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#51
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fast glass?
"Skip M" wrote:
That, in no way, contradicts what I said. The Leica f2.8 will likely be sharper at 5.6 than at 2.8, and will certainly be sharper than a 5.6 lens will be at 5.6. Sorry, Skip, but you are wrong. The Leica 24mm f/2.8 ASPH is sharper in the centre at f/2.8 than at any other aperture. It is marginally sharper at the edges at f/4 than at f/2.8, however sharpness diminishes at smaller apertures as the lens is effectively diffraction limited. The edges are sharper at f/2.8 than f/5.6, and of course sharpest at f/4. Sorry to repeat myself but I wish to emphasise the point. Similar properties are to be found in other modern Leica lenses. It isn't just this one plus the 50mm f/1.0 Noctilux, you will find similar optical performance in lenses such as the Leica Elmarit-M 21mm f/2.8 ASPH, the Summilux-M 35mm f/1.4 ASPH, the Summicron-M 35mm f/2.0 ASPH, both 75mm M lenses, both 90mm M lenses and the superlative 135mm. Slightly older Leica M lenses do perform at their best stopped down, but you typically only need to stop down by 2 stops to get the best performance, whereas most lenses for 35mm SLR cameras need to be stopped down by 4 stops. For example, a 4th version Leica Summicron-M 35mm f/2.0 is sharpest at f/4, whereas an AF Nikkor 35mm f/2D peaks at f/8 to f/11. These are significant differences, and coupled with the excellent drawing (almost zero distortion), outstanding level of correction of aberrations and extreme consistency between samples, they go a long way to explaining the high price of Leica glass. |
#52
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fast glass?
"Tony Polson" wrote in message
... "Skip M" wrote: That, in no way, contradicts what I said. The Leica f2.8 will likely be sharper at 5.6 than at 2.8, and will certainly be sharper than a 5.6 lens will be at 5.6. Sorry, Skip, but you are wrong. The Leica 24mm f/2.8 ASPH is sharper in the centre at f/2.8 than at any other aperture. It is marginally sharper at the edges at f/4 than at f/2.8, however sharpness diminishes at smaller apertures as the lens is effectively diffraction limited. The edges are sharper at f/2.8 than f/5.6, and of course sharpest at f/4. Sorry to repeat myself but I wish to emphasise the point. Similar properties are to be found in other modern Leica lenses. It isn't just this one plus the 50mm f/1.0 Noctilux, you will find similar optical performance in lenses such as the Leica Elmarit-M 21mm f/2.8 ASPH, the Summilux-M 35mm f/1.4 ASPH, the Summicron-M 35mm f/2.0 ASPH, both 75mm M lenses, both 90mm M lenses and the superlative 135mm. Slightly older Leica M lenses do perform at their best stopped down, but you typically only need to stop down by 2 stops to get the best performance, whereas most lenses for 35mm SLR cameras need to be stopped down by 4 stops. For example, a 4th version Leica Summicron-M 35mm f/2.0 is sharpest at f/4, whereas an AF Nikkor 35mm f/2D peaks at f/8 to f/11. These are significant differences, and coupled with the excellent drawing (almost zero distortion), outstanding level of correction of aberrations and extreme consistency between samples, they go a long way to explaining the high price of Leica glass. Hmm, interesting. I guess I need to backpedal a bit... -- Skip Middleton http://www.shadowcatcherimagery.com |
#53
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fast glass?
Tony Polson wrote: "Skip M" wrote: That, in no way, contradicts what I said. The Leica f2.8 will likely be sharper at 5.6 than at 2.8, and will certainly be sharper than a 5.6 lens will be at 5.6. Sorry, Skip, but you are wrong. The Leica 24mm f/2.8 ASPH is sharper in the centre at f/2.8 than at any other aperture. It is marginally sharper at the edges at f/4 than at f/2.8, however sharpness diminishes at smaller apertures as the lens is effectively diffraction limited. The edges are sharper at f/2.8 than f/5.6, and of course sharpest at f/4. Sorry to repeat myself but I wish to emphasise the point. Similar properties are to be found in other modern Leica lenses. It isn't just this one plus the 50mm f/1.0 Noctilux, you will find similar optical performance in lenses such as the Leica Elmarit-M 21mm f/2.8 ASPH, the Summilux-M 35mm f/1.4 ASPH, the Summicron-M 35mm f/2.0 ASPH, both 75mm M lenses, both 90mm M lenses and the superlative 135mm. Slightly older Leica M lenses do perform at their best stopped down, but you typically only need to stop down by 2 stops to get the best performance, whereas most lenses for 35mm SLR cameras need to be stopped down by 4 stops. For example, a 4th version Leica Summicron-M 35mm f/2.0 is sharpest at f/4, whereas an AF Nikkor 35mm f/2D peaks at f/8 to f/11. These are significant differences, and coupled with the excellent drawing (almost zero distortion), outstanding level of correction of aberrations and extreme consistency between samples, they go a long way to explaining the high price of Leica glass. Tony, there is a link that documents Leica lens manufacturing which I have forgotten. The piece is quite lengthy but extremely informative. It's a great read. Would you have an idea what I may be referring to? Thanks, JT |
#54
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fast glass?
