Mamiya マミヤRB Prism Finder & the "G" adapter

[Ray Rogers]

I need a prism finder for my RB.

It seems there were several made that will fit,
but I am having a hard time figuring out whats what
What do I want?
How are they different... and what is/is not a good choice?

All thoughts appreciated....

Also, does anyone know what a G* adapter is? Where they can be found?
I know the G should let me use my RB filmholder on the RZ

(I guess thats not the same adapter for the Polaroid holder is it... ?)

 

[dougjgreen]

Not sure what to tell you about Prisms for the RB - all of them weigh a ton. I prefer the chimney mag finder, which is much lighter.

The G adapter is just what you surmise it to be. It allows RB backs to be used on an RZ body. BTW, I have one that I'd be willing to sell, make me an offer (+ shipping for an under 1 pound item from the U.S.). I really don't know what they are worth, as they rarely come up on the 'bay. I found one at a used photo fair several years back, in the original box, but I've never used it - I prefer to use RZ backs on my RZ bodies.

 

[EdColorado]

The main difference on RB finders is metering or no metering. All are heavy, its a big chunk of glass and all show an unreversed image.
Lets see, you have the basic prism finder. No meter, just a plain finder. This is the one I have, its nice if your on a high tripod but awfully heavy for hand holding. Then you have the CDS prism finder. This one has an averaging meter. I've never used one but I have held one and its also heavy. The last one is the PD finder which has spot and averaging functions. I've never seen one of these up close but it looks like it could be lighter than the other two, but maybe not. So it all comes down to the metering. Do you need it or not, and if so do you need spot metering. The basic prisms are generally pretty cheap, the CDS isn't bad, the PDs get kinda pricey (KEH bgn grade for $299 and the moment). Oh wait, I forgot, there's also a model 2 prism finder. I think, not sure, but I think its a PD minus the meter. I think too that the viewing angle might be different on the PD and model 2, more of a downward angle when compared to the basic and CDS prisms.
When I was putting together my RB system I thought a prism finder would be my most used. I have the waist level, chimney, and basic prism finders. I nearly always use the waist level unless for some reason I have the camera on a high tripod. For hand holding I use the waist level and the adjustable grip. With the prism its just too heavy. The chimney stays on my light table as a 6x7 lupe. Now if the model 2 is considerably lighter than the basic prism I might consider one for hand holding as an unreversed image would be nice.

 

[largely]

According to my reading the model 2 is over a pound lighter than the model one.
I have a model one but also find it heavy for handholding so it stays home and I use the waistlevel in the field.

Larry

 

[k_jupiter]

For hand held 65mm work I use the chimney finder. For any other shots, camera hung around my neck or low tripod use, either the chimney or waist level. For higher tripod use, the unmetered prism is best. When I put the 645 back on, it seems the WLF works best with a mask.

tim in san jose

 

[Ray Rogers]

Maybe I am confused... I thought the Chimney finder was the same thing as the waist level... I have the square box that pops up, and the meter that still makes you look straight down... What are you calling the Chimney finder ?

For hand held 65mm work I use the chimney finder. For any other shots, camera hung around my neck or low tripod use, either the chimney or waist level. For higher tripod use, the unmetered prism is best. When I put the 645 back on, it seems the WLF works best with a mask.

tim in san jose

 

[dougjgreen]

Maybe I am confused... I thought the Chimney finder was the same thing as the waist level... I have the square box that pops up, and the meter that still makes you look straight down... What are you calling the Chimney finder ?

The chimney finder is a rigid (not folding) pyramid-shaped magnifying finder that is also used vertically. The Waist Level finder folds into the body, and can be used from a distance away, while you need to put your eye closer to the chimney finder, but the magnification is superior.

 

[k_jupiter]

The chimney finder is a rigid (not folding) pyramid-shaped magnifying finder that is also used vertically. The Waist Level finder folds into the body, and can be used from a distance away, while you need to put your eye closer to the chimney finder, but the magnification is superior.

Correct...

Easy to use. If you like sharp photos... that's the one to get.

tim in san jose

 

[EdColorado]

At a pound lighter I might have to get a model 2, thats a considerable savings!

 

[paul ron]

There is a sepecial flip up magnifying eye piece for the prism that are very good for critical focusing. I prefer the chimney finder myself since it is so much lighter than the huge chunk of glass of a prism.

 

[Ray Rogers]

I have not decided what to do about the prism finder... I may need one for what I will be shooting next week, as I won't have a ladder and well... I have found a used Model 2 Prism Finder for quite cheap... However, it has a LOT of dust inside...

Are they pretty easy to access and dust out?

It looks lke the dust is everywhere!
Near the eye and near the camra body...

Is this model a METER as well, or just a finder?

Thanks,

Ray

 

[EdColorado]

I've never taken a prism apart so cant help you there but the Model 2 is a non meter prism. The metered version is the PD. KEH has an ugly graded model 2 for $37.00. Might be worth a gamble, I've received a couple of ugly graded lenses from them that were fine and pretty clean.

 

[Ray Rogers]

I've never taken a prism apart so cant help you there but the Model 2 is a non meter prism. The metered version is the PD. KEH has an ugly graded model 2 for $37.00. Might be worth a gamble...

Thanks... that is about the price I found locally;
I am thinkng it is not dif. to open and clean....
Ohoooo...

 

[paul ron]

The entire prism is one piece of glass, all glued together, so there is absolutely nothing to clean except the inside of the diopter n face of that end of the prism. All the surfaces are painted over silver. It generally is delicate and wiping it will destroy the silvering in most cases, espcially on the peaks.

Toying with the variable reisitor, the main dial control, is a very delicate matter not to be played with. These parts are no longer available and were custom made for Mamiya. The actual VR is a gold etching on ceramic and will wipe right off if toutched or cleaned because it is that thin.

So open the case of the prism and gently clean the diopter adn the prism end there and close it back up as fast as you can.