View Full Version : converting the old Symmar 150/5.6 to 265/12

Mike Kovacs
21-Sep-2005, 16:23
I've been avoiding using my Schneider Symmar 150/5.6 in its converted 265/12 mode but I've been shown some compelling photographs suggesting that maybe I should drop my pre-conceived biases against doing this.

Question is, do you remove the front or rear group? I believe that the "official" way is to remove the front, but I've found many references on the web that it is fact better to remove the rear.

Any thoughts before I burn film trying both ways?

If anyone has some nice colour and B&W photos made with this lens in the converted mode posted on the net, I'd love to see them.

Kevin Crisp
21-Sep-2005, 17:13
Yes, it is best to test the conventional wisdom and actually try it. Remove the front element. Stop down to f:22 (at least, f:32 might be better) and recheck the focus after you stop down as it may shift. Some people think it works better with a yellow filter but I've not noticed any improvement with that.

21-Sep-2005, 18:05
The GREEN aperture scale is calibrated for the rear element (front element removed).

Mike Kovacs
21-Sep-2005, 18:13
Here is the beast, by the way - green aperture scale I had figured since the 2nd focal length is written in green on the namering.


Craig Wactor
22-Sep-2005, 16:18
When you say "element", do you mean just unscrew the entire front cell (so that the iris is exposed), or do you have to get a spanner wrench and take the actual front element? I'm not being jargon police, I'm actually confused and I've always wondered these lenses work.

Dan Fromm
22-Sep-2005, 16:21
Unscrew the whole front cell.

Good luck, have fun,

Michael Ting
22-Sep-2005, 19:34
Is this doable with all 150mm Schneider Symmars? My lens is a Symmar-S, but it doesn't have the green engraving on it.

Mike Kovacs
22-Sep-2005, 20:09
Don't know about the feasibility from an optics standpoint, doing it with a Symmar-S, but you won't have the green scale for the aperture. You can't see it in my photo but it is visible when you unscrew the front cell. f/12 corresponds to f/5.6, f/45 is just about aligned with f/22 on the white scale.

Mark Sampson
23-Sep-2005, 12:01
When Schneider designed the Symmar-S lenses (and all subsequent models) they gave up the convertible feature, in order to get better corrections with both cells combined. That's from a brochure introducing the Symmar-S, about 1972. Doesn't mean you couldn't try it though.

Jeff Genung
23-Sep-2005, 17:18
Does the instruction to:"remove the front cell" work for all the Dual Symmars?---Are there any that you have to remove the rear cell?---I have a "new" 180-315 that I have yet to try out.

Dan Fromm
23-Sep-2005, 18:44
All, Jeff. See http://www.schneiderkreuznach.com/archiv/pdf/sr_5.6_a.pdf

26-Sep-2005, 03:27
I purchased my 150 symmar new, way back in the late 1960's and am still impressed to this day with the images, sharpness and contrast are outstanding. I have never had any luck using the convertable feature, even when adjusting for the focal shift when stopping down. There was no conventient way to mount filters without the front element in place. Considering the trouble and the unreliability of image quality, I solved this problem by purschasing a 300 mm lens.

Ed Richards
26-Sep-2005, 05:54
I dug around and found a negative I shot with mine converted - looks OK with the 8x magnifier. Grimes can make you a filter adapter for the front element mounting thread for about $50. I decided that taking lenses apart in the field was an invitation to disaster - right after watching a B&W filter disappear into tall swamp grass.:-) Bought a Fuji 250 F 6.3 - they are cheap, take 67mm filters, are multi-coated, and very very sharp.

Mike Kovacs
26-Sep-2005, 08:09
I agree that a dedicated lens is in order eventually, but baby steps! (just bought a 90/8 Fujinon-SW)

Ed Richards
26-Sep-2005, 14:01
Even before the filter dropped off the front of my lens and disappeared into the swamp grass, I got really nervous about putting my finger or something else through the shutter or diaphragm when I had the front element off. I also thought about grit getting inside.

My bet, having tried this at 270, is that you can get as good a quality cropping the normal 150 shot at F16 where diffraction is not affecting the image as you can shooting the 270 at F32 to minimize the artifacts.