Gidday MF
There has been no lens test here (AFAIK, please correct me if I am
wrong ... ) where the lens out-performs the Olympus f2/50 macro
across the board.
... But
certainly the SLRGear results from Canon's 100/2.8 on the 5D suggest
that they can be competitive (not quite as sharp from f/2.8-4,
sharper from f/5.6 on up).
I have no doubt whatsoever that there are lenses that will match almost any other lens, IF one chooses the ground on which to make the comparison. My aim with the comparison of the 50mm lenses was to look at their best performance, across the aperture range, on the best resolving body, with the same "true" FL lenses. This allows one to then assess what a camera has to achieve in order to have similar IQ under circumstances that are commonly bandied around here (often for less than charitable reasons ... ). I.E., try to factor in ALL the variables that allow one to reasonably assess the conditions under which a given camera/lens will achieve reasonably similar IQ when compared to another camera/lens.
To me, the things that are involved are:
- the quality of lenses available for the system;
- the quality of the sensor (e.g. the well-known problem that Olympus 4/3rds sensors have with noise above about ISO1250 {the E-3}, and ISO800 for any of the other modern Olympus cameras); its noise characteristics and therefore its ISO performance;
- the build quality and feature set of a given camera. e.g. most Olympus dSLRs have in-body IS. This impacts in that one is then faced with comparing other manufacturers' IS lenses, rather than their non-IS lenses. It is very easy to say, "Oh just use a tripod/monopod", but that rather avoids the issue doesn't it?
AFAIAC, the arguments about DoF are completely spurious. If one wants shallower DoF from a 4/3rds camera, one uses a longer FL lens - this is a given, IMO&E. If one wants more DoF from a larger sensor camera, one stops the lens down, assuming that the lens is of sufficient quality to allow this.
If one wants an UWA it appears that the 7~14 and 9~18 are not exactly bad lenses ...
If one wants quality, one spends the money ...
However, if I had chosen an "equivalent" FL, I would have been damned for doing that, too ... Since the aspect ratios are different, there are NO
exact EFLs; so I opted to look at "true" FLs, in front of the sensors that they were designed for.
... it appears that
ALL the SHG Olympus lenses are sharper and better than the f2/50
macro ...
I don't believe that to be the case. Look at SLRGear's 14-35 and
50/2 results for example. At no aperture is the 14-35 unambiguously
sharper than the 50/2, and indeed at least wide open, the 50/2 has
the better corners.
Again, MF, it becomes very difficult to compare differing "true" FLs. The design challenges facing the company are very different for (say) the 7~14; even when comparing it to the 14~35; let alone the Nikon which has a similar EFL, at 14~24.
These design parameters and constraints will also be different for (say) the 7~14; 14~35; f2/50 and the 50~200.
I fully expect the f2/150 to outperform the 50~200 at 150mm, and it does. Ditto, the plane of apparent focus of the f2/50 macro is outside of the design constraints that designing a zoom lens imposes, so it has a flatter plane of focus. NOTHING prevents CanNikSig etc from designing their 'fast 50s' the same way ... .
I have done some comparisons with the various 70~200 lenses also. Just LOVE that lens widget here at DPR! I will wait until DPR review the 50~200 Olympus before I make any comment on their performance. I will be guided by the opinion of mates who own Canons & Nikons as to which of these lenses are considered "good" by their fraternities; as the subject appears to be a minefield to me - certainly on the surface!
Unfortunately, there is a shortage of good test data, but I strongly
doubt the 7-14/4 is anywhere near as sharp at f/4 or f/5.6.
There was a post here recently by someone expecting to see the same detail in the distance in images taken with his 7~14 (I cannot remember what the comparative lens was ... ). WADR, I did wonder what he had been smoking! We all know why we use binoculars, telescopes and magnifying glasses and microscopes, yet this fellow thought he would get the same distance detail from the 7~14 at 7mm as he was seeing from his (IIRC) 40~150 at 150mm ...
AND, according to Olympus, all their lenses will resolve to
20MP on a 4/3rds sensor ...
I'd be a lot more excited by that statement if it was clear what it
meant in practice.
Quite right. I think I am quoting a 'secondary source', the good Mr Jay Turberville on this, rather than Olympus. But then maybe he was quoting Olympus ... ;-).
At 20MP, diffraction will be cutting into resolution rapidly above
f/4 or so. ... .
Since it is highly hypothetical, we will just have to wait and see ...
). Gazing fixedly into my crystal ball for a moment, I suspect that we will see new sensor technologies before we hit 20MP - lol! Look at what Sigma are doing with the Foveon chip. Stacking pixels gives much better "resolution", with a far lower "pixel density", than setting them out in a planar linear array as the Bayer sensor does ... .
Anyway, I am becoming very tired; so please forgive any obvious errors in this post ;-).
--
Regards, john from Melbourne, Australia.
-- -- --
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