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02-12-2014, 03:42 AM   #1
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Samyang 16mm f2

Just received my new Samyang 16mm f2.
Nice lens but I thought it would provide exif data and a lens ID to the camera.
Are all of the Samyang lenses the same ?

02-12-2014, 03:51 AM   #2
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All of lenses with PK and PKA mount are!
02-12-2014, 05:47 AM   #3
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What software are you using to read the EXIF data? The lens is a new one, and third party, so the EXIF library has to be updated to support the EXIF code for that lens. And third party lens EXIF codes are usually hit or miss. You should be getting the focal length and aperture though.
02-12-2014, 06:04 AM   #4
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Light room is one of them. The quick way to check is pressing "I" twice.

02-12-2014, 06:52 AM   #5
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The best you will get from any manual focus lens on a Pentax body is the camera asking you what the focal length of the lens is, which will get recorded in EXIF (along with ISO, aperture, exposure, etc). The brand and model specific hex string for a lens only gets transmitted to a camera from AF lenses. Manual lenses with an 'A' mode expose a bit pattern through the mount that communicates max and min aperture, and that's it.
02-12-2014, 06:58 AM   #6
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QuoteOriginally posted by mtux Quote
All of lenses with PK and PKA mount are!
Almost true. There's a difference in the EXIF output with A lenses in A mode compared to M lenses or A lenses outside A mode. There's another output for no lens mounted or M42 adapted.

That in combination with the user input FL that's also output into the EXIF will, if your lens selection is small enough, limit the list down to just a few lenses, sometimes just one. But of course, nothing is as convenient as F-and-forwards lenses.
02-12-2014, 07:13 AM   #7
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And if you turn off SR the camera won't even write your selected FL in EXIF. At least my K30 do so.
02-12-2014, 08:16 AM   #8
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Yes, my Samyang 14mm also doesn't communicate with the camera. The camera only knows the aperture, and if you input the focal length (and you can input the wrong one..) (you must have SR enabled or you can input it if you press Menu and choose the "focal length" thingy)

Lens ID is problematic even for other third-party brands, like Tamron and Sigma (depending on lens).

Hope the lens is good optically, though

02-13-2014, 03:10 PM   #9
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Original Poster
Ok well I had hoped for a little more info from the lens. I didn't think the contacts on it were for nothing.
Still experimenting with it because it seems to be front focusing a little. So if it gave the camera the right info, I could change the fine focus settings and not have to worry about resetting them later since with no focal length data I only get the 'change all' option.
Anyway so the best thing to do is, I'll set a user profile in the K-5 just for this lens and I should be ok.

P.S. I use photoME for exif.

Last edited by chromo; 02-13-2014 at 03:28 PM.
02-13-2014, 03:47 PM   #10
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QuoteOriginally posted by chromo Quote
Nice lens but I thought it would provide exif data and a lens ID to the camera.
Your Samyang only communicates:
  • Whether the aperture ring is on the "A" position
  • Maximum aperture
  • Minimum aperture
AFAIK, that is the case with all lenses using the non-AF version of the K-mount. Only the AF mount lenses use the data pin to transmit focal length and lens code information.

Your best option if you want that information in the image EXIF may be to edit it in after the fact. I use ExifTool for that purpose.


Steve
02-13-2014, 05:48 PM   #11
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QuoteQuote:

Lens ID is problematic even for other third-party brands, like Tamron and Sigma (depending on lens).
Dear Pentax Ricoh:

Please allow custom lens naming, sort of like AF adjustments...
02-13-2014, 06:44 PM   #12
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QuoteOriginally posted by SpecialK Quote
Dear Pentax Ricoh:

Please allow custom lens naming, sort of like AF adjustments...
This could be solved in a more comprehensive way by Pentax openly adopting an approach like the unofficial Canon CHDK:

CHDK Wiki

This would allow the equivalent of what DD-WRT has done for home routers, which has been great (and a selling point for routers):

DD-WRT - Wikipedia, the free encyclopedia

More specifically, why a CHDK-like solution would be useful is because I think the logic for what you (and myself and others) want is a few steps, and Pentax may not have enough incentive to develop it themselves.

First, text names for lenses do not exist in EXIF. EXIF holds a hex string ID for a lens. EXIF processing software (Apple's Aperture, Adobe's Lightroom, etc.) has it's own lookup tables for lens IDs to text strings for lenses. Different EXIF processing software will have different tables. They also apply some algorithms when they know that multiple third-party lenses of different focal lengths share the same lens ID by saying things like "lens A or lens B or lens C" at some focal lengths, "lens A or lens C" at other focal lengths, or "lens C" when only one focal length is possible for a given third-party lens ID.

Now camera bodies should be able to combine both the hex string and other info from the lens (min and max aperture for instance) and at least narrow down if not isolate the lens choices when a lens is mounted. If the camera had a database in it (or could load one from a file the user provides) the camera could also present a short list of lens possibilities and then use a new field (or perhaps just a comment field) in EXIF to store a string of the lens for the user.

If Pentax for whatever reason didn't want to create this functionality for end-users (primarily because it would help users with third-party lenses more than first-party lenses), if they had an open-architecture camera that could be extended by end-users we could provide this functionality (and other great photographic functionality that Pentax currently doesn't do in their bodies, making their products more appealing to everyone). I've written about this before in the forum, but received less enthusiastic feedback than I believe is warranted.

I'm not sure if anyone has documented the lens EXIF situation for Pentax, but here's someone who's documented it well for Nikon, for reference:

CPU Nikkor lenses listed by LensID

F-Mount lenses listed by Extended LensID
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