Just bought a Canon G1X
Convet the Canon CR Raw files to Adobe DNG. (Cany Use Canon CR Raw files on my Adobe Camera Raw CS3
All the DNG images taken at the wide angle end of the zoom lens have very pronounced vignetting - appearing like there is a very long lens hood on.
The same images appear fine on the camere screen and in the Canon software.
This seems to just happen during the DNG conversion process.
At the moment I cannot process Raw images in my CS3 and have to use the less than substantial software that Canon gives with the camera
Any help would be greatly and gratefully appreciated!
From what I know about DNG conversion, something else must be going on. I don't think there is anything in the conversion process that should cause that. Have you set the appropriate compatibility options in the DNG converter?
I would speculate that the camera, and the Canon software, have been performing some kind of auto vignetting correction which has up to now concealed from you the true optical behaviour of the lens.
The lens may even have been subject to some engineering compromises, perhaps allowing some vignetting (which is easily corrected for with image processing), as a trade-off against some other constraint.
ACR, including the older version you are using with CS3, includes lens vignetting correction controls. This is done subjectively by eye, to your preference.
Later versions of ACR (the version for Photoshop, not IIRC the one for Elements) and also of Lightroom, add the option to use a lens correction profile which accurately reverses both vignetting and lens distortion in an objective, programmed way.
In due course when you decide to move to newer software, this "profile" feature will make the whole issue of lens aberrations, remarkably, just go away. By then a readymade profile supporting your particular camera/lens will likely be available too - which it is not, yet, so far as I know.
Thank you both for your suggestions - it was greatly appreciated.
I have played around with the compatibility and preferences to no avail!
I have tried to attach one of the images here but it will not let me. I can email it to anyone interested! If anyone can work out what is going on, I would be appreciated!
Probably what's happening is that the DNG file is trying to use the DNG 1.3 extensions to devignette, which CS3 will not recognise.
I'd suggest trying "Custom DNG Compatibility", Backward Version 1.1 and Linear (demosaiced) for compatibility settings.
OUCH!!!!! - I have now repeated the process, and now the images only appear as icons in the Bridge content panel! When I tried it just now they could be viewed like any of my other raw files. Any ideas why it was OK the first time but not the second time???
I think I have solved it, or should I say, it solved itself! The files are 50MB each and obviously take time to embed in Bridge. After waiting a bit the icons changed to images.
A BIG THANK YOU TO EVERYONE WHO HAS HELPED ME HERE. YOUR HELP HAS BEEN GREATLY AND GRATEFULLY APPRECIATED!
ANOTHER SPANNER IN THE WORKS?????
Having converted files in the new way suggested above (Backward Version 1.1 and Linear (demosaiced) for compatibility settings) I am no longer getting vignetting ..... fair enough.However, when comparing these conversions with my previous conversion method where vingnetting occured, the only difference that has occured in the conversion process is that the images have been cropped to remove the vignetting. This has meant I loose the wide agle component of my lens. Also in the new conversion process, the file size has gone from 16MB to a huge 50MB!Any ideasThanks
Yes - basically, unless you force DNG converter to render the image, you're getting vignetting. That's not ideal however because of the cropping and file size.
All the other solutions are even less ideal, I'm afraid:
1. You can manually correct for vignetting with CornerFix. However, that's a very manual process, and given the lens that the G1X uses, you'd need to create profiles at multiple points in the zoom range. Possible, but not very practical
2. The only other solution is to upgrade to the latest version of either CS or Lightroom.
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