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AF-C + backbutton focusing + spot photometry + wide/tracking


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I am in spot photometry with AF tracking, which is AF-C mode (front dial on C) with wide/tracking, and I am using the back button to focus. When I focus with the back button and then re-compose, the exposure changes. This is because the AF is locked while pressing the back button, but the exposure is not locked to the same place where I am focusing.

Is there a way to lock both the AF and the exposure while in AF-C mode with wide/tracking using the back button "AF ON"?

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Welcome to the forum.

I could be mistaken about this, but you are supposed to be able to change the settings for the function buttons (afl ael, etc. are called function buttons) from their defaults.


One of the available choices is to assign both focus lock and exposure lock to the back button focus button.

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Posted (edited)

Thank you, @jerryy. The most relevant items on that menu are:

  4. AF-ON

With any of the first three above, I lose the ability to track. The most promising would be AE/AF LOCK, but when I assign that function to the back button, even though I am in AF-C (front dial on C) and the AF MODE is on wide/tracking, the focus point is locked in the middle and does not move anymore when I recompose, in other words, is not tracking the subject anymore. The autofocus point does not lock on the subject anymore; it just stays in the middle when recomposing.

Tracking works as expected when in AF-ON. The camera tracks the subject while I move the camera or the subject moves, and it stays focused on the subject. But the spot exposure is totally decoupled from the autofocus point. I think it stays in the middle, therefore not exposing the subject but, instead, whatever happens to be in the middle of the frame at any given moment.

I feel that the function I am looking for would be called AE/AF-ON, but it seems that doesn't exist.

Another option could be to have the top shutter button expose while half-press on wherever subject the focus point happens to be while tracking.

So, while tracking, the back button would keep the focus on the subject while pressed, and the shutter release would keep the exposure while half-pressed.

Another workaround would be to lock the exposure on the subject first using the AEL button and then focus tracking with the back button, but if the subject is moving through different light conditions, which is a reason for using focus tracking, the exposure will be totally wrong, or awkward to change since my thumb is on top of AF-ON (back-button) tracking the subject.

Before the X-T5 I had a Nikon Z6II. This camera in autofocus tracking was also exposing the same place where the tracking was happening. If I wanted to, I could even decouple the exposure as explained above, i.e., the back button is autofocusing while tracking, but the exposure is not locked until the shutter release is half-pressed, and even in spot meeting, it would expose exactly where the focus point happened to be while tracking.

I am trying to achieve similar settings with the X-T5. Ideally, I would like the back button to both focus and expose whatever is focusing while tracking, I am not sure if this is not possible with the X-T5 and I have to change the way I shoot or I just cannot find the right menu combinations to achieve it.

If anyone knows, please let me know!


Edited by hayate
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There is the option of shooting manual exposure. I know, I know, that is not always a favored approach.

It sounds like the half shutter press will give you the fastest response time for the cases when your subject(s) are moving quickly from dark to light to ...


p.s. just to check, toggling INTERLOCK SPOT AE & FOCUS AREA on / off has no effect?




Edited by jerryy
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INTERLOCK SPOT AE & FOCUS AREA it's ON. It works well when photometry is in spot, and AF MODE is in Single Point.
In this setting, wherever I move the focus point, for example, with the joystick, the exposure is done exactly where the focus point is. For example, if the focus point is on the top right, that is where the exposure will happen instead of the center.
But it doesn't work when AF MODE is in WIDE/TRACKING.

I wish the same would happen in AF-C with WIDE/TRACKING, but unfortunately, in this setting, the exposure and the focus point are not interlocked, so if I am tracking a subject that is moving from left to right, the exposure is always happening depending on the photometry used, with spot is in the center for example and not following the focus point. 

If the camera is AF tracking a moving subject, I think it is reasonable to expect the exposure to AE wherever the AF tracking is, or at least give the option in the setting menu to interlock them.

For example, I am tracking someone running from left to right, I point the focus to the running person pressing the back button focus, now I am tracking the running person, but also I want to recompose to have the running person running into the frame when I recompose if the area the person is running towards is lighter or darker then the current position of the running person the subject will be over or under expose because while the person is on the left, the focus point is on the left but the AE is on the center. 
I hope Fujifilm revisits this because the AE in tracking mode should really be where the AF is, or at least give the option to interlock them as is available in photometry spot and single-point AF mode.


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This sounds like something, that if you really wish the folks at Fujifilm to take another look into the issue, you should gather your thoughts into written explanations and send to their development teams. You have a good start already.

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