Phase One XF Camera EXIF Focus Distance

[spassig]

Oh. I read it as one point three two eight meters. How do you write that?

I'm not sure.
English vs German Writing of numbers with point or comma?

Jochen

[spassig]

@Gerd

I use GraphicConverter 10.6.2.
GC use for reading Metadata the
---- ExifTool ----
ExifTool-Version: 11.03

I check two different files with lens 150 mm and 30 mm.
Both don't show the focus distance.

Jochen

[Gerd_Peters]

Hello Jochen,

I have my IQ3100 Tr. / Achromatic files checked. I could not find any value with SubjectDistance in the EXIF data. I was sure I would have seen the value at some point, but I also had different firmwares over time. I can not keep up with that.

But I also took a closer look at the EXIF data from IQ4. For this I have built a tripod and always shot the same motifs with different lenses. The focal point/Object is about ~ 4m away.


Schneider Kreuznach 35mm Br. LS F3.5



Schneider Kreuznach 45mm Br. LS F3.5
The lens does not write a SubjectDistance value in the EXIF data.



Schneider Kreuznach 80mm Br. LS F2.8
The lens does not write a SubjectDistance value in the EXIF data.



Schneider Kreuznach 120mm Macro Br. LS F4
Focus distance switch on the lens to "LIMIT".



Schneider Kreuznach 120mm Macro Br. LS F4
Focus distance switch on the lens to "FULL".



Schneider Kreuznach 120mm Macro Br. LS F4
Focus distance switch on the lens to "FULL".
Nonsense value - camera / lens was not moved or refocused.



Schneider Kreuznach 240mm Br. LS F4.5



Mamiya/Phase One 300mm APO F4.5
The lens does not write a SubjectDistance value in the EXIF data.




It is strange that the SK 45mm Br. LS - as one of the newest lenses - does not write a SubjectDistance into the EXIF data. The SK 80mm Br. LS supports AFR with the HAP-2 (Honeybee Autofocus Platform 2.0). To support AFR, I think the camera / lens must know the SubjectDistance to recalculate the autofocus when panning the frame. The SK240 says that it had 1m more distance - which is not true. The SK120 writes - from time to time - nonsense values. And look at the different notations with the thousands point.


From what I've seen, I would not rely on the SubjectDistance values in the EXIF data at IQ4.

I hope this information will help you further, I can not tell you more ...

Greeting Gerd

[spassig]

@Gerd

Thanks for screenshots.
I have discussed your result with PO.
They don’t know what happened with her system and focus distance.
Crazy.

Jochen

[Gerd_Peters]

I admire your stamina to write bug reports to the PO Support.

I thought again about the problem.
The XF knows the MCU position (Motor Control Units) with every modern lens. An MCU is one step with the stepper motor in the lens. With the current MCU value, the aperture and the focal length, PO can calculate the SubjectDistance relatively accurately.

MCU values work on all AF lenses (even older ones) working on the XF. You can see the MCU values in CP1 if you use the XF hyperfocal point tool to find an optimal DoF setting for your lens.

Greeting Gerd