Teleconverter off brand

[seedsca]

Hi,

I'm trying to add my "POSS AUTO TELE CONVERTER 2X MULTI-COATED" as a teleconverter for my Minolta (film) cameras. I see there is an option, but it's only for Minolta branded ones. I also see there are several other brands of teleconverters, but none are "POSS".

How would you recommend I tag my film scans when I use this teleconverter? I'm also thinking of changing the FocalLengthIn35mmFormat to be double of what the lens uses, since the teleconverter doubles it. Or is there another standard to use here?

Finding tagging film scans a bit on the complicated side 

[Phil Harvey]

I would say that lens/teleconverter combinations should be stored in the EXIF:LensModel tag.  And yes, all of the FocalLength tags should also be affected.

- Phil

[seedsca]

Thanks for you input. So then you recommend adding the teleconverter to the LensModel tag. Like "MD ROKKOR-X 50 mm 1:1.4 / POSS AUTO TELE CONVERTER 2X MULTI-COATED". Then double the FocalLength to 100 mm.

Too bad I can't override the teleconverter tag, but it makes sense from a reliability/standards perspective.

[Phil Harvey]

Yes.

The Teleconverter tag you mention is stored as a numerical value, so overriding it doesn't make sense.  (See here for the lookup table.)

- Phil

[seedsca]

Well, right. It's a numerical value. I was more thinking of being able to add my Teleconverter information properly. But I'm guessing I'm getting into the realm of using tags from my photo editing software (Dark Table).

Thanks for the help and input!
Sergio