Thu 06-Dec-12 04:16 AM | edited Thu 06-Dec-12 04:36 AM by KnightPhoto
I haven't looked at your test photos yet but this comment drew my attention:
"What I see: -There is variation in focus across all sensors - The image sets where all three shots were framed the same show a large variation in file size. In some cases as much as 2 MB with the SAME SHOT."
With my newly purchased FocusTune software, the testing protocol calls for shooting 4 identical shots at each AF fine tune setting. The software then throws out outliers(!) and then proceeds to chart the variation, with those values showing the best average result being the suggested AF fine tune value. What is my point? We can expect variation in PDAF result from shot to shot, even on a locked down tripod under identical condition.
Also you ask about shutter speed, I try and get at least 1/250 with 3 second delay timer. I had to buy a 500 watt construction light to actually achieve this. This is on a locked down 5-series Gitzo. I've got enough variables to deal with without adding camera vibration into the mix. The job is about eliminating variables.
Anyhow if +20 is consistently needed, yes your camera is way out of whack. Your remaining problem doesn't sound like the left AF problem, at least not the way you are describing it, though that may be what you started with.
It might be helpful to just post the real-world images. We can check for motion blur vs. focus or possible suggestions for technique changes.
Edit: I looked at some photos on your website. It's hard to tell and not even sure I was looking at the right photos. It's too bad we can't reach out and shoot your camera and form some conclusions The mailbox ones (with house/garage in background) strike me as too small an AF target. I.e. On the shots where the mailbox is blurry, it looks like the AF grabbed onto the garage door way way back in the background, so the mailbox ones don't look indicative of anything to me. Nice looking neighbourhood BTW!
Make sure you look for consistent patterns. Then you know you need to AF tune. Sorry, not much help.