Prism resilvering for Canon FTb...possible? Practical?

[mel_snyder4]

I know this sounds wierd, but about six months ago, in celebration of my 50

years in photography, I became obsessed with the idea of assembling one of

every camera I had owned during that period. And so, I spent a lot of time on

eBay. I wanted every camera to be fully functional.

 

I ended up buying three Canon FTb before I got one I liked. The problem with

two of them was prism de-silvering...at the top edge. I happen to think the

FTb was one of the nicest basic mechanical cameras, and would like to fix

those two up, if I could get rid of the strip of desilvering on that edge, and

give them to a local school for their black-and-white photo course. I bought a

CD on eBay which details disassembly of the top deck, and I think I have all

the tools.

 

What I don't have is any idea what I would do once I got the deck off, and was

facing the prism. The company in Newark mentioned elsewhere on photo.net

doesn't do resilvering any more. I wondered if the old method of silvering

mirrors with mercury (I have an old pool thermometer I might carefully

sacrifice) might work -- but I have no idea how to do it. I also thought of

just putting a strip of shiny-side aluminum foil over the top edge, just to

possibly reduce the darkness of the stripe, since it's not focused.

 

The people on photo.net seem to have all the answers...so here I am.

 

Mel Snyder

 

(the other cameras, in order of when I acquired them over 50 years (* = never

sold them): Minolta Autocord, Leica IIIa, Kalloflex (still searching for

one!),Topcon RE*, Canon IVS2, Mamiyaflex C2, Konica Auto S, Canon FTb, Canon

AE-1, Canon F1*, Mamiya m645*, Olympus XA*, Canon T90*, Leica M4P*)

[casualcollector]

Mel,

 

Find an amatuer astronomer. Many of them build their own telescopes, right down to grinding the parabolic mirror. They have to get that silvered or aluminized somewhere. Here's a link to a telescope maker site they may have a clue.

 

http://www.stellafane.com/atm/atm_main.htm

[User_502260]

I think you would be better off just looking for one with a good prism. Does the desilvering affect the camera's ability to make images or is it just annoying to look at? I have two FTbN bodies and an FTb. All three have good prisms. What's bad about them? All are missing the small spring mechanism which is part of the accessory shoe. The FTb seems more solid to me than the FTbN and its depth of field preview button is also nicer. This comes in handy for using older FL lenses in stop down mode.

[keith_lubow]

My suggestion is to just shoot with the cameras and forget about it. A little mirror silvering never hurt anyone. I think you are picking nits. None of my FD bodies (FTb and 2nd gen. old F-1) have any foam or light seals at all, and I forget about it and shoot and have never had a problem at all in this area. My only problems have been with the shutter brake at '500 or above. (At $150 for repair, I just avoid the high shutter speeds.)

 

Do not bust open that thermometer to do this. That is not a good idea. You could get hurt by both the fine shards of glass and the mercury.

 

Also, you can find most instruction and repair manuals as Adobe Acrobat Reader files on the web without having to pay a crook for them on E-Bay.

 

Also, I would check closely to see if the silvering is, indeed, in the prism and not on the mirror. If it is on the mirror, just have a shop switch mirrors from one of your parts bodies.

 

If it is in the prism, and you decide that you must have this done, I am sure that the best solution would be to swap in a clean prism from another camera, rather then disassembbling the prism and replacing one part of it.

 

Honestly, I think you should stay away from E-Bay and buy locally if you don't want to deal with stuff like this.

 

Keith

[mel_snyder4]

Thanks to you all. I guess I am nit-picking a bit. I am going to take off the deck on one and fiddle with it, and I will let you all know what works. The desilvering doesn't affect photo-taking, but it is annoying, because as you move your eye against the finder, the dark area moves.

 

Your point on Ebay is taken. I figure I am still ahead, although I have gotten two bad Konica rangefinders, and one great mint one -- paid about $10 each for those that were bad, and $14 for the good one. Bought a terrific Pellix with a mint mirror and FL 1.4 lens for $34, more to have a chance to play with a pellicle camera than because I seriously wanted one. My Mamiyaflex C2 was embarrassingly cheap ($45, with the 80mm f2.8 lenses) in great shape, and a mint 135mm lens was $26. Bought a mint Porro for it for $28. I paid $15 for one of the FTb bodies with a problem prism, but it had a nice 1st-generation FD f1.4 lens. I almost died at the mailbox when I realized a $40 AE-1 body I bought had been simply slipped into a bubble-wrap bag and mailed...but damned if it wasn't perfect, with a new battery, no squeaky shutter, a terrific shooter.

