[Azergoth]

Hi,

I have a little question.

Does someone know how the lens corrections (distortion, chromatic aberration and peripheral illumination correction (vignetting)) are stored in the raw file?
Is the "raw" file modified? Is it "written" somewhere?

Thanks :-)

[TheOneAndOnlyJH]

They are stored in exif tags in the raw file. (See link here, half way down the page under "Pentax LensCorr Tags")
You can look at tags by uploading a photo here and searching for 'correction'

If you use the Pentax supplied SilkyPix it might use the correction information you have set, but I know that when I open the raw DNG in DXO it doesn't use the in camera corrections and I apply the DXO correction files it loads for camera / lens combinations. (Probably similar for Lightroom)

In camera lens corrections only works with specific later Pentax lenses (most DA / DA* lenses I believe). Lens corrections will not work with old manual lenses or third party lenses (Tamron, Sigma, etc) One advantage of DXO is that they have a good set of correction files for many common lenses that Pentax cameras doesn't have lens correction for. (Tamron, Sigma, Samyang).

Another advantage if you use raw and turn off in camera lens correction is that you avoid the 1 second delay after taking a picture when it process the corrections. (Most important to me since I like to zoom in on the image preview somewhat often, and if you turn the back e-dial before the lens corrections are finished you end up changing your aperture setting without realizing it.)

[Azergoth]

They are stored in exif tags in the raw file. (See link here, half way down the page under "Pentax LensCorr Tags")
You can look at tags by uploading a photo here and searching for 'correction'

If you use the Pentax supplied SilkyPix it might use the correction information you have set, but I know that when I open the raw DNG in DXO it doesn't use the in camera corrections and I apply the DXO correction files it loads for camera / lens combinations. (Probably similar for Lightroom)

Thanks for your reply :-)
I'm using Lightroom exclusively, so I could turn it off without losing anything? If only LR had more profiles!!

In camera lens corrections only works with specific later Pentax lenses (most DA / DA* lenses I believe). Lens corrections will not work with old manual lenses or third party lenses (Tamron, Sigma, etc) One advantage of DXO is that they have a good set of correction files for many common lenses that Pentax cameras doesn't have lens correction for. (Tamron, Sigma, Samyang).

I've noticed that. Only my 35 f2.4 works. Not even my FA50 :/

Another advantage if you use raw and turn off in camera lens correction is that you avoid the 1 second delay after taking a picture when it process the corrections. (Most important to me since I like to zoom in on the image preview somewhat often, and if you turn the back e-dial before the lens corrections are finished you end up changing your aperture setting without realizing it.)

OMG! I've had that sooooo many times! It's really annoying!

[TheOneAndOnlyJH]

If you work entirely in raw it sounds like you don't need them enabled. (Unless you shoot RAW + JPEG and want to use it for the JPEG's.) I hate that pause, but I sometimes use the JPG's before I can process the raw files, so I leave in camera corrections on anyway.

Try a quick comparison. Set the camera to RAW + JPEG and Manual mode and take a shot on a tripod using your 35m f/2.4 with and without in camera correction enabled. Comparing the JPG files the distortion difference should be obvious. Run the raw files for the same photos through Lightroom and compare to see if the distortion is different. If they both look the same then Lightroom isn't using the correction info and you can disable in camera corrections without noticing any change except for ditching that annoying pause.

[Adam]

I'm using Lightroom exclusively, so I could turn it off without losing anything? If only LR had more profiles!!

Right. Lens corrections don't really do anything in RAW mode apart from telling the Pentax desktop software that they should be applied.

Lightroom uses its own suite of lens profiles, which you can choose to apply on a per-photo basis when developing.

[Azergoth]

Right. Lens corrections don't really do anything in RAW mode apart from telling the Pentax desktop software that they should be applied.

Lightroom uses its own suite of lens profiles, which you can choose to apply on a per-photo basis when developing.

If you work entirely in raw it sounds like you don't need them enabled. (Unless you shoot RAW + JPEG and want to use it for the JPEG's.) I hate that pause, but I sometimes use the JPG's before I can process the raw files, so I leave in camera corrections on anyway.

Yes, I always shoot RAW, never Jpeg...

Try a quick comparison. Set the camera to RAW + JPEG and Manual mode and take a shot on a tripod using your 35m f/2.4 with and without in camera correction enabled. Comparing the JPG files the distortion difference should be obvious. Run the raw files for the same photos through Lightroom and compare to see if the distortion is different. If they both look the same then Lightroom isn't using the correction info and you can disable in camera corrections without noticing any change except for ditching that annoying pause.

Ow! Great idea! I tried two different photos, but the RAW + JPEG mode is the way to go! 👍🏻