Ebony RSW45 adding another fresnel lens to the original screen

[Valmidira]

If this helps anyone, I recommend adding an additional fresnel lens to the original EBONY RSW45 focusing screen—one with a focal length of 300 mm for lenses ranging from 80 to 120 mm (optimal performance) or one with a focal length of 120 mm for optimal performance with lenses shorter than 80 mm. The original fresnel lens (integrated into the focusing screen) performs optimally with focal lengths above 135 mm. That is in fact a little bit dissapointing as the RSW is intended for wide angle lenses.

 

[DREW WILEY]

The first thing I did with my Ebony was to permanently remove its fresnel. I hate those in general.

 

[Valmidira]

So you completely removed the screen and installed a new one?
I have a screen with a built-in fresnel lens—a matte surface on one side and the Fresnel lens grooves on the other. I have to say the original Ebony screen is very nice, almost non existent "grain", nonobstrusive grid and fresnel grooves and the fresnel works fine for longer lenses. It was just "weak" for short lenses.

 

[DREW WILEY]

No - just removed the fresnel. Not only do I dislike their concentric lines interfering with viewing; but in the case of the Ebony fresnel right against the ground glass, condensation was common between them (I did a lot of bad weather shooting in the mountains). Later on, I replaced the original Ebony ground glass itself with Satin Snow glass, which has a more versatile, slightly coarser grind to it. I see no point for fresnels with longer lenses at all, since they exhibit no illumination falloff.