Author Topic: Non-CPU lenses  (Read 1329 times)

Rex Block

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Non-CPU lenses
« on: January 16, 2017, 05:18:43 pm »
How do I tell DxO to use a module for a particular lens? I have a non-CPU lens (Nikkor 180mm f/2.8 ED manual focus). Does DxO need to know about the particular lens here? Is it sufficient for it to know it was a generic (?) 180mm lens?

I'm fairly new to this lens, and while results looked ok, I did notice that when playing around with adjustments on barrel distortion, things improved somewhat.

Thanks for your help!

Alan9940

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Re: Non-CPU lenses
« Reply #1 on: January 16, 2017, 11:45:07 pm »
See my answer to your similar post.

Kind regards,
AlanH

MikeFromMesa

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Re: Non-CPU lenses
« Reply #2 on: January 18, 2017, 03:44:06 pm »
AlanH:

I know of no way to do what the OP is asking so I would be interested in seeing your response to this question. Perhaps there is something interesting I could learn about using OP, but I could not find a previous post from the OP that you responded to concerning this.

Perhaps you could post a link?

Alan9940

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Re: Non-CPU lenses
« Reply #3 on: January 18, 2017, 10:35:55 pm »
Hello Mike,

http://forum.dxo.com/index.php/topic,13171.0.html

However, if you read my responses in that thread you'll see that I don't provide a definitive answer. I could be dreaming and I'm old so, maybe, I'm totally mistaken, but I seem to remember reading something on these boards over the years concerning modifying the EXIF tag for lens data. I, also, vaguely remember that it's a bit of a crap shoot because each camera/lens combo stores this information in different places. Perhaps it's not in EXIF, but someplace else. Regardless, OP reads this information from somewhere in order to load the correct lens module, yes?

To confess fully, I've never done this myself for a lens. I've only ever modified EXIF information to enable OP to properly recognize pics from my iPhone 6+ when I've used a third-party camera app that writes their own proprietary data into EXIF.

Kind regards,
AlanH

platypus

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Re: Non-CPU lenses
« Reply #4 on: January 19, 2017, 07:45:44 pm »
...hmm, OP's magic comes from having exactly the module that you need. Applying a different module could work if the lens construction and the glasses used are the same as the one of the lens you used.

Editing exif data seems to be a bigger hassle than using manual corrections except if you change exif on a bigger batch of files using, say, exiftool. But first, you need to find the right exif section(s) to edit. Sections might differ with camera model and firmware used. Using a hex editor might be good enough or not, depending on wether you can read the data you get...

Adobe provides a toolset that you can use to create lens profile, but they only work in Lightroom and maybe some other products.

Cheerio
Platypus
iMac late 2012 / 2.9 GHz 4 Core i5 / 24 GB / GeForce GTX 660M 512 MB

platypus

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Re: Non-CPU lenses
« Reply #5 on: January 19, 2017, 08:31:54 pm »
...did a brief test on two Canon CR2 files.

First image taken with an EOS 5D Mark III and he EF 100-400L IS II USM
- edited with iHex, so that the lens was the mark I version, patching the leftover places with "0"
- opened with OP and it took the old lens to correct distortions

Second image taken with an EOS 5D and he EF 100-400L IS II USM
- tried to find lens information and found none, the lens is obviously not coded in plain text, the camera is fairly old and does not report the lens the same way as the 5D3 does.

My conclusion is to use manual correction instead of working on exif data.

Cheerio
Platypus

iMac late 2012 / 2.9 GHz 4 Core i5 / 24 GB / GeForce GTX 660M 512 MB

Alan9940

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Re: Non-CPU lenses
« Reply #6 on: January 19, 2017, 10:28:04 pm »
Thank you, Platypus...exactly the point I was trying to make...more of a pain to modify EXIF than to manually correct and create a preset.

Kind regards,
AlanH

 

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