Steve;

About the HDR shots from last week.  One last question. If the F2.8 lens would always produce such severe CA inside the temple, how could I have prevented it?

Koen

 

Interior, Sanctuary of Truth during a recent workshop

Oh my!  Sever CA (purple fringing) from using a wide aperture lens wide open with a bright background  

 

Hi Koen

About CA..  CA manifests under certain conditions.  On areas where there is a darker vertical/horizontal line.. with a very bright background.  The transition pushes the lenses ability to resolve producing CA.  Almost any lens at larger apertures will make CA.. with very few very expensive exceptions.  If you had metered for the outside sky.. the inside of the temple would have been very dark, but the CA would not have been there.. or it would be very well controlled.. enough so that the CA controls in LR could easily take care of it.  That would give you one image without CA.. and HDR or blending.. would have allowed you to create a finished/processed image without CA.

So.. Any lens at wider apertures will manifest CA under those conditions and that exposure.  The key is to modify the exposure.. eliminating or reducing the CA.. and that will give you a CA free base image in the CA prone areas..

Hard to explain..

On a tripod.. you could also have shot at F8-11.. and tackle CA that way.  Your exposure times would have been greatly reduced, everything sharper, better image quality..

Steve

 

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