 

I look at eBay like a camera museum. Right now I am stalking a Clarus and a Voker for my U.S. 35mm collection. I stay away from "estate sales" and "I know nothing about camera" jerks, and have done pretty well, I think.

 

Mel

[User_502260]

Greg Weber can fix your Konica RF cameras. He just overhauled a C35V for me and did a great job. You can reach him at 402-721-3873 or by going to gweber@webercamera.com.

[mel_snyder4]

Jeff -- thanks for the advice about Konica repair -- if he can fix Konicas, he's probaby capable of fixing some others as well. I have a Walz that needs a rangefinder evaluation and shutter CLA, and a Beauty Lighomatic I just received today that needs a shutter lube. This generation of cameras fascinates me -- talk about chunks of metal and glass! -- the Beauty has a parallex-compensating viewfinder, and a selenium meter that still works.

[kristian_heitkamp]

Even though this thread is nearly 20 years old, the topic today is even more relevant, since these cameras are getting older.

@mel_snyder4, did you got that prism resilvered ?

I am actually getting my FTb with desilvered prism today and also ordered acrylic silver mirror paint for it.

I will paint the desilvered areas with it and cover them in copper spray to prevent corrosion.

the paint is especially made for creating mirrors. You paint the backside and the flat polished glass surface gives it the reflectivity.

another possibility would be chrome paint, you can get markers containing liquid chrome paint.

[Ken Katz]

Unfortunately, according to PN, @mel_snyder4 has not checked into PN for over 8 years.  Best of luck with you resilvering.

 

[gordon_yee]

This is a project I never got around to, along with making a new mirror for an old Minoltaflex TLR. If I ever get the energy, my first thought was a front surface mirror as used in making kaleidoscopes:

4 Pack Glass Front Surface Mirror for Kaleidoscopes - 9" x 12" Sheets 1 mm thick,

These can be found in acrylic or glass. Another possibility is to use a film material with a mirror surface, such as mylar.

[kristian_heitkamp]

Resilvering an SLRs mirror is something I believe is a more complex task, since you would have to disassemble the mirror and resolver it from the back or, if it is silvered on the reflective surface itself, the surface needs very delicate polishing, and then any change in thickness would disalign focus.

but the prism itself is not involved in focus accuracy any more, it just reflects and flips the picture that already is focused on the ground glass.

also, the prism gets silvered from the outside, just like a simple mirror in your bathroom, where the glass provides the flat and polished surface and the silver that gets applied does not need to get polished or anything like this.

but still, I am curious about the results like you are, and that’s the reason I ordered the camera with this defect.

Btw, the camera already arrived, I added a picture of the view inside the finder. Especially with light from the front if the desilvered parts are inside a flare, they get visible especially well.

about @mel_snyder4, I saw in his profile, that he started following another user in 2022, so maybe, he is still passively using the forum.

[kristian_heitkamp]

Resilvering an SLRs mirror is something I believe is a more complex task, since you would have to disassemble the mirror and resolver it from the back or, if it is silvered on the reflective surface itself, the surface needs very delicate polishing, and then any change in thickness would disalign focus.

but the prism itself is not involved in focus accuracy any more, it just reflects and flips the picture that already is focused on the ground glass.

also, the prism gets silvered from the outside, just like a simple mirror in your bathroom, where the glass provides the flat and polished surface and the silver that gets applied does not need to get polished or anything like this.

but still, I am curious about the results like you are, and that’s the reason I ordered the camera with this defect.

Btw, the camera already arrived, I added a picture of the view inside the finder. Especially with light from the front if the desilvered parts are inside a flare, they get visible especially well.

about @mel_snyder4, I saw in his profile, that he started following another user in 2022, so maybe, he is still passively using the forum.

edit:

Just tried resilvering and unfortunately came to the conclusion that it did not work.

It seems that the mirror paint I used just is not reflective enough. It somehow improved a bit but still you get these annoying dark areas, as you can see in the pictures.

I ended swapping it against the prism of a broken Canon T70 I had lying around.

 

[gwhitegeog]

Yes agree - re-silvering is a pain in the a** = better to look for an example in better condition. FTn are not that expensive and would be cheaper than resilvering another one.