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Post by Randy on Nov 23, 2006 10:00:59 GMT -5
I think I know what the term "fast lens" means, but for the benefit of those here that don't, could someone please define the term?
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Post by Peter S. on Nov 23, 2006 11:45:57 GMT -5
I think, it is a fuzzy and highly relative label. The fastness, that is assigned to a lens deals for some part with the competition, for the others it deals with the film format (can we assume, were're talking on 35mm film, only?), with focal length, whether we're talking on a zoom.
For normal lenses (I'll only talk on 35mm now) some tend to say, F1.4 and below is fast, while others say, all normal lenses are fast, since they are F2 or below. I don't know, and it might be pointless. The only point to note seems to me, that there are F1.4 available for most the camera systems. And half a f-stop might be gained by selecting a different film...
For wide angles in the range from 28 to 35mm everything equal or below F2 can be considered as fast. I don't know, whether anybody ever labeled an MD W.Rokkor 2.8/24 as fast...
Even more important is the focal length of a telephoto lens. For 80..100mm F2 might be available easily (though not without being seriously acompangied by cost). At 135mm F2 is already a scarce thing (I got one, and it cost me a *lot* of money). So taking up the number of deployed units argument, F2.8 might be called fast for a 135mm without much hesitation. F2.8 means fast for 200, and superfast for 300+mm lenses. For 500mm lenses F4 is already a super-tele, which is a dream lens for virtually all photographers out there.
Well and then there is this Carl Zeiss Apo Sonnar T* 4/1700 for Hasselblad. I suspect even a Quatari sheik will call this one fast. Maybe referring to the speed his money had been vaporized.
Best regards Peter
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Post by kiev4a on Nov 23, 2006 12:08:52 GMT -5
Given the apertures on many of the entry level lenses today, especially zooms, I consider f2.8 or larger as "fast". If a 2.8 lens and 400 film won't handle a situation, I'm probably gonna strap on a flash anyway.
The fastest lens I have is a f1.5 on a Contax II. In my Nikon lenses F1.8 is the fastest. The f1.4 is too bulky for what would be gained, IMHO. With today's films "fast" lenses aren't as important as they once were. Once you get above 1.8 -- especially in SLR lenses ---the bulk and weight increases dramatically.
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bobm
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Post by bobm on Nov 23, 2006 12:45:10 GMT -5
Canon make two WA zooms in their top end 'L' series - 2.8/16-35 and 4/17-40 and it's the 17-40 which seems to be more popular, although I suspect that that's more to do with the fact that the 16-35 is nearly twice the cost of the 17-40 just for that extra stop. As does the cost...... Canon EF400 2.8 - nearly 5k GBP.......
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Post by doubs43 on Nov 23, 2006 14:52:19 GMT -5
In the days when the first "fast" lens were introduced to 35mm photography, the critical limiting factor was the available film. Pre-war film was either slooow or grainy (or both) and IIRC, Kodak Super-XX at ISO 200 was the speed king of it's day. There were those who "pushed" film to higher values with a corresponding loss of overall quality but for some any image was better than no image. "Available light" photography was the rage for pros such as news photographers and for amatures. The "fast" lens helped to satisfy the need for speed.
As already stated, it began with the f/2 and escalated with the f/1.5, 1.4, 1.2 and .095 lenses. The later f/1.9, 1.8 and 1.7 lenses offer little speed improvement over the f/2 lenses but were a good selling point. In spite of rather poor edge resolution by today's standards, the early Sonnars and Xenars and such turned out some excellent work..... and a good example still can.
Once manufacturers went to rangefinder lenses faster than f/1.4, physical size and weight became a negative for many photographers. That's not even taking the astronomical prices they demanded into account. Even some of the f/1.4 lenses made for SLR cameras were large, as Wayne points out with a specific reference to Nikon. I'll add Rikenon, Yashinon and Mamiya-Sekor to that list. Two makers who managed to keep their f/1.4 normal lenses smaller than most are Asahi (Takumar) and Olympus (Zuiko). Both are top quality mechanically and optically and both use 49mm filters.
With film cameras now taking a back seat to digital, the likelyhood of a new, improved "fast" normal lens being introduced is as remote as a warm sandy beach in Antartica. The Nikkors, Takumars and Zuikos are likely to be the zenith of fast normal lenses for film cameras. However, no one need feel blue if you have an f/1.4 50mm lens from any of the three as they are all outstanding. I look at slides I took over 30 years ago with my first OM-1 and it's Zuiko 50mm f/1.4 lens and I'm still impressed by the quality. When I traded up to an MD body a few years later, I kept the lens.... and I still have it today. I recently picked up another OM-1 MD body with a pristine 50mm f/1.4 Zuiko on it and I'll be keeping it too.
Pairing today's fast films with yesterday's fast lenses makes us among the luckiest photographers ever. We can all indulge our "available light" desires.
Walker
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bobm
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Post by bobm on Nov 23, 2006 16:20:48 GMT -5
Agreed - the best of yesteryear coupled with the best of current technology. I suspect this may explain the current obsession, for want of a better word, of the DSLR brigade (of which I'm a fully paid up member... )with using older glass, especially WA since the current crop of DSLRs, especially Canon ( ) have such good higher ASA speed performance with their digital equivalent. Not that there's anything wrong with that of course, although it does tend to push the price up due to simple supply and demand, especially with 'classic' lenses like Flektogons and the like.
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Post by Just Plain Curt on Nov 23, 2006 17:34:40 GMT -5
Fastest lenses I have are f1.4 by Ricoh, Yashica, Pentax, Minolta, Canon and Fuji.
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Post by Randy on Nov 23, 2006 22:18:21 GMT -5
I don't think you guys have defined the term "fast" yet.
