Archived from groups: rec.photo.digital.slr-systems (
More info?)
In article <cq51rg$544$1@inews.gazeta.pl>,
Alan Browne <alan.browne@freelunchVideotron.ca> wrote:
>John Francis wrote:
>
>> True. But that's going to be the case no matter who does the conversion.
>> But it's a fair bet that software running on a 3GHz Pentium 4 with 1GB of
>> RAM, and no real time constraints, can probably do a better job than any
>> in-camera conversion running on a processor whose main design goal is low
>> power consumption. Plus, of course, if you delay the conversion to a later
>
>Bah! Such simple conversion/interpolation can be done on the fly while storing
>to flash with a handful of machine instructions.
I really suggest you do a little research into this subject before
dismissing it in quite such a cavalier fashion. If all you want is
some of the most simplistic interpolation, then all it takes is a
few processor cycles. But that also ends up with some of the worst
algorithms. There has been quite a bit of research, and more than a
few thesis papers, done in this field. A good place to start would
be some of the work referenced in the description accompanying dcraw,
but that's only one part in a very complex field. The algorithm
that dcraw uses is more than a plain context-free interpolation, but
it is still a fairly simple algorithm, with limited requirements for
processor resources. There are algorithms with much heavier demands.
>> stage you always have the option of trying a different algorithm if you
>> don't like the effects on any given image.
>
>Camera firmware can be upgraded on most DSLR's.
Which just ends up locking you into a different fixed algorithm.
There's no "best" answer that is appropriate in every case
>> No. It does not. Neither automatically nor optionally.
>> Sharpening occurs during the conversion from RAW to TIFF/JPG/PSD/...
>
>It doesn't have to happen. There is no need to sharpen an image until the
>photog has seen and decides what the USM parameters should be.
>
>>>>You can also see when and where artifacts are introduced by trying
>>>>different conversion software. If you don't have access to a full
>>>>version of PhotoShop, PhotoShop Elements 3.0 includes Adobe Camera Raw
>>>>(which can read DNG as well as the RAW format of many cameras).
>>>
>>>I'll just use the OEM -> TIFF converter then continue in PS E 2.
>>
>>
>> OK. But that locks you into the Bayer interpolation algorithms chosen
>> by your OEM, complete with any artifacts introduced during that process.
>> Some sharpening will be done at this stage of the processing (just how
>> much may, or may not, depend on the value of the sharpening control set
>> on the camera at the time of image capture).
>
>You're confusing me. If no sharpening occurs in camera, then no on the camera
>values should be considered.
What's so difficult to understand? You can set a sharpening parameter
on the camera, and the value you set is stored along with the image data.
The later software processing *may* decide to take the value you set as
a starting point to control how much sharpening to apply. Or it may not,
and only sharpen based on values set interactively at that time. Just
which approach is taken depends on how that later stage software is written.
Don't assume all conversion is done interactively, with the photographer
reviewing each image. Sometimes a converter will be run as a batch process
to convert a large number of images. In that case it is sometimes worth
using values selected on-camera (for sharpening, white balance, etc.)
But in no case is any of the sharpening actually performed in-camera.