Follow-up on Compon 150 mm f/5.6 as a convertible

[Donald Qualls]

A few months ago, I asked a question on this forum about the picture taking qualities of the Componon (not Componon-S) 150 mm f/5.6 lens as a taking lens, including whether it was convertible as the Componon-S (very similar to a Symmar) is.

I can now report that I'm pretty happy with the results of using the rear group of the Componon by itself. I haven't measured precisely, but have reason to believe the focal length is similar to the 265 mm f/12.5 I've been quoted for the Componon-S rear group; using a 2.5 stop compensation from the whole-lens aperture scale, I've gotten good exposures and image size consistent with a 265 mm focal length. Detail and sharpness over the 4x5 field looks good, to my eye, at least in prints up to 8x10 (I don't have the space to process larger prints, nor paper to print on, nor the enlarger column height to crop at much higher magnification from 4x5), as well as in 2400 ppi scans. I've (so far) only shot at around f/22; using a monorail, there's little incentive to sacrifice DOF for shutter speed. Once I get my bellows translucency issues corrected, I'll likely experiment with smaller openings -- I should be able to stop down as far as f/107, though I'd surely be trading off resolution for DOF well before then.

[tor kviljo]

Thanks for interesting info, Donald!! I have never thought about that myself, even though I have tinkered a lot with optics. With heaps of homeless enlarger lenses around, this may be a very fine entry set as the 150/5.6 componon fits directly into a nr. 0 shutter I belive - making up a very light 4"x5" travel set with one shutter & two FL for the backpackers set. This idea ought to be added to Tuan's page as part of the LF primer as it is a healty addition to a minimum budget LF set-up..

By the way, the componon have also been sold mounted in shutters , for macro & tabletop work, so I guess it - as many repro/enlarger lenses, function nicely in the light as well as in the dark...

[Donald Qualls]

Actually, Tor, mine is in a #1 Polaroid Prontor-Press (from which I recently removed the restricting collar); it has the same threads as a 13.5 cm f/4.5 Skopar and 13.5 cm f/4.5 Radionar that I own, both in mid-1930s vintage #1 rim-set Compur shutters.

Say, I should see what the Componon can do on my Kawee Camera. No way will the camera close with it on there, but it should work otherwise, as long as I focus on the ground glass...

But yes, the only difference between a macro/repro lens and an enlarging lens is which side the light comes from. The imporant thing with these lenses is they also work well at and near infinity focus, and with the front group removed.

[Dan Fromm]

Donald, I'm not sure you're right about the difference between taking and enlarging lenses, at least as far as Componon Ss and Symmar Ss go.

As far as I can tell, the cell spacing differs. And that's why I haven't hazarded the price of a 100/5.6 Componon-S to try one as a taking lens.

If someone has done the experiment and I'm mistaken about how good a 100 Componon-S is as a taking lens, I'd love to know it.

Cheers,

[Turner Reich]

Donald you are the most inventive investigator I have seen. I never thought of looking at the enlarging lens as a taking lens not to mention as a convertible. You never know what you will find until you check it out.

Thank you

tr

[Donald Qualls]

Turner, I bought the lens already mounted in a shutter, and I've read tens of thousands of words on forums about using enlarging and process lenses as taking lenses. What led me to test the Componon as a convertible was the somewhat convoluted chain of similarities -- Componon is similar to Componon-S, which is similar to Symmar, which were once sold as convertible lenses. In practice, any plasmat ought to be convertible, but depending on the optimizations made in design and manufacture, some will be more useful converted than others (just as some enlarging and process lenses work better as taking lenses than others do, depending on the compromises made or needed to optimize them for macro focus as opposed to infinity).

I won't claim the Componon is equal in image quality to a modern Symmar-S; in fact, it seems to be very slightly less sharp (as a whole lens) than my 13.5 cm f/4.5 Skopar. OTOH, the Componon, in shutter, was only $180 with shipping, and that's for effectively two lenses. Given the problems with my Aletta and my lack of time and resources to make effective repairs there, the lens is currently mounted for my Speed Graphic -- where it will see most of its use with only the rear group, since that makes it a pretty nice long lens for that setup (albeit not very hand holdable, given it's both long and slow) (otherwise, the 150 mm is too close to the 135 mm Skopar to have much attraction).

[Turner Reich]

Donald now that's a good idea, putting it on a Speed Graphic, I have a Bush 2x3 so this route looks encouraging. I might come up with long lens for it and save some weight and money. I just have to look at the shutters I have and find something to match to one.

Thanks

tr

[Donald Qualls]

One of the advantages of mounting lenses under test to a Speed is that, by using the focal plane shutter, you don't have to find a shutter the lens will fit; you can just mount the lens on a #1 board as you would on an enlarger board and test away. In fact, my Componon is in shutter, and was that way when I purchased it -- but with a Speed, it wouldn't technically need to be. However, use of the FP shutter does produce a "no man's land" range of exposure, between the 1/10 slowest shutter setting and the 1/2 or 1 second that's the shortest manual exposure comfortable with the T setting: trigger, allow shutter to run to Open, and trigger again to run to Closed -- absolute mechanical minimum is about 1/4 second and I can't be sure of getting under 1/2. I suspect in the original top-handle Speed and early Annies, normally sold only with barrel lenses, the technique was to use lens cap shuttering for speeds slower than the slowest FP speed.

[Turner Reich]

Donald that's something I wish now I had thought about, having a focal plane shutter on a Speed Graphic. I do have a one of those bulb and one speed shutters but I havn't used it on anything. It came with a lens I bought so I got it free. I once had a Graflex, the old box type with a loud big focal plane shutter, nearly forgot about it until now. It was kinda fun and funky. It smelled like the Goodwill bargan basement though. It's funny how that "old" smell relates to the that camera for me.

tr