What kind of focusing screen is in my Nikon F?

[Ariston]

I picked up a parts body for almost nothing that turned out to be completely fine. I just shot with it for the first time today, and the focusing screen has a diagonal micro-prism in it. This is genius!

I hate micro-prisms because I hate having to hunt for a horizontal line, and the point of focus does not always have a horizontal line. Why aren't all micro-prisms diagonal?

Now almost any line will do! I wish my FE and FM had this.


EDIT: Are these center focusing spots microprisms or split image rangefinders? Is there a difference...?

 

[Paul Howell]

I think it's the L, same as the standard A, with the diagonal split screen.

 

[Ariston]

Ahhh - I see it now. Thanks!

 

[narsuitus]

It could also be the "P" screen that has diagonal split-image rangefinder surrounded by a 1mm wide micro prism collar.

It also has an etched horizontal line and an etched vertical line that divides the view screen into four quadrants.

 

[wiltw]

I picked up a parts body for almost nothing that turned out to be completely fine. I just shot with it for the first time today, and the focusing screen has a diagonal micro-prism in it. This is genius!

I hate micro-prisms because I hate having to hunt for a horizontal line, and the point of focus does not always have a horizontal line. Why aren't all micro-prisms diagonal?

Now almost any line will do! I wish my FE and FM had this.


EDIT: Are these center focusing spots microprisms or split image rangefinders? Is there a difference...?

'split image' rangefinder aids are different from 'microprism'.
Split image rangefinders are typically horizontal split, but they can be diagonal split.
Microprisms 'fracture' the presented image, and the object being viewed will seem to 'shimmer' as you move the microprims across the subject.

I prefer microprism centers over split image centers, simply for the reason that in the real world the subject may have zero horizontal or vertical lines to align...a 'simmering' eye in a portrait is much more useful, IMHO.

 

[pentaxuser]

'
I prefer microprism centers over split image centers, simply for the reason that in the real world the subject may have zero horizontal or vertical lines to align...a 'simmering' eye in a portrait is much more useful, IMHO.

So the answer to the OP's question which I am not sure we have managed to do yet, That question being: Why aren't all split image finders diagonal, is that in the real world there is no more of a chance that a scene will have diagonal line in it than horizontal or vertical?

In a nutshell the diagonal split image does not "square the circle" to become the universal answer whereas the microprism does?

Does that cover it or are there still flaws in the above "nutshell"

Thanks

pentaxuser

 

[Ariston]

...in the real world there is no more of a chance that a scene will have diagonal line in it than horizontal or vertical?

pentaxuser

The reason I said the diagonal split is genius is because it works on horizontal AND vertical lines, either of which will intersect a diagonal line. . You have to try it!

 

[pentaxuser]

The reason I said the diagonal split is genius is because it works on horizontal AND vertical lines, either of which will intersect a diagonal line. . You have to try it!

Thanks Ariston. While I have never had a camera with either a microprism or a split image finder I think you may be right and that the diagonal split does indeed square the circle and my question was not an indirect challenge to you but was an attempt to get an answer to what seemed to be a good question of "Why aren't all splits diagonal? "

Everyone who asks questions here deserves answer which answer the question or say simply that they have no direct answer to "why not?" It is that aspect at which we are not very good at times

pentaxuser

 

[Ariston]

Thanks Ariston. While I have never had a camera with either a microprism or a split image finder I think you may be right and that the diagonal split does indeed square the circle and my question was not an indirect challenge to you but was an attempt to get an answer to what seemed to be a good question of "Why aren't all splits diagonal? "

Everyone who asks questions here deserves answer which answer the question or say simply that they have no direct answer to "why not?" It is that aspect at which we are not very good at times

pentaxuser

Hi Pentaxuser, I was not offended and did not think you were being argumentative at all - I hope my post didn't make it seem that way. I had never tried a diagonal one (I didn't know they existed), and it never occurred to me how much easier it is when you can engage vertical OR horizontal lines. I had actually been looking to get Type B screens for all my Nikons because I found the horizontal split so useless and cluttering... but it turns out I actually don't mind the split so much if it is as useful as the diagonal one is.

 

[narsuitus]

I had actually been looking to get Type B screens for all my Nikons because I found the horizontal split so useless and cluttering... but it turns out I actually don't mind the split so much if it is as useful as the diagonal one is.

When I first started using Nikon SLRs, the body usually came with a Type A view screen with a horizontal split-image rangefinder focusing aid. I replaced those Type A screens with the Type B screens. However, as I aged and my eyesight deteriorated, I could no longer focus accurately with Type B. I ended up going back to Type A screens.

I never had trouble finding straight lines to use as a focusing target. If the lines were horizontal, I would simply rotate the camera body into portrait orientation so the split-image rangefinder line was perpendicular to the horizontal line. If the straight lines were diagonal, I would simply rotate the body until the split-image rangefinder line was perpendicular to the diagonal line.

 

[Ariston]

When I first started using Nikon SLRs, the body usually came with a Type A view screen with a horizontal split-image rangefinder focusing aid. I replaced those Type A screens with the Type B screens. However, as I aged and my eyesight deteriorated, I could no longer focus accurately with Type B. I ended up going back to Type A screens.

If you have any of those old Type B screens lying around you want to sell, let me know. I have some Type K screens setting around I could trade, too.

 

[narsuitus]

Sorry, I do have two B screens that I rarely use but I still find them useful when shooting macro.

 

[wiltw]

Thanks Ariston. While I have never had a camera with either a microprism or a split image finder I think you may be right and that the diagonal split does indeed square the circle and my question was not an indirect challenge to you but was an attempt to get an answer to what seemed to be a good question of "Why aren't all splits diagonal? "

Everyone who asks questions here deserves answer which answer the question or say simply that they have no direct answer to "why not?" It is that aspect at which we are not very good at times

pentaxuser

I checked 6 SLRs that I still own both camera and user manual, which shows the standard screen in illustration

1. Beseler Topcon Auto 100: microprism center
2. Beseler Topcon Super D: horizontal split, coarse GG surround (7 screens alternative)
3. Olympus M-1 (model not a typo!): horizontal split
4. Olympus OM-1n: horizontal split, with microprism surround (13 optional screens incl one diagonal split)
5. Olympus OM-4: horizontal split, with microprism surround (13 optional screens incl one diagonal split)
6. Bronica ETRSi: diagonal split (7 screens incl one option screen having diagonal split with microprism surround, which I have installed in my body)

So it seems that answer to your question is simply "Just because..."
As for lack of answers previously, it must simply be that NO ONE KNOWS, and does not want to speculate.