is capture one 7 the only program that can correct lens color cast?

Kolor-Pikker wrote in post #16775607
Probably sarcasm, but...

It's not so much a problem with the lens as the way light interacts with digital sensors, with film light could hit the surface at a 45° angle and still register detail with no color shifts, but now with sensor pixels and their narrow light-sensitive wells, an acute angle of incidence will cause purple/magenta/green/b​lue all over the place and it looks even worse than vignetting.

You'll never notice this with DSLRs because every lens has to "throw" the image circle past the mirror box, but in cameras where the lens can potentially press right up against the sensor surface you either need LCC correction or the lens needs to be a retro-focus design, substantially increasing it's weight, size, price, complexity and potentially reducing sharpness. Though, with especially large sensors and extreme lens shifts/tilts, a retro-focus lens needs to be used anyway.

Part sarcasm but part reality too. I have more than enough trouble with my photography that I don't need to be courting more.

But then, I honestly don't know the value and use of a lens as described or the gear it would be used on. I guess if it's unique enough in performance the color cast could be overlooked. And since there is a way to correct it the options can certainly be weighed.

Dave it seems that this problem is found mostly on medium and large format technical cameras which are essentially a board with a lens mounted and a similar board with the sensor mounted and a lightproof bellows in between. These can be moved about to give you large amounts of tilt and shift (within the image circle thrown by the lens), very much more than you can get by using a tilt shift lens on a DSLR.

As the software is the default provided with the digital backs often used on these types of camera it is not surprising that they have developed this fix for the problem.

Although I would love to have a go with a technical camera and MF digital back the costs are pretty high, Even using large format film is not a cheap option, 4×5 sheet film is not exactly cheap as I found out when looking at doing some pin hole work Ilford FP4 was about £5 a sheet IIRC.

Alan

hi
seems the colorcheck password & dng creator don't remove the color cast(lens shade)

but i found out a lightroom plugin DNG Flat Field Plug-in

http://labs.adobe.com …ads/lightroompl​ugins.html

the documentation is very limited

they told about plastic diffuser card , i haven't it
i'm wonder if i can use a white printer paper

thanks to all

hollis_f wrote in post #16774603
Could you not use a ColorChecker to create a LightRoom profile just for that lens?

Hi
i did it
but it doesn't the color cast (lens shade) sadly

kirkt wrote in post #16773612
translucent neutral material so that you get a map of the color and exposure issues caused exclusively by your lens.
Kirk

Hi Kirk
must be a translucent neutral material?
i mean i can't find in a store
i have a similar tool but for my film medium format but it's matt,opaque
about white paper is it out of the question?
thanks

Most printing paper are not really opaque. I guess you might try tracing paper, but might need a couple or three layers depending on just how opaque it is. Other options would be the lid off a tube of pringles (other potato snacks in tubes may also work) or maybe a coffee filter paper. What you need is something that is not going to give a colour cast of it's own and will allow a very even illumination of the whole of the lens front element. This will allow the software to map the errors induced by the lens. If you try any of these ideas out, then turn the item through ninety/one hundred and eighty degrees and repeat the process, if the error map changes between positions then your chosen method is not working and introducing errors of it's own.

Alan