Film & Soup for Lens Rez testinggreenspun.com : LUSENET : Large format photography : One Thread
In the old days we shot Panatomic -x and developed in Accufine. Both seem defunct now. I want to test some MF and LF lenses using the big Edmunds wall chart.
I have some TMax 100, 400 in 120 APX100 & Arista 100 in 4x5, and Tri-X in both. I tried TMax100 in TMax developer but ran into grain problems before I lost the patterns.
I have Rodinal, D76, Dektol and Microphen available.
What would be the best combo for lens testing? Should I shoot at a high ISO? (ie: 100 at 400).
-- Bill Brady (email@example.com), December 17, 2000
Acufine is still around.
http://www.calumetphoto.com/calumet/ProdSearch.taf? _function=detail&qryItem_Copy_Parent_uid1=BR5732&type=SPDSEARCH&_UserR eference=DE0811FDF45CBAE63A3D49E5
If you want the best res though, wouldn't Tech Pan be your meat? Then you'd have to use Kodaks Technidol or Rodinal at 1:125 or something
-- Sean yates (firstname.lastname@example.org), December 17, 2000.
Isn't what you get on film a combination of lens and film resolution. If its a lens test you want to do, I suspect you need to examine the aeriel image. If that's not possible, I would second Sean's suggeestion of Tech Pan - the ceiling should be high enough to yield better data than other films with lower resolution. Good luck. DJ
-- N Dhananjay (email@example.com), December 18, 2000.
Like Fred Picker used to say, don't shoot test charts, shoot pictures. Find a bare limbed tree and shoot that and see if it is sharp, after all the rez charts and stuff, the proof of the pudding it in the quality (sharpness/contrast)of the picture the lens takes. Pat
-- pat krentz (firstname.lastname@example.org), December 18, 2000.
>Bill - What's the deal on testing the lenses?<<
1. By using a standard target, I can compare lenses I do have with the published numbers for lenses that I don't have. Why? because I may want to sell one and replace it. I would even like to know how the individual lenses compare with others of the same type.
2. I can test my lenses at various distances, allowing me to choose the proper lens for, say, close-ups.
3. I can compare my lenses with each other. Knowing the relative sharpness of each lens helps me decide which lens to use to obtain the desired results.
4. By testing now, and in the future, I may be able to detect any change in a lens' performance.
5. It helps me to judge a film/developer performance and to find any weak spots in my technique.
6. I have aquired a taste for lenses made in the former Soviet Union. These lenses are often a mystery performance wise, and there is an awful lot of misinformation circulating about them.
The Edmunds target also allows me to judge the color performance of my respective lenses. Important for astrophotography and very hard to judge by "eye".
I shoot enough variety that I find that every lens gets used, sharp or not. In fact, I have often used a lens that was *not* sharp for portraits. I also understand that "sharpness" is more often a product of local contrast and edge effects than lens resolution.
Thanks for your interest!
-- Bill Brady (email@example.com), December 18, 2000.
Bill, The answer has always seemed simple to me but maybe I'll get feedback to this. Get some Arista APHS halftone graphic arts film from Freesyle (cheap!) Make your exposure, turn on the red light, pour in some Dektol or whatever else is laying around, and the stuff will turn black and white. No grain no tones. I suppose this precludes the "real life situation" testing idea, but if you just want to know how many lines a lens will make............Jim
-- Jim Galli (firstname.lastname@example.org), December 19, 2000.