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View Full Version : Less than actual resolution question...

michael.luczkow
1st of February 2005 (Tue), 20:53
sorry if this is a repost, but I searched and didn't find anything.

I was wondering what portion of the sensor is used when taking a picture at less than the actual resolution... is the whole sensor used, then the file goes thru some resizing algo. and stored on the media?

1. full size from the sensor then resized and stored (bad image quality)
2. central rectangle of sensitive pixels on the sensor (changes the lenses X factor)
3. interpolated pixels adding up to the resolution specified. (really ****ty quality)

I think it's number one, but I was wondering if anyone knew for sure. Or could point me somewhere that has the facts.
PacAce
1st of February 2005 (Tue), 21:10
Yup, it's #1.
Andy_T
2nd of February 2005 (Wed), 03:58
The option 2 you mentioned is used on Nikon's new D2X to get to 8 FPS, doubling the crop factor.

It is not used on Canon cameras.

Best regards,
Andy
Jon
2nd of February 2005 (Wed), 11:10
I'm not sure what the difference would be between options 1 and 3, though. It definitely is full-sensor capture resized down, but are you considering Option 3 to be a resample, where colour for each "theoretical" pixel is computed based on the physical pixel data captured by the underlying sensor sites, where 1 is a straight casting-out of all sensor sites except those which occur at the "theoretical" sensor site centers? I believe they do do a resample in the downsizing process. If nothing else, the lack of any consistent relationship between the smaller sizes and the base sensor size would almost require a resampling.

All things being equal, I'd rather they didn't offer those options, anyway. What's next? Digital Zoom on the 1Ds Mk II? (Now, a digital wide-angle, that'd be useful!)
KevC
2nd of February 2005 (Wed), 11:29
Mm. That's why I always shoot in RAW. :D
CyberDyneSystems
2nd of February 2005 (Wed), 11:33
In every res/file type setting the camera takes a full raw image.. which is then either converted to a jpeg file, or saved as a RAW data file,..

...but no file can be created and saved to the card without this first step of taking the FULL image.... whether shooting RAW or jpeg.
michael.luczkow
2nd of February 2005 (Wed), 15:33
In every res/file type setting the camera takes a full raw image.. which is then either converted to a jpeg file, or saved as a RAW data file,..

...but no file can be created and saved to the card without this first step of taking the FULL image.... whether shooting RAW or jpeg.

very good point.