All CCDs have limits to how bright or dark a value they can record. RAW
formats can allow software to recover blown highlights to an extent, but
it's really more of an educated guess based on surrounding pixels.
When the sensor in my Maxxum 7D blows a highlight, it's really blown,
and unrecoverable. Other sensors, such as the ones Canon uses in their
lower-end DSLRs, don't blow highlights as quickly as my camera does. But
they will all blow highlights sometime.
That's why true HDR shoots sets of images with a range of exposure
settings. One's exposure is set so the blackest blacks fall within the
camera's dynamic range. The lightest exposure is set so the brightest
whites fall within that dynamic range. (I've shot HDR sets with about 9
stops exposure). Bracketing is just an automatic, less flexible way of
doing that. Faux bracketing doesn't have the same dynamic range
available to start with, although it can work out effectively where you
have a contrasty scene but want to pull detail from both the bright and
dark portions of the image.
Or something like that. I'm tired! #-/
On 12/18/2012 12:43 PM, JohnPW wrote:
Sure, in fact I have the camera default set to underexpose by .75 stop
(which is probably the only thing you can do if you can't shoot RAW.)
But the fact that the detail exist in o1 shows that the detail is lost
in the transformation, not because of the camera.
On Tuesday, December 18, 2012 4:34:30 PM UTC-6, Frederic Da Vitoria wrote:
Yes, you are right, I didn't look closely enough. The details in the
T shirt are more immediately visible, but the textures in the
lightest zones now seem uniformly white. In my experience, P&S
cameras have a tendency to over-expose pictures. Maybe choosing
picture with a better exposition (that is under-exposed by the
camera's standards) would give better results.
2012/12/18 JohnPW <johnpw...@gmail.com>
Are you sure you didn't mix the two up?
o1 is the original and o2 is the output.
In my opinion the shirt detail in o2 is very clearly blown out
compared to o1.
BTW, I agree that it's best to compare o1 and o2. I
included c100 to show that at least one of the intermediate
image isn't blown out at Bugbear wondered.
On Tuesday, December 18, 2012 3:37:17 PM UTC-6, Frederic Da
Vitoria wrote:
Hello JohnPW
IMO, you shouldn't compare the highlights between any image
and c100: since c100 is the darkest, it will always show
more details in the highlights than any other picture. You
should always compare with the original. Does o2 do better
than à1 in the T shirt? I believe so.
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