Sigma or Panasonic macro lens for scanning film

[pkr1979]

Hi all,

I am considering scanning with a Panasonic S1R instead of a film scanner. And there seems to be two solid lens options. The Sigma 105mm f/2.8 DG DN Macro Art and the Panasonic Lumix S 100mm f/2.8 Macro. Things like weather sealing, auto focus speed and size/weight are not important at all. But the image I get from the lens without the use of lens correction profiles is (software I use are not able to apply lens profiles). With that in mind - does anyone have any experience or opinions on which of these two lenses are best suited for 'scanning' film? I might also want to stitch larger negatives.

Cheers
Peter

 

[koraks]

(software I use are not able to apply lens profiles)

Doesn't RawTherapee do this? It's open source/free.

 

[pkr1979]

Doesn't RawTherapee do this? It's open source/free.

Possibly. But I am not using that. I could switch, but prefer not to (not the best for inverting negatives) so my question remains

 

[koraks]

OK, but with all due respect, I think it only makes sense to include software into the consideration here. Some things in the digital domain you can solve either through software and hardware and the best option often is only available if you are willing to optimize across both domains.
Also, I wonder whether it's necessary at all to use the same software tool for negative inversion and digital capture processing. I use RawTherapee for the latter and GIMP for the former. There are strengths and weaknesses to any option; I'd consider playing on their strengths.

 

[250swb]

If we assume the native lenses for the Panasonic S1R have the necessary corrections in their firmware wouldn't a Sigma with the Panasonic mount also? Meaning the lens corrections are already done in-camera. It is a problem of the digital age that we have lenses that need firmware but my guess is 99% of people wouldn't expect to look for lens correction in third party software to make it work? For example I use a Nikon 105mm S lens with my Nikon Z7 and the lens corrections are embed in the RAW file that I open in Adobe Camera Raw, Camera Raw does not apply an additional or replacement profile so why would RawTherapee need a separate loadable profile?

 

[pkr1979]

OK, but with all due respect, I think it only makes sense to include software into the consideration here. Some things in the digital domain you can solve either through software and hardware and the best option often is only available if you are willing to optimize across both domains.
Also, I wonder whether it's necessary at all to use the same software tool for negative inversion and digital capture processing. I use RawTherapee for the latter and GIMP for the former. There are strengths and weaknesses to any option; I'd consider playing on their strengths.

I agree. Unless I can get away with. But this means that I would first have to invert the negative (FilmLabApp), then apply the lens profiles in RawTerapee, and then use PhotoLine for the remaining. And Im not sure how well this would work if stitching is done too.

If we assume the native lenses for the Panasonic S1R have the necessary corrections in their firmware wouldn't a Sigma with the Panasonic mount also? Meaning the lens corrections are already done in-camera. It is a problem of the digital age that we have lenses that need firmware but my guess is 99% of people wouldn't expect to look for lens correction in third party software to make it work? For example I use a Nikon 105mm S lens with my Nikon Z7 and the lens corrections are embed in the RAW file that I open in Adobe Camera Raw, Camera Raw does not apply an additional or replacement profile so why would RawTherapee need a separate loadable profile?

The corrections done in the camera isnt delivered as a corrected RAW-file. Its part of the EXIF so the software needs to understand it.

The 'best' lens does make everything afterwards easier for me.

 

[koraks]

But this means that I would first have to invert the negative (FilmLabApp), then apply the lens profiles in RawTerapee, and then use PhotoLine for the remaining.

The order should be different:
1: first apply the lens profile to fix any possible problems with distortion etc.
2: stitch the image together
3: invert and color balance

Everyone has their own preferences; my route of choice would be to do #1 in RawTherapee, output to TIFF and then do #2 + #3 in GIMP. I personally do not use dedicated negative inversion/color balancing software, but this could of course be handled in a separate tool if so desired.

 

[pkr1979]

The order should be different:
1: first apply the lens profile to fix any possible problems with distortion etc.
2: stitch the image together
3: invert and color balance

Everyone has their own preferences; my route of choice would be to do #1 in RawTherapee, output to TIFF and then do #2 + #3 in GIMP. I personally do not use dedicated negative inversion/color balancing software, but this could of course be handled in a separate tool if so desired.

