Digital lens-correction

[scott morrish]

Does anyone manage to get equivalent levels of 'digital' lens-correction from Lightroom as they would from either C1 or Phocus?

This is any area of digital photography that i have not paid much attention to until recently, but i am also curious to know how specific the 'corrections' are. In the absence of movements, can one simply determine correction settings per lens? ... or is it more complex?

I know Hasselblad make a big thing of their DAC... and by all account it is very good.
Phase also make a big thing about the fact that C1 allows corrections for Hassy lenses, as well as their own lenses.
Should Lightroom be able to equal either?

Regards,
scott

[Nick_T]

Does anyone manage to get equivalent levels of 'digital' lens-correction from Lightroom as they would from either C1 or Phocus?

This is any area of digital photography that i have not paid much attention to until recently, but i am also curious to know how specific the 'corrections' are. In the absence of movements, can one simply determine correction settings per lens? ... or is it more complex?

I know Hasselblad make a big thing of their DAC... and by all account it is very good.
Phase also make a big thing about the fact that C1 allows corrections for Hassy lenses, as well as their own lenses.
Should Lightroom be able to equal either?

Regards,
scott

In my opinion Hasselblad don't make nearly enough of a big thing about their corrections. (I think they made a mistake calling them corrections in many ways as it leads people to believe they are fixing an inherently bad lens which isn't the case, but I digress).

To answer your question (in part) There is no one correction per lens. There is a correction for a given focal length (think zoom here), at a given aperture, and crucially at a given subject to sensor distance. Hasselblad (via Phocus) is the only medium format option that has and uses all this data and the results are outstanding.
Other companies allow you to manually select a correction and tell the software wether you were close or far focussed so the software can apply a fairly generic correction.
(As an aside I used to have a V series 50mm lens that had a floating front element that the user manually adjusted depending on focus distance).

Oh and you mentioned "in the absence of movements" well with an H3D and an HTS the corrections with movements as the degree of tilt/shift/rotate is embedded in the raw file. Pretty clever stuff IMO.
Nick-T

[Schewe]

Does anyone manage to get equivalent levels of 'digital' lens-correction from Lightroom as they would from either C1 or Phocus?

At this point in time it's impossible to get it in Lightroom. The only lens correction you can get in LR is lateral chromatic aberration correction and vignetting. C1 (and I would expect Phocus) is also prolly doing spherical aberration as well as distortion correction. But I wouldn't be surprised to see that stuff come to LR/ACR as well in the future. Some stuff is _SO_ much easier to fix after the fact in software than it is in designing and building lenses that it makes more sense to fix it after the shot instead of in the lens.

[Guy Mancuso]

To date the lens corrections in C1 are

Distortion
Sharpness Falloff
Purple Fringing
Lens vignetting
Chromatic Aberrations

Now most of these are with all of the Mamiya lenses and than also has the H Hassy lenses the V Hassy lenses and also supports the Contax lenses. Give or take some of those features depending on the lens itself.

Also you can do LCC profiling. Very nice addition to the program

[Thomas Krüger]

It would be nice to use PTLens from Tom Niemann as a real Lightroom plugin and not as an external editor for Lightroom.
http://epaperpress.com/ptlens/

[yaya]

It would be nice to use PTLens from Tom Niemann as a real Lightroom plugin and not as an external editor for Lightroom.
http://epaperpress.com/ptlens/

I've seen very good results from Acolens. It seems that their targets/ charts and their algorithm are the most advanced out there.

[Dick Roadnight]

Does anyone manage to get equivalent levels of 'digital' lens-correction from Lightroom as they would from either C1 or Phocus?

Regards,
scott

Phocus makes zooms adequate for critical work by the 50Mpx or 24*34" @240 ppi yardstick (on a tripod with mirror locked up).

With a full range of movements with my Apo-digitars and P3 I hope that I will get even better results as apo-chromatic lenses are supposed to be free of chromatic distortion, or fringing or whatever... but can apo-digitars benefit from digital correction?

Has anyone tested apo-digitars against the Hassy lenses?

[Graham Mitchell]

I know Hasselblad make a big thing of their DAC... and by all account it is very good.

