Roger, Bob, Peter, Simon and anybody who is still interested!
First off the histogram is one of the most important things to check
when shooting. It is basically a digital map of that image showing the
range of shadows and highlites. It comes in real handy when determining
what will show properly. For instance if your shooting a dark Pennsy
GG-1 near a dark building but you pose a bride dressed in white next to
those items you'll want to know what will reproduce in the shot, what
will be lost and what will be saved. The usual thing to do is say--Wow
that's dark scene, I'll open up a stop or two and shoot--which is what
your camera's meter is liable to do. If you do that, you will likely
overexposure the bride and the bride's father won't pay you for the
shot. The histogram would show a 'spike' where the white would be and a
low level of information in the shadows. If you 'open up' too much the
brides dress and it's corresponding spike will go beyond the
graph--meaning you've lot detail. If you overexpose with digital you'll
never recover the image--the color negative that you probably shot back
in film days was designed to accept a lot of overexposure and still be
printable. With digital, if it's over exposed, better luck next time.
When it comes to RAW and working with it, I did a whole day seminar that
solved tons of problems, so it does take some learning time and practice
time to really understand how it works. One of the advantages of using
the Adobe system (Adobe is somewhat like MS--considered pretty close to
God himself) is that you do a DNG conversion first--that Digital
Negative is becoming the standard of the industry. The Digital Negative
Converter is a free download from Adobe I believe. Once you have the
negative it goes into the RAW converter. This is where a lot magic
happens! You can make adjustments to the RAW file without destroying
the original data--impossible in the past! For instance you can crop an
image creative a JEPG and email it. A week later you can pick up that
same DNG, put in back into the RAW converter create a high end color
image in TIFF format to be used for a large poster. So its very much
like making several trips to the darkroom or photo lab. So keeping the
RAW file or DNG is just like storing a piece of film that can be used
over and over again without throwing away data. Peter is incorrect in
stating that editing in TIFF retains all the data. If you have to make
a radical color change or if you try to save a poor exposed image you
will notice a unfortunate change in the histogram (there it is again).
Often times when you have to make these changes the histogram will look
like a comb. It will have spikes of detail next of open areas; and the
slang term is called combing. The open areas contain no data, because
you threw it away often resulting in posterization of the image. Now he
is correct in stating that you can save the image many times without
loss of quality however.
My recent updating of computers hopefully will keep me in the loop in
processing many large files in rapid fire time span. We did things like
arrange hard drives into a RAID, we will take some more and put them
into a Drobro. This new box has 'time machine' built into the Snow
Leopard--man we come a long way from Mac and cheese!
Bob Werre
BobWphoto.com
On 10/22/10 7:38 PM, shabbona_rr wrote:
>
> That's one reason I haven't succumbed to DCC. It's one more digitized
> headache I can live without, and I would rather use my obviously
> limited brain capacity on more productive pursuits.
>
> Knowing how much time I spend on electronic nincompoopery anyway, I
> don't know how some of these people get so much done, yet, I know they
> do, because we see the results of their efforts every day.
>
> The other day, on some website, someone was raving about the value of
> histograms in improving photographs, so I looked it up. I might as
> well have been up against a ten foot thick glass wall. I could
> visually see people happily applying information from histograms to
> improve their pictures, but I had no idea what they were doing, or how
> they got to the other side of that glass wall!
>
> On the other hand, I FNF for the day was installing a microswitch to
> kill the North Yard storage tracks at Terminal District when the
> switch is lined against them. It worked and I feel great. Life is good!
>
> "S"tring Bob
>
[Non-text portions of this message have been removed]
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/S-Scale/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/S-Scale/join
(Yahoo! ID required)
<*> To change settings via email:
[email protected]
[email protected]
<*> To unsubscribe from this group, send an email to:
[email protected]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
