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Old Jan 11, 2005, 11:12 AM   #11
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The 1ds-mkII is currently the only body I know who's raw fileswill convert directly to a 50mb tiff. Others with different bodies do a bit of interpolation before submission.

If the image is ofhigh quality it is tough to tell if it has been up-sized a bit(if done properly), unless "Original Decision Data" is appended to the image, then monkeying with it is a no-no.
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Old Jan 11, 2005, 12:25 PM   #12
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Wow! I just can't afford 4 grand or more for a body.

Thanks for the responses. Both of you are referring to Canons, I believe(?) Which kinda leads to: Is there a straight forward relationship between sensor size and file size(there must be some relationship). Also the 50 megs is a target with a +/- 2 megs allowed. They specifically don't want EXIF data included if I remember correctly. I think Peter implied an image could be upscaled which suggests the image would be degraded(?)
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Old Jan 11, 2005, 12:56 PM   #13
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Actually the 1ds-mkII is selling for 10K$cdn. :?so thats about 50$us ?:blah:

Yes there are some methods and programs like Genuine Fractals that will do a very good job of resizing an image. There will be degradation, so you need to start with a very good original. Also some images seem to take expansion better than others.

It is a not uncommon practice:crazy: , one of the first discussions on some of the professional org lists I am on when a new camera hits the street is how well its images take interpolation to the current submission size. Even pros don't want to have to replace equipment as often as technology moves ahead. And the current submission size seems to keep pace with the highest available camera capability.



The ODD(Original Decision Data)is not part of the exif data, it is a sort of tamper seal. There are programs available in this case from Canon that will identify if the image is original as shot or has been modified. It is Canon pn# dvk-e2 (Data Verification Kit - 950$cdn)

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Old Jan 11, 2005, 1:23 PM   #14
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Yes Canon is the only dslr at the moment with a 16mp sensor.

It is the number of of pixels and how many bits they are, on the sensor that has the relationship to thefile size. The sensor physical size has no relationship.

I'm not exactly sure how to calculate the tif size from raw, it seems to be about 3X the raw size.

DennisA wrote:
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Thanks for the responses. Both of you are referring to Canons, I believe(?) Which kinda leads to: Is there a straight forward relationship between sensor size and file size(there must be some relationship).
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Old Jan 11, 2005, 2:20 PM   #15
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Thanks sjms and PeterP. I gather both of you a referring to Canon. Can you tell what you think the relationship between sensor size and file size is? BTW LiquidLibrary specs the TIFF file as 50 megs =/- megs.

I'm a little bummed, I thought I had a possible outlet. I just can't swing 4 grand for a body plus lenses. I'm going to look at their specs again.
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Old Jan 11, 2005, 7:42 PM   #16
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How about this for a calculation:

From Steve's review: D70 max resolution 3008x2000.
3008*2000 = 6,016,000 pixels
Also from the review in RAW D70 generates 12 bits/pixel.

total = pixels * bits/pixel.
hence 6016000*12 = 72192000 bits
divide by 8 bit/byte
hence 9,024,000 bytes of RAW (dammit, I thought I had a bigger number going here)

Similar argument for a 16 meg sensor yields a 24 meg RAW.

Now what? or is this argument totally wrong.
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Old Jan 11, 2005, 8:01 PM   #17
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DennisA wrote:
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Thanks sjms and PeterP. I gather both of you a referring to Canon. Can you tell what you think the relationship between sensor size and file size is? BTW LiquidLibrary specs the TIFF file as 50 megs =/- megs.

I'm a little bummed, I thought I had a possible outlet. I just can't swing 4 grand for a body plus lenses. I'm going to look at their specs again.
The relationshipbetween sensor dimensions and image size is pretty straightforward. There are two different equivalent calculations that are done by Photoshop for example:

A. Size = X dimension pixel count * Y dimension pixel count * # bytes per pixel.

B. Size = X dimension size * # dots per dimension size Y * dimension size * dots per dimension size * # bytes per pixel.

A and B are equivalent because dimension size * # dots per dimension size = dimension pixel count.

E.g. for an image of dimensions 3504* 2336 pixels, 8 bits per colour (24 bit colour)

Size = 3504 * 2336 * 3~ 23.4 MB. This would be a typical 20D image size for 8 bits per colour -- double this for 16-bits per colour. The image bank quoted requires only 8 bits per colour.

Dimension sizes at 300 dpi are 11.7" * 7.8"

Enlarge the dimension sizes to say 17" * 11.3", you get

5100 pixels x 3400 pixels, which is 49.6 MB

This enlargement is around 45%.

The files sizes calculated by Photoshop and the above calculations are also very close to actual TIFF sizes -- TIFF files are very slightly larger, presumably containing some overhead in addition to the pixel data.

The above enlargement factor, which is needed to get an 8-bit colour file to 50 MB, is relatively large (45%). This means that interpolation will be noticable at high magnification for detailed images.

At these magnfications, photographic technique will also be very critical -- you'll see a lot (or lack thereof) of image detail, and notice focusing, movement and image detail errors.

The image bank also specifically says that they do not want digital submissions with less than 8MP cameras. It seems to me that this image bank's standards are kept high to keep the riffraff (e.g. me) out.
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Old Jan 11, 2005, 8:20 PM   #18
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Madwand's calculations seem to be about right.

You have to remember that even though the sensor is outputting 12 bits(1.5 bytes), computers prefer things on byte/word boundaries so it pads with nulls to the next byte, ending up with 16bits per pixel.

Here are the file sizes for an image from my 20D
3504*2336 (20D 8mp sensor)
_MG_0115.CR2 9,052KB 12bit RAW
_MG_0115.psd 47,978KB 16bit psd(photoshop native)
_MG_0115.tif 47,978kB 16bit tif
_MG_0115_8.tif 23,997kB 8bit tif
_MG_0115_8.psd 23,997kB 8bit psd
_MG_0115.stn 10,403kB 8bit stn(Genuine Fractals, old version)


Now if your image service accepts 16bit files with the 20D you are in the ballpark already :lol:





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Old Jan 11, 2005, 8:20 PM   #19
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UGH double post again, last time I did this I ended up wiping both posts. Here's crossed electron beams hoping it doesn't happen again.

Double Post Wipe ...




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Old Jan 12, 2005, 7:24 AM   #20
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it is a great regret that nikon falls well short in the pixel count especially lacking full frame. i use nikon too for film in places that canon digitals fall short like real cold for extended times and such. from an ergonomic point nikon has it over canon by a long shot and up until the new 580ex flash i often felt it was better to use a couple of candles for more consistant results on canon vs nikon flash setups.

the tolerances for submissions to LL are fairly tight. example: "All images should be reviewed on screen at 100% or a 1:1 ratio. (We recommend using Photoshop for this.) Dust, lint, hairs, banding, pixelation and moirés need to be removed".

in short you better be serious and inspect your image real careful because they will too. i have a feeling that there is a high rejection rate.

a scanned 35mm chrome is about 65MB in a nikon 4000ED scanner

2 other cameras will go 50MB tif out of the box in the 35mm form factor:

canonEOS 1Ds

Kodak DSC Pro 14 series


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