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Old Jan 25, 2009, 4:26 PM   #1
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The Canon XT set on 8MP and max quality JPEG usually makes files in 2-3MB range, but my Casio 7MP P&S almost always makes 3-4.5MB files.

Why's this?
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Old Jan 25, 2009, 6:11 PM   #2
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It's all to do with the algorithms used by the individual cameras. When I switched form a 6mp Konica Minolta 5Dto my first Canon dSLR I was concerned that even going to 8mp I was getting smaller file sizes. After some digging I found out that Canon is well known for having good quality but small file sizes.
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Old Jan 25, 2009, 9:46 PM   #3
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File sizes depend on the amount of jpeg compressin used, as well as the amount of detail in the picture. On many point & shoot cameras, there is considerable noise, which is interpreted as detail, resulting in larger files. This may be the reason for the difference, as well as the jpeg compression level.

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Old Jan 26, 2009, 4:45 AM   #4
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It's a useful experiment to take a favourite fine-detailed full size image from your camera, and save it from your photo-editor at various different degrees of jpeg compression. Remember always to go back and start with the original image each time.

Then view the results side by side (a) at normal viewing size, and (b) enlarged, to see how small a file size you can tolerate for different purposes. For example, I have never found the least-compressed 'fine' compression level to be necessary for my purposes on any of my digicams.
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Old Jan 26, 2009, 9:49 AM   #5
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VTphotog wrote:
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On many point & shoot cameras, there is considerable noise, which is interpreted as detail, resulting in larger files. This may be the reason for the difference, as well as the jpeg compression level.

brian
Bingo. See for yourself, take a photo at ISO 100 and then at the largest ISO the camera has - see how the file size grows.

Believe me, your XT is not 'losing detail' in the compression compared to your Casio. Again, run this test with both cameras and you'll see both produce larger files at higher ISOs because of the added noise.

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