[quote name='AAC7man' timestamp='1329674808' post='15921']
Yes, very different. I wonder why the difference is SO big?
As the tests are 3 years apart I assume they are different lenses and not the original sample retested?
[/quote]
Because at higher resolution sensors, the system resolution comes into play more, amongst others. This is no longer obfuscated by the AA-filter, which just cuts off real resolution at a specific point anymore.
When you check the different reviews, you will likely find that this happens probably around 12-14 MP for APS-C, and 16-18 MP for FF.
Furthermore, with twice the number of pixels, one only gets a maximum increase in resolution of about 40% (square root of two, - 1 of course) at most, as MPs increase with area, two-dimensional IOW, and resolution is expressed as a linear, 1-dimensional parameter. However, that si just the sensor. System resolution still is the inverse of (the inverse of lens resolution plus the inverse of sensor resolution) by formula.
Essentially, MTFs start looking more like MTFs obtained with film with higher resolution sensors, be it at about twice the resolution obtained with (colour negative) film.
Kind regards, Wim
Yes, very different. I wonder why the difference is SO big?
As the tests are 3 years apart I assume they are different lenses and not the original sample retested?
[/quote]
Because at higher resolution sensors, the system resolution comes into play more, amongst others. This is no longer obfuscated by the AA-filter, which just cuts off real resolution at a specific point anymore.
When you check the different reviews, you will likely find that this happens probably around 12-14 MP for APS-C, and 16-18 MP for FF.
Furthermore, with twice the number of pixels, one only gets a maximum increase in resolution of about 40% (square root of two, - 1 of course) at most, as MPs increase with area, two-dimensional IOW, and resolution is expressed as a linear, 1-dimensional parameter. However, that si just the sensor. System resolution still is the inverse of (the inverse of lens resolution plus the inverse of sensor resolution) by formula.
Essentially, MTFs start looking more like MTFs obtained with film with higher resolution sensors, be it at about twice the resolution obtained with (colour negative) film.
Kind 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 ....