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Scott
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 25, 2004 - 11:52 am: | 
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I'm putting my Welmy 6 back together, and was checking the focus at the film plane. The image was clear only in the middle, so I thought I must had accidentally reversed the middle element (both sides look the same to me). I tuned it around, but saw the same thing at the film plane. Is there a back and a front to it? How can I check, short of exposing a roll and making prints? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 25, 2004 - 12:37 pm: |
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If I remember it correctly all lens elements of the Welmy6 lens are hold by retainer rings, none is pressed into its mount as you find it pretty often on other triplet lenses.
Check whether you inserted the other lenses correctly. These are plano-convex (or almost plano-convex) lenses where one surface has much stronger curvature than the other. These strongly curved surfaces should show to the outer sides of the lens barrel.
I shot a roll with my Welmy6, with quite good results. At least the lens is not vignetting as the lens of the MizuhoSix. The 90 deg. viewfinder is a bit hard to handle, since left and right are reversed - not easy to hold the camera vertically when using this finder.
BTW I accidentally reversed the center element of a Novar lens (of similar design) which gave an interesting effect on the ground glass. The image was very soft and blurry. |
Scott
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 25, 2004 - 06:39 pm: |
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So, do you mean that with the center element reversed, you could not focus sharply on the ground glass? I'm going to try again with a better magnifying glass, but it looked like I could get a sharp image at least in the center, both before and after I turned the center element around. The center element I have looks the same to me on both sides- concave. I know I could expose one roll and make prints with the center element in one way, and then do another roll with it reversed, and then compare the prints. I assume the difference would be immediately obvious. But I was hoping there would be a clever trick to check it more easily.
Mine has only a normal viewfinder- does yours have both the normal and the 90-degree finder? Any explanation as to why they put 90-degree finders on there? Was there some advantage I can't see?
Thanks |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 26, 2004 - 12:04 am: |
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As I mentioned I could clearly see whether the center element was in right position on the Novar lens although this lens element is also concave on either surface - there are minor differences in curvature which do the trick.
The 90 deg. viewfinder on the (later) Welmy6 is often described as a 'waist level finder' (as a replacement for the 'brillant finder' you find on the lens standart of older cameras) but this it is not. It is probably designed to make shots 'around the corner' - your face won't look at the person to be photographed, and the strange position of the camera might puzzle probable victims. Some models of the Mamiya6 also have a 90 deg finder but I don't know whether it is designed as a waist level finder. |
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