LF Lens Design - Que?greenspun.com : LUSENET : Large format photography : One Thread
I just have to ask the question - why does anyone really care if the lens is a tessar design, triplet design etc.? I have used a number of lenses over a nearly 40 year time period and haven't given the actual lens design any thought.
Since I have no control over the design chosen by the lens designer/manufacturer - what result should I expect to get from a different type of lens design? At the moment, I use two Rodenstock Sironar-S lenses, one Rodenstock Grandagon, and a Schneider XL series (oh, and one really old Schneider convertible). I look for circle of illumination, MTF, and contrast.
What am I missing? Is looking for a certain lens design important - or is it like putting a lead brick on my stereo amp to "damp out microphonics"? (Or, should I only use electricity generated from a hydroelectric plant because it's "cleaner sounding" than that from a nuclear plant?) You get the idea - am I looking at a lens design or the end result (photo)?
-- steve (email@example.com), August 29, 2001
Lens design is not really of any importance. Like you mentioned, image circle is the most important (it must cover your film and provide for movements). You will find that the more modern designs with large circles of coverage are more complex designs, using up to 6 or more elements.
-- Ron Shaw (firstname.lastname@example.org), August 29, 2001.
I think it's like saying, "a vacuum tube amplifier or a transistor amplifer, who cares, I only want the one that sounds best." While that statement is true, an audiophile would tell you that each type amplifier has characteristics that are distinct, characteristics that don't necessarily equate to which one is better. I think the same may be said of lenses, someone who really knows his stuff may have a very good idea of the characteristics of a lens simply based on the fact that it is a triplett.
-- Dave Schneider (email@example.com), August 29, 2001.
Steve: I couldn't agree with you more. We all tend to get hung up on triviality to a point. A good four element tessar design offers great contrast and plenty of sharpness. I use one a lot. I also have three six element lenses in addition to a couple of tessar design lenses. The biggest difference is in coverage. The tessar designs don't cover as much as the six element designs, which can make a difference with normal or shorter than normal lenses. However, in actual use, I seldom run out of coverage with my 150mm Schneider Xenar. The four element designs usually have great contrast. The three element designs are about the minimum that will give sufficient quality for 4x5 and smaller. Some good photographs were made on 8x10 and larger negs with two element lenses. As for hydroelectric power for your stereo system, the electricity may be cleaner but it has a higher moisture content, which can warp speaker cabinets under some conditions.
-- Doug Paramore (firstname.lastname@example.org), August 29, 2001.
"I look for circle of illumination, MTF, and contrast." "I use two Rodenstock Sironar-S lenses, one Rodenstock Grandagon, and a Schneider XL series"
you don't need to care about lens design, you've already considered important effects of lens design. some people like to know how and why things work. sometimes more information can be helpful, sometimes it's unnecessary.
-- adam (email@example.com), August 29, 2001.
To digress slightly because it's so much fun...
"I think it's like saying, "a vacuum tube amplifier or a transistor amplifer, who cares, I only want the one that sounds best." While that statement is true, an audiophile would tell you that each type amplifier has characteristics that are distinct, characteristics that don't necessarily equate to which one is better."
The interesting thing about that statement is about 12 years ago Bob Carver (don't you just love him?), came to Santa Fe, NM to challenge the folks at Stereophile magazine. He said that he could make a transistor amplifier sound exactly like a tube amp. They set up a double blind test using a Conrad Johnson tube amp and one of Carver's transistor amps. Those with really good ears could tell the difference. Carver then made electronic measurements of the tube amp and went to a local motel for 24 hours to modify his transistor amp.
The next day the double-blind test was performed again, and no one could tell the difference between the sound of the two amps. Carver said it wasn't all that difficult to modify the transistor amp (mostly had to do with slew rates and damping factors) and a few components added to give it a "warmer" sound...
But, I digress..
And thanks to Doug for pointing out the true problem with hydroelectric power.
-- steve (firstname.lastname@example.org), August 30, 2001.
The main difference is in the covering power. No triplet or Tessar design will give you the same covering angle as a symmetrical lens, but you lose a little contrast with more complex lenses.
Lens design is not completely irrelevant if you have a particular need in mind, but it's very much a case of 'horses for courses'.
BTW, none of the lenses you've mentioned are 3 or 4 element designs.
Another Hi-Fi test that I read of, had a panel of audiophiles split over whether a live quartet hidden behind a curtain had less distortion than the recording made of them earlier.
May your bass be 'fast' and your treble have sincerity. (I'm not sure if that's a blessing or not. Wouldn't the tuba finish ahead of the rest of the band?)
-- Pete Andrews (email@example.com), August 30, 2001.
Hey, looking at the lens cross section diagrams is a great way to kill time while your waiting for the lens to come in the mail. Dean
-- Dean Lastoria (firstname.lastname@example.org), August 30, 2001.