Help with the Certo 6 viewfinder

J

jga

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Dear all,
well, this is my first post, my name is José, and I live in München, Germany.
I bought a Certo6 that looked abandoned for decades, I had to clean everything, but now is in a decent condition. My problem is the viewfinder. when I look through it, I cannot focus to infinity (with my eyes). It feels like looking though a close-up lens.
To explain it better, I made a picture:
14517801706_bdbcac54c0_o_d.jpg


First of all, do you see something that could be wrong? I assembled as it came, but I don't know if someone else worked on it before me.
I've tried flipping the lens (4), and with the concave side pointing to (1) the image is slightly better, but still far from good.
If I take (1) and (4) and place them at roughly half the distance in the camera, I can focus properly.
So, I was thinking that maybe the lens (4) is the wrong one, or there is something I cannot figure out that is wrongly assembled.
BTW, the beamsplitter (2) and the mirror (5) are good (so maybe already changed them?), but I think I will change them in the mid term for better ones (If I manage to fix the rest).

Thanks for your help!

Jose
 
You could ask Jurgen Kreckel (ebay member Certo6).
He has a lot of experience with this camera and especially with
the viewfinder/rangefinder.
 
At least one optical element seems to be missing. A minimum telescope type finder needs at least two lenses - concave front, convex to the rear. Where is the latter?
 
I've been discussing with Jurgen, and it looks like (4) is just the wrong lens. Probably someone changed both mirrors (because it is very strange that they are still good), and put the wrong lens in (4).
So, I need to find a new lens there, and it doesn't look very easy.
If anyone has an idea, just let me know...

Cheers!

Jose
 
sevo said:
At least one optical element seems to be missing. A minimum telescope type finder needs at least two lenses - concave front, convex to the rear. Where is the latter?
Click to expand...

In position (4) in the drawing. It is glued to a metallic part.

Cheers!
 
jga said:
In position (4) in the drawing. It is glued to a metallic part.

Cheers!
Click to expand...

Sure? The moving part in that place ought to be a parallel plate. Maybe they use a plate/lens tuplet to simplify matters, but in the picture its rear looks nowhere as convex as it should. Either the lens component (or another assembly holding a separate lens) is missing or that thing is assembled the wrong way around (lens to the front).
 
Hi!
I made a couple of pictures of the lens:
14364340730_8e7f7b2cdc_o_d.jpg

14571111023_23d9c8f212_o_d.jpg


So, the lens is quite flat. I measured roughly 12.5 and 14 dioptres, depending on the side (I think I measured correctly).
I'm not sure what's normal there, but I have a Minolta rangefinder that I plan to disassemble to have a rough idea of the lens I need.
 
I had one which a previous owner let open itself too hard - it eventually bent the bar which communicate the focus. The result was that it didn't focus to infinity. I'm not sure if it's the issue you have but with that spring tension, I wouldn't be surprised if it was a common issue.
 
Thanks! Cool mods! If I manage to fix it, I think I'll copy the idea of painting to remove the inner reflections. Also, in your picture I can see that the lens I think is the wrong one is fairly similar to the one I have...

Cheers!

RichC said:
Can't help with the problem, but here's a link to pictures of the Certo 6 I once owned: http://www.rangefinderforum.com/forums/showthread.php?t=65609

If you need a manual: http://www.rangefinderforum.com/forums/showthread.php?t=64229
Click to expand...
 
Hi! Mine is ok there. But I almost screwed that bar myself when I was disassembling the camera...
My problem is not with the rangefinder focusing mechanism, but with the optics of the primary path (lenses 1 and 4 in the first picture I posted), I cannot focus the image itself with my eyes (It feels like wearing a pair of super strong glasses).

Cheers!


Brian Legge said:
I had one which a previous owner let open itself too hard - it eventually bent the bar which communicate the focus. The result was that it didn't focus to infinity. I'm not sure if it's the issue you have but with that spring tension, I wouldn't be surprised if it was a common issue.
Click to expand...
 
Second try here...

I have very nice Certo6, with clouded rangefinder...

Would it be better to just add a Wata type rangefinder and use it instead of fixing orig...?

Anyone used a cast off SLR mirror to replace original in the Certo?
 
BobBill said:
I have very nice Certo6, with clouded rangefinder...

Would it be better to just add a Wata type rangefinder and use it instead of fixing orig...?
Click to expand...

The point in a Certo is that it has a coupled rangefinder viewfinder. If you don't need that, a Tessar Mess Ikonta is the less quirky camera with the better lens for less than half the price (and if you can live with a stick-on Wata, even lesser ones will do).

BobBill said:
Anyone used a cast off SLR mirror to replace original in the Certo?
Click to expand...

The mirror usually is perfectly fine in the Certo Six, its issue is with the beamsplitter, where they omitted the protective coating so that the silvering has oxidized away. There is no useful beamsplitter to be taken from the usual SLR (the main mirror of AF SLRs technically is a beam splitter, but the ratio is wrong, and they tend to have a masking applied that renders them useless for other purposes). Pro grade 50/50 VIS beamsplitters of matching type and size sell for less than $50 (e.g. Edmund #31-414 or Linos G344142000). The swap is fairly trivial.
 
Much thanks. I have no clue about these things. I have the Zeiss Mess 6x9 and love it. It is like a tank, but this Certo6 is like a bigger tank. I was unaware the camera was "coupled," and, obviously, way off on what is wrong with it...I will attempt to locate the part and fix...

I am very grateful for your assistance, very grateful.
 
Well, to be safe, the plan is to replace the beam splitter using the source noted above and also the mirror, after I acquire some special tools to remove the screws etc.

I still craft stained glass and am amazed some are able to cut glass with a carbide scribe instead of wheel, though it does make sense.

I have a spare Nikon mirror just in case.

Thanks again.
 
sevo said:
The point in a Certo is that it has a coupled rangefinder viewfinder. If you don't need that, a Tessar Mess Ikonta is the less quirky camera with the better lens for less than half the price (and if you can live with a stick-on Wata, even lesser ones will do).

The mirror usually is perfectly fine in the Certo Six, its issue is with the beamsplitter, where they omitted the protective coating so that the silvering has oxidized away. There is no useful beamsplitter to be taken from the usual SLR (the main mirror of AF SLRs technically is a beam splitter, but the ratio is wrong, and they tend to have a masking applied that renders them useless for other purposes). Pro grade 50/50 VIS beamsplitters of matching type and size sell for less than $50 (e.g. Edmund #31-414 or Linos G344142000). The swap is fairly trivial.
Click to expand...

I understand this thread is over a year old but need specificity re the above beamsplitter noted by Sevo:

The Edmund number noted is for a 50-50 item that is 2mm thick. Am thinking the Certo uses a 1mm thick splitter???

And, would a 30/70 1mm splitter function, knowing it would be more faint?
 
Getting back to it: The splitter is held by a fork with (I guess) 1mm slits for the mirror. But as the critical item to be properly positioned is the front coating, you can get away with a thicker beam splitter, if you grind away the edges at the rear.
 
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