Archived posting to the Leica Users Group, 2013/05/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Very clear, Bob, thank you! I've seen the translucent white covers but only thought of them for white balance and not for lens cast. I didn't know it applied to the Alpa. Is it also the case for say medium format cameras or is this a technical camera domain issue? Adam On May 19, 2013, at 1:37 PM, Robert Adler <rgacpa at gmail.com> wrote: > Hi Adam, > As I understand it, as you go out further towards the edges of an image > circle, the reds, greens and blues hit the pixel sights at ever increasing > (in nano seconds no doubt!) increments. Thus the colors begin to separate. > You start to to get more red and less green as you go further out. I > actually have to address this quite significantly on my Alpa because I move > the digital back from right, to middle to left across the image circle for > a pano It is known that "lens cast" is a problem for MFDB on tech cameras > where shifting is used quite often. CaptureOne has a Lens Cast Correction > feature just for this. > > At some point in shooting a venue, I put an opaque white piece of plastic > in front of the lens. I then take an exposure, usually two stops more open > than the exposure that I'm using for the image; and using the shutter speed > to open up, not the aperture). These LCC shots are then used in CaptureOne > to even out both the vignetting and the color cast. I also use the middle > of the shot that is taken through this opaque device as a white balance and > it works pretty well. > > Seems Fuji has somehow allowed a user to adjust in the camera for third > party lenses that aren't already corrected by them and that are using their > X mount to M mount adapter. > Clear as mud? :-) > Bob > > > On Sun, May 19, 2013 at 8:51 AM, Adam Bridge <abridge at mac.com> wrote: > >> On May 18, 2013, at 8:12 AM, Robert Adler <rgacpa at gmail.com> wrote: >> >>> If it a Fuji adapter supported lens, there are built in adjustments for >>> distortion (barrel/pincushion), color separation and light falloff. This >>> information is passed in the metadata with the RAW file and can be read >> by >>> ACR/CaptureOne/Aperture (all accept the color separation unfortunately, >> but >>> this can be corrected in various 3rd party software if needed). >> >> Bob, I don't understand "color separation" in this list of items. >> >> Is that like color temperature? >> >> Adam >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > > > -- > Bob Adler > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information