03-10-2011, 11:43 PM
[quote name='Klaus' timestamp='1299740143' post='6645']
So let's say that we've got a signal X. Assuming the AA filter dampens the signal by say 20% we try to use USM to equalize this to some degree. +25% would be perfect here.
e.g.
signal = 1 -> 1 * 0.8 (AA) = 0.8 -> 0.8 * 1.25 (USM) = 1
It is, of course, not possible to find the perfect compensation values which is why we're generally sticking relatively close to the default USM settings in the RAW converter. After all that's exactly what most users do.
[/quote]
Klaus, how do you determine the USM radius?
[quote name='Klaus' timestamp='1299740143' post='6645']
Just to mention - the quality of the demosaicing engine (of the RAW converter) is also affecting the resolution. You may argue that you could use the same engine for all brands (e.g. dcraw or so) but these engines are never static. They are getting better (thus different) over time.. e.g. ACR has changed its engine at least 3 times as far as I can tell. So some sites may argue that they're sticking to the same engine but if they've a naive approach they'll get very different results after certain updates (Adobe did one change even in a minor version update for instance).
[/quote]
Why not stick to a single version of something primitive (that doesn't apply brand-specific profiles) like dcraw and then convert all files to DNG v1 using the latest Adobe DNG converter?
GTW
So let's say that we've got a signal X. Assuming the AA filter dampens the signal by say 20% we try to use USM to equalize this to some degree. +25% would be perfect here.
e.g.
signal = 1 -> 1 * 0.8 (AA) = 0.8 -> 0.8 * 1.25 (USM) = 1
It is, of course, not possible to find the perfect compensation values which is why we're generally sticking relatively close to the default USM settings in the RAW converter. After all that's exactly what most users do.
[/quote]
Klaus, how do you determine the USM radius?
[quote name='Klaus' timestamp='1299740143' post='6645']
Just to mention - the quality of the demosaicing engine (of the RAW converter) is also affecting the resolution. You may argue that you could use the same engine for all brands (e.g. dcraw or so) but these engines are never static. They are getting better (thus different) over time.. e.g. ACR has changed its engine at least 3 times as far as I can tell. So some sites may argue that they're sticking to the same engine but if they've a naive approach they'll get very different results after certain updates (Adobe did one change even in a minor version update for instance).
[/quote]
Why not stick to a single version of something primitive (that doesn't apply brand-specific profiles) like dcraw and then convert all files to DNG v1 using the latest Adobe DNG converter?
GTW