[Leica] IMG: Yosemite too... and Raw exposure for dynamic range

[kcarney1 at cox.net (Ken Carney)]

Hi Geoff,

Here is the link to a thread on making a custom white balance:

http://luminous-landscape.com/forum/index.php?showtopic=22250&st=0

The idea is that the JPG histogram, as displayed, is now closer to the
histogram of the raw file, after conversion.  I tried it today, and watching
the green channel on the camera histogram, it was indeed further to the
right (than auto white balance), and the resulting ACR histogram was not as
compressed.  As a bonus, your camera display is now green, like night vision
gear, to impress your friends.  As far as the real WB, I always take a gray
card shot (with the WhiBal) for that.  From the thread, I noted that some
raw converters (specifically ACR) are not supposed to be able to handle this
well, but the images looked fine to me in ACR.  I will try it in Capture One
4.1, but I'm out of play time for today.

Evidently this is a technique well known to everyone but me(no surprises
there), but I will try it some more.  I don't have anything critical coming
up until late June, when I am to do a Blurb book for a big gathering of
Benedictine nuns here, something they do every 40 years or so.  If I screw
that up, my next email address will be in Belize!  BTW I have to learn
on-camera flash by then too!

Ken

> -----Original Message-----
> From: lug-bounces+kcarney1=cox.net@leica-users.org [mailto:lug-
> bounces+kcarney1=cox.net@leica-users.org] On Behalf Of Geoff Hopkinson
> Sent: Sunday, May 18, 2008 4:22 PM
> To: 'Leica Users Group'
> Subject: RE: [Leica] IMG: Yosemite too... and Raw exposure for dynamic
> range
> 
> Ahaa, I am drawing a HDR guy into my web!
> The histogram in the Raw converter shows any clipping more accurately than
> the preview on the camera LCD (which uses the jpg conversion). Remember
> that
> you are editing the linear Raw information there, although the preview is
> displaying the gamma corrected output. That means that adjusting the
> exposure in the converter is more flexible and powerful than the same type
> of adjustment to a TIFF conversion. Gazillions more than a jpg conversion.
> Of course the histograms only show the tonal range represented as 256
> values, not the original 1000's. You would need a screen about 3 metres
> wide
> otherwise!
> In LUGspeak - Clipped ain't always clipped. It may not always matter. But
> if
> you want to extract the maximum tonal range, treat the camera preview as a
> broad guide, expose and edit in Raw to use as much of the tonal range as
> you
> can.
> 
> Cheers
> Geoff
> http://www.pbase.com/hoppyman/e
> http://gallery.leica-users.org/v/gh/
> -----Original Message-----
> From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org
> [mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf Of
> Ken Carney
> Sent: Monday, 19 May 2008 02:23
> To: 'Leica Users Group'
> Subject: RE: [Leica] IMG: Yosemite too... and Raw exposure for dynamic
> range
> 
> > Make your exposure for the highlights without any -EV in camera. Ideally
> > as
> > close to clipped as you can. Keep in mind that the camera histogram is
> > from
> > the jpg preview, not accurate for the Raw information.
> 
>       I don't think I knew that.  Wonderful, another calibration process
> to learn - at what point does the histogram represent the raw file?  I
> think
> HDR has some promise, but you have to be really careful to avoid a
> painterly
> look.  For subjects that move, you are of course forced to use faux HDR,
> i.e., the same raw file opened at different ev's.  It can sometimes
> enhance
> the image with a light touch.  Photomatix has a trial copy.
> 
> Ken
> 
> 
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