32 bit photoshop CS2?

This is copied from a tangent in another thread in the 35mm group. I'm
posting separately to get comments from the folks involved in the recent
8 bit vs 16 bit discussion.

Mardon wrote:
Paul Furman wrote:
Mardon Erbland - lightbulbs
http://www.pbase.com/shootin/image/59462384

Amazing demonstration of HDR and a really nice clean catchy
image. Well done!

PS there was a discussion of 16 bit in the dslr group and I
think the conclusion was that 16 bit is very rarely helpful.

An HDR image is actually
32 bits. PS CS2 can handle 32 bit images. 16 bits would not be
sufficient to handle the dynamic range in this scene. Once I had
created the 32 bit HDR composite image from the individual photos, I
tone-mapped the 32 HDR image into the 8 bit JPEG that is seen here.
It takes a very special (and super expensive) display to view HDR
images directly (see http://www.brightsidetech.com/)

Very interesting. I did not know that. Is it only the HDR 'plugin' that
works in 32 bit? I'm surprised this didn't come up in that discussion I
mentioned.

Paul Furman wrote:

Very interesting. I did not know that. Is it only the HDR
'plugin' that works in 32 bit? I'm surprised this didn't come up
in that discussion I mentioned.

Here's how I understand it:

CS2 has built-in support for 32 bit images. You do not require a
"plug-in", although there are companies that make them. A 32 bit HDR
image contains luminance levels that far exceed the luminance data
that can be stored in 8 or 16 bits-per-channel image files. CS2 lets
you make exposure and contrast corrections so that converting a 32
bits-per-channel HDR image to 8 or 16 bits per channel results in an
image with the dynamic range (tonal range) you want. (Tonal
mapping.)

CS2 also has an item under "File--Automate--Merge to HDR" that
takes multiple 8 or 16-bit images and merges them into a single 32
bit HDR image.

I'd guess that no one raised the issue of 32 bit images in your other
discussion because no cameras (as far as I know) yet support 32 bit
images. My take on this whole question of 8-bits versus more is that
most current display hardware can't handle more than 8 bits. I guess
the argument some people make is that you don't need more bits than
what you can ultimately display. That's not true in my opinion. The
extra bits provide lots more opportunity to manipulate and edit the
image without losing colour resolution in the final 8-bit image. For
example, there is no way that anyone could photograph two fully lit
lightbulbs as a single 8-bit image and still maintain rich detail in
both the highlights and shadows. That requires more bits to record
the full luminance range and eventually for manipulation and tone
mapping. This is despite the fact that the final result is still
displayed as 8 bits.

Mardon wrote:

Paul Furman wrote:


Very interesting. I did not know that. Is it only the HDR
'plugin' that works in 32 bit? I'm surprised this didn't come up
in that discussion I mentioned.


Here's how I understand it:

Thanks. Interesting. Roger Clark claims photoshop does sloppy math and
does not get the best out of images but I guess that's more an issue
with the RAW converter, I'm not clear on that. Maybe CS2 does better in
this regard. Can Camera Raw output 32 bit? It seems to me, not much
value in 32 bit HDR if you can't even percieve it with your eyes in a
print. I often have the desire to capture high dynamic range images,
this is rather important to my way of shooting but I think once you get
all the data stretched they way you like, 8 bits should be plenty to
display it.

CS2 has built-in support for 32 bit images. You do not require a
"plug-in", although there are companies that make them. A 32 bit HDR
image contains luminance levels that far exceed the luminance data
that can be stored in 8 or 16 bits-per-channel image files. CS2 lets
you make exposure and contrast corrections so that converting a 32
bits-per-channel HDR image to 8 or 16 bits per channel results in an
image with the dynamic range (tonal range) you want. (Tonal
mapping.)

CS2 also has an item under "File--Automate--Merge to HDR" that
takes multiple 8 or 16-bit images and merges them into a single 32
bit HDR image.

I'd guess that no one raised the issue of 32 bit images in your other
discussion because no cameras (as far as I know) yet support 32 bit
images. My take on this whole question of 8-bits versus more is that
most current display hardware can't handle more than 8 bits. I guess
the argument some people make is that you don't need more bits than
what you can ultimately display. That's not true in my opinion. The
extra bits provide lots more opportunity to manipulate and edit the
image without losing colour resolution in the final 8-bit image. For
example, there is no way that anyone could photograph two fully lit
lightbulbs as a single 8-bit image and still maintain rich detail in
both the highlights and shadows. That requires more bits to record
the full luminance range and eventually for manipulation and tone
mapping. This is despite the fact that the final result is still
displayed as 8 bits.

Paul Furman wrote

Can Camera Raw output 32 bit?

It will save as 8 or 16, as I understand it.

It seems to me, not much
value in 32 bit HDR if you can't even percieve it with your eyes in a
print.

Actually, that's not the main point of it.

I often have the desire to capture high dynamic range images,
this is rather important to my way of shooting but I think once you get
all the data stretched they way you like, 8 bits should be plenty to
display it.

