BebuLamar

I don't think the depth is the problem. I think for the DSLR the AF focusing algorithm in order to speed up doesn't recheck the focus after focus is achieved. The Phase Detect sensor can tell how far off focus the image is and thus the camera can simply make the move by that amount. If some error in the move the focus may not be correct.
With contrast detection AF the sensor can tell whether the image is in focus but can not tell how much off focus the image is and thus the AF system must move the lens and check for focus until focus is achieved. This is slower but introduces no error.
However there are many mirrorless camera with phase detect sensor on the imaging sensor and thus the same technique used for the DSLR can be used and has the same speed and the same possibility for error.

davesit Loc: Media, PA

[quote=whitehall]As always your opinions based on your experience will be much welcome:

Do lenses (300 PF) need to be adjusted for back or front focus?

IGW[/quote

With a few exceptions, I happened to have done a AF fine-tune with my many lenses (yeah, I know) and my 3 bodies (D5, D850 and Z7). The lenses are mostly Nikkors, with a few Sigma and Tamrons. With the DSLR bodies, the AF fine-tune numbers ranges from -17 to +5, but with the Z7, there were all either 0, -1 or -2 (just 1 lens). So I can say that you don't really need to AF fine-tune the lenses with Z camera bodies.

Attached is a pdf file of a spreadsheet showing the AF fine-tune numbers with each of the camera bodies. As you can see, with the Z7, the numbers are so small that it's irrelevant. So there is really no need to AF fine-tune lenses with the Z camera bodies.

Attached file:
(Download)

davesit Loc: Media, PA

Architect1776 Loc: In my mind

Discussing Z7

Brucej67 Loc: Cary, NC

Not mine.

JD750 Loc: SoCal

Yes. One of the many advantages of mirrorless Tech, is the lens focuses directly on the sensor.

Is it possible they have 2 focus systems? Contrast on the sensor and Phase Detect (PD) externally? External PD would suck. But I thought they had PD Sites on the sensor as well As contrast detect. But I am not an expert in the internal workings of the Z7.

Tony Northrop had a “mild rant” about micro focus adjustments on DSLRs. Same would apply to mirrorless. Mostly a waste of time according to Tony. What I got out of it was all focus systems have a tolerance. And all focus systems have hits and misses. When you are fooling around with the micro focus, then you are inside the tolerance of the system. Now If your lens has an obvious bias, that you can tune out, then the lens is out of tolerance. Send it in for repair. Or else, like Tony says if you lens focuses slightly close, “just lean in a little”. Just saying.

Now my Z7, does a nice job. I get sharp results. And occasional misses. And of course I mess up focus sometimes. Just like with my D750. Pretty much the same thing. In fact, I think the Z7 might have a little bit better hit ratio. I have not tried to quantify this. Just my feeling. I have not fooled around with tuning etc. Nor will I.

Mostly, I shoot things that don’t move much. So YMMV if you are shooting things that move fast.

Architect1776 Loc: In my mind

gwilliams6

I never have to micro adjust on my Sony mirrorless cameras. They have it in the menu solely for adapted non-mirrorless-designed lenses used with adapters, like the Sony A-mount lenses used with the Sony A-mount to E-mount adapters which have built-in mirrors in the adapters.

Otherwise mirrorless Sonys do not need to be micro lens adjusted as the focus is taken directly from the sensor.

I am a pro of over 40 years in the business and a university photography professor with my Masters Degree in Digital Photography, and this is the gospel truth folks. I have 13 E-mount lenses from 10mm to 600mm from Sony, Sigma and Tamron and never have to micro adjust any of them and have perfect focus with my Sony A7RIII, A7RIV, and A9. . I feel for you DSLR users. Cheers

sscnxy

You are absolutely right on! Any photographer who cares about getting maximally sharp focus out of a lens needs to check for front or back focus. What would be the point of trying to take a fine portrait if the photo always ended up with the nose or the ear being sharp, but the catchlight in the eye always fuzzy?
I suspect that the usual UHH'ers who diminish the need to do AF fine tuning have never taken the small amount of time to learn and do it correctly. As you state, it is not difficult to download or buy a precisely printed chart for the AF tuning.
With camera set on a tripod and good lighting, it is so simple to shoot a series of shots, adjusting/tuning the AF one step at a time and then studying the images to see whether the correction is + or - and by what amount!
I have no idea why the detractors keep pushing their untruths on this important topic.
True, a mirrorless camera with a native lens may not need AF fine tuning, but the other setups should really be checked for front or back focus if one really cares about sharpness.

NMY

Architect1776 Loc: In my mind

I have been lucky.
My 7D and all my AF lenses did not need adjustment.
I checked them all and they were all at their best straight from the factory.

IDguy Loc: Idaho

No because focus happens on the sensor.

IDguy Loc: Idaho

You need to update your thinking for mirrorless cameras that use the sensor for focus.

Architect1776 Loc: In my mind

IDguy Loc: Idaho

Yes, the Zs have both systems using the sensor. One is preferred for video.

I highly recommend Northrup’s book on the Nikon Autofocus System ( Mirrorless version). Thought I knew it all. I was mostly ignorant.

FTn

I wouldn't waste my time on Tony Northrup. He's basically a Click Bait Clown with no real understanding of photography or optical physics. Steve Perry has a new book on Nikon Mirrorless Autofocus that, based on his Nikon DSLR autofocus book, should be quite good. Unfortunately, Nikon hasn't come out with a Mirrorless camera that tempts me yet so I haven't bought Steve's new book.

- FTn