AF accuracy flash vs no flash?

I noticed something weird today. For the first time in a long time I went out shooting available light, till today for the past year or so Ive used flash pretty much 100% of the time. With that all of my lens were dialed in with AF micro adjust while using flash, and have had consistent and repeatable results.


I went out today playing with my 85mm 1.8 and 30mm 1.4 and noticed that everything was off without flash. Where all of my lens are dialed in the +7~ range I noticed that without flash they are pretty close to 0.

Anyone else ran into anything similar?

The light temperature will affect AF and what you're seeing is not unusual. I believe that the 7D uses adjusts the AF based on the light temperature read by the metering sensor.

Bob

Hmm I see then. So would it be best to dial in my AF under neutral sunlight?

I guess the best values are the ones required for your primary shooting mode. It would be good if the MA values could be registered for the custom user modes....the implication in the user manual is that all CFn's are registered but MA values aren't.

Bob

I've never heard of the temperature of the light being a deciding factor. This post gives great insight into how Canon Cameras attain focus. more light could = more contrast

http://www.fredmiranda​.com/forum/topic/24152​4

This theory has enabled me to get good results in many challenging circumstances because I know how the camera will act.
A good example would be shooting airshows.. if you are using center spot focus, and you keep the center spot on the middle of a gray (navy/marine) jet plane, yo uwill probably have some OOF shots due to the lack of contrast...