I bought recently that lens, a 150/5.6 Componon-S on Compur #1 marked Linhof. The front and back elements have the same thread and are mounted with adapting rings so they can be reversed. My questions: what is the enlargement ratio where reversing the elements is advisable; and has anyone used that lens for macro work on 3 dimentional objects and what were the results like?

-- Paul Schilliger (pschilliger@smile.ch), April 19, 2002

Answers

Paul, I have a 135 f5.6 Componon S in a regular Copal 0 shutter that I use for general photography at f16 1/2 and smaller. Results are startling. I don't see a difference from my regular lenses. I would want to remount the 150 f5.6 in a factory barrel and measure the distance front to back and make sure that is the same with adapters in the size 1. That correct I'll wager you'll like it for macro things very much. Give it a go at infinity. You'll be surprised.

-- Jim Galli (jimgalli@lnett.com), April 19, 2002.

At Schneider's suggestion I mounted a 150mm Componon-S in a Copal 0, and it worked great. I know that the 100mm Componon-S Copal shutter, but I don't know which size.

-- neil poulsen (neil.fg@att.net), April 19, 2002.

After reading numerous posts on this subject I finally yanked my 150S elements out of the barrel and mounted them in a shutter. The assembled lens is now .020" shorter than it was in the barrel. Any opinions as to whether or not this is significant? I'll be testing it in the future, but I just want other's "educated guesses" as to whether I should get myself a .020" washer or not.

-- Wayne DeWitt (wdewitt@snip.net), April 22, 2002.

Thanks guys. Wayne my 150 on shutter measures 53 mm outer to outer. Unfortunately I have no precise scale to convert in inches but would wish to know if it matches your normal mount distance. Maybe this number can vary from one make to another, my Componon is in the 13 millions series.

In regard to my original question, I suppose that it would be worth exchanging the elements for ratios bigger that 1:2. (?)

Another question is boggling my mind: could someone tell me how I can translate DOF from MF to LF for the same image? For example, if I use a 90mm on 6x7 at f22, what would be the matching aperture on 4x5 for a 150 mm? I take a guess at f45, would that be right? (MF has some clear advantages over LF in this regard!)

-- Paul Schilliger (pschilliger@smile.ch), April 22, 2002.

Thanks guys. Wayne my 150 on shutter measures 53 mm outer to outer. Unfortunately I have no precise scale to convert in inches but would wish to know if it matches your normal mount distance. Maybe this number can vary from one make to another, my Componon is in the 13 millions series.

Coming back to my original question, I suppose that it would be worth exchanging the elements for ratios bigger that 1:2. (?)

Another question is boggling my mind: could someone tell me how I can translate DOF from MF to LF for the same image? For example, if I use a 90mm on 6x7 at f22, what would be the matching aperture on 4x5 for a 150 mm? I take a guess at f45, would that be right? (MF has some clear advantages over LF in this regard!)

-- Paul Schilliger (pschilliger@smile.ch), April 22, 2002.

Paul - My Componon 150S measures 52.9mm in barrel. My ser.# is 14,682,xxx. My guess is that +/-.1mm is not a problem with this type of design (I've never seen a shim on an enlarging lens). As for reversing the elements I would suppose that once you pass 1:1 the elements should be reversed, but until you pass 1:3 or 1:4 the differences probably aren't even noticeable at shooting apertures. And as for depth of field I find that there is about 2 stops difference between 35mm and 6x7 and another 2 stops (more or less) between 6x7 and 4x5 for the same acceptance angles.

-- Wayne DeWitt (wdewitt@snip.net), April 22, 2002.

Thanks Wayne, I think the small difference in length is due to the lack of precision in my measurement, obviously the lens is mounted correctly.

DOF is the real problem for macro work on 4x5. I have tested the same image recently on 6x7 and 4x5 with another lens even shorter (110) and despite the possibility of some tilt, I could not put the whole subject in focus. The 6x7 was in focus. But the Componon will be a perfect repro lens for flat objects.

-- Paul Schilliger (pschilliger@smile.ch), April 23, 2002.