Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Mark_Seng on August 21, 2015, 03:12:19 pm

Title: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: Mark_Seng on August 21, 2015, 03:12:19 pm

Does anyone know why adobe raw converter is so bad in fixing chromatic aberration (when using shift lenses)?
I`m used to ps and lightroom and don`t want to change my workflow. Otherwise its just too annoying and time consuming to correct stuff like this manually.
I`m having this issues with various shift lenses, for example 24mm ts-e II, 17mm ts-e, zeiss pc 35mm ... It looks like capture one is handling cromatic aberrations a lot better:

ACR
(http://fs2.directupload.net/images/150821/drywzj4k.jpg) (http://www.directupload.net)
Capture One
(http://fs2.directupload.net/images/150821/nfyylrqm.jpg) (http://www.directupload.net)

Title: Re: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: Jack Hogan on August 21, 2015, 03:57:57 pm

Quote from: Mark_Seng on August 21, 2015, 03:12:19 pm

Does anyone know why adobe raw converter is so bad in fixing chromatic aberration (when using shift lenses)?

Starting from the basics: do you have 'Remove CA' ticked in the Lens Corrections/Profile tab?

Title: Re: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: Mark_Seng on August 22, 2015, 04:02:24 am

usually, yes.
But somtimes (when the lens was shifted a lot) it makes it even worse in some parts of the image.

Title: Re: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: Jack Hogan on August 22, 2015, 04:25:37 am

I thought so.  I don't use LR/ACR often so I am afraid I cannot help you.  I can only guess that your lenses are not in LR/ACR's database. I have noticed in the past that they do not do as good a job as, for instance, Nikon software at correcting lateral CA.

Jack

Title: Re: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: fdisilvestro on August 22, 2015, 04:30:35 am

Lens correction profiles don't work directly with shifted lenses because the corrections are applied radially from the center of the image. One possible solution is to increase the size of the canvas in Photoshop and move the image so that the optical center is in the center of the canvas (you can use a non-shifted reference image to determine this) and then apply the optical corrections. Here (http://epaperpress.com/ptlens/shift.html) is a demonstration with the plugin PTLens

Title: Re: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: jrp on August 22, 2015, 11:07:49 am

If you go into the colour tab, you can use the colour picker to select the colours that you want removed.

If you hit Alt/Opt while sliding you will see which parts of the photo are being affected.

Title: Re: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: Georgecp on August 29, 2015, 11:20:24 pm

Hi Mark,

Adobe has a flat-field plugin that allows  you to make a fully corrected profile for a shift lens when shifted.  It was explained in one of LL's LR video series.  I am sure that you can find reference to it on the adobe labs website.

Regards,
George

Title: Re: Cromatic Aberration - Shift Lenses - Raw Converter
Post by: tom b on August 30, 2015, 08:01:57 am

 Chromatic aberrations, damn pedants!

Cheers,