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11-26-2010, 01:57 PM   #16
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I think what Nick means is that the entire image does not have to be re-interpolated. Rather, when an image is rotated 1, 2 or 3 degrees to account for leveling a horizon, the only change is a slight cropping of each edge (in a long triangle cut on each side), not a complete re-interpretation of the image.

11-26-2010, 07:17 PM   #17
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QuoteOriginally posted by pxpaulx Quote
when an image is rotated 1, 2 or 3 degrees to account for leveling a horizon, the only change is a slight cropping of each edge (in a long triangle cut on each side), not a complete re-interpretation of the image.
I don't think this is true, but i'll wait for someone more knowledgeable. I believe the whole image IS "re-interpreted".
11-26-2010, 07:25 PM   #18
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+1 for Itai for answering an uncalled for post in way that made the whole situation not turn into a childish discussion.
I'm curious about the horizon adjustment tool now, and its effect on the overall image. I didn't know it affected anything at all. I had imagined it just cropped it slightly.
11-26-2010, 08:00 PM   #19
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QuoteOriginally posted by Itai Quote
- Itai Danan
Neocamera Principal Editor & Professional Pentaxian
Itai,

thank You for taking the time and visit our forum. I much appreciate reviewers doing that.

I also like how you replied to the rotation issue when a new member (nickmeertens) challenged you in a childish way (back to school) and later "forgot" to apologize when proven wrong.

BTW, you're right, rotation for angles other than multiples of 90 decreases image quality. Rotation by 3 can increase the blur width by as much as 10%.

11-26-2010, 09:14 PM   #20
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An explanation of interpolation and what happens with rotating an image amounts other than 90, 180, 270-

Understanding Digital Image Interpolation

Now this type of cropping/image adjustment is a post-processing issue. I do not know what is happening inside the K5, if it is interpolating or if it is rotating the sensor to avoid the need to interpolate. I thought it was rotating the sensor, but am happy to be corrected.
11-26-2010, 10:56 PM   #21
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Thanks for posting that cambridgeincolour link Dan.

I guess i'll be sitting in the corner for a while apologizing and straightening pictures while framing them.
11-28-2010, 08:21 AM   #22
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QuoteOriginally posted by falconeye Quote
Itai,

thank You for taking the time and visit our forum. I much appreciate reviewers doing that.

I also like how you replied to the rotation issue when a new member (nickmeertens) challenged you in a childish way (back to school) and later "forgot" to apologize when proven wrong.

BTW, you're right, rotation for angles other than multiples of 90 decreases image quality. Rotation by 3 can increase the blur width by as much as 10%.
Thank you Falk!

I appreciate everything you said. My goal is to provide information and dissipate misinformation, of which there is plenty around but I wouldn't follow any discussion turning childish. Only people with an open mind will listen and learn.

Forums are valuable for photographer educators because they tell us what issues people are having. How else would we know? Actually, nearly every article on Neocamera is a based on a frequently recurring forum or email questions.

I learned from this very thread that people don't understand rotation of digital images, someone even thought it was simply a form of cropping (but we can't crop in arbitrary directions without re-interpolation). I happen to know how it works because I've spend 9 years working on an image processing pipeline for film special effects but most people don't know that about me. At least I don't have to write an article this time because someone pointed to the Cambridge In Color link which illustrates the process well

Thanks again and to everyone else who expressed their support!

- Itai
11-28-2010, 02:16 PM   #23
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QuoteOriginally posted by dandaniel Quote
I do not know what is happening inside the K5, if it is interpolating or if it is rotating the sensor to avoid the need to interpolate. I thought it was rotating the sensor, but am happy to be corrected.
I'm pretty sure it's a function of the floating sensor and SR mechanism, which is why it's so fantastic!

Can anyone tell me whether Optical Image Stabilisation is capable of this? I have a feeling it's not.

11-28-2010, 02:45 PM   #24
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I read the review and found it very very good. Thanks for posting
11-28-2010, 11:45 PM   #25
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QuoteOriginally posted by secateurs Quote
Can anyone tell me whether Optical Image Stabilisation is capable of this? I have a feeling it's not.
No, to put it simply. The sensor itself needs to be level. Skewing an image with prisms (or using lens elements as prisms for this purpose) will not rotate it around its axis, only shift it laterally.
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