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Kaboom371
09-04-2001, 10:51 PM
i took this picture with my digital camera...i have never taken a photography class in my life. even though i was freinds with one when i was in high school. do you think that digital photography is gonna take over a good portion of photography classes? do you think that people will have to start being specific about what kind of photography it is wether its with an SLR/digital camera?

anyway...something has always seemed a little off with this picture. its titled "SoHo Gent"..which was taken the last time i was in NYC.

Midwest Painter
09-05-2001, 12:33 AM
What about SLR digital cameras?


Perhaps your poll should be about film vs. digital camera.

phil_m
09-05-2001, 12:33 PM
I love my "digital darkroom" toys, but I still prefer my SLR to any digital camera I've seen on the market. (Canon D30 comes closest...at least it accepts good quality, interchangeable lenses...and if it cost 20% of its current selling price....)

Of course, as soon as I get the slides/negatives back I scan 'em. 2700 dpi is really nice!

The main drawback I see is storage. I can easily spend a half-day at a sports event and come back with 250 shots. Even if I'm willing to live with digital camera resolutions, i think that works out to 800MB+ of data.

Now, if I can burn CDs directly from the camera, in the field, and do it as fast as I can change a roll of film, the economics might start to work. :)

Midwest Painter
09-05-2001, 01:43 PM
Originally posted by phil_m
I love my "digital darkroom" toys, but I still prefer my SLR to any digital camera I've seen on the market. (Canon D30 comes closest...at least it accepts good quality, interchangeable lenses...and if it cost 20% of its current selling price....)

Of course, as soon as I get the slides/negatives back I scan 'em. 2700 dpi is really nice!

The main drawback I see is storage. I can easily spend a half-day at a sports event and come back with 250 shots. Even if I'm willing to live with digital camera resolutions, i think that works out to 800MB+ of data.

Now, if I can burn CDs directly from the camera, in the field, and do it as fast as I can change a roll of film, the economics might start to work. :)

My Olympus C-3040Z has interchanable lenses. At 2048 x 1024 resoultion a 64MB SmartMedia card hols 82 images in a JPEG format. You may want to note that IBM has just released a 1 GB microdrive that's about the size of a postage stamp.

But as far as taking hundreds of pictures you do realize that a Digicam allows your to preview the shot so you can delete the duds. You might end up with fewer, but better pictures.

phil_m
09-05-2001, 02:14 PM
Originally posted by Midwest Painter


My Olympus C-3040Z has interchanable lenses. At 2048 x 1024 resoultion a 64MB SmartMedia card hols 82 images in a JPEG format. You may want to note that IBM has just released a 1 GB microdrive that's about the size of a postage stamp.

But as far as taking hundreds of pictures you do realize that a Digicam allows your to preview the shot so you can delete the duds. You might end up with fewer, but better pictures.

Concerning the microdrive, it's certainly an indicator of how digital will catch up in the future. (Since I've been working and playing with computers for over 20 years, it would be silly to bet against it!) When it hit's about 6GB for a quarter the price, it'll be about on target. JPEG is only an option as the very last step in image processing, not for storing original shots that you might want to edit later.

That's the thing with digital...all of the features need a multiplier compared with today to be competitive. Resolution x 5 or so; storage X 6; price x 0.2. The great thing is that it's going to happen!

(Previewing pictures instead of taking so many is a great idea for landscapes, some nature, still life...but if I tried it at the local rugby pitch, I'd miss a half-dozen opportunities for good shots while deciding about the first one. That 'fps' rating isn't entirely a joke :) )

Midwest Painter
09-05-2001, 02:42 PM
Originally posted by phil_m


.. JPEG is only an option as the very last step in image processing, not for storing original shots that you might want to edit later.


:confused:


I have no problem editing JPEG files. I do it all the time. I can crop, chage the size, adjust the sharpness, contrast, color saturation, beta, apply filtering, etc.

Kaboom371
09-05-2001, 04:04 PM
sorry i used bmp version of my phtotgraph. so i went and foudnt he jpeg version of it. sorry abotu that.

phil_m
09-05-2001, 04:12 PM
Originally posted by Midwest Painter

I have no problem editing JPEG files.


