DXO Module Ambiguity - why can't PL5 detect the specific lens used?

I have both the Canon RF24-105 f4L IS USM and RF24-105 f4-7.1 STM lenses. I have the modules for both installed, and use them on EOS R and EOS R5 bodies. I’m using PL5.1.3 on Windows 10.

When loading a folder containing images from for example the RF24-105 f4 L, I get a little yellow icon and the message “DXO module ambiguity detected”, even though only one lens is used. I’ve checked, and the EXIF metadata stored in the image clearly lists the lens as “RF24-105mm F4 L IS USM”.

Now I know I can resolve the ambiguity for any single image, or for all images in the folder. This might be confusing if I used both lenses during the course of one shoot (unlikely), or if I combine images from various shoots into one folder (much more likely). But surely this shouldn’t be necessary - why can’t PL detect the exact lens used, from the EXIF?

I also wish PhotoLab was smarter about this. I used to have this ambiguity all the time with some of my lenses (native micro-four-thirds Olympus and Panasonic lenses that received “mark II” updates). Fortunately, I’ve only owned one iteration of each lens, so could delete the unwanted optics module from PhotoLab. But it was a process to figure this out and seems unnecessary to me.


To match an image and a module we use several Exif/MakerNote information in following order:

  • LensName
  • LensID
  • LensInfo (for example : 18-35mm F3.5-5.6)
  • Current information of focal and aperture (to check if they are accepted by LensInfo)

Information 1 and 2 are not always available (especially for cameras of old generation).
Any of this information could fit several lenses (1 and 2 are supposed to be unique but all makers don’t respect that).

So when a module for a couple doesn’t exist yet PhotoLab can propose a module for one or several other lenses.

There are some tricks, one of them is for canon LensInfo can be wrong when TC are used (FNumber values are not multiplied by TC) so we don’t take FNumber in LensInfo values.

Concerning Olympus, detection will be improved in release of mid-March so your lens mark II will only be associated with module for it (no more ambiguity) with mark I.


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Any sign of a fix for the Sony distance issue with the Windows version

Thanks Marie - I understand your description what PL is doing, and how some parameters can be ambiguous, but the lens is clearly named in the EXIF as Canon RF 24-105 f4 L IS USM. Therefore if this lens identification is readable by PL, as it can be read by numerous other programs, including even my iPhone (!) surely it should be possible for PL to identify it without ambiguity? Also many lenses cannot be used with teleconverters - neither of the RF 24-105 lenses can be used with a TC. These two lenses require completely different geometric correction, so it is important to detect them correctly.
I would be happy to send you some RAW files (or jpegs) that have been taken on the Canon R5 with not two but three different Canon 24-105 lenses - the EF 24-105 f4 L mkii IS USM (used with the EF-RF adapter), the RF24-105 f4-7.1 STM, and the RF 24-105 f4 L IS USM. Would that be useful?

Hello @nputtick ,

yes please put some RAW images on https://upload.dxo.com/ (check “forum”) so we can analyze it and fix this issue quickly.

Best regards,