I think the simple answer is that the Hasselblad solution is the best 'out of the box' solution, but if you want to use other custom solutions you can perform the same corrections or more on any lenses, perhaps even better. Might be a lot slower though. I don't know how well third party corrections can be integrated into Photoshop or Lightroom - would be the obvious place to do it.

[Doug Peterson]

To answer your question (in part) There is no one correction per lens. There is a correction for a given focal length (think zoom here), at a given aperture, and crucially at a given subject to sensor distance. Hasselblad (via Phocus) is the only medium format option that has and uses all this data and the results are outstanding.
Other companies allow you to manually select a correction and tell the software wether you were close or far focussed so the software can apply a fairly generic correction.
(As an aside I used to have a V series 50mm lens that had a floating front element that the user manually adjusted depending on focus distance).

I think the simple answer is that the Hasselblad solution is the best 'out of the box' solution, but if you want to use other custom solutions you can perform the same corrections or more on any lenses, perhaps even better. Might be a lot slower though. I don't know how well third party corrections can be integrated into Photoshop or Lightroom - would be the obvious place to do it.

Please post a real world example where the Hasselblad DAC system creates a better final image than Capture One Lens Corrections for a Hasselblad H series lens.

I agree that in theory the focus distance is an element in the aberrations in a lens, but you'll have to show me a real world example before I believe that difference makes a meaningful difference.

The Capture One lens corrections for Hasselblad H series lenses are really excellent so I don't see where the improvement would be.

Doug Peterson (e-mail Me)
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[David Grover / Capture One]

Please post a real world example where the Hasselblad DAC system creates a better final image than Capture One Lens Corrections for a Hasselblad H series lens.

I agree that in theory the focus distance is an element in the aberrations in a lens, but you'll have to show me a real world example before I believe that difference makes a meaningful difference.

The Capture One lens corrections for Hasselblad H series lenses are really excellent so I don't see where the improvement would be.

Doug Peterson (e-mail Me)
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Head of Technical Services, Capture Integration
Phase One, Canon, Apple, Profoto, Eizo & More
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Well, lets take the implementation of lens corrections in Phocus.  Here is the tool...

[attachment=14449:Picture_18.png]

Doesn't get much simpler than that and you are guaranteed to be absolutely perfect.  No distortion, no vignetting and no CA.  Bear in mind that not all distortion is text book 'pin cushion' and is much harder to correct generically.

In our experience we have seen much better corrections in terms of overall accuracy.  When time is money ticking a box is far easier than tuning a dialogue for every capture.  Yes, I am aware you can save presets but how comfortable are you in using those presets over a broad range of images?  Plus you would then have to refer to meta data on each image to be sure what the conditions were.

Best,


David

Quick Edit - I should add there are approximately 60,000 tables of corrections in Phocus relating to Lens, Aperture, Distance and HTS movements (the last element was close to 10,000 alone).  This is a lot of presets to make yourself!

[David Grover / Capture One]

I think the simple answer is that the Hasselblad solution is the best 'out of the box' solution, but if you want to use other custom solutions you can perform the same corrections or more on any lenses, perhaps even better. Might be a lot slower though. I don't know how well third party corrections can be integrated into Photoshop or Lightroom - would be the obvious place to do it.

Better, no, slower, yes.

[Graham Mitchell]

Better, no, slower, yes.

I think it stands to reason that with the best software out there and using your own specific lens to build correciton profiles, the results should be better? Is that difference even noticeable? Perhaps not

[yaya]

Is there a reason for having these corrections as an option? For vignetting yes the user might want to control it but for CA and (moustache) distortion, why would anyone want to leave those in the images? Why not correct the images on the fly and drop those checkboxes?

[Graham Mitchell]

Is there a reason for having these corrections as an option? For vignetting yes the user might want to control it but for CA and (moustache) distortion, why would anyone want to leave those in the images? Why not correct the images on the fly and drop those checkboxes?

Any pushing around of pixels degrades resolution. If you are not shooting anything with straight lines (e.g. tree bark or rocks or faces) then you might prefer not to apply the correction.

[Dustbak]

Is there a reason for having these corrections as an option? For vignetting yes the user might want to control it but for CA and (moustache) distortion, why would anyone want to leave those in the images? Why not correct the images on the fly and drop those checkboxes?