Certainly software will let you do it.

But every time you save as JPEG, you lose some of the information that was captured. Even if you save without compression during subsequent edits, there are still bits that have been thrown away -- and possibly ones that have been created out of "thin air" -- during that first save that let you put 82 images at 3.3MB each into a 64MB space.

(For an example: create a new file in PhotoShop or something; fill half with red and half with blue; save as .jpg with a small file size; open it again and look at the area where the colors meet. Where did those funny vertical lines come from?)

Kaboom371
09-05-2001, 04:22 PM
sorry i used bmp version of my phototgraph. so i went and found the jpeg version of it. sorry about that.



http://www.wetcanvas.com/Community/images/05-Sep-2001/SoHo_Gent.jpeg

Midwest Painter
09-05-2001, 07:13 PM
Originally posted by phil_m


Certainly software will let you do it.

But every time you save as JPEG, you lose some of the information that was captured. Even if you save without compression during subsequent edits, there are still bits that have been thrown away -- and possibly ones that have been created out of "thin air" -- during that first save that let you put 82 images at 3.3MB each into a 64MB space.

(For an example: create a new file in PhotoShop or something; fill half with red and half with blue; save as .jpg with a small file size; open it again and look at the area where the colors meet. Where did those funny vertical lines come from?)


I hope this clears things up.


From Phil Askey


"The JPEG image format (actually JPEG is strictly speaking the name of the compression algorithm) is the predominant format used by digital cameras. Even professional cameras will have a JPEG mode and despite its lossy compression it has become the de facto image format for electronic storage of photographic images. The reason for this is this compression algorithm's ability to reduce an image file size by 8 or 10 to 1 without any degradation in image quality (to the human eye at normal viewing magnification). A 1.5 MB 3 megapixel JPEG image will be hard to distinguish from the same image saved as a lossless TIFF weighing in at 9.2 MB.

I'll not delve too deeply into exactly how JPEG works (there are too many papers available on the web which cover that in far more detail) but I'll summarise roughly what happens:

The image data is converted from RGB (if it was already in the RGB colour space) to YUV, YUV is a colour space scheme that stores information about an images luminance (brightness) and chrominance (hue) separately. Since the human eye is much more sensitive to luminance than chrominance, you can afford to discard much more information about an images chrominance, especially the higher frequencies.


Image is broken up into 8x8 blocks which are then processed independently.


Each block is processed by the DCT (Discrete Cosine Transform) algorithm "The ultimate goal of the DCT is to represent the image data in a different domain using the cosine function. The image data is transformed into numerous curves of different sizes. When these curves are put back together, through inverse Discrete Cosine Transform, the original image (or an extremely close approximation to it) is restored."


Quantization - two tables of quantization constants are created, one for luminance and one for chrominance. These constants are calculated based on the image quality variable (the "JPEG quality").


Encoding - elements of representing low frequencies are moved to the beginning of the matrix and elements representing high frequencies (more likely to be zeros and thus better to compress together) are moved towards the end of the matrix. The matrix is then compressed (generally) using Huffman encoding and written to the output file.


When editing an image in several sessions, it is recommended to save the intermediate image in an uncompressed format (tiff, bmp, jpeg maximum quality) to avoid cumulation of JPEG losses. If you save for instance an image at Photoshop JPEG Quality 4, close it, open it again and save it again at Photoshop JPEG Quality 4, the file size will not reduce further, but quality will have degraded further. So only compress after all editing is done. "

Mark4583
09-06-2001, 05:18 PM
Im a traditional photographer and I like the Film. There are now studio's that use digital and they also have digital backs that I could put on my RB67 pro sd for a preview, So digital is allready here. I dont own a Digital camera and I dont know alot about them, My brother had some family portraits done last year for xmas that was digital and I did some for him with my Mamiya.
The digital shots were nice but I didnt think the quality was a good as the medium format, they just seemed flater and skin tones where off, this could have been the photographers doing.
I would have thought the price would have been less than film but they where just as expensive if not more than if he went to another studio.
I wouldnt mind buying a Digital and if I did it would be the Nikon, I have 20+ Nikon lense for my 35mm that fits there digital so that would save lots of $$$