[quote name='BG_Home' timestamp='1283088908' post='2307']
Sorry, but I have to wave the bullshit flag on that comment. There's no way a normal image requires "desharpening" when downsizing with a normal bicubic resampling algorithm, no matter what the lens was. Quite the contrary, actually. Downsampling causes some loss of edge definition, which is why most people slightly re-sharpen images for web publication. Things may be different if you use a resampling alrgorithm that applies sharpening to the output (but that's independent of the lens, too).
[/quote]
Sorry, but you're wrong. I did have to use "bicubic smoother", and I still got sharpening artefacts nonetheless. Do note that normally you'd have to use "bicubic sharper" for downsampling, effectively as you state, and as I do with all of my other lenses, although not for every step, because with f.e. 24L II and 135L I also get into sharpening artefacts trouble occasionally that way. I also use steps of approximately 1.4X, 1.5X max (down obviously in that case, so 1/1.4, or 0.7, just in case I get another undeserved reprimand), so that the algorithm has to make a choice when downsampling (or upsampling for that matter, same thing, step wise), rather than just divide by 2 in the case of downsampling, or multiply by 2 in th ecase of uprezzing.
In short, I used "bicubic smoother", which is normally used for uprezzing, instead of "bicubic sharper", and still had to desharpen a bit.
BTW, there are nicer ways to say things than using the words you did. I'll be the first one to admit a mistake, so no need even to raise a flag, just ask.
Regards, Wim
Sorry, but I have to wave the bullshit flag on that comment. There's no way a normal image requires "desharpening" when downsizing with a normal bicubic resampling algorithm, no matter what the lens was. Quite the contrary, actually. Downsampling causes some loss of edge definition, which is why most people slightly re-sharpen images for web publication. Things may be different if you use a resampling alrgorithm that applies sharpening to the output (but that's independent of the lens, too).
[/quote]
Sorry, but you're wrong. I did have to use "bicubic smoother", and I still got sharpening artefacts nonetheless. Do note that normally you'd have to use "bicubic sharper" for downsampling, effectively as you state, and as I do with all of my other lenses, although not for every step, because with f.e. 24L II and 135L I also get into sharpening artefacts trouble occasionally that way. I also use steps of approximately 1.4X, 1.5X max (down obviously in that case, so 1/1.4, or 0.7, just in case I get another undeserved reprimand), so that the algorithm has to make a choice when downsampling (or upsampling for that matter, same thing, step wise), rather than just divide by 2 in the case of downsampling, or multiply by 2 in th ecase of uprezzing.
In short, I used "bicubic smoother", which is normally used for uprezzing, instead of "bicubic sharper", and still had to desharpen a bit.
BTW, there are nicer ways to say things than using the words you did. I'll be the first one to admit a mistake, so no need even to raise a flag, just ask.
Regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....