Archived posting to the Leica Users Group, 2012/12/10

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Subject: [Leica] DNG compression???
From: kanner at acm.org (Herbert Kanner)
Date: Mon, 10 Dec 2012 00:11:20 -0800
References: <540D27C0-778A-4F70-BAD7-C8A0EB0F9F5A@acm.org> <CAE3QcF6OzuDrm6JRNHz62j7a6_Rw9W5667s2y9P+A4=JKVcHhQ@mail.gmail.com> <E0208BBC-5357-41B8-A808-2FC5BBE0C083@frozenlight.eu>

Nathan, 

Judging by an article I read in LFI, the M8 compressed DNGs unconditionally. 
In the M9 you have the choice between compressed and uncompressed. The 
article actually gave the formulae for compressing and uncompressing. If you 
are interested in knowing what the arithmetic is, I can look it up and email 
you off-line if you send me an email address.

Herb



Herbert Kanner
kanner at acm.org
650-326-8204

Question authority and the authorities will question you.




On Dec 9, 2012, at 4:17 PM, Nathan Wajsman wrote:

> I had no idea I could set DNG compression levels in my M8. But then again, 
> I have only had it 4 years, so I'm still learning ;-)
> 
> Cheers,
> Nathan
> 
> On 9 Dec 2012, at 21:23, 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
>> 
> 
> Nathan Wajsman
> Alicante, Spain
> http://www.frozenlight.eu
> http://www.greatpix.eu
> 
> Books: http://www.blurb.com/bookstore/search?search=wajsman&x=0&y=0
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> Blog: 
> http://www.nathansmusings.eu/
> 
> 
> 
> 
> 
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information



In reply to: Message from kanner at acm.org (Herbert Kanner) ([Leica] DNG compression???)
Message from hopsternew at gmail.com (Geoff Hopkinson) ([Leica] DNG compression???)
Message from photo at frozenlight.eu (Nathan Wajsman) ([Leica] DNG compression???)