08-29-2011, 07:57 PM
[quote name='dhazeghi' timestamp='1314641610' post='11143']
Any ideas why Olympus' m4/3 designs consistently underperform their 4/3 designs? They seem to be trying to destroy their reputation for excellent lenses at semi-reasonable prices.
DH
[/quote]
Part of this is caused by designing for m4/3. A shorter back focus, or even no real back focus at all, means that the designs especially at the short end of the spectrum, are true, non-retrofocus (U)WAs. This implies by definition a lot of vignetting, and with a lot of vignetting and rectilinear distortion at large angles comes a decrease in contrast and resolution, exponentially increasing towards the corners.
One could overdesign a lens, but unfortunately that makes a lens, especially a WA or UWA, much, much bigger very rapidly, thereby defeating the object of a small design.
Furthermore, where in larger formats and similar megapixel sizes generally speaking assembly tolerances are larger than required from an optical POV already, this increases rather strongly when sensors become smaller, as the resolution of a lens has to be drastically higher - and here you run against physical limits, as in, the laws of physics. And all this apart from the fact that smaller sensels have their own (physical) drawbacks, amongst others that they don't like high incident angles, which is exactly what UWAs do happen to have.
The question, IMO, really is whether this is good enough resolution and performance. If it is, for a specific set of circumstances, or for the photographer, it doesn't really matter. And where 4/3 and m4/3 really have the advantage, is at the long end, with their cropfactor of 2, and long lenses really being much lighter for the same AoV, and having approximately the same resolution too for the same AoV.
Kind regards, Wim
Any ideas why Olympus' m4/3 designs consistently underperform their 4/3 designs? They seem to be trying to destroy their reputation for excellent lenses at semi-reasonable prices.
DH
[/quote]
Part of this is caused by designing for m4/3. A shorter back focus, or even no real back focus at all, means that the designs especially at the short end of the spectrum, are true, non-retrofocus (U)WAs. This implies by definition a lot of vignetting, and with a lot of vignetting and rectilinear distortion at large angles comes a decrease in contrast and resolution, exponentially increasing towards the corners.
One could overdesign a lens, but unfortunately that makes a lens, especially a WA or UWA, much, much bigger very rapidly, thereby defeating the object of a small design.
Furthermore, where in larger formats and similar megapixel sizes generally speaking assembly tolerances are larger than required from an optical POV already, this increases rather strongly when sensors become smaller, as the resolution of a lens has to be drastically higher - and here you run against physical limits, as in, the laws of physics. And all this apart from the fact that smaller sensels have their own (physical) drawbacks, amongst others that they don't like high incident angles, which is exactly what UWAs do happen to have.
The question, IMO, really is whether this is good enough resolution and performance. If it is, for a specific set of circumstances, or for the photographer, it doesn't really matter. And where 4/3 and m4/3 really have the advantage, is at the long end, with their cropfactor of 2, and long lenses really being much lighter for the same AoV, and having approximately the same resolution too for the same AoV.
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 ....