Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: yalag on September 04, 2014, 08:20:37 pm

Title: Does camera calibration negate lens color quality?
Post by: yalag on September 04, 2014, 08:20:37 pm
One of the quality of lenses are the way it renders color. Some say, a lens of a certain brand has a special color quality to it etc.

But if you do camera calibration, will it matter at that point? Since the definition of calibration is to standardized all the data.
Title: Re: Does camera calibration negate lens color quality?
Post by: Jim Kasson on September 04, 2014, 08:27:37 pm
One of the quality of lenses are the way it renders color. Some say, a lens of a certain brand has a special color quality to it etc.

But if you do camera calibration, will it matter at that point?

Depends on how good the calibration is, and how close to Luther-Ives the camera/lens combination is.  In a negative feedback system with a large loop gain, lens coloration is seen as a defect, and the system attempts to calibrate it out.

Jim
Title: Re: Does camera calibration negate lens color quality?
Post by: Slobodan Blagojevic on September 04, 2014, 09:03:28 pm
My assumptions is that it does negate lens color. Just like using a WB card during sunset will negate the warm glow.
Title: Re: Does camera calibration negate lens color quality?
Post by: supercurio on September 04, 2014, 09:13:17 pm
I'd say yes potentially.

I recently implemented flat-field correction on a smartphone and it corrected with very convincing results both light fall off of various kind and color casts (aka awful pink spot as seen before on some products)

In this case, the light fall off was not looking like the typical vignette correction, and color cast was intense due to the physical constrains: the camera module being as small as possible, light ends up hitting the sensor with steep angles.

The task was made easier thanks to the fact it was on fixed a focal length and aperture lens, otherwise I suppose additional profiles + interpolation would have been necessary.
Title: Re: Does camera calibration negate lens color quality?
Post by: Chris_Brown on September 04, 2014, 10:19:03 pm
From my experience when using large format Schneider, Rodenstock & Fujinon lenses, the answer is yes. Each brand of lens has a unique transmission of color. I did not experience any color shifts within each brand.

My inclination would be to calibrate each DSLR or MF camera according to ISO and lens brand.
Title: Re: Does camera calibration negate lens color quality?
Post by: JRSmit on September 05, 2014, 01:58:35 am
One of the quality of lenses are the way it renders color. Some say, a lens of a certain brand has a special color quality to it etc.

But if you do camera calibration, will it matter at that point? Since the definition of calibration is to standardized all the data.
Camera calibration is a description of how a camera electronics sees color: the camera profile. Usually with a lens in front. So the lens is part of the system calibrated.
Title: Re: Does camera calibration negate lens color quality?
Post by: supercurio on September 05, 2014, 03:14:12 pm
Is there an absolute description of lens color quality?

I'm sure some lens still perform better than others in some conditions thanks to less internal reflections and various kind of flare.
Such thing can't really be calibrated once and for all because it depends on the light source nature and placement, and I'm sure it can affect the perceived color quality.

Another thing about calibration: correction also increase noise, which can reduce color quality noticeably in low light conditions.
Title: Re: Does camera calibration negate lens color quality?
Post by: rubencarmona on September 12, 2014, 11:00:28 am
You can't "calibrate" your camera or camera-lens combinations.

What I do is creating a camera raw preset with the SpyderCheckr. It's a reference with color patches.

Loading photos of it into the SpyderCheckr software will automatically generate Lightroom or ACR presets that will automatically correct the color hues of a picture to get the result you had in front of your camera...
Title: Re: Does camera calibration negate lens color quality?
Post by: stamper on September 13, 2014, 03:50:42 am
Can someone explain to me why photographers go to the bother of

Loading photos of it into the SpyderCheckr software will automatically generate Lightroom or ACR presets that will automatically correct the color hues of a picture to get the result you had in front of your camera...

and then proceed to alter the colours with processing in LR or PS? :'(
Title: Re: Does camera calibration negate lens color quality?
Post by: ErikKaffehr on September 13, 2014, 04:05:06 am
Hi,

I would say that using a WB card negates lens colour. But, if lens colour is significant enough to disturb colour rendition, camera calibration would try to get around it.

Using Color Checker Passport or Adobe DNG Editor employs a baae profile that will be tweaked. To build a real camera profile 'from scratch' takes a lot more than two shots of a ColorChecker card.

Best regards
Erik


My assumptions is that it does negate lens color. Just like using a WB card during sunset will negate the warm glow.