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Post by nikonbob on Nov 23, 2006 22:31:17 GMT -5
For me a fast lens is a 50mm/1.4, any wide angle and any short telephoto lens at F2 and any long telephoto at F2.8. Anything faster is silly fast but fun and expensive. Not being a big fan of expensive fun I virtually own no silly fast lenses. The exceptions being a 35 pre asph lux rarely used at F1.4 and an 85 Nikkor F1.8 used wide open ocassionaly. With todays really good 400/800 asa C41 films I have not found a real need for anything faster with an SLR. In RFs I can settle on slightly slower lenses and still be OK.
Bob
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Post by Randy on Nov 23, 2006 22:49:34 GMT -5
When we say a lens is fast, it's a reference to its largest aperture, or widest possible opening. A fast lens has a very wide maximum opening, allowing more light to pass through the lens, therefore permitting the photographer to use faster shutter speeds or to shoot in dimmer light. Generally, the larger a lens's maximum aperture, (or iris opening) the more expensive the lens is. Depending on Focal Length, (28mm lens short, 500mm long) an F Stop of less than F-2 is considered Fast. A low F Stop being F-2 or below. Albeit when the lens is wide open it allows more light into the camera but Depth of Field is sacrificed..............Now here is another poser, which is faster, a 50mm F-1.2 lens with a 49mm filter ring, or a 50mm F-1.2 lens with a 58mm filter ring? Does the latter let in more light?
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mickeyobe
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Post by mickeyobe on Nov 24, 2006 2:43:47 GMT -5
Randy,
"I don't think you guys have defined the term "fast" yet."
It is simply a lens with loose morals.
Mickey
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bobm
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Post by bobm on Nov 24, 2006 3:59:43 GMT -5
Some lenses also seem to suffer more from light fall-off in the corners and/or vignetting when used wide open. Yet another factor is edge to edge sharpness compared with the centre - this is why lenses designed for FF invariably perform very well on 1.6x crop DSLRs as the camera sensor only ever 'sees' the centre. Having said that, it's not all a bed of roses as the crop factor naturally determines any lens' field of view on that camera, so that a 35mm becomes a 56mm or a 50mm becomes an 80mm etc. Hey Randy - bet you wish you hadn't started this now, eh......? ;D
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Post by Randy on Nov 24, 2006 8:50:30 GMT -5
No Bob, it's okay. Actually, I was looking for an answer in the simplest form, not a lot of technical jargon which may confuse someone just starting out. I have a KODAK Photography book, and the definition I gave came from it. One would assume that the larger a window is, the more light gets into the room, no? Hope you guys had a great holiday.
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PeterW
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Post by PeterW on Nov 24, 2006 9:24:04 GMT -5
OK, you guys have got me going again.
What is a fast lens? Fast is a very imprecise relative term. Fast compared with what? With lenses fast, meaning with a large maximum aperture, is relative to the technology at the time and, as Walker pointed out, the need to produce ‘faster’ lenses was driven by the slow emulsions available at the time. It also depended on the type of picture the photographers of the time wanted to take, the image size on the plate or film and the focal length of the lens.
One of the earliest ‘fast’ lenses was the Petzval Portrait designed by the Hungarian professor of mathematics Josef Petval and made by Voigtländer in 1841. It had a, for the time, massive maximum aperture of f/3.6. Definition fell off rapidly outside the middle third of the image, but for studio portrait work that didn’t matter. I don’t remember the focal length, but it was made to cover plates 8 ½ by 6 ½ inches and also 10 by 8 inches. It brought daylight studio exposures down to under a minute.
Later, in the middle 1860s, Dallmeyer made a different design of portrait lens with a maximum aperture of about f/3 and a focal length of 300mm. Maximum sharpness was better than the Petzval lens but was confined to the very centre of the image, usually the subject’s eyes, and then fell off rapidly. However, by moving a lever the photographer could alter the sharpness so that it was slightly reduced at the centre but spread more widely over the image, so he could produce whatever degree of ‘soft focus’ he wanted.
No-one outside portrait work needed such ‘fast’ lenses until the rise of illustrated newspapers and magazines and the ‘news photographer’ who needed to take informal pictures by available light, often indoor artificial lighting. In 1924 Ernemann startled the news world by producing the Ernostar f/1.8 lens, a huge chunk of glass mounted on the front of a 6 by 6.5mm plate camera called the Ernox (nox from the German word for night) which was later renamed the Ermanox.
The Ermanox reigned supreme in this type of work till the advent of the 35mm precision camera, first the Leica and then the Contax. It’s interesting that Bertele, who designed the f/1.5 Sonnar for the Contax in 1930 worked for Ernemann before that company was absorbed into Zeiss Ikon in 1926, and was one of the design team on the Ernostar.
These early ‘fast’ lenses were very expensive and were confined to professional photographers who needed them, or a relatively few moneyed amateurs who wanted them because they were the latest thing available.
As lens technology and optical glass improved, the price of ‘fast’ lenses dropped until any lens for 35mm SLR with a maximum aperture smaller than f/2 was considered slow. At the same time, emulsion technology improved until we got ASA 1600 emulsions with acceptably fine grain. Most amateurs didn’t need an aperture as large as f/2 or f/1.8 or f/1.4, but the technology was there so lens makers made them because to the average amateur ‘faster’ meant ‘better’. How many average amateurs, I wonder, ever used these lenses at maximum aperture?
PeterW
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bobm
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Post by bobm on Nov 24, 2006 9:32:14 GMT -5
Leaving aside all the other factors referred to previously, in a nutshell, the answer is yes.
Interesting - someone on another photography board raised a similar question of who nowadays uses any lens at maximum aperture?
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