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Old Jan 11, 2004, 5:59 AM   #1
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Default Sigma SD9/10 max. printable document size

new camera, new list of questions

Since the SD9 and 10 Sigma cam. came with the new Fovion Image Sensor a problem started with calculating the max. printable document size of the images.
The 3.2 MP camera can be compaired with a 6 MP camera.

Still, PS sees the files just as they came from a 3.2 MP camera. So, at 300dpi the doc. size will be 20x13cm (res:2268x1512 px) How can I print, (ore confince a printer) to print at a size of 34x22cm without having to resample the image. (what nobody wants in this case)

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Old Jan 22, 2004, 11:18 PM   #2
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There are three layers in the FOVEON chip so you need to multiply 3.5 x three = 10.29 pixels. Only ONE layer in all other chips.

IN the adjustment control window of Sigma Photo Pro there is a box under Save Image As- Processing Options -where you can change the file size when converting the RAW file which is 8mb to a tiff file, ( I think tiff is the best as you do not lose any information) the options are half size, normal size, or double size, these can be 8 bit or 16 bit. The double size image in 16 bit is a huge 78mb of information at 24 inches x 16 inches at 180 dpi.

In Photoshop images can be re sized under Images- Image Size, with the resampler box unchecked (bottom lefthand corner) to any smaller size with the dpi increasing as you get smaller, e.g. A3 13 x 16 inch will be about 300 dpi which can be printed pin sharp.
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Old Jan 27, 2004, 5:29 PM   #3
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Both the SD9 and SD10 can print up to at least A0 size (33.1" x 46.8") while still retaining high quality. Look Here:


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Old Jun 9, 2004, 11:18 PM   #4
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Awesome poster. I have sucessfully shot 25 by 16 prints at 300 DPI which is a nice size photograph for framing. As I sell my prints much larger ie 50inches by 50 inches, I have yet to figure out how to do it with my SD9 and maintain the quality that I get with my medium format film camera. If you know of a way ( I use photoshop 8.0 cs for mac) and have used bicubic interpolation to enlarge my prints. At 50inches by 35 inches, the pixalization was too high for me to be able to use the print. Let me know. I've tried genuine fractals 3.0 and all the interpolation methods in photoshop cs. Thanks. Gary

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Old Jun 20, 2004, 3:32 PM   #5
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Use Genuine Fractals and print whatever size/res you want. I am printing my photos with online service bureaus at 10 by 15 inches at 300 DPI (yes that is 4500 by 3000 pixels). Bayer cameras generaly scale badly, even with Genuine Fractals, but the SD10 scales fantastically.
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Old Jun 20, 2004, 6:54 PM   #6
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I've tried genuine fractals and the scaling was fine, but the end quality was still too pixallated compared to enlargements from negative film. I was however impressed by the size of the blowups I could get with my SD9. Thanks. Gary
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Old Aug 13, 2004, 1:18 PM   #7
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How large you can print without loosing quality depends greatly on the subject and the angle of view.

Let's examine the possibilities. When we shoot an image like a head and shoulders portrait with a relatively small angle of view we have more than sufficient pixels to produce a dynamic large print without visible stairstep aliasing or other issues related to file matrix array size. Typically, it should be possible by using a good interpolation algorithm to make quite satisfactory prints at even 100 inches on the horizontal aspect.

On the other hand, when we shoot a detailed landscape at infinity hyperfocal wide angle, we have a tremendous amount of "real estate" within the frame which spreads the available pixels very thinly. For smaller prints up to 11x14 or so, the "marker pixels" (I'll explain later) are below the threshold of human visual acuity and the print looks fine. When we try to enlarge this print to a huge size, the interpolation algorithm encounters and accurately reproduces marker pixels which greatly detract from the appearance we wish to see.

Let's see how this works with a greatly simplified example. Let's assume we have an imaginarydigital camera with a resolution of 16 pixels in an array of 4 pixels wide by 4 pixels tall. We want to photograph a group of flat, white, smooth plastic discs on a featureless solid black plastic background. Now these discs have no texture or detail other than their disk shape and their pure white color. The background has no detail, only pure black color. Let's say we zoom in and take a macro shot of just one of these discs. We have a total of sixteen pixels which is adequate to define the boundaries of the disk and also provide the color information for the black background and the white disc. The image can be enlarged and looks fine.

Now let's zoom out and include all sixteen discs in the frame. But now we have a serious problem! There are sixteen discs and only sixteen pixels with which to try and define both the color, shape, position and so on. What we have is simply the essence of "marker pixels" which can define position, shading and such but are insufficient to properly describe the true "detail" of the subject and backdrop.

When an artist paints a beautiful oil of a forest scene, we are quite happy to accept a few brush strokes as leaves, grass, pine needles on the tree and "detail" in the bark of the trees, etc. But if we take a magnifying glass or microscope and examine the painting under great magnification the "illusion" is shattered and we are forced to "realize" that what looked to us like perfectly normal pine needles, grass, leaves and bark are only brush strokes in oil paint.

So it is with a photograph. When pixels are spread too thinlybut the print is small enough, our brains are perfectly willing to accept "marker pixels" as detail.However, when interpolation algorithms encounter marker pixels during the enlargement process, theyact somewhat like the microscope and reveal the "deception" and shatter our "illusion" of detail.Interpolation algorithms are very accurate. They accurately reproduce precisely what they find. If they find detail then they reproduce that detail in the enlargement. If they find "marker pixels" they make large marker pixels. Now with a large printfull of "marker pixels" we can view from a great distance once againit looks fine, but when viewed close up, it's like looking at the oil painting under magnification.

The same issues apply to film photography with one important difference. With film we don't run out of "resolution" simply because film grain intercedes during enlargement long before the loss of detail and "marker pixels" can be seen. In other words with a 35mm color print we have to quit at about 16x24 inches because the film grain becomes increasingly apparent at greater enlargement and ruins the aesthetic. With digital, we have such noise free (noise being the digital equivalent of film grain) images that we "can" enlarge greatly beyond what is possible with 35mm color film to the point that marker pixels become the limiting factor rather than grain.

The essence is that film is "always" grain limited for enlargement purposes and digital is always resolution limited.

Hope this helps a bit with the understanding.....

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Old Aug 14, 2004, 4:51 PM   #8
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That was a wonderful explaination. I recently compared a kodak dcs 14mp head to head with my SD9. Using genuine fractals, I was astounded at how close the SD9 image was to the enlarged kodak DCS image. In fact, I put off purchasing a DCS for that reason. I'm hoping that sigma corporation and foveon release an upgrade to their current line up of sensors--maybe an SD11 to compete with the kodak dcs. In the interim, I'll continue to experiment with genuine fractals. Thanks

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Old Sep 19, 2004, 7:21 AM   #9
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You can print this crop at 4 x 6 inches to see what an SD9 image looks like when it is enlarged to 20x30 inches:


Here is the same crop enlarged to 55MP (total image size)using geniune fractals, still print it at 4 x 6 inches to see a 20 x 30 inch print, but it should be a little sharper:


Here is the full size original (well, the JPEG of it):

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