Because you do not want to use those corrections with eg. the HC35 and people in it. it can distort people in a really ugly way. In that case I am very glad I can turn it off  (I was very happy to be able to turn it off in these cases). CA, I cannot think of a reason to turn that off.

[Steve Hendrix]

Because you do not want to use those corrections with eg. the HC35 and people in it. it can distort people in a really ugly way. In that case I am very glad I can turn it off  (I was very happy to be able to turn it off in these cases). CA, I cannot think of a reason to turn that off.

I would say that the Hasselblad DAC works and works well. It does what it is supposed to do. Distortion is corrected, Chromatic Aberrations are removed (in the vast majority of cases) and vignetting control is there to lighten the corners.

Since the beginning of the thread was about all the options, I will say that some of the pluses of the Phase One approach are a little different. First, there are many more options for control, including:

*purple fringing
*sharpness falloff
*light falloff
*distortion control
*vignetting control
*chromatic aberration
*and of course color cast, (LCC)

Also, while Hasselblad's DAC corrects the distortion or does not, Capture One's corrections allow you to manually adjust the amount of correction. And while most images just need to be corrected, for some things it's nice to be able to allow for distortion if it suits the end result, people for example. You can still correct that lens exactly the way you want and save that as a setup to be used as the default for that lens.

In addition, the vignetting tool in Capture One allows for darkening the corners as well, something that not all lens correction tools allow. And not only do these corrections work on the Phase One lenses, most of them are available for ANY lens - Hasselblad HC, Hasselblad V, Contax, Canon, Nikon, Schneider Digitars, etc.


Steve Hendrix
Phase One

[yaya]

Because you do not want to use those corrections with eg. the HC35 and people in it. it can distort people in a really ugly way. In that case I am very glad I can turn it off  (I was very happy to be able to turn it off in these cases). CA, I cannot think of a reason to turn that off.

So for some applications it would be better, I suppose, to use a straight lens?

[Doug Peterson]

[retracted]

[John.Williams]

I agree with Nick-T, Hasselblad does not do a good job letting photographers know about the digital corrections available for the system. It is the natural outcome of designing the lens and knowing the optical and mechanical properties intimately that provides the ability to do these types of adjustments that are not just a "best guess" or "average."

Of course, this is not just a Hasselblad thing, Canon and Nikon do it too. I imagine PhaseOne and Mamiya are shooting test targets now to build a similar tool with tens-of-thousands of data points so that the photographer can confidently shoot and correct without playing with sliders and hoping to get the correct image.

Vignetting tool on/off is not just about a single photo and the traditional look of light falloff; this is a very efficient and effective way to compose panoramic images as well.

Right now, I believe Hasselblad has a better tool for these operations but I know this will only inspire others to deliver their best as well.

John
---
hotwire-digital.com
Atlanta GA USA

"don't believe what you read - get a demo!"

[Doug Peterson]

Of course, this is not just a Hasselblad thing, Canon and Nikon do it too. I imagine PhaseOne and Mamiya are shooting test targets now to build a similar tool with tens-of-thousands of data points so that the photographer can confidently shoot and correct without playing with sliders and hoping to get the correct image.

We have the tool you're talking about. We just ALSO allow end-user control for those who want it.

Please note that Phase One allows you to "play with the sliders"
 1) so that you can apply corrections to lenses like Rodenstock/Schneider large-format glass, classic glass (e.g. Mamiya manual focus glass), and Canon/Nikon/Leica glass for which there are not specific test-target-based adjustments
 2) so that YOU have control over the type of corrections being applied when adjusting images from "known" lenses. Phase One HAS shot hundreds of test targets to compile their lens correction database and knows with scientific accuracy the *mathematically correct* adjustments. However, as numerous people on this thread have pointed out, there are many cases where you do not want the mathematically correct amount of distortion, light fall-off, or sharpness adjustments.

Doug Peterson (e-mail Me)
__________________
Head of Technical Services, Capture Integration
Phase One, Canon, Apple, Profoto, Eizo & More
National: 877.217.9870  |  Cell: 740.707.2183
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