Nikon F6 focusing screen

[dmtnkl]

This one goes out mostly to F6 users, but anyone is welcome to share his thoughts, especially DSLR users with similar problems.

I am mostly used to manual focusing by eye anywhere in the frame, without the aid of split-image rangefinders or miscroprisms and i tend to have results that satisfy me. This way i can concentrate on the subject and compose and focus in one fluid motion, without resorting to focus and recompose which may also produce bad results due to field curvature and other stuff....

From the ones i have used, the best screens for this purpose is the Nikon F3 B screen, along with its brighter 'red dot' variant. A similar situation holds for the FE/FE2/FA screens. Due to their coarseness and grain, it is possible to see depth of field at least down to f/1.2 (and f/1.4 for the 'red dot' variant), and while you focus you also have a sense of 'pop' that helps a lot.

On the F6, the focusing screen is optimized for brightness and is very similar to the B3 focusing of the FM3A. I think it only shows depth of field down to about f/2, thus making it more difficult to use with fast lenses and even with slower ones due to the lack of apparent 'pop' when hitting the plane of focus.

Moreover, and especially with fast glass like the 50mm f/1.2, the screen generates interference patterns ('sparkles') as you focus slightly in front of bright areas. Such patterns may give a misleading impression of sharper focus, when in fact you are front-focusing.

What are your thoughts on this? Currently there is no real ground glass screen for the F6. One would have to make it by hand and while i know it is possible for medium format, i am not sure how easy it would be for 35mm where the screens are slimmer and have to be cut quite exactly.

This is my only real gripe with the most outstanding camera i have ever used.

 

[dmtnkl]

Oh, and while i am on it, what do you think about sanding/grinding very carefully the existing screen to make it coarser?

Would it be possible to do it while preserving its dimensions and without making it look like a total mess?

 

[Paul Howell]

I have converted split image screens from dead Mirandas for Pentax SF1s for use when shooting manual K and M42 lens. Not all that hard, the Miranda screens are just a tab larger than Pentax, needed to cut to size. I masked off the Miranda Screen to size I cut with a Dirmal, could have used a very sharp utility knife just as well. Thickness is not any issue between the Miranda and Pentax, seems to be the same with both. I now shoot Minolta AF and have no need for any other screens. I would look into the possibly of using a F2, 3, 4 or 5 screen to your liking, may be possible to cut size.

 

[dmtnkl]

I tried the F3 Screen. You have to dismantle it and detach the lens element that sits on top of it, as well as file some extra stuff around it. Then you end up with a screen that is the right size, but a bit thicker and is a very very tight fit under the retaining mechanism. Also, aligning the 12mm circle on the F3's screen with the one in the F6 viewfinder is an issue.

What is the size of the miranda screens you are refering to. Do they also have a fresnel side, and are they blank or do they have a circle engraved on them?

 

[Paul Howell]

I don't recall off the top of head the size, it was just a tab larger than the standard Pentax SF1 screen, it was a Miranda EE, it is split image, Not too hard to remove as the shutter was toast, I just cut off the shutter speed dial and film rewind, removed the top plate to get to the penta prism, a small frame and a few screws hold the screen in place. The SFI1 had interchangeable screen, easy replace. Maybe others know which Nikon screen may work in a F6, my only thoughts are check on Ebay and buy a few screen, Nikon, Canon, Minolta AF, Pentax AF, LX, problem you have a very spefic need, I think all of the new screen are going to be made from Resin, not Glass.

 

[dmtnkl]

The F6 has an 100% finder and as such the screen is only slightly larger than a 35mm frame. I think most screens from other cameras are smaller since the vast majority of them don't offer full coverage finders. This is why i think it might be really hit and miss trying random screens.

What about making a new one that is thin enough or carefully sanding/grinding the existing screen? Anyone tried this?

 

[Chan Tran]

I don't have the F6 so I can't measure the brightness of the screen. I think it's actually about 1 stop darker than the F3.

 

[dmtnkl]

maybe you meant brighter than the F3's screen?

The F6 screen is very similar to the B3 screen for the FM/FE, which is about 2/3 of a stop brighter than the simple B screen, which in turn looks as bright as the plain B screen for F3.

But the F3 screens are too thick, while the ones for FM/FE are smaller.

 

[Paul Howell]

You can try a EOS 1, Minolta 9, and Pentax LX screen, all are 100% viewfinder, doubt that any will be as bright as the screen in the F6, well maybe the EOS 1, how about a F or 5 screen?

 

[dmtnkl]

The LX is a bit smaller than 100% from what i read on various sources. But hey, i will try to look further into these screens.

 

[Chan Tran]

maybe you meant brighter than the F3's screen?

The F6 screen is very similar to the B3 screen for the FM/FE, which is about 2/3 of a stop brighter than the simple B screen, which in turn looks as bright as the plain B screen for F3.

But the F3 screens are too thick, while the ones for FM/FE are smaller.

I thought modern cameras screen are brighter until I stick a meter in the viewfinder and found that old cameras are brighter. The difficulty of focusing has to do with the fact that the focusing screen has a layer o LCD on it.

 

[dmtnkl]

The F6 screen is almost the same, if not the same, as the B3 screen that was introduced with the FM3a. It is similar to most modern brightness-optimized screens.

When i put it in my FE2, it underexposes by about 1/3 of a stop compared to the B2 screen, and about 2/3 of a stop compared to the plain B screen. This happens because the meter receives more light. This is of the top of my head, i haven't run this test for quite a while now and i don't have all my screens with me now. Nikon manuals also confirm this observation.

I am not sure what and how you measured it.

 

[Chan Tran]

To measure I simply use the Minolta booster (which is designed to attach to a Minolta meter to measure light thru the viewfinder).