[Leica] Question about M8 exposure

[hoppyman at bigpond.net.au (Geoff Hopkinson)]

Henning as always your input reflects your extensive experience.
What also happens in these threads is that different issues become
intertwined.
Please keep in mind this is strictly M8 Raw exposure I am talking about. Not
film and not any other dSLR. I have zero experience in trying to recover
highlights or shooting with any other dSLR. Obviously film is a whole
different plate of sushi too.
This line of yours is very important to what I have been trying to say too. 
"If you see no clipping, and have information in the furthest right short of
clipping, you have the best chance of having as much accurate information as
possible."
When you set -.33 or -.66 you may not be getting as much highlight
information as possible. And in turn you are potentially capturing much less
tonal information, which is redistributed by the gamma curve applied.
Absolutely agree that may not matter for some situations or even many
situations or may be preferable to risking clipping. I try to manage
clipping by the way I meter rather than automatically shifting everything
left.
I never assume that the DNG will always be fine when there is clipping
evident in the LCD preview, but it is not gospel either.
I understand what you are saying about recovering highlight information if
one or more channels are clipped too.
I don't know if you looked at my posted examples of the 1,200 year old tree
in the snow at Red Rock Canyon. That exposure was made with +.66 exposure
initially. The LCD showed significant clipping, then as the camera processed
the preview you see the white balance and clipping indication both shift, on
the LCD in the first couple of seconds (with later firmware). The white
balance shift alone will tell you that you are seeing a preview of jpg
settings.
Most importantly the histogram of the DNG in ACR shows zero clipping. In
fact there is room in the last 10% to the right.
Contrast, clarity etc were adjusted afterwards. The final exposure is in
fact +.61 on what the meter wanted to set (and that based on metering the
tree, not the snow). There is a small amount of recovery but from zero
clipping in any channel which conforms to what you have explained too.

I'm not trying to be argumentative here and I greatly respect your
experience. I do think that it is a very on-topic discussion for us with so
many M8 shooters that are active here. For me it also demonstrates the
capability of the M8. For my style of photography I have not at all had the
experience of great recovery from underexposed shadows. A number of people
have said that they do. For me any underexposure of the shadows makes for
poorer quality there. More noise for example.

Cheers
Geoff
http://www.pbase.com/hoppyman/e
http://gallery.leica-users.org/v/gh/
Pick up your camera and make the best photo you can.

-----Original Message-----
Subject: RE: [Leica] Question about M8 exposure

A suggestion has been made that the clipping shown on the histogram for the
jpeg might not be accurate, so just give a bit more exposure and check the
clipping in the RAW later.

As long as _NO_ channel is clipped, things are fine. The problems arise if
one or two channels are clipped, and the other(s) aren't. 
Then when you try to bring some of that highlight info back, you'll get the
info from that one or two channels, but the other will have nothing. You
then get unbalanced information which is erroneous, and distorted.

It's true that the jpegs aren't accurate, but you can't therefore assume
that the DNG's will be fine. That doesn't follow.

If you see no clipping, and have information in the furthest right short of
clipping, you have the best chance of having as much accurate information as
possible.

My Canons certainly do not give me that with a + exposure compensation on
average subjects on matrix metering, and with my metering technique (which
works perfectly on my M6's with the meter set to 400 for Tri-X developed in
D-76 1:1 etc.) I generally leave my
M6 set to -2/3.

When I bring the DNG's into LR, I try to use the highlight recovery as
little as possible, and the exposure slider doesn't get used much unless I'm
shooting in very dark circumstances (I've explained my technique there
previously). Mostly I use the curves tool to do contrast adjustments,
although the LR curves tool tries to outsmart me and not allow me the fine
control I'm used to in PS.

If I do have to use the exposure slider, I'm much happier to increase the
exposure than decrease it, as I know that while I might be increasing some
noise in the shadow areas which is quite easily dealt with, I won't be
introducing uncorrectable distortion in the highlights.

-- 

    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  /###\   mailto:henningw@archiphoto.com
  |[ ]|     http://www.archiphoto.com

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