Luminous Landscape Forum
Raw & Post Processing, Printing => Adobe Lightroom Q&A => Topic started by: Artem on September 25, 2007, 10:56:07 am
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alamy stock photo site wants photographers to upload JPEGs that were of initial
size of at least 17MB. My Rebe's Xti the biggest JPEG file was 10MB and
that was only after conversion from RAW. I am thinking of getting 40D, but I could not find the information if 40D will pass alamy's requirements as
a pro camera. Here is the quote from them: "
Use a pro-level camera with a “true” (non-interpolated) resolution of at least 6 megapixels. This will give a file size of at least 17MB at 8 bit."
thanks.
Arthur
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alamy stock photo site wants photographers to upload JPEGs that were of initial
size of at least 17MB. My Rebe's Xti the biggest JPEG file was 10MB and
that was only after conversion from RAW. I am thinking of getting 40D, but I could not find the information if 40D will pass alamy's requirements as
a pro camera. Here is the quote from them: "
Use a pro-level camera with a “true” (non-interpolated) resolution of at least 6 megapixels. This will give a file size of at least 17MB at 8 bit."
thanks.
Arthur
[a href=\"index.php?act=findpost&pid=141751\"][{POST_SNAPBACK}][/a]
You get 3 colours per pixel after conversion from raw to RGB. At 8 bit depth that gives 3 times raw resolution as a non-compressed file size and 6 times at 16 bit depth. As Megabytes are actually 2^20, the 40D will give around 29Mb files at 8 bit depth. The 350D and 400D (UK rebels names) both have sufficient resolution.
Of course this ignores the fact that a Bayer arrays true resolution is not the same as the number of photosites etc...
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You get 3 colours per pixel after conversion from raw to RGB. At 8 bit depth that gives 3 times raw resolution as a non-compressed file size and 6 times at 16 bit depth. As Megabytes are actually 2^20, the 40D will give around 29Mb files at 8 bit depth. The 350D and 400D (UK rebels names) both have sufficient resolution.
Of course this ignores the fact that a Bayer arrays true resolution is not the same as the number of photosites etc...
[a href=\"index.php?act=findpost&pid=141753\"][{POST_SNAPBACK}][/a]
thanks. You think that one get from Rebel Xti a jpeg of size more than 17 MB. I could
not, if when shooting macros with f32.
Arthur
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thanks. You think that one get from Rebel Xti a jpeg of size more than 17 MB. I could
not, if when shooting macros with f32.
Arthur
[a href=\"index.php?act=findpost&pid=141762\"][{POST_SNAPBACK}][/a]
Alamy want an image size of at least 17Mb - they rfer to resolution. If you save as a jpeg this is compressed and so the file size is less than the 'resolution' of the image. A 6+ megapixel camera will produce images of sufficient resolution for Alamy's purposes.
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... My Rebe's Xti the biggest JPEG file was 10MB and that was only after conversion from RAW. I am thinking of getting 40Da pro camera. Here is the quote from [Alamy]:
"Use a pro-level camera with a “true” (non-interpolated) resolution of at least 6 megapixels. This will give a file size of at least 17MB at 8 bit."
[a href=\"index.php?act=findpost&pid=141751\"][{POST_SNAPBACK}][/a]
Alamy seems to be asking for 8-bit TIFF, not JPEG: from the Xti's 8MP RAW files, you will get about 24MP TIFFs, and make them happy. (Unless they play the game of having a list of acceptable "pro-level" camera models.)
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alamy stock photo site wants photographers to upload JPEGs that were of initial
size of at least 17MB. My Rebe's Xti the biggest JPEG file was 10MB and
that was only after conversion from RAW.
[a href=\"index.php?act=findpost&pid=141751\"][{POST_SNAPBACK}][/a]
As has been noted, they're referring to TIFF files not JPEGs.
Use a pro-level camera with a “true” (non-interpolated) resolution of at least 6 megapixels. This will give a file size of at least 17MB at 8 bit.
Consider 6 million pixels ("Mp" to some people) with each pixel having 8-bit red, green and blue values. Each 8-bit value is a byte, so 6 * 3 == 18 MB. (Not "Mb" which is used to refer to megabits, commonly used in data communications)
That's when saved as a TIFF: when you save as a JPEG all that data gets squashed down dramatically.
A point of confusion for some people, if you open up a JPEG file from a 6 Mp camera and look in Photoshop's Image Size dialog it will say something like "Pixel Dimensions: 18.0M". That's the number they're referring to, but it's not necessarily the same as the file size.
As for the issue of "non-interpolated" resolution, some cameras (e.g. those with Fuji SuperCCD sensors) have a smaller number of pixels arranged in a non-square pattern, and the camera or RAW converter rearranges these to produce a different number of pixels in the final image. In the current Canon cameras the sensor has a square sensor pattern and this isn't an issue.
I am thinking of getting 40D, but I could not find the information if 40D will pass alamy's requirements as a pro camera.
It does, as does your XTi. At least the number-of-pixels requirement...
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As has been noted, they're referring to TIFF files not JPEGs.
Consider 6 million pixels ("Mp" to some people) with each pixel having 8-bit red, green and blue values. Each 8-bit value is a byte, so 6 * 3 == 18 MB. (Not "Mb" which is used to refer to megabits, commonly used in data communications)
That's when saved as a TIFF: when you save as a JPEG all that data gets squashed down dramatically.
A point of confusion for some people, if you open up a JPEG file from a 6 Mp camera and look in Photoshop's Image Size dialog it will say something like "Pixel Dimensions: 18.0M". That's the number they're referring to, but it's not necessarily the same as the file size.
As for the issue of "non-interpolated" resolution, some cameras (e.g. those with Fuji SuperCCD sensors) have a smaller number of pixels arranged in a non-square pattern, and the camera or RAW converter rearranges these to produce a different number of pixels in the final image. In the current Canon cameras the sensor has a square sensor pattern and this isn't an issue.
It does, as does your XTi. At least the number-of-pixels requirement...
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thanks for the thorough explanation. I got it: they want Tiffs, and i want 40D.
Arthur