

That was my first thought as soon as I read "through an open window".<br>

Sometimes it's not the equipment's fault...</p>