abe4652
Senior Member
Poetry in motion
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A7riii Focus - Any reason not to be in C-AF all the time?
texdpl
Leading Member
Jim
What did you mean to say in this statement?
"AF-C has a higher statistical variance in focus distance than AF-C."
Please clarify.
What did you mean to say in this statement?
"AF-C has a higher statistical variance in focus distance than AF-C."
Please clarify.
profound - I've never read truer words... :-D
sportyaccordy
Forum Pro
Before I had a baby AF-S was fine. Now I use AF-C pretty much all the time. I do need to see if AF-S works better for adapted glass though.
B
BBQue
Guest
What Jim really meant to say was "AF-C has a higher statistical variance in focus distance than AF-S." (see the link to his blog above).
Last edited:
PhilthePhrame
Leading Member
You seem to have made a typo, Jim, in comparing AF-C with AF-C. One of those should be AF-S, I am guessing.
It would be helpful for you to correct that.
Well, I can't. because I'm not a mod. All I can do is apologize profusely. Sorry, sorry, sorry.
Jim
texdpl
Leading Member
Thanks. All I wanted to know was about the typo. Which AF-C was suppose to be AF-S.
That's all I was asking.
That's all I was asking.
Yeah. Shame on me for not figuring that out. I knew what it was supposed to say so well that I didn't realize that I'd just typed gibberish.
sportyaccordy
Forum Pro
Do you have any photographic demos to help qualify the effects of this phenomenon?
For example what does a 10 micrometer CoC translate to in terms of affecting sharpness? And why is a front focus bias a good thing?
For example what does a 10 micrometer CoC translate to in terms of affecting sharpness? And why is a front focus bias a good thing?
Look at the 2 and 2.8 pixels-blur images, and you'll get an idea:
Simulating motion blur: MTF50 and pictures - the last word
Yesterday, I reported on the results on simulations of a Zeiss Otus 55/1.4 at various f-stops, and showed how MTF-50 values translated into picture sharpness with simulated photographs. Today I'll do something similar, but varying motion blur instead of f-stop. I set up the sim with the pixel...
blog.kasson.com
I don't think I said that it was.
Jim
sportyaccordy
Forum Pro
OK, thanks! I imagine that's not noticeable at 100% (the max I zoom to).
You did here:
"In AF-C mode, the Sony’s shot-to-shot variation gets worse. The D850’s does not. The D850 also becomes a bit more front-focus biased, which is a good thing here."
D850 58/1.4 vs a7RIII 55/1.8 AF-S and AF-C - the last word
This is a continuation of a series of posts on the Nikon D850. You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There's a drop-down menu there that you can use to get to all the posts in this series; just
blog.kasson.com
I may have missed some context there. It also appears the D850 gets less front focus biased as you stop down as positive numbers = back focus. Not trying to pick your analysis apart; just gain understanding and context.
It's context. When you've been back focused biased, moving the focus bias forward is a good thing.
If you've been neutral, becoming more front focus biased is a bad thing.
Neutral bias is the objective. Not front focus biased in the absolute sense.
Jim
Paul Barnard
Senior Member
It all depends on your goals. Want to leave the driving to the camera? Like the green position on the mode dial? Then, sure, go for it.
AF-A is... meh. I have tried it on Nikon, canon, and Sony, and I definitely can’t trust the camera. Rather keep things in af-c, and back button focus. For static objects or landscape I switch to MF or af-s.
i is so easy to do the above the above that anyone choosing to do AF-A is just being lazy or sloppy.
sportyaccordy
Forum Pro
I call it AF-UHHHH. Very indecisive and when it finally makes a decision it's usually wrong.
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