Shouldnt lens profiling be done after the negative has been inverted. If not - wouldnt fall off be wrong?

 

[koraks]

You need to correct any issues with the lens you used for photographing the film negative before you do anything to the negative as such.

 

[brbo]

You need to correct any issues with the lens you used for photographing the film negative before you do anything to the negative as such.

Have you verified that?

I wonder how much better does laCA correction work on a shot of an uninverted vs inverted negative. I'm pretty sure that loCA correction will be spectacularly inefficient in uninverted shots (luckily it's not needed in a properly focused negative capture). Geometry is trivial to get correct whether you do it before or after. Light falloff correction will indeed be easier to correct before inversion if you work in a destructive mode (which you really shouldn't be, but I can see how many would still not know of the obvious benefits of non-destructive image manipulation).

It's a moot point anyway, since most of the lens correction will only work on RAW files.

 

[koraks]

Have you verified that?

To be clear, I'm talking about the following:
1: Original photo is capture onto film with 'analog lens'
2: Processed negative is captured digitally, perhaps in segments, with 'digital lens'
3: Lens corrections are performed on digital capture(s) to correct imperfections of 'digital lens'
4: Analog image is stitched, inverted & color balanced
5: optionally, at this stage corrections could be done to correct for imperfections of 'analog lens'

What I referred to was step 3, so the corrections of 'digital lens'. And yes, I feel these by definition need to precede any work that happens on the negative. Especially problems with barrel/pincushion/mustache distortion as well as vignetting correction will avoid problems in particular on a segmented digitization that needs to be stitched back together. If the 'digital lens' suffers from issues like laCA that manifest in a negative digitization (I expect this to be minimal for a variety of reasons), it would also work best to correct those at this stage and before any digital files are processed further and perhaps stitched together.

For me this is kind of evident on a 'Russian doll' principle or something analogous to the V-model. Not a literal relation, but a conceptual one, mind you, if that make sense (if it doesn't, forget about these analogies).

I was not talking about step 5, which could also be done for the 'analog lens', but I assumed the thread to focus and be limited in scope to the digitization part and how to best manage that.

It's a moot point anyway, since most of the lens correction will only work on RAW files.

yes, you'd do these corrections on RAW files, that's what I meant. I hope the above clarifies it.

Apologies to @pkr1979 for any digression of the actual question you asked!

 

[pkr1979]

To be clear, I'm talking about the following:
1: Original photo is capture onto film with 'analog lens'
2: Processed negative is captured digitally, perhaps in segments, with 'digital lens'
3: Lens corrections are performed on digital capture(s) to correct imperfections of 'digital lens'
4: Analog image is stitched, inverted & color balanced
5: optionally, at this stage corrections could be done to correct for imperfections of 'analog lens'

What I referred to was step 3, so the corrections of 'digital lens'. And yes, I feel these by definition need to precede any work that happens on the negative. Especially problems with barrel/pincushion/mustache distortion as well as vignetting correction will avoid problems in particular on a segmented digitization that needs to be stitched back together. If the 'digital lens' suffers from issues like laCA that manifest in a negative digitization (I expect this to be minimal for a variety of reasons), it would also work best to correct those at this stage and before any digital files are processed further and perhaps stitched together.

For me this is kind of evident on a 'Russian doll' principle or something analogous to the V-model. Not a literal relation, but a conceptual one, mind you, if that make sense (if it doesn't, forget about these analogies).

I was not talking about step 5, which could also be done for the 'analog lens', but I assumed the thread to focus and be limited in scope to the digitization part and how to best manage that.


yes, you'd do these corrections on RAW files, that's what I meant. I hope the above clarifies it.

Apologies to @pkr1979 for any digression of the actual question you asked!

No problem

 

[brbo]

To be clear, I'm talking about the following:

And to be clear I was talking about the stated "fact" that you need to get rid of any digital lens aberrations as the first step. Your point about stitching is valid of course, but stitching is not always involved in "camera scanning".

What I was curious about was whether you had any first hand experience on how well the more advanced lens corrections (those dealing with colour aberrations) work directly on the uninverted raw files. I can easily imagine that laCA correction will rely (at least to some degree) on the image analysis which could be thrown off by the "shifted" RGB channels of the negative and "compressed" nature of the individual channels of the negative.