06-14-2010, 09:38 PM
Hi Sylvain,
[quote name='Sylvain' date='14 June 2010 - 08:26 PM' timestamp='1276540004' post='511']
Thanks Geno, nice comparison.
Is the front element shape really a function of the maximum aperture? Although designed for four thirds, pana & oly 7-14 f/4 lenses are similarly shaped. Same with sigma 8-16 & 12-24 lenses (wider of course but still).
If so, complaining about this shape seems like complaining about a FWD car having a four wheels transmission.
Greetings,
S.[/quote]
Yes, for optimal edge to edge behaviour, and minimum amount of vignetting, a large, bulging front lens is unavoidable. Of course the pana and oly lenses are designed for a much smaller sensor, therefore can be quite a bit smaller, and hence have less of a problem than a lens designed for a FF sensor. Add a very wide aperture to that for these UWAs, and th eonly outcome can be a huge bulging front element. Don't forget that the actual focal length is very small, the AoV very wide, and the front element far away from the actual aperture. That is really why such a huge front element is needed.
Kind regards, Wim
[quote name='Sylvain' date='14 June 2010 - 08:26 PM' timestamp='1276540004' post='511']
Thanks Geno, nice comparison.
Is the front element shape really a function of the maximum aperture? Although designed for four thirds, pana & oly 7-14 f/4 lenses are similarly shaped. Same with sigma 8-16 & 12-24 lenses (wider of course but still).
If so, complaining about this shape seems like complaining about a FWD car having a four wheels transmission.
Greetings,
S.[/quote]
Yes, for optimal edge to edge behaviour, and minimum amount of vignetting, a large, bulging front lens is unavoidable. Of course the pana and oly lenses are designed for a much smaller sensor, therefore can be quite a bit smaller, and hence have less of a problem than a lens designed for a FF sensor. Add a very wide aperture to that for these UWAs, and th eonly outcome can be a huge bulging front element. Don't forget that the actual focal length is very small, the AoV very wide, and the front element far away from the actual aperture. That is really why such a huge front element is needed.
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 ....