I agree that several of the ZFs appear to have the best "wide open" performance. Alas they are pricey, but you may find that with the introduction of the ZF2s, the slightly older ZFs may now be affordable. It's funny, people who think they need the very, very best performance will throw money at it, so if you just wait a while, you can get some good deals when something incrementally better hits the market ;)
For low light work, I do like RFs a lot, and there are some lenses that are quite legendary. If you find something with a nice big viewfinder, you can have all kinds of fun with that, e.g. the bessa T with a 21mm lens and aux VF is very hard to beat, even though the lens is only f/4. There are faster, longer lenses available though, of course. And it is true that many RF lenses deliver very good performance wide open.
With SLRs, I find RF confirmation (in the viewfinder) very useful, and also scale focusing plus an auxiliary finder can be handy. Unmentionable objects with live view also are fun for this, but on the other hand, their glowing screens quickly make you the most noticeable object in the room. Anyway, I have a Nikon 50/1.2, and that thing is a weapon at wide apertures. And of course, just because it is f/1.2 doesn't mean you have to shoot it at 1.2, but you do get to focus it at 1.2, which of course is a treat.
Indeed most lenses are not at their best wide open, but that is seldom useful to know. Right about now is when some lp/mm wanker pulls out some charts and shows that MTF isn't quite at its peak wide open... What!Ever! We shoot wide open because we like to and/or because we have to and/or we like to use shallow DOF... and all that is fine. No need to justify any of it to somebody who'd rather have an MTF chart in their bag than a 1.2 lens.
Go with your gut. Have fun and don't let technicalism slow you down! Shoot lots of film, and post your shots to the gallery.
It's also helpful to know that all optical design has tradeoffs. Sure, you can get a sharp 1.4, but to get that usually there is corner falloff. They have to make choices. It's just the way optical physics works. There is no optimum design. price and size also impact.
Also, as the colour film (and TV) era dawned, many fast lenses of the 1970's to 1980's were actually designed to be less than sharp, and one way to do so was shallow DOF. Colour film was often too revealing of blemishes etc., so "soft" became an aesthetic.
Many of us choose to use tools that do not have the means for a variety of very creative reasons.
Originally Posted by stavrosk
This is one of many examples available:
Lenses and formats and film type and processing and aperture and coatings and paper choice and e
Originally Posted by Aristophanes
Lighting and enlarger light source and many other factors each influence the final photo.
Every choice we make effects the rest of our choices.
While in principle I agree that that all optical design is a tradeoff, I disagree with your implication that that means that there are no fast lenses out there with great all-round performance.
Originally Posted by Aristophanes
Using the same Nikkor 35mm f/2.0 AIS as an example, while a fine lens in its own right, I have 35mm lenses which:
1) are sharper wide open
2) vignette less
3) distort less
4) flare less
5) have more or less the same size & weight
Admittedly those "better" lenses were once much more expensive when new. But the tradeoffs can be much less than you seem to imply.
That said, I'm a fan of very compact and corrected slow lenses as well...
I've never ever heard of lenses expressly being designed to be less sharp, unless you're talking about portrait and/or "soft" lenses
If you're thinking of Zeiss optics, and are looking at a rangefinder, seriously consider the Contax G2. Brilliant camera, brilliant optics. They're actually some of the very best optics ever made for 35mm. I have the 45 f2, 35 f2, 90 f2.8, 28 f2.8, and 21 f2.8 lenses. They are all super sharp even wide open, with the exception being the 35. It's still a great lens, but it falls short in comparison to the rest of them. I'll post a scan of a shot I took with the 21, hand-held, wide open at around 1 second. It is of Gaudi's plaster model workshop in the crypt level of the Sagrada Familia cathedral in Barcelona. Most of the room is white from the plaster models. The image was shot through a sheet of plexiglass. I've had the print enlarged to a 12x18 and it still looks great. Film was Fuji Reala 100.
The G2 has become my primary travel camera. I've taken it with me to Argentina, Puerto Rico, and Spain. All the Puerto Rico shots in my gallery here were taken with the G2, if you want to get a better idea. Oh, and the Puerto Rico shots were all done on Ektar 100.
The best lens I've used wide-open lately has been the Nikon 50mm F1.2 AIS version - simply phenomenal. I assume a Leica Noctilux is better, but I'll never be able to afford one. The Canon 50mm F1.2 is usable wide open, but nothing to write home about (fine lens overall however). The CV 50/1.1 has a pretty good rep wide open or otherwise.
i've yet to seer a 35mm lens that doesn' pperform it's best at f8-11.
Oh I'd be willing to bet a matted print that the contax g lenses are at their best a few stops wider than that.
Originally Posted by RalphLambrecht
But anyway I have yet to see a photograph for which any of this matters.
P.S. Ah-Ha! Contax G 45/2 has better MTF at f/4 than at f/8. Not really a surprise to those of us who've beheld one.
I'd expect the same of the konica hexar AF 35 and the comparable Leica and Zeiss lenses.
The tradeoffs inherent to the physics of optics are usually mitigated by increasing the size of elements across the axis, added elements, better coatings, etc. A major tradeoff is mass. For many brands a 50/2 is almost 30% less weight than a 50/1.4, and usually less than half the price, with both having near equal sharpness and distortion at f/2.8.
Originally Posted by Rol_Lei Nut
I had a Zeiss 50 for my Pentax system. It had superb center sharpness and resolution and great colour rendering. Its edge distortions were noticeable until 2 stops down from max. It was also worth 2.5x more than a Pentax brand equivalent but in real life photos, it was hard to see the differences. It had great all around performance, but there was a flaw based on the unavoidable optical physics limitations. I could get the same performance out of much less expensive glass at the expense of 1-stop.
I therefore concluded biggest discrepancy is price vs. noticeable distortion in real life photos.