Archived posting to the Leica Users Group, 1997/12/15
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>> Jesse Newcomb wrote... I'm looking at a Canon rangefinder lens guide, and they show the 25mm f3.5 (a neat lens for your LEICA III but a bit clumsy to change the f-stops). Get this: The diagram of the lens shows 4 elements, all severely crescent-shaped (a wild lens you should see it). But anyway, there's a fifth element at the very rear and guess what: It's a FLAT piece of glass!!! Canon says in the book that "Aberration compensation balance of this lens is achieved at the rear plane with special optical glass." So one would assume that flat glass [in front of or behind your lens] will change the lens characteristics -- I had a 25/3.5 Canon which did the darndest thing when I put (kept) a filter on it. Although it was a Canon filter, I think they were the only firm that produced 40mm filters... It created a vignette at the corners (perhaps it was one of their thicker ones, I've learnt now they made them in three thicknesses) though NOT a dark vignette but a light one!! Wierd! It was a silver filter and my only theory was that it was a reflection (unlikely) coming back into the camera... It was a cute lens though, tres petite, eventually the camera was dropped, the finder was broken, and the lens was 'useless'. I sold the lens to Paul Henry van Hasbroeck and recieved an insurance cheque to enable the purchase of my first Super Angulon. Many years later I coaxed a reshaped lens element to vaguely replace the missing front element in the finder and sold that as well. The funniest incident happened a day or two after I'd got the lens, I was on the seafront at Skegness, a small seaside town in Eastern England and saw a fight between some 'bovver boys' and the police. I put the camera to my eye and ran towards the fight, anxious to be ready to fire the shutter as soon as the composition was right. I got there, took a couple of photos of the three policemen restraining three lads and then put the camera down, I nearly jumped out of my skin! I was only two feet away from them all! The phrase, 'Get in close' comes to mind, but boy, does that photo have impact! Jem