When is a 180° split focusing screen better than a 45° one?

Question

My camera eventually ended up with severe scratches on the original plain matte focusing screen.

eBay currently offers:

• an exact replacement for $20.45
• one with a 180° split image rangefinder for $37.80
• another with a double 45° split and microprisms for $21

Which one would likely be the most effective for my use?

My usage of relatively slow zooms (up to ƒ:5.6) would support a matte only model, my personal preference claims the 180° one but its significantly higher price relatively to the 45° one coupled with the fact I often switch between portrait and landscape orientations would suggest the latter…

Answer 1

I'm not exactly sure what you mean, I am guessing that by 180 you mean a single split, perhaps horizontally framed and the double 45 is really an X shaped dual split.

The reason that the old SLRs had so many different screens is that its very much a personal preference, there is no one answer, it varies by photographer by what they are shooting.

I personally never liked microprisms. I liked the simple horizontal (single) split. I rarely had a problem finding something vertical or horizontal to focus with even when switching from portrait to landscape.

But F5.6 is simply not going to work with a split prism. It will be black. So people have problems with the prisms going black even with F2.8.

My eyes are no longer good enough to get a proper focus using just a matte screen.

Answer 2

Double 45° can be X shaped, but also it could be two parallel splits. And yes, using too small aperture (high f-number) the split may become useless, black as Pat said. Often there is also a microprism ring around the split circle, and sometimes the microprisms is good for focusing when there's no good lines for splitting, and microprism may still be useable when the split is not. Anyway, I made this an answer instead of a comment only to include a pic for reference of double 45° split..

Of the tens of different focusing screens I have used only a focusing screen with single 45 degree split, with a ring of microprisms around it. And I liked it. The world is full of vertical and horisontal lines and a 45° split catches them both.