I want my Yashica mat viewfinder brighter....

[TooManyShots]

I have been trying to understand why my Yashica Mat viewfinder is dark. I have cleaned the mirror as well as the ground glass and the original focusing screen. I cleaned the viewing lens too. There are several aftermarket focusing screens I could get (one from Hong Kong or the Kiev 88 one from Ukraine). When I look at the ground glass, it is usually dark. Even though I would be using a brighter viewfinder, would the brightness improve if my ground glass looks kind of dark. I hold up the original focusing screen and it looks extremely bright. When looking it through the ground glass, everything looks darker. I say about 1 stop or a bit more darker.

 

[Chrismat]

What is the condition of the mirror? A dirty mirror will dim any viewfinder.

 

[TooManyShots]

Pretty good. I could hardly see any scratches or any blemishes....

 

[Dan Daniel]

Yep, put a new mirror in. Cleaning a front surface mirror is usually not very effective, and the mirror surface is often tarnished.

You do have the plastic fresnel installed, along with the ground glass? It is a two-piece system. Starting from the top/your eyeball side, there will be the ground glass with the ground side facing down, and then the fresnel bleow it with the grooves facing up.

 

[TooManyShots]

Yes, of course, the focusing screen and the ground glass are in place. Nah, I don't think the mirror is tarnish since I could barely tell if I am looking at it.

 

[snapguy]

Compared to what?

Your YM screen is dark compared to what? I just checked out my Rolleiflex and my Yashicamat screens and the YM seems to be brighter even though the YM viewing lens is f3.2 and the Rollei viewing lens is 2.8. I have used a Rollie professionally beginning in the late 1950s and a Yashicamat since the 1970s and they were never the brightest screens around. But they can take killer photographs.

 

[bernard_L]

Yep, put a new mirror in.

Need to ensure that focus planes of taking and viewing lenses still coincide...

 

[shutterfinger]

Cleaning procedure for ground glass and fresnel any medium or large format camera:
1. remove the ground glass and fresnel from the camera body handling each by the edges only.
2. hold the ground glass under a small stream of running water and wet the surfaces, apply a drop of dish detergent about the size of your small finger nail.
3. using your finger tip only gently rub the entire surface with the soap and water, rinse and repeat for the other side.
4. rinse thoroughly then rinse in a weak concentration of PhotoFlo then stand on edge and allow to air dry or towel dry with a lint free towel when well drained.
Repeat the procedure for the fresnel rubbing the ribbed side in the direction of the rings only never across them. it is best to allow the fresnel to air dry.
If the mirror is easily removed then wash it in the same manner.
If the mirror in not easily removed use lens cleaning solution and cotton balls to clean it.
The proper amount of pressure to apply to a front surface mirror, a plastic fresnel, or focusing screen is equivalent to rubbing an over ripe grape and not moving the skin while removing the outermost debris.

 

[gone]

Simply replacing the mirror and focus screen will not affect focus if it's done correctly, so I wouldn't worry about that. There's a very nice gentleman on eBay that sells replacement mirrors for TLRs that I would recommend if you want to try that. I actually made the measurements for him on various cameras that I owned (Brillant, Rolleicord, Rolleiflex, etc). $10 will get you a brand new mirror. Might give that a shot. If that doesn't do it, and you have a clean viewing lens and a bright focus screen, you're just going to have to live w/ it. There's nothing left to try other than a fresnel (which it sounds like you already have).

 

[MDR]

Stray light can also be a source of less than satisfactory screen brightness. The screen is bright but due to light entering the finder hood it seems less so. This used to by a problem on my Yashicamat but ever since I shield the hood from light the screen seems brighter.

 

[tessar]

I've had the same experience with similar cameras as snapguy, above, but Rick Oleson does supply new focusing screens for the YashicaMat series:
http://rick_oleson.tripod.com/index-175.html
Might be an idea to send him an e-mail and inquire whether one of his screens ($35 inc. shipping) would make an appreciable difference. I got one for my 1950 Rollei Automat a few months ago. It makes the screen brighter, about as bright as the one on my YashicaMat. Rick is a nice guy, easy to communicate with.

 

[TooManyShots]

Ok. Here is my solution. Is cheap and is free and I used what I already have. I manged to adapt the Mamiya c330 original focusing screen + the clear glass onto the Yashica. I used to have a C330 and some additional focusing screens. I sold the C330 and still have one of the original focusing screen left. The Yashica focusing screen requires a ground class to focus. The Mamiya TLR does not. The problem is that, with the mamiya system, with the clear glass and the focusing screen, is too thick. The mamiya focusing screen is too close to the mirror. If the distance is too far, I can add shims. To get around it, I installed the mamiya focusing screen without the clear glass. Then I put the clear glass "above" the waist level finder. I used some blue masking tape, the 3M good kind, to tape down the clear glass. This clear glass isn't really needed and it is only used for protection for the focusing screen. Now, the focusing screen is too far from the mirror. That's an easy fix because I can add few layers of blue masking tape to shim the focusing screen.

Before I attempted this improvement, I put the Yashica on a tripod and to have it to focus on an object. Then, I marked down the distance scale when the desired focus is achieve. I used this setting to fine tune how much layers of masking tape I need to get the proper distance. Focusing clarity has been improved greatly since I am not looking at a ground glass but a clear glass. The brightness has improved too but nothing earth shattering. Let's say right now the image in the viewfinder looks very pleasant. Let's just say that I can read off tinny words off my computer screen now.....

 

[Xmas]

I've had the same experience with similar cameras as snapguy, above, but Rick Oleson does supply new focusing screens for the YashicaMat series:
http://rick_oleson.tripod.com/index-175.html
Might be an idea to send him an e-mail and inquire whether one of his screens ($35 inc. shipping) would make an appreciable difference. I got one for my 1950 Rollei Automat a few months ago. It makes the screen brighter, about as bright as the one on my YashicaMat. Rick is a nice guy, easy to communicate with.

Ricks screens will make the outer part of the field brighter.

But you need to get your face down into the hood it is not a waist level viewfinder it is a nose into hood finder.

 

[aoresteen]

Also consider having a Maxwell screen installed. They are fantastic.