k-man wrote:
perhaps people don't realise that you're just not going to get the same image quality out of wide open lens and are mistaking 'softness' for focus issues. Just a thought. Untrue. I've seen f/1.4 lenses shoot better at f/1.8 than f/1.8 lenses of equal focal length (better meaning better bokeh, brightness, sharpness.etc.). I'm not saying that's been the case for all 1.4 vs. 1.8 lenses. But in those cases, you just might want the faster lens just because it's a better lens. That's the thing... there's such a wide range in quality (and prices) of lenses that you just can't make those kinds of generalizations. Somehow I expect an 18mm, f/1.4 Canon L-series lens (dunno if it exists, just tossing out some numbers for illustration) would be a LOT sharper than my 300D's 18-55mm f/4 "kit" lens, even wide open. --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 0602-1, 01/09/2006 Tested on: 1/11/2006 7:34:47 AM avast! - copyright (c) 1988-2005 ALWIL Software. http://www.avast.com |
#55
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fast glass?
Jeremy Nixon writes:
David Dyer-Bennet wrote: Indoors, it's even worse. I shoot my 58mm f1.2 NOCT at f1.2 fairly often. That lens is actually designed to be at optimum wide open. It's a great portrait lens, especially for available light candid portraits, on a 1.5x DSLR. Lets me blur the background if needed, too. Don't suppose you want to sell it? I've been looking for one of those at a non-insane price for quite some time now; very difficult to get hold of. I wish they hadn't discontinued them -- they were $1500 new, and I'd be willing to pay that for a like-new one, but people seem to hold out until someone comes along willing to pay much more. (I've watched people list and re-list them on eBay for weeks and weeks until someone finally steps up and pays $2k or whatever for a worn-out one with dust inside.) I lucked into mine for $700 used, back somewhere in the early 90s I think, at the National Camera Exchange "tent sale" at their store out on I394 here in Minneapolis. It was kind of a stretch, but that seemed like an awfully good price. (Then, B&H was listing them new for $1589 as I remember it; they may already have been out of production.) -- David Dyer-Bennet, , http://www.dd-b.net/dd-b/ RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/ Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/ Dragaera/Steven Brust: http://dragaera.info/ |
#56
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fast glass?
"Skip M" wrote:
"Tony Polson" wrote in message snip These are significant differences, and coupled with the excellent drawing (almost zero distortion), outstanding level of correction of aberrations and extreme consistency between samples, they go a long way to explaining the high price of Leica glass. Hmm, interesting. I guess I need to backpedal a bit... Only a little bit, Skip. What you said is true of over 99% of lenses. ;-) |
#57
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fast glass?
"Tony Polson" wrote in message
... "Skip M" wrote: "Tony Polson" wrote in message snip These are significant differences, and coupled with the excellent drawing (almost zero distortion), outstanding level of correction of aberrations and extreme consistency between samples, they go a long way to explaining the high price of Leica glass. Hmm, interesting. I guess I need to backpedal a bit... Only a little bit, Skip. What you said is true of over 99% of lenses. ;-) True, I did say I can _think_ of no exceptions... ;-) -- Skip Middleton http://www.shadowcatcherimagery.com |
#58
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fast glass?
everyone seems to want 'fast glass' - f/2.8, 1.7, 1.4, etc, but I'm left wondering 'why' As most people know, lenses are not at their sharpest wide open - usually requiring f/7 - 9 (ish) before they attain their maximum potential. So why the fuss about 'fast' lenses?, and why pay the huge premiums to own them? Most of my own lenses are 2.8, with one at 1.7, and one at 1.4 - yet I invariably have to stop down in order to get a nicely sharp image, which sort of defeats the object of the 'fast glass', doesn't it? I mean, why pay three times the price for a 'fast' lens, when you only end up stopping it down? I've got a theory that it's the mania for bright lenses that's behind a lot of the 'focus fuss' that clogs up the various forums - perhaps people don't realise that you're just not going to get the same image quality out of wide open lens and are mistaking 'softness' for focus issues. Just a thought. for the most part, you tend to get what you pay for in quality. There are exceptions of course. The advantages for having fast glass means that you have more options and choices. While its true that lenses are typically sharper a stop or two down, that suggests that my f/2.8 is great at 4 or 5.6 while your 5.6 might be ok at 8 or you might not even get a contrasty sharp image at 11. Along with faster exposure, you should get better contrast and resolution, less flair. Should, sometimes not. Keep in mind that most of the time the best lighting is found at minimum levels, twilight, open shade, window light. I find myself shooting at wide or a stop down, with a 1/15th second or slower quite often. Shooting at f/4 or 5.6 with a long shutter speed lets me shoot a wedding party on an altar and getting a nicely lit subject, and a lot of detail out of the background as the ambient levels build up to one stop under the flash exposure. This reply is echoed to the z-prophoto mailing list at yahoogroups.com |
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