kimknapp Offline Upload & Sell: On
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Has anyone else noticed a slight amount of focus creep when using manual focus?
Background:
I spent many hours before the eclipse testing combinations of lenses and bodies, focusing on the sun's surface disturbances to get the best combination of ease of focusing and sharpness. The bodies were: A7Rii, A6300 and Olympus EM1-2 and the lenses were 100-400GM w/ 1.4TC and Sigma 150-600S for the Sonys and Olympus 300 Pro and the Sigma on the Olympus.
End results were very close, but I found that the 100-400 w/TC on the A6300 gave me the best results pretty much tied with the Sigma on the A7Rii, but easier to get perfect focus. The Oly lens and body were also very close, but the Oly lens' focusing was too touchy.
Procedure:
I had two tripods, one with the A7Rii/Sigma and the other with the A6300/100-400.
I intended to take a series of partial eclipse shots with the A7 and the full eclipse with the other. With lots of bracketing.
Problem:
During the whole eclipse, the Sigma stayed focused as I had set it, and there was enough time to use the other combo for backup shots of the partial phase. During the full eclipse, there was enough time to use both and still observe the amazing sight.
Throughout the whole eclipse I occasionally turned body power off and on.
During Post, I found that the 100-400 full eclipse images are very slightly out of focus and the Sigma images are as good or better.
The good news is that I ended up with some neat photos, but I learned that I should recheck focus regularly. Probably obvious, but in the past when I did star trails with an intervalometer, I never worried about refocusing between shots.
Please note that this could have been caused by user error. It was very difficult getting perfect focus in the shooting conditions. And, we are talking real pixel peeping. The results were great, I was just looking to get some real details of the red flares.
Kim
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