From: Tom Ferguson (tomf2468@pipeline.com)
Date: 08/01/03-09:27:03 AM Z
I'll throw in my 2 cents here. It isn't "RAW" that is magic here, it is
high bit depth files. What you want is to do as much work as possible in
"16 bit" mode. Because we have to put our digital neg files through a
pretty extreme curve an 8 bit files is in danger of posterizing
(spelling??)............ It is in danger of missing tones and blocky
images.
Most digital cameras will only give you high bit depth files in "RAW",
many scanners (mine at least) will output the high bit Tiffs directly.
By the way, I wrote "16 bit" in parenthesis because most (if not all)
current cameras and scanners actually write 12 bits of data into a 16
bit word. Four of the bits are "wasted" so we really are getting a
choice between 8 or 12 bits (256 tones versus 4096 tones), not true 16
bit (65,536 tones) per channel.
On Friday, August 1, 2003, at 07:01 AM, Clay wrote:
> Well, sort of. If you use Vuescan, there is an obscure check box that
> allows you to write the raw TIFF file to disk, which will then allow
> the software to use that as input if you decide to re-scan with some
> different parameters. It can save a lot of time on a large scan. Not
> quite the same as a RAW camera file, but similar in concept...
>
> clay
> On Friday, August 1, 2003, at 08:46 AM, Sandy King wrote:
>
>> Mark,
>>
>> So if I understand this right, the RAW stuff only applies to digital
>> cameras, not to files made by scanning negatives?
>>
>> Sandy
>>
>>
>>
>>
>> Content-type: text/html; charset=UTF-8
>> Content-language: en
>>
>> Sandy,
>>
>> This time of year in South Carolina, I'd be very careful about going
>> "RAW".... with all the poison ivy and critters down there you might
>> need Dick's Mesquite Gum for more than making images.
>>
>> On the serious side regarding RAW files:
>>
>> I sometimes shoot with a Nikon D1X, which has RAW capabilities.
>>
>> First, I never shoot in JPEG format-you lose a lot with JPEG
>> compression.
>>
>> Second, TIFF files take up much room on your compact flash cards-I
>> think it is around 15 Megs each. A compressed RAW file (its a
>> lossless compression in NEF format, which is Nikon's proprietary RAW
>> format.) only takes up 3 Megs.
>>
>> Third, the cool thing about RAW format is that when you import them
>> into Photoshop, they also contain what is called EXIF data-all the
>> info about the camera settings. It even tells you the date and time
>> of the shot, the lens you used, the f-stop & shutter speed, what zoom
>> setting you used on the lens, whether you turned on image
>> stabilisation on a lens that has it, and other camera settings such as
>> sharpening, contrast, etc. Thus, think of it as the raw image data
>> (just like scanning with no adjustments applied) with none of the
>> camera settings applied to it. In the camera, the thumbnail you see
>> on the little screen is shown with the settings applied-plus you have
>> a histogram of the image. When you import the image into Photoshop or
>> some of the Nikon software, you get access to all the camera
>> settings-so if you made any error, you can apply any of the settings
>> you want, modify them, not use them or whatever. Its like getting a
>> reprieve on each shot before the pellets drop in the bucket at
>> midnight.
>>
>> By the way, I always turn off sharpening and contrast when I am
>> shooting. That is much better done in Photoshop and you get a longer
>> tonal range and less chance of highlights sucking.
>>
>> So I usually shoot to get as rich of a histogram as I can-full tonal
>> range without blowing out the highlights and then, of course, the
>> image is in 16 bit color, so it is very rich in tonality. I can tell
>> right away from the histogram of the shot on the camera. If there is
>> an extreme contrast range in the shot, I can put the camera on a
>> tripod and shoot two images-one for the highlights and one for the
>> shadows and then combine the two in Photoshop and blend the best of
>> both shots.
>>
>> Also an interesting little quirk of the D1X is the fact that RAW files
>> allow you to do something else with the image. Normally D1X images
>> are interpolated DOWN by the software to get 6 Megapixel images.
>> However, with RAW you have the option to interpolate the narrow side
>> UP and get around a 10-11 megapixel image. This is sort of like the
>> scanning companies screwing with the stepper motors to get that higher
>> scanning resolution. But it works and since you are only
>> interpolating in one direction, it doesn't look bad at all and its a
>> much bigger file.
>>
>> There...that's almost all I know about RAW and my digits are raw so I
>> will stop here before everyone falls asleep.
>>
>> Mark Nelson
>>
>>
>>
>>
>>
>>
>> In a message dated 7/31/03 10:19:29 PM, sanking@clemson.edu writes:
>>
>>
>> OK, why should I want to go RAW? What are the advantages of RAW over
>> TIFF?
>>
>>
>>
>>
>> Sandy King
>>
>>
>
>
--------------
Tom Ferguson
http://www.ferguson-photo-design.com
This archive was generated by hypermail 2.1.5 : 09/05/03-09:30:45 AM Z CST