Re: [Leica] 32 bit digital cameras

[Henning Wulff <henningw@archiphoto.com>]

At 2:03 PM -0500 2/2/04, Jonathan Borden wrote:
>Henning Wulff wrote:
>
>>Most digital cameras have sensors that capture more than 8 
>>bits/channel, but most reduce this to 8 bits to be able to output 
>>the files as JPEGs. That's standard JPEG, as understood by most of 
>>the industry, not JPEG2000, which can handle high bit images, but 
>>is understood by few programs.
>>
>>Cameras that can output RAW, or NEF, or DCR output more than 8 
>>bits/channel. Generally 12 or 14 at this time. Software is then 
>>needed to convert that to a useable 16 bit/channel file that 
>>Photoshop can deal with, or reduce it to 8 bits than any program 
>>and the web can deal with.
>
>Photoshop can read 48 bit TIFF files -- indeed the TIFF format is 
>the only one I use with Photoshiop (7/CS) as it can save layers, 
>alpha channels etc. It is unfortunate that the cameras don't save in 
>TIFF format directly, but in any case one might consider converting 
>from a device dependent RAW TIFF colorspace into a device 
>independent colorspace (e.g. Adobe1998/ProPhoto etc.) for editing 
>purposes.
>
>Jonathan*
>
>*who exclusively uses digital Leica products, the Digital M3 -- 
>Tri-X etc. souped in whatever and scanned into Photoshop -- 5400 x 
>7000+ x 48 bit resolution for under a grand :-))

I believe you're talking about a couple of different and not 
necessarily related items.

Photoshop can read and write a large number of file formats, 
including TIFF at various bit depths, and the .psd format, which is 
its own and will retain the greatest amount of information, as far as 
Photoshop is concerned. If you intend to work further on a file, it's 
best to save it in the Photoshop format.

Photoshop can also now read certain RAW formats, as long as they 
aren't proprietary, encrypted, or made available since the last 
Photoshop plug-in revision.

Some cameras _can_ save in TIFF format directly, and they can be 
colour space tagged. The reason few companies do this and few people 
that have cameras that can do this use it is that TIFF files are 2 to 
3 times as large as the RAW formats, which are losslessly compressed 
and hold the same information. So TIFF for the most part is 
pointless, as the data throughput issues are already a limiting 
factor with almost all cameras and storage media.

Colour space is a whole different topic, which has other wise little 
to do with the above discussion. It has, however been addressed in 
most DSLR's now. JPEG's, RAW and TIFF can all be tagged with one of a 
number of colour spaces.

A nice thing about RAW is that the colour space can be (losslessly) 
determined at the time of conversion to a Photoshop readable file.

- -- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  /###\   mailto:henningw@archiphoto.com
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