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Post by nikonbob on Nov 24, 2006 10:05:02 GMT -5
All things being equal, I do not use my lenses at wider aperatures than F4 normally with 35mm film. Digital with the very small sensors in the digi cams that I have is another story. I do shoot wide open very often just to try and get the same OOF that is possible at F4 on a 35mm film camera. If you are not an available dark shooter you are wasting your money on fast lenses and paying a price in poorer image quality and increased size/bulk to carry around. OTH it is nice to have those wider aperatures available when really needed. No I do not think many amerature photographers use fast lenses wide open.
Bob
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bobm
Contributing Member
Posts: 36
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Post by bobm on Nov 24, 2006 10:17:49 GMT -5
The main reason I have a Flektogon 4/20 isn't for the speed, or lack of it, it's for the lens' field of view, but especially for the lack of distortion when compared with the f/2.8 version of the same lens. That, and I just had to have it..........
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Post by nikonbob on Nov 24, 2006 14:23:37 GMT -5
The main reason I have a Flektogon 4/20 isn't for the speed, or lack of it, it's for the lens' field of view, but especially for the lack of distortion when compared with the f/2.8 version of the same lens. That, and I just had to have it.......... I could say the same about my 21/4 CV lens. OTH the faster lens stopped down to the slower len's max aperture maybe just as good. I think I would still pocket the difference and get the slower lens being the grinder that I am. Bob
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Post by John Parry on Nov 24, 2006 15:41:43 GMT -5
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? Randy - that's easy! The 1.2 with the 58mm filter has vastly different glass to that with the 49mm. It's all down to the production of the glass. It's final ingredient is down to the production process - the final stage consists of a hot bubbling crucible of molten glass, and somebody stirring it with a big wooden sp'oon.... Regards - John
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Post by doubs43 on Nov 24, 2006 16:56:55 GMT -5
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? HAH! That's a trick question as I don't believe you can design an f/1.2 50mm lens that can use 49mm filters! The other possible answer is that filter ring size has nothing whatsoever to do with the ability of a lens to transmit light. Assuming the same optical formula is used for both lenses, the transferal of light would be identical. Placing a filter in front of each with the same factor would result in the same amount of light being seen by the film. However, the larger filter may be subject to creating flare to a greater degree. For me it's all academic because I seriously doubt that I'll ever own an f/1.2 50mm lens. Too much money for me to even consider. Walker
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PeterW
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Post by PeterW on Nov 24, 2006 19:49:53 GMT -5
Walker wrote I agree with Walker, The size of the front element shouldn't have anything to do with the amount of light transmitted through the lens. I have an idea though, just my own idea with nothing to back it up, why some faster lenses, particularly some of the older ones, have what seem to be oversized front elements. As we all know (I hope) the image thrown by a lens at the film plane is circular. The further you get away from the centre of the circle the less sharpness you get and the more aberrations start to creep in. The designer is concerned with getting a sharp image with as few aberrations as possible right to the corners of the film format, so for 35mm he has to work on the diagonal of a 24x36mm rectangle. He is more likely to achieve this if he makes the lens throw a larger circle and uses only the middle part. The larger the format, the bigger he has to make the circle. Possibly one reason why, as maximum apertures got larger, the popular 6x9 format gave way to 6x6, and possibly why a 24x24mm format 35mm camera like the Robot got away with f/3.5 with a small diameter front lens and a simple rotary disc shutter OK, just an unsupported and unresearched idea. Actually I'm too lazy to research it. You'd probably have to find several lenses of the same focal length and max aperture but different diameter front elements and project their circular images on to a screen. Anyone care to knock it down? PeterW
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Post by Peter S. on Nov 26, 2006 8:35:24 GMT -5
I wonder, why the Noct-Nikonians didn't opt for those Rodenstock lenses, aparently available in a small selection with focal length from 24mm to 80mm. The fastest lens got F/0.75, the slower F/1. They might not have been intended for photography rather than TV (where in former days the cameras seemed to be terribly slow using all these Vidicons and other assorted tubes). Anyway, I found an interesting site: www.naturfotograf.com/need_speed01.htmlBesides he renders the argument pointless, that says, those lenses weren't able to produce good images. Best regards Peter
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bobm
Contributing Member
Posts: 36
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Post by bobm on Nov 26, 2006 11:49:42 GMT -5
So that's where I've been going wrong all these years - why can't manufacturers specifically state this in the instruction manual.............?
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Post by Peter S. on Nov 26, 2006 12:20:05 GMT -5
If You were in the US, there might be some hope in sueing them... P - :-P
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Post by John Parry on Nov 26, 2006 14:26:44 GMT -5
Another good tip is "don't wear black eye patches on both eyes at once" LOL
Regards - John
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bobm
Contributing Member
Posts: 36
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Post by bobm on Nov 26, 2006 15:15:54 GMT -5
That too....? I'll tell you something, there's more to this photography malarkey than meets the eye..... LOL
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Post by Randy on Nov 26, 2006 17:03:49 GMT -5
OCH! Malarchy!
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bobm
Contributing Member
Posts: 36
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Post by bobm on Nov 28, 2006 4:09:16 GMT -5
Aye, it's the banter I tell ye....
"Hoots mon, there's a moose loose aboot this hoose...... da da dah da dada dada da da da....."
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Post by wolves3012 on Dec 9, 2006 15:02:00 GMT -5
For me a "fast" lens varies with focal length. An 800mm F/2 would be VERY FAST but for a 50mm it'd just be averagely fast. "Fast" is a vague term with no definition really. Faster lenses generally cost more, weigh more and sacrifice quality. Slow lenses can also sacrifice quality if they are slow for cost reasons. Minolta's MD 50mm standard lenses are a good example, where the F/1.4 isn't as good as the F1.7 because it's compromised for speed and the F/2 is a budget mdel - so the F/1.7 ends up the best.
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Post by Peter S. on Mar 31, 2007 18:56:17 GMT -5
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