radiojohn

Someone here made and offhanded remark about focus peaking not always being accurate.

Would someone care to expand on that?

User ID

It simply accents contrasty edges. Successful use simply requires awareness of how that can ignite "false positives". Without the nexessary awareness, accuracy suffers.

A typical false positive is an out of focus background highlight that is surrounded by a dark area, which creates a contrast edge even tho the bright spot is NOT in focus. Such bright spots need not be large blobs. They can be verrrry numerous sparkles on a glossy but textured surface. The textured object can be out of focus but liberally sprinkled with colored speckles of peaking color.

Good technique is to only pay attention to peaking color on trustworthy details. Generally that mean ignoring specular highlights and small light sources.

CHG_CANON Loc: the Windy City

It's a well understood fact. Focus peaking is not always accurate. Just look at the pixel-level details your resulting images, especially the manual focus results, essentially the only purpose of 'focus peaking'.

My experience is that I (you, everyone) gets better manual focus results by first using 'Focus Assist' where you leverage the MILC EVF to zoom to the details of the lens focus, looking at the 1:1 pixel-level details. Even those of us with older / questionable eyesight should be able to accurately focus when we can 'see' the fine details with the camera held to our eye in a shooting position.

If you've configured your Focus Peaking color to the maximum contrast, now when you drop back to the unzoomed view of the composition, that Red shimmer (or Yellow or White, you pick) should now be both accurate and easy to track the subtle forward (or backward) movements of the plane of focus, if you adjust your manual focus within the same composition. You can also use the old MF trick of not adjusting the lens focus, rather, just lean your entire body slightly forward or backward and watch that shimmer move.

These two digital mirrorless technologies - Focus Peaking and Focus Assist - have breathed new life into ancient film-era MF lenses. My MF results are far superior to any of the just-by-luck results these same lenses delivered on MF film bodies.

radiojohn

Many thanks for the useful responses.

Orphoto Loc: Oregon

I can only speak for nikon dslr s. Focus peaking gets you close but not quite right. Live view at 100% is the unquestioned best practice.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

NO

imagextrordinair Loc: Halden, Norway

For me focus peaking is the perfect tool for Tilt (Tilt-shift) focus adjustments. Examples could be a surface you want to capture in extreme depth of focus at a wide open aperture like F2.8. Fast way to get results.

BurghByrd Loc: Pittsburgh

You will notice that focus peaking takes in the entire "acceptable" DOF in focus. If you want the point of sharpest focus you're better servied zooming into the display.

a6k Loc: Detroit & Sanibel

It may be only me and perhaps only Sony. Or both. I've spent a lot of effort on testing focus peaking on my 𝜶6500 including on a tripod. I have a favorite target for sharpness. It's a pool cage more than 200 feet away. The good shots show the threads on the brace wire fittings and the wires in the screens.

The autofocus is better than any manual focus I've been able to do.

Focus peaking, at least on my camera, shows a gradual transition from off to on to off. There isn't any "snap" like you'd get from my old Nikon FM2 prism, for example.

The DOF isn't really being shown but what is helpful is that it shows all the points that are in decent focus even if they were not where I was trying to get. That is something the old film technology in my SLR didn't do.

I've adjusted the focus peaking on the camera to its weakest in an attempt to make it more precise. It did that, but not to my satisfaction. Autofocus is simply better and being able to configure it to a small spot makes it even more so.

Sample shot merely to show what I use for a test target. It was one of the best I've been able to get. I don't know for sure but most pool cages around here are a special, fine screen because of "noseeums". This was AF. No sharpening done, just convert raw to JPG.

𝜶6500, Tamron 150-500. F8, 1/1000, auto ISO. Notice the tiny lizard.

BurghByrd Loc: Pittsburgh

I agree!!! It sure does help get the tilt set up right.

jcboy3

Focus peaking gets you close; focus assist closes the deal. But it's a question of time. Do you have time to use focus assist? Or should you just put the camera in burst mode and once focus peaking starts to indicate you are in the focus area, shoot off a burst while slowly adjusting the zoom. Old school, but can be quicker than the alternative.

CHG_CANON Loc: the Windy City

Did you 'focus assist' to the details of any aspect of the image, like maybe the bolts in the center? Did you think to attach the image file to show the pixel-level details for confirmation of the focus in those details?

a6k Loc: Detroit & Sanibel

First question: focus assist magnification doesn’t work with the A-mount Minolta 500/8 reflex AF. That would likely help if enough time. But that’s the lens I’m most concerned with. The Tamron was rented. I do sometimes use focus magnification with my RX10m4.

Additional note: my Sony LA-EA4 adapter was modified with the Monster kit. I posted about that previously. It made the AF very accurate and no longer needing adjustment.

Second question: I thought you would be the one to ask that. In my post I tried to make clear that my only purpose in showing the picture was to illustrate what I used as a target. So I deliberately avoided pixel peeping discussion. I’m not trying to prove anything. Just offering one experience to help a discussion. The example shown was on AF as you may have noticed. Anyway, to compare and come to a conclusion would require many shots. That’s what I did. Several lenses over many weeks. Many shots. Lots of comparisons at 100% and beyond.

imagextrordinair Loc: Halden, Norway

Just an added note,

If you use the touch screen and the merging arrows while in live view (for Canon) you can set your point of focus and then use then "Focus Peaking" to determine the depth of focus and angle of focus, in addition to the merging arrows.

For the 1DX MK3 I can touch any point on the screen and verify with 100 percent accuracy by merging the arrows. Works extremely well for more complicates tilt lens adjustments.

The old stone dlsr even has eye detect in manual focus mode that is 100 percent accurate. I rarely lose a shot due to miss focus.

CHG_CANON Loc: the Windy City

As mentioned earlier, focus assist and focus peaking are MF enabling technologies provided by MILC technology ....