Archived posting to the Leica Users Group, 2012/12/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks Geoff. I take it then that it's the RAW processor in Lightroom and not a camera firmware update that introduced the lossless compression. I think that change was between LR2 and LR3. Re the compression from 16 (actually only fourteen bits of data in a 16 bit container) to 8 bits being undetectable, I believe it, but I have plenty of disk space; at the rate I'm shooting, disk space will outlive me. However, I tried compressing in the camera in the hope that I would see a speed-up, i.e. an increase in the number of continuous exposures that could be made before the camera stopped dead because of a full buffer. I could not see a noticeable change in this number between compressed and uncompressed, so I just reverted to uncompressed for no particularly valid reason. Herbert Kanner kanner at acm.org 650-326-8204 Question authority and the authorities will question you. On Dec 9, 2012, at 1:23 PM, Geoff Hopkinson wrote: > Herbert you have several items in there. > Firstly if you use compressed DNG set in camera you give up almost nothing > to gain the savings in file sizes. Some argue that you cannot see any > difference at all. While it is technically lossy, this does not mean the > change is significant and there is no futher loss on resaving, unlike where > you save new versionsa as new JPGs.. > Secondly on import in an Adobe raw processor (ACR or LR) truly LOSSLESS > compression is applied. In recent program versions that is the default (and > now only) process because there is no downside at all. > If you open previously uncompressed on import DNGs and do some editing, for > example a WB change that LOSSLESS compression is applied. > Thirdly , whether you originally shot with your camera set for compressed > or uncompressed DNGs, those files are further losslessly compressed by the > Adobe program on import (or first editing and saving for earlier program > versions). > > Cheers, > Geoff > http://www.pbase.com/hoppyman > > > > On 10 December 2012 06:39, Herbert Kanner <kanner at acm.org> wrote: > >> Hi LUGers, >> >> I'm looking for some enlightenment from anyone who knows. The question has >> to do with the size of Leica DNG files. Back in August, 2010, I had a set >> of DNGs all but one of which were 36.4 MB in size. All of those taken the >> same afternoon at the same general location. Similarly, using Leica's >> compression, in December, 2011, I found a set of DNGs taken the same day, >> at 18.3 MB. >> >> Then, in November, 2011, there was a set taken the same day, where the >> file sizes varied from 19.6 to 23.1 MB. Was this a result of a firmware >> update in which Leica probably introduced LOSSLESS compression? To round >> up >> the picture, I found a set in August, 2012, where the size range was 8.5 >> to >> 10.3 MB, undoubtedly where I set "compressed DNG" on the camera. >> >> >> >> Herbert Kanner >> kanner at acm.org >> 650-326-8204 >> >> Question authority and the authorities will question you. >> >> >> >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information