That *is* the point. You take multiple exposures of the same
seen (2 or perhaps three is plenty). The idea is to capture the
darker detail (by exposing for it) in one shot, and the
highlights (by exposing for them) in another, and then the
"merge to HDR" tries to give you the best of both, in a way the
camera can't capture on its own. It's sort of like a much
better split ND filter that doesn't work along straight lines
only.

http://www.luminous-landscape.com/tutorials/hdr.shtml

http://www.cambridgeincolour.com/tut.../high-dynamic-
range.htm




--
Randy Howard (2reply remove FOOBAR)
"The power of accurate observation is called cynicism by those
who have not got it." - George Bernard Shaw

Randy Howard wrote:

Paul Furman wrote

Can Camera Raw output 32 bit?

It will save as 8 or 16, as I understand it.

It seems to me, not much
value in 32 bit HDR if you can't even percieve it with your eyes in a
print.

Actually, that's not the main point of it.

I often have the desire to capture high dynamic range images,
this is rather important to my way of shooting but I think once you get
all the data stretched they way you like, 8 bits should be plenty to
display it.

That *is* the point. You take multiple exposures of the same
seen (2 or perhaps three is plenty). The idea is to capture the
darker detail (by exposing for it) in one shot, and the
highlights (by exposing for them) in another, and then the
"merge to HDR" tries to give you the best of both, in a way the
camera can't capture on its own. It's sort of like a much
better split ND filter that doesn't work along straight lines
only.

I heard you cannot use multiple RAW conversions of the same shot though.
That's a shame because it means you are limited to shooting with a
tripod. I can get a lot out of a raw file with different settings in two
passes but it's hard work merging them.

http://www.luminous-landscape.com/tutorials/hdr.shtml

http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm

Paul Furman wrote:

Can Camera Raw output 32 bit?

No.

It seems to me, not much value in 32 bit HDR if you can't even percieve
it with your eyes in a print.

It's an intermediate format, not used for output.

I often have the desire to capture high dynamic range images,
this is rather important to my way of shooting but I think once you get
all the data stretched they way you like, 8 bits should be plenty to
display it.

It is. The point is that you compress the range into something usable.

--
Jeremy |

Paul Furman wrote:

I heard you cannot use multiple RAW conversions of the same shot though.

There would be no benefit in doing so; the whole point of HDR is to get more
range than a single shot is capable of capturing. If you only have one shot,
you can just use the normal image.

I can get a lot out of a raw file with different settings in two
passes but it's hard work merging them.

Learn "curves" instead, and you'll never have to do that again.

--
Jeremy |

Paul Furman wrote
(in article ):

Randy Howard wrote:

Paul Furman wrote

Can Camera Raw output 32 bit?

It will save as 8 or 16, as I understand it.

It seems to me, not much
value in 32 bit HDR if you can't even percieve it with your eyes in a
print.

Actually, that's not the main point of it.

I often have the desire to capture high dynamic range images,
this is rather important to my way of shooting but I think once you get
all the data stretched they way you like, 8 bits should be plenty to
display it.

That *is* the point. You take multiple exposures of the same
seen (2 or perhaps three is plenty). The idea is to capture the
darker detail (by exposing for it) in one shot, and the
highlights (by exposing for them) in another, and then the
"merge to HDR" tries to give you the best of both, in a way the
camera can't capture on its own. It's sort of like a much
better split ND filter that doesn't work along straight lines
only.

I heard you cannot use multiple RAW conversions of the same shot though.
That's a shame because it means you are limited to shooting with a
tripod. I can get a lot out of a raw file with different settings in two
passes but it's hard work merging them.

Well, the HDR merge just sort of cancels out the interpretations
you took from a single raw image, if I understand it correctly.
Yes, a tripod is the basic idea.

Apart from sports/action photography, just about anything worth
an HDR process is worth carrying a tripod for in my opinion.

http://www.luminous-landscape.com/tutorials/hdr.shtml

http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm



--
Randy Howard (2reply remove FOOBAR)
"The power of accurate observation is called cynicism by those
who have not got it." - George Bernard Shaw

Paul Furman wrote:
I heard you cannot use multiple RAW conversions of the same shot
though.

that's right; there is no point in using single RAW for HDR, as curves
do better job when applied on single (RAW) image.

That's a shame because it means you are limited to shooting
with a tripod.

tripod is not strictly required. HDR may counterbalance small camera
movements between shots (i.e. bracket exposition from hand is usually
OK). Subject movement (between shots) is much worse problem - e.g. HDR
will not produce good results from nature shots in a windy day.


B.

Randy Howard wrote:
It seems to me, not much
value in 32 bit HDR if you can't even percieve it with your eyes in a
print.

Actually, that's not the main point of it.

theoretically it's possible to capture multiple RAW images (ISO
bracketing) from single exposure on CMOS sensor. Sadly, camera vendors
that use CMOS are not innovative enough to even try it.


B.