Well the sample images are nice and the other results not horrible; so is this a 2 1/2 * lens ?
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Oh well bit of a disappointment i guess.
What is the exact impact of post-distortion correction?
You lose a bit of angle of view and softer corners?
[quote name='edge' timestamp='1312645653' post='10430']
What is the exact impact of post-distortion correction?
You lose a bit of angle of view and softer corners?
[/quote]
Yes
And after you lost about 1-2 MP resolution, the image is bloated back to the full resolution of the sensor? Does this also affect center quality (depending on the extrapolation algorithm)?
[quote name='Tiz' timestamp='1312646911' post='10432']
And you after you lost about 1-2 MP resolution, the image is bloated back to the full resolution of the sensor? Does this also affect center quality (depending on the extrapolation algorithm)?
[/quote]
You stretch the image while "correcting", and clip the excess off (ending up with similar pixel resolution as the sensor generates. So you lose lens resolution mostly on the edges and corners, but only once... not twice.
[quote name='Brightcolours' timestamp='1312648309' post='10433']
You stretch the image while "correcting", and clip the excess off (ending up with similar pixel resolution as the sensor generates. So you lose lens resolution mostly on the edges and corners, but only once... not twice.
[/quote]
I agree. Not twice. I just wanted to emphasize that also the center is affected. If you just cut the corners, the image size will be reduced from 4000*3000 to maybe 3850*2900 (4:3 12MP example). If you now save the image, you will not have a 12 MP image. But the cameras and also Adobe Lightroom do not do that. They save a full 12 MP (4000*3000) image. Therefore, it is necessary to extrapolate the entire, cropped image. I am wondering about the impact on IQ (depending on the extrapolation algorithm). In any case, I do not like the idea.
08-06-2011, 07:25 PM
(This post was last modified: 08-06-2011, 07:25 PM by dave9t5.)
[quote name='edge' timestamp='1312645653' post='10430']
What is the exact impact of post-distortion correction?
You lose a bit of angle of view and softer corners?
[/quote]
[quote name='Klaus' timestamp='1312645919' post='10431']
Yes
[/quote]
The article claims that they checked the field of view:
"It’s also worth mentioning here the field of view issue. We measured it for JPEG files using the method of panoramic sequence and the sky photo method - taking angular distance measurements between stars of the celestial sphere. Both methods produced the same result of 73.7 degrees on the longer side (with the margin of error not exceeding 0.2 of a degree) so exactly as much as we expect from a 12 mm lens on a 4/3 sensor. You should remember that the field of view in RAW files will be by several degrees wider. "
So seems the true focal length is "several" degrees wider. I don't know if it's always the case for m4/3 manufacturers to accurately label their lenses' corrected focal lengths or the true focal length. It must be tempting to label the true focal length (which cheats the user), so kudos to Olympus for being a bit more truthful about the effective focal length. Or is there a standard for m4/3 focal length labeling?
/Dave
http://dave9t5.zenfolio.com
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