CHG_CANON Loc: the Windy City

No worries. Not everyone recognizes much of my input is intended as humor when not focused on specific actionable advice.

amfoto1 Loc: San Jose, Calif. USA

I use focus peaking as a manual focus assist.

Modern cameras are designed for auto focus lenses and that's what the vast majority of people use on them. As a result, today's cameras don't have any of the manual focus features we had available on cameras in the last century. There were split image rangefinders, micro-diaprisms, matte screens and other features that helped with manual focus. Some modern cameras allow interchangeable focus screens where you can add one or more of those features. But even if possible many of the accessory screens mess with metering. And they simply aren't possible with "smart" optical viewfinder screens in DSLRs or electronic viewfinder screens in mirrorless. Not to mention, many modern camera's viewfinders aren't as big and bright as they were on some manual focus cameras. Accessory screens don't work with Live View, either.

But modern cameras have some other things going for them that can help with manual focusing. One is the ability to magnify the image being seen to more closely inspect if the subject is sharply focused. That can be done in Live View with many cameras, or in a lot of electronic viewfinders that mirrorless cameras use. "Focus Confirmation" may be possible too. Focus peaking that can be done in Live View or in electronic viewfinders is a third option. Further, in many cases where both are available, focus peaking also can be used in conjunction with magnification.

Focus Peaking or any form of manual focusing is slower than AF. As a result, it's most useful with stationary subjects such as landscapes, still lifes, posed portraits, etc. and is less useful with active, moving subjects. However, that was the case "back in the day" when all we had was manual focusing lenses, too. There are techniques that can be used to assist capturing action without the help of AF.... Pre-focus at a point where you anticipate the subject will pass. If a lens has it, learn to use the distance scale to preset focus. And use a smaller lens aperture when you can to increase depth of field, making minor focus errors irrelevant or far less critical.

I suppose you could map an off/on switch for Focus Peaking... But it may not be necessary. I use some manual focus lenses on my Canon M5 and have it set up to do Focusing Peaking with those (Meike 12mm f/2.8 ultrawide, Rokinon 21mm f/1.4, Kamlan 50mm f/1.1 II and vintage Tamron SP 90mm f/2.5 Macro Adaptall). I recently got a couple autofocus lenses for use on the M5 too (Canon EF-M 22mm f/2 and Sigma 56mm f/1.4) and noticed that Focus Peaking is disabled with those. I didn't do anything to set it up this way. In fact, I simply turned on the Peaking feature when I first got the camera and was only using the MF lenses on it. Somehow the camera just "knows" when a manual lens is on it, only using Focus Peaking then. Conversely, Peaking is automatically disabled when an AF lens is installed. I did have to set the camera to "shoot without lens" in order to use manual focus/manual aperture lenses on it. But I don't see how that would cause it to work this way. By the way, the M5 allows you to select a color for the Focus Peaking, which is something I might map to a button, to be able to toggle through the alternatives. Depending upon the scene, one color or another may work better. I think most mirrorless allow this choice of color.

While it's very useful with MF lenses, Focus Peaking isn't all that precise. It will get you pretty close, but not in absolutely perfect focus every time. If your camera has it, use the magnification function... with Peaking if possible... for more critical manual focusing.

Retina Loc: Near Charleston,SC

Magnification is great for still life. For hand held and with moving subjects, peaking seems much more practical. These aids help when it comes to manual focus because newer cameras don't seem to have the clarity in the viewfinder that older film SLRs have. For many people with high acuity vision this is not a problem. I just find it very difficult to focus manually, even with FF cameras, as compared with the Spotmatic, SRT-100, or F. My first impression about auto-focus was that it is always found on modern cameras by necessity because the viewfinders are inadequate. Like others have already mentioned, using lenses from 60's, enlarging lenses with bellows, or general macro work benefit greatly from the ability to focus accurately. One of the reasons I will purchase a mirrorless camera is to have both magnification and peaking as tools when needed.

olemikey Loc: 6 mile creek, Spacecoast Florida

Nor is there anything wrong with humorous advice..........

bwana Loc: Bergen, Alberta, Canada

I find it almost essential when using manual focus lenses and use it all the time for astrophotography; it works very nicely on stars. I normally set the Peaking parameters to Medium/Yellow.

bwa

Miami39 Loc: Florida

I think that it is useful for manual focusing, particularly if you are adapting a lens from another camera system to your camera. I found it useful for portraiture.

bleirer

On my canon the peaking glow does not include the dof impact of stopping down, so you get to focus wide open in that sense. To see impact of f stop you must push the dof preview, then the glow area gets bigger. I think some cameras do use the stopped down aperture for peaking but that might be settable. Some, like the Canon R dont glow but have symbols that converge as you turn the ring. On mine you cannot use peaking and magnification at the same time. I wish I could.

amfoto1 Loc: San Jose, Calif. USA

I kinda think it's the other way around.... That viewfinder features, functionality, size and brightness all were reduced ("cheapened") because of autofocus. It simply was no longer "necessary" to provide an excellent viewfinder, once "everyone" was using AF lenses.

Which came first? Chicken or egg?

Doesn't really matter. Very few cameras today have optical viewfinders as good as some of them in 20th century cameras.

Electronic viewfinders are another matter (I just wish they didn't drain batteries so fast).

amfoto1 Loc: San Jose, Calif. USA

Which is why God, Bill Gates and Steve Wozniak invented smilies!

Side note: Spellcheck doesn't like "smilies"! What does it want to change it to? "Smelly"?

Toment Loc: FL, IL

I don’t like focus peeking because I can’t see the edges of things that I’m trying to tell whether they are in focus or not. I turned it off and I can see easily what I want to be in focus. All the rest is not important

Longshadow Loc: Audubon, PA, United States

Ditto.
More Bells & Whistles create more technophotographers.
I find no need for them either.

Latsok Loc: Recently moved to Washington State.

Can someone explain to me in plain people language: what is Focus Peaking?

selmslie Loc: Fernandina Beach, FL, USA

That's where the parts of the image that are closest to being in focus are overlaid with a color fringe, maybe red but you can pick a different color.

CHG_CANON Loc: the Windy City

There's two mirrorless concepts being used somewhat interchangeably.

First, are you familiar with the LCD-based LiveView of a DSLR? Or, the focus zoom of a smart phone? This tool where you can see what the camera sees, and then 'zoom' into the details as much as a 10x zoom. For a mirrorless camera, you can have this same 10x zoomed / magnified display in the view finder with the camera held to your eye in a shooting position. This 10x zoom is referenced as 'magnification' in the EOS mirrorless manual.

Another feature of mirrorless is a setting that has a shimmering highlight color (in red, white or yellow) that shows within the view finder of the image where the plane of focus exists. This shimmering color is not as accurate as seeing the image details at a 10x zoom. Nor is the shimmering color as accurate as run-of-the-mill autofocus on any AF-capable camera. This shimmering color is referenced as 'MF peeking' in the EOS mirrorless manual.

The two tools together are very helpful for manual focus. You'd have to play with the tools to 'see' for yourself, but if you first zoom into the details for a sharply focused and manually focused image, as long as you don't dramatically change your position / distance relative to the subject, you can use that shimmering color at a normal view to consider where you've changed the focus either forward or backward as the shimmer moves back n forth within the image.

Urnst Loc: Brownsville, Texas

I use it on my Pen F Olympus for manual focus only lens and it works great.