Forced to Use Manual Focus

Tom Schum wrote:

rlx wrote:

What settings are you using Tom? I have assigned "preview depth of field" to the Fn button. In AF-S I use AF+MF. In either AF-S or AF-M modes I first press the Fn button, THEN I press the back control dial to zoom in (a nose double-click also does it!). Half-press the shutter release button in AF-S mode; don't touch the release in AF-M. At this point the iris is stopped down to the shooting aperture and turning the focus dial will leave the iris stopped down.

The camera will get out of "preview depth of field" very quickly and one needs to press the Fn button each time. This is not a choice the camera will remember like a toggle switch.

I assigned "preview depth of field" to the Fn button of my X-T3. I set it for AF-S using the front switch, and enabled AF+MF in the menu.

How do you get the camera into AF-M mode?

"Focus check" is disabled. Maybe it works with "focus check" enabled but I didn't try it.

1. Click once on the Fn button to activate "preview depth of field". An icon appears on the upper left part of the viewfinder (an iris). This is a click once affair; don't keep the finger on the Fn button. I might have confused you with my comment that the camera does not remember that choice; I meant the camera resets "preview depth of field" after a picture is taken. At this point the iris is closed to the shooting aperture.
2. Click the back command dial to magnify the display if you want to (if Focus Check is disabled). You can also double-tap the LCD if you didn't disable that option..
3. Half-pressing the shutter and turning the focus ring activates he AF+MF mode, the display will show any focus peaking if focus peaking was selected in AF-M mode (Yes you have to go to AF-M just to change that and then back to AF-S). No need to keep a finger on the Fn button. The iris is still stopped down.
4. Taking a picture or just releasing the shutter button takes the camera out of "preview depth of field".

Anyway I pressed the Fn button and while holding it down I pressed in the back control dial briefly to bring up focus magnification. Then, while continuing to hold down the Fn button I half-pressed the shutter button and was able to move the focus ring on the 50mm F2 WR lens and manually focus at the shooting aperture.

This involved three of my ten fingers at once, in addition to fingers committed to holding the camera itself: One to hold down the Fn button, one to half-press the shutter button, and one to move the lens focus ring. I see that it works but it seems tremendously cumbersome, and because of this I don't think I'll ever use this trick.

Maybe I am doing it wrong. If so please let me know.

Just press once on the Fn button. I bet that function was designed for occasional use only, while checking a new lens or for technical shooting.

And, finally, is this discussed at all in the user manual?

"preview depth of field" is mentioned I think. AF+MF was introduced when it was found that the shutter lag in AF-M mode was too long and inconsistent when using AF lenses. Doing MF in AF-S mode solved the lag issue on the XT-1 and on my XE-1. The shutter lag has disappeared in AF-M in a subsequent iteration of the firmware but there are still good reasons to do manual focusing in AF+MF instead of using AF-M when using an AF lens.

Why? I hear you asking. That's a software development strategy; patching old code.

(Edit) I use back-button focusing in AF-S so the auto-focus does not activate when I half-press the shutter to get in AF+MF. I am saying that in case AF interacts with "preview depth of field".