I have been using a Bronica S2A for the past few years that had the standard issue focusing screen & fresnel assembly. I found it fairly dark, so after replacing the foam in the viewfinder area, I decided to do some work on improving it. I am passing this information along for people who may be considering the same thing or may have more information to add to the mix.
The first thing I did was replace the standard ground glass with one purchased from Steve Hopf, who runs a small custom ground glass business (look for him on ebay). He had a regular glass and a super bright glass, and I chose the latter. A few days later it was installed in the Bronica. With a before/after test, it was about 1.5 to 2 stops brighter, still using it with the original fresnel from the Bronica.
Next I tried an Acute Matte screen from a Hasselblad. It was a full 2 stops brighter than the ground glass & fresnel combination above, but, being a combination fresnel & ground glass, it did not have the same infinity focus as the regular ground glass & fresnel combination and it was not small enough to fit into the fresnel "compartment" in place of the original fresnel. And with the cost of it, I was not willing to try to trim it to fit.
Finally, I just recently tried a Kiev bright screen. Combined with the original fresnel, it would reach infinity focus at the exact right spot, but it was not kind to the Bronica fresnel - - it was very hard to see anywhere on the matte surface of the glass. It showed the rings of the fresnel as dark shadows. When I removed the fresnel, the brightness dropped a bit, but the infinity focus shifted, as is to be expected, since a fresnel has a shorter index than the equivalent distance of air. And, while the focus shift would have been easily adjustable with shims, the other problem of this screen is that it was not conducive to slower lenses. With the f/4 200mm Nikkor and the f/8 165mm Rapid Rectilinear I use on this camera, the split image rangefinder goes dark and cannot be used as a focusing aid. So in the end, not a satisfactory solution, either. I had high hopes for this screen.
So, if there are folks out there who are considering ways to improve the brightness of the Bronica S2A, I recommend the customized replacement from Steve Hopf with the original fresnel. All in all, a good combination. If there are folks who have gotten the Kiev screen to work, I'd be interested in hearing about how it was done. Given the price of the screens (mine was about $15 shipped to the US), I'd be willing to grind it to fit, if necessary - - but I don't see how to overcome the darkening of the split image rangefinder prism.
The first thing I did was replace the standard ground glass with one purchased from Steve Hopf, who runs a small custom ground glass business (look for him on ebay). He had a regular glass and a super bright glass, and I chose the latter. A few days later it was installed in the Bronica. With a before/after test, it was about 1.5 to 2 stops brighter, still using it with the original fresnel from the Bronica.
Next I tried an Acute Matte screen from a Hasselblad. It was a full 2 stops brighter than the ground glass & fresnel combination above, but, being a combination fresnel & ground glass, it did not have the same infinity focus as the regular ground glass & fresnel combination and it was not small enough to fit into the fresnel "compartment" in place of the original fresnel. And with the cost of it, I was not willing to try to trim it to fit.
Finally, I just recently tried a Kiev bright screen. Combined with the original fresnel, it would reach infinity focus at the exact right spot, but it was not kind to the Bronica fresnel - - it was very hard to see anywhere on the matte surface of the glass. It showed the rings of the fresnel as dark shadows. When I removed the fresnel, the brightness dropped a bit, but the infinity focus shifted, as is to be expected, since a fresnel has a shorter index than the equivalent distance of air. And, while the focus shift would have been easily adjustable with shims, the other problem of this screen is that it was not conducive to slower lenses. With the f/4 200mm Nikkor and the f/8 165mm Rapid Rectilinear I use on this camera, the split image rangefinder goes dark and cannot be used as a focusing aid. So in the end, not a satisfactory solution, either. I had high hopes for this screen.
So, if there are folks out there who are considering ways to improve the brightness of the Bronica S2A, I recommend the customized replacement from Steve Hopf with the original fresnel. All in all, a good combination. If there are folks who have gotten the Kiev screen to work, I'd be interested in hearing about how it was done. Given the price of the screens (mine was about $15 shipped to the US), I'd be willing to grind it to fit, if necessary - - but I don't see how to overcome the darkening of the split image rangefinder prism.
