From: DRS on
"Floyd L. Davidson" <floyd(a)apaflo.com> wrote in message
news:87pr8xpx5u.fld(a)apaflo.com
> "DRS" <drs(a)removethis.ihug.com.au> wrote:

[...]

>> Yes, they do, in terms of *accuracy*.
>
> You simply do not know how to read a histogram, and until you
> learn there is little point in talking to you on any topic
> that requires it.

According to you. Not according to everybody else. You maintain you're the
only one here who understands what's going on but that's not supported by
the evidence so I'm quite happy to let you drift off in your fantasy world.



From: Ray Fischer on
Floyd L. Davidson <floyd(a)apaflo.com> wrote:
>Doug McDonald <mcdonald(a)scs.uiuc.edu.remove.invalid> wrote:
>>Floyd L. Davidson wrote:
>>
>>> Hence if the right edge is set correctly with high
>>> contrast or low contrast, either way it is exactly the
>>> same exposure and neither is more accurate than the
>>> other.
>>> You continue to say that low contrast makes it easier
>>> to
>>> see where the edge is, but that is only true for special
>>> cases, and for an equal number of special cases high
>>> contrast would make it easier!
>>>
>>
>>In NO CASE would high contrast make it easier ...
>>at least on a Canon 30D.
>>
>>Mr. Davidson: Let me ask again: What is the serial
>>number of the Canon 30D you have checked this on.
>>
>>If you have not done so, SHUT UP.
>>
>>We admit that you are right if somebody using
>>a Canon 30D is willing to allow 2/3 stop more "slop"
>>than is really necessary.
>
>It does not appear that you understand how to read a
>histogram.
>
>Hmmm... tell me what you make of these two histograms:

You're trying to change the subject.

--
Ray Fischer
rfischer(a)sonic.net

From: Floyd L. Davidson on
"DRS" <drs(a)removethis.ihug.com.au> wrote:
>"Floyd L. Davidson" <floyd(a)apaflo.com> wrote in message
>news:87pr8xpx5u.fld(a)apaflo.com
>> "DRS" <drs(a)removethis.ihug.com.au> wrote:
>
>[...]
>
>>> Yes, they do, in terms of *accuracy*.
>>
>> You simply do not know how to read a histogram, and until you
>> learn there is little point in talking to you on any topic
>> that requires it.
>
>According to you. Not according to everybody else. You maintain you're the
>only one here who understands what's going on but that's not supported by
>the evidence so I'm quite happy to let you drift off in your fantasy world.

The evidence is rather extensive, and nothing I'm saying
is unique. Everyone who does understand it says
basically the same things...

Here is a tutorial that explains how to get an accurate
histogram.

<http://www.guillermoluijk.com/tutorial/uniwb/index_en.htm>

As for reading histograms, I don't know of any tutorials
that don't have at least some errors, but this one is
pretty good:

<http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml>

This tutorial is a pretty good one for learning how to use ETTR:

<http://www.luminous-landscape.com/tutorials/expose-right.shtml>

If you want a lot of detail, do a google search on Iyla Borg and
"white balance" or "histogram".

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd(a)apaflo.com
From: Floyd L. Davidson on
rfischer(a)sonic.net (Ray Fischer) wrote:
>Floyd L. Davidson <floyd(a)apaflo.com> wrote:
>>Doug McDonald <mcdonald(a)scs.uiuc.edu.remove.invalid> wrote:
>>>Floyd L. Davidson wrote:
>>>
>>>> Hence if the right edge is set correctly with high
>>>> contrast or low contrast, either way it is exactly the
>>>> same exposure and neither is more accurate than the
>>>> other.
>>>> You continue to say that low contrast makes it easier
>>>> to
>>>> see where the edge is, but that is only true for special
>>>> cases, and for an equal number of special cases high
>>>> contrast would make it easier!
>>>>
>>>
>>>In NO CASE would high contrast make it easier ...
>>>at least on a Canon 30D.
>>>
>>>Mr. Davidson: Let me ask again: What is the serial
>>>number of the Canon 30D you have checked this on.
>>>
>>>If you have not done so, SHUT UP.
>>>
>>>We admit that you are right if somebody using
>>>a Canon 30D is willing to allow 2/3 stop more "slop"
>>>than is really necessary.
>>
>>It does not appear that you understand how to read a
>>histogram.
>>
>>Hmmm... tell me what you make of these two histograms:
>
>You're trying to change the subject.

*Narrowing* the subject.

It is exceedingly difficult to discuss histograms with
people who do not understand what a histogram shows and
how to read it.

Until we get all participants on the same sheet when it
comes to how to read a histogram there simply isn't much
point in discussing the other aspects of their use, eh?

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd(a)apaflo.com
From: Kyle D. on
On Thu, 08 Oct 2009 14:14:55 -0700, John McWilliams <jpmcw(a)comcast.net>
wrote:

>Clues wrote:
>> On Wed, 07 Oct 2009 17:19:12 -0500, John Sheehy <JPS(a)no.komm> wrote:
>>
>>> Exposure to the right is usually given as advice for RAW shooting. The
>>> RAW data usually clips well above the level where a JPEG would clip it,
>>
>> Very true, for all those cameras that intentionally do a poor job at the
>> RAW to JPG conversion. This is why RAW became so popular. DSLRs are
>> inherently poor at this process. In fact it's the very reason that having
>> access to the RAW data became so popular. Far too many DSLR owners wanted
>> to repair in their resulting images what the DSLR's firmware programmers
>> failed to do correctly in the first place. Companies then realized that
>> they could turn this into an asset. Not only sell a camera that didn't work
>> quite right, bundled with a kit-lens that wouldn't provide images any
>> better than a Barbie-Cam, conning them into buying a $5,000-$10,000 lens to
>> make their $500 DSLR functional, but now also sell them expensive editing
>> software to fix what their cameras weren't doing properly to provide a
>> useful image right out of the box.
>
>'Ceptin' the major camera mfg's provide software with the purchaseof the
>camera, and excellent lenses can be had for a mere grand. One or two
>{Nikon} may also try to sell "Pro" RAW converters.
>
>Most in-camera conversion for JPEGs is above very decent, and is
>excellent for daylight/time normal exposures.

If your camera's resulting JPG file's dynamic range does not closely match
the dynamic range of your RAW data, then there's something obviously very
wrong with your camera, your camera's settings, or you.

(To enlighten the ignorant: There is zero difference in the amount of noise
in a 2 minute exposure in low light and a 1/2000s exposure in bright light.
Photons are photons. If you collect enough to get over the base
noise-threshold then all those parts of the image that are properly exposed
will be noise-free in any image, no matter the initial light levels.)