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150mm G-Claron the WRONG lens for Over 25" Paintings?
Hi,
I got a hold of a brochure for the G-Claron: "The normally used range of linear magnification is between 5:1 and 1:5. ...the G-Claron may also be used for distances up to infinity by stopping down to f/22 or less." Ok, so if i understand this correctly, the reduction is 1:5, so if you take the largest side of 4x5, this would be a maximum of 5x5=25" on the largest side of the painting. So i was taking about 35" images @f16, so perhaps this was out of the range of the lens? Or perhaps i really needed f22, even at this size, and not just for infinity? One fellow at KS said that the G-Claron is mainly for really up close marco work, like product pics of wallets and purses and stuff like that. And that some people use it for landscape work when stopped down more than f/22, because it's a very light shutter and lens. Then he recommended a 150mm Rodenstock Apo-Sironar-N, and didn;t charge me for the rental because the pics i took with the G-Claron didn't turn out (nice, eh?). Said this would be good for 8.5"x11" up to 3'x4', as well as infinity. The brochure says the optimum aperture for 4x5 is f16-22. I'll try f16, f22, and f32 tonight! Slick |
#2
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150mm G-Claron the WRONG lens for Over 25" Paintings?
"Dr. Slick" wrote in message om... Hi, I got a hold of a brochure for the G-Claron: "The normally used range of linear magnification is between 5:1 and 1:5. ...the G-Claron may also be used for distances up to infinity by stopping down to f/22 or less." Ok, so if i understand this correctly, the reduction is 1:5, so if you take the largest side of 4x5, this would be a maximum of 5x5=25" on the largest side of the painting. So i was taking about 35" images @f16, so perhaps this was out of the range of the lens? Or perhaps i really needed f22, even at this size, and not just for infinity? One fellow at KS said that the G-Claron is mainly for really up close marco work, like product pics of wallets and purses and stuff like that. And that some people use it for landscape work when stopped down more than f/22, because it's a very light shutter and lens. Then he recommended a 150mm Rodenstock Apo-Sironar-N, and didn;t charge me for the rental because the pics i took with the G-Claron didn't turn out (nice, eh?). Said this would be good for 8.5"x11" up to 3'x4', as well as infinity. The brochure says the optimum aperture for 4x5 is f16-22. I'll try f16, f22, and f32 tonight! Slick |
#3
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150mm G-Claron the WRONG lens for Over 25" Paintings?
"Dr. Slick" wrote in message om... Hi, I got a hold of a brochure for the G-Claron: "The normally used range of linear magnification is between 5:1 and 1:5. ...the G-Claron may also be used for distances up to infinity by stopping down to f/22 or less." Ok, so if i understand this correctly, the reduction is 1:5, so if you take the largest side of 4x5, this would be a maximum of 5x5=25" on the largest side of the painting. So i was taking about 35" images @f16, so perhaps this was out of the range of the lens? Or perhaps i really needed f22, even at this size, and not just for infinity? One fellow at KS said that the G-Claron is mainly for really up close marco work, like product pics of wallets and purses and stuff like that. And that some people use it for landscape work when stopped down more than f/22, because it's a very light shutter and lens. Then he recommended a 150mm Rodenstock Apo-Sironar-N, and didn;t charge me for the rental because the pics i took with the G-Claron didn't turn out (nice, eh?). Said this would be good for 8.5"x11" up to 3'x4', as well as infinity. The brochure says the optimum aperture for 4x5 is f16-22. I'll try f16, f22, and f32 tonight! Slick It should work fine for the paintings. They are not much out of the optimum correction range. The main aberation picked up when outside of the optimum object to lens distance is coma. Coma is proportional to the f/stop so stopping down gets rid of it. You should be able to work at f/16 without any loss of quality at the corners. The APO Sironar-N may or may not be a better lens but its optimised essentially for infinity (actually for around 20 feet) so the G-Claron is actually more nearly in its optimum range. To find the widest f/stop you can use look at the corners of the image. Check using a small bright highlight, even a pen light at the corner. When wide open the image may have a slightly tear-drop shaped smear. As you stop down it will shrink and finally disappear. That's the largest stop you should work with. Symmetrical and semi-symmetrical lenses are automatically corrected for coma when the entire system is symmetrical but have very substantial cancellation of coma even at infinity focus. Field flatness and other aberrations should not be a problem. -- --- Richard Knoppow Los Angeles, CA, USA |
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