Exchanged opinions with German bear last night, he would like to have Ysarex 4.7/127mm lens a lens shade, but since the lens does not have filter ring, so asked me if I know any shade available for it.
I remember reading a post, a Chinese lives in Canada ever glued a step-up ring on lens, then he can use filters/shade in front of Ysarex.
I think this is not bad idea, a little more improvement makes Byron better, I can do this as basic conversion, so I went to find the ring this afternoon.
49-52 step-up ring is almost perfect fit for the lens, but the inner diameter of ring is 46.0mm, and the outer diameter of the lens is 46.5mm, that I need to visit my mechanist to do some work.
Lathe the inner diameter into 46.5, step-up ring is tightly fit on the lens. Inner circle is shinny silver due to the lathe work.
And then I squeezed to fit the ring, no any glue needed, it is just so tight, you will need to use a philip screwdriver to take it off.
It looks neat and pretty, with this ring we can install any 52mm filter on, and of course a 52mm lens shade. With ring on the lens, it safely stay in the camera body when fold.
Another improvement is to unify distance scales.
Byron is a conversion turning a fixed lens camera into an interchangeable lens system, besides one prime lens is range coupled with range finder, other lenses planning to use must have their distance scale for un-coupled focus.
But Polaroid designed distance scale in a merely weired way, distance scale original on 110B is not engraved in between object and focal plane, which is a common way to do, instead, they measured distance between objects and lens. Two system differ on the length of camera body, that is about 8inches.
For object locates far away, say 20feet, 8 inches makes no difference for both two scale, but if object is near, maybe 5feet away, then 8 inches means a big focus error.
I was reminded by Raymond, a Byron client, he wrote me one day said that the distance scale is not right, I followed what told and found out the same situation. Then I finally found that all lenses I measured and set are based on focal plane, but distance scale on 110B is based on lens tip, that caused errors.
So I redesigned the scale, remeasured and remarked it, image on top is what original distance scale shows and what it measured, below is what new scale shows and it measured.
New scale has bigger numeric numbers, to help people like me, in the middle age, weak eye sighted. And by using colors to more clearly display.
Not only scale in feet, also there is version in meter, reminded by a French client, some people get used to use metric system.
Last edited by salihonba; 04-16-2010 at 07:44 AM. Click to view previous post history.