11-26-2010, 05:22 AM
[quote name='thw' timestamp='1290610366' post='4402']
But it's strange that Pentax applies a stronger AA filter than Nikon and Sony.
[/quote]
The AA filter in the K-5 is a bit stronger than the one in the D7000 and that's good.
GordonBGood reckons the difference in resolution might be around 4% but this is hard to judge on the basis of JPEGs where the sharpness parameters are not directly comparable.
Note that the D7000 exhibits colour moiré which is bad and due to an AA filter that is too weak.
You might also be interested in Falk Lumo's first assessment in which he states for the K-5 "A weaker as well as a stronger AA filter wouldn't be good". He also says "the K-5 renders tack-sharp images".
So in conclusion there is nothing wrong with the AA filter of the K-5. Were it any weaker then all you'd get is spurious detail, i.e., detail that wasn't in the scene in the first place. Spurious contrast looks good, but is wrong.
Klaus, I'd be very interested to learn from you why you think that removing the K-5's AA filter makes sense. What it doesn't let through, should not be recorded by the sensor in the first place. Why do you want to record moiré artefacts?
It might be the case that for your special application involving B&W patterns only it could make sense to process the RAW data prior to demosaicing. Are you doing this? If not then I suspect that results based sensors with weak or no AA filters may not be entirely reliable.
It strikes me as being very odd that you think that the difference between the K-5 (2500 LW/PH) and the K10D (2350 = 2500-150) is just 6% (while there is a nominal 26% difference in # of vertical pixels). Nothing that I saw from the K-5 and read about its resolution indicates that it is possible to defend this statement. It seems that different levels of (over-) sharpening are applied.
There might be something about your methods that I don't understand and I'm curious as to how the apparent mismatch between your's and Falk's findings can be reconciled. Maybe there isn't such a disparity in assessment after all, but to me it certainly appears to be like one.
If there is any chance that your initial quick statement needs more rectification than saying that you need a camera for lab tests then I think you should act quickly because your reputation might be at stake. I would truly hate to see your and your fine site's reputation suffer from a quick, loose comment that wasn't followed up properly.
But it's strange that Pentax applies a stronger AA filter than Nikon and Sony.
[/quote]
The AA filter in the K-5 is a bit stronger than the one in the D7000 and that's good.
GordonBGood reckons the difference in resolution might be around 4% but this is hard to judge on the basis of JPEGs where the sharpness parameters are not directly comparable.
Note that the D7000 exhibits colour moiré which is bad and due to an AA filter that is too weak.
You might also be interested in Falk Lumo's first assessment in which he states for the K-5 "A weaker as well as a stronger AA filter wouldn't be good". He also says "the K-5 renders tack-sharp images".
So in conclusion there is nothing wrong with the AA filter of the K-5. Were it any weaker then all you'd get is spurious detail, i.e., detail that wasn't in the scene in the first place. Spurious contrast looks good, but is wrong.
Klaus, I'd be very interested to learn from you why you think that removing the K-5's AA filter makes sense. What it doesn't let through, should not be recorded by the sensor in the first place. Why do you want to record moiré artefacts?
It might be the case that for your special application involving B&W patterns only it could make sense to process the RAW data prior to demosaicing. Are you doing this? If not then I suspect that results based sensors with weak or no AA filters may not be entirely reliable.
It strikes me as being very odd that you think that the difference between the K-5 (2500 LW/PH) and the K10D (2350 = 2500-150) is just 6% (while there is a nominal 26% difference in # of vertical pixels). Nothing that I saw from the K-5 and read about its resolution indicates that it is possible to defend this statement. It seems that different levels of (over-) sharpening are applied.
There might be something about your methods that I don't understand and I'm curious as to how the apparent mismatch between your's and Falk's findings can be reconciled. Maybe there isn't such a disparity in assessment after all, but to me it certainly appears to be like one.
If there is any chance that your initial quick statement needs more rectification than saying that you need a camera for lab tests then I think you should act quickly because your reputation might be at stake. I would truly hate to see your and your fine site's reputation suffer from a quick, loose comment that wasn't followed up properly.