[tempelorg]

When I recently tested a few Sigma lenses (150-500, 120-400, 50-500), I noticed that Mac OS X doesn't recognize these lenses, which means that all Apple-made photo apps don't, either.

I'm more a software maker than a photographer. So, instead of waiting for Apple to release an update to deal with this (which they eventually do, usually many months later), I've written myself a quick-n-dirty program that fixes this - it scans all image files in a folder (and sub folders) and identifies those that aren't detected by OS X - and then automatically adds a Lens Model Exif tag to them (by using another app, "exiftool", as a helper), or a generic ID if even exiftool doesn't know this lens yet (as it was with two of the Sigma lenses, in fact).

Now Aperture and iPhoto can show me the lens names of all images in my photo libraries.

Here's my question to you all:

As I'm making my living with software development, I wonder if folks here would be interested in using (and paying for) such a tool that adds lens IDs to all those lenses that Apple doesn't recognize yet. I'd target a price of no more than $20 for it, but if only 3 people are interested in it, it's not even worth the effort for me to put it up a website, as it requires still a lot of work (documentation, making an icon, etc.).

I also wonder if there are other lenses that OS X currently doesn't recognize. And if the same problem exists with other systems (Canon, Nikon etc.).

[normhead]

I only have one Sigma lens so, I know which lens it is even if APerture doesn't. Currently I have no SIgma's on my wish list... so I'm not sure it will ever be of use to me....the one Sigma I have is the one I'd like to sell.

[tempelorg]

@normhead, good point. I came up with the idea for a such tool when I remembered that when Pentax brought out the new WR lenses the past 2 years, OS X didn't recognize any of them for several months. So, this might be a recurring situation. But I see that it's not a big deal for most, probably.

[VictorDA]

I'm not really going to vote, because
- I'm a PC user
- I don't own SIgma lenses
- however I would love to tag my M and K lenses... I don't think you can help me with that unless you have magic powers
So yes I see your point, but no I don't think I'm really your audience.

[tempelorg]

Oh yes, the M/K lenses. If Pentax would AT LEAST put the manually set focal length into the Exif data, but they don't even do that, so there's not even that hint in the data for automatic processing.
And I guess there's no use in contacting them about it, since it's never going to reach their dev department, would it?

You can, however, look into the free "exiftool" program, which allows you to add Exif data to your images. If you _know_ which imgs used which pictures, you could add this information afterwards. In fact, I could add such a feature to my app as well, and make it work on Windows, too - it would then mainly be a front-end to exiftool, listing the lens that aren't identified, and giving you the option to selectively tag them with presets you can enter and save.

[VictorDA]

I'll look into it, thanks for the tip!

[tempelorg]

Uh-oh! Turns out that exiftool can't currently edit the Pentax MakerNotes "LensType" value. I've notified its author, maybe he'll implement a solution in an upcoming version.

I have already been able to "fix" that with some trickery, though. I'll keep investigating and let you know if I manage to solve this.

[VictorDA]

I've been trying it with the GUI from Bogdan Hrastnik and it's quite great. Like you said, the only drawback is it isn't able to write a lens name, but I guess it's not so crucial. Are we being obsessive over this?

[tempelorg]

Are we being obsessive over this?

I know I am. After a night's sleep over it I realize that it's not worth making a payable app out of this. I should just release it as-is to the public.

[nono]

Oh yes, the M/K lenses. If Pentax would AT LEAST put the manually set focal length into the Exif data, but they don't even do that, so there's not even that hint in the data for automatic processing.

Yes they do, I have a few exiftool-based scriptlets which use exactly that.

[tempelorg]

Yes they do, I have a few exiftool-based scriptlets which use exactly that.

Oh, you're so right! I had missed that because it's stored under a different entry in the Exif data: "SRFocalLength".
Oddly, it's always 4mm more than what I've set it to, e.g. 204 instead of 200mm. Is that the same for you?

Great, I can use that. Merci bien pour le feedback!

[VictorDA]

Great, I can use that. Merci bien pour le feedback!

It's become a French area here!
Anyway, the focal length appear to be entered correctly for all of my lenses (assuming I set the SR correctly in camera): 24, 50, 100mm.
So I now realize Lightroom is going to display correct focal length and "K or M lens" as Lens type. I guess I can live with that.
Exiftool is still great for correcting the focal length when I mess up in camera though!

[tempelorg]

Victor, which camera do you use - a K-5, I suppose? I checked with K20D and K-5, and looked at the "SRFocalLength" in exiftool.
How did you check the focal length? With exiftool or in an app that may "correct" the value on its own?

[VictorDA]

I have a K-5 indeed.
I used ExifToolGUI, I don't think it's supposed to "fix" anything, but maybe it imports the SR FL into the FL field? Anyway I was able to check and modify this value under "FocalLength" in the EXIF section. The correct FL also appears in Lightroom's library and even in Windows properties, for all shots with a K/M lens, both DNG and JPG. Hope this answers your question ?

[tempelorg]

Victor, I agree that the exiftool nor the GUI would "correct" the exif values in any ways. Can you see the SRFocalLength value explicitly? It's really odd that I see them all by 4mm increased here, with both cameras. I'll ask in the exiftool forum about it.