Schneider Componon S 50mm 2.8 construction/optics?greenspun.com : LUSENET : B&W Photo - Printing & Finishing : One Thread
ok, i got to check out one of my Christmas presents yesterday, a new to me Schneider Componon S 50mm f/2.8 fresh off ebay, i think it's the new kind as it has the slide lever that opens/closes the irises without twisting the aperture ring... it looks to be in very good condition except for one thing, the short metal ring that exists around the rear element (where the filter ring is for front element, i presume it's only function is to protect the lens element?) is slightly bent on two separate spots right across from each other. i dont think this should effect quality but i'm trying to convince myself this has nothing to do with image gathering properties of the lens (the bent areas do not cover any part of the lens).
the whole design of this lens seems quite different from the two 50mm f/3.5 lenses i've had, on those the rear element was located down inside the lens in a black circular concave parabolic disc, this design makes sense to me as this is the part that when installed within the bellows first captures the light... now the Schneider when viewed facing the rear element looks more like a smaller pipe (containing the glass) sticking out of a big pipe (thread mount), the rear element is certainly in a different position relative to the bellows and light source with these two designs, does this not matter? i know the bellows height adjustment can more than make up for this but i wonder about the light bouncing around in there, do the manufactures do something else within the lens to account for this? many many thanks to anyone that can explain this light path or maybe give me a URL (i've been looking)!!
one last difference with the Schneider, the irises are configured in a way that produces almost straight sided polygons for the aperture, really squared off compared to other lenses i've seen, i'm sure you know what i mean if you have one, what is the reason? better diffraction control? better wide open performance? cheaper since we dont mention "brokeh" with enlarging lenses?
i'll stop now, this new toy has aroused my curiosity and i'm not allowed to use it until after Christmas!
-- Joe Holcombe (firstname.lastname@example.org), December 21, 2001
joe, i can't really speak to the design and construction issue re: the 50/2.8 componon-s, but i can tell you you're going to love the images this lens will help you produce. ;-) i've been using this lens on an old Leitz focomat 1c for two years, and i'm quite happy with what it produces for me. sounds like you've got a fine Christmas present there.
-- kim sherman (email@example.com), December 23, 2001.
What you have there certainly started out as a great lens. It is a six element design. The f3.5 lenses you refer to are mostly likely three or four element lenses. I would be concerned about the dings rear of the lens. It took a pretty solid impact to dent that ring. The lens may no longer be in proper alignment. You should carefully check the edge sharps and make sure that light and focus are the same at all four corners. Even if it is not perfect, you may be happy with lens if you got a good deal on it. If you paid the full used price (I think about $150US) you may want to consider sending it back if you can.
-- Ed Farmer (firstname.lastname@example.org), December 24, 2001.
You'll love it. I am using one on my Omega B-7 and it replaced my 50mm Componar 2.8 and the difference is like night and day!
-- John Wade (email@example.com), January 08, 2002.