X-T4, BBs and touchscreen

[paulpp]

Would appreciate any views/advice.

Have my X-T4 set up for BBF i.e. AF-M and focus decoupled from shutter so can focus with the AF-On button on the rear.  All works ok.

Today tried as an experiment to take some landscapes with the camera on a tripod (16-80 f/4 lens) using the touchscreen to frame the image.  I touched the touchscreen to set the focus point and used the shutter button to take the image.  All were out of focus.

It seems to me there are three possibilities -

1.  I should have turned the OIS system off (although Fuji seem to say it can be left on?

2.  Using the touchscreen to select a focus point only just does that i.e it selects the point but doesn't actually focus on that point?

3.  Something else, or a combination of 1 and 2.

So what I want (if possible) would be for BBF to work for handheld (as it does) but when using the touchscreen, the touchscreen "taking over" for both selecting the focus point and actually focussing.

Or am I expecting too much?

[Greybeard]

Do you have the touchscreen setup to focus?

https://fujifilm-dsc.com/en/manual/x-t4/menu_shooting/af_mf_setting_movie/index.html#touch_panel

[paulpp]

I do (using still mode - not movie) and having checked it does appear to focus both in M mode and S mode, although not on a tripod..

The attached image might give a better idea.  The focus point is the centre of the cliff just below the brush stroke I have added. Was taken at 1/8th sec @ f/22 with the camera on a tripod.  Others take at the same time were much the same

Have just tried it handheld focussing with the touchscreen and the image looks sharper which makes me wonder if the issue is the tripod and the ois system?

FXT40277-Edit copy.jpf

Edited April 19, 2022 by paulpp
Further detail

[paulpp]

And to complete the story have just taken an image twice.  Camera on the tripod.  Once with iOS on and the second with it off - no noticeable difference.  Focussing seems ok.

The image of the cliff was taken with a Cokin ND filter and was at 1/8th sec where as my two test shots were at 1/12th. 

Could it be that either the filter is degrading the image and/or interfering with the focussing, or that the longer time exposure gives more opportunity for the iOS to produce camera shake?

 

[Greybeard]

Tough to tell what is going on from that sample. Do you have an original sample SOOC - not via any software.

It's certainly worth testing without filters.

Maybe your problem is diffraction at f/22?

Edited April 19, 2022 by Greybeard

[paulpp]

Hadn't thought of diffraction.  Some reviews of the lens mention diffraction at f/22 so that may be the issue.

All that has been done to the image is a conversion to a jpg.  Original RAW too large to be attached.

Probably need to do more testing.

Thanks for your comments

 

Edited April 19, 2022 by paulpp
Add additional info