Using manual focus lenses on electronic Nikon film cameras with manual focus confirmation. What do you trust more?

[albireo]

For what it's worth.. Quick test.

Two sequential shots.

Left: I focused manually, but following the focus aid in the viewfinder until it reached the 'O' position
Right: I focused manually and visually, ie by looking at the image getting sharper on the focusing screen - as you would do with a manual focus camera without focus aid.

Note: I always use the second method (my eyes) with all my lenses and all my cameras. I always get tack sharp images. I think what this 'test' suggests is that there is a mismatch between the distance detected by the AF sensor and used by the focus aid, and the distance rendered on the focusing screen. I thought this was interesting and I wonder if it's time to send the camera for a CLA. Or perhaps I'll just bin it and look for a new one.

 

[Sirius Glass]

For what it's worth.. Quick test.

Two sequential shots.

Left: I focused manually, using the focus aid in the viewfinder until it reached the 'O' position
Right: I focused visually, ie I stopped searching when I decided the image was sharpest on the screen.

Note: I always use the second method (my eyes) with all my lenses and all my cameras. I always get tack sharp images. I think what this 'test' suggests is that there is a mismatch between the distance detected by the AF sensor and used by the focus aid, and the distance rendered on the focusing screen. I thought this was interesting and I wonder if it's time to send the camera for a CLA. Or perhaps I'll just bin it and look for a new one.

The openings on the plastic bin and the sponge[?] that sticks up are much sharper on the left. I have found that except for focusing on closer branches or dirt on a glass screen, the AF focuses sharper, faster and more consistently except if the focus point or points are on very low contrast or very low light.

 

[albireo]

The openings on the plastic bin and the sponge[?] that sticks up are much sharper on the left. I have found that except for focusing on closer branches or dirt on a glass screen, the AF focuses sharper, faster and more consistently except if the focus point or points are on very low contrast or very low light.

Exactly. Forgot to say I focused on that plastic bin, centre.

 

[George Mann]

I use an F90x with Ai/Ai-S lenses. I also use the optional J type focus screen with it.

I find the electronic rangefinder to be accurate enough that I don't have to depend on the custom focus screen when there is sufficient contrast at the point of focus.

The same can be said with my D2x/D300s.

 

[Craig]

To my eye, the bin that you focused using the focus aid seems sharper.

 

[RalphLambrecht]

To fix your camera, there is usually an adjustment on the secondary mirror and a software adjustment, but I believe the Rollei Hy6 is the only film camera in which the focus point can be adjusted in the camera without additional software.

the old story; if something is adjustable it must be adjusted.

 

[RalphLambrecht]

I use an F90x with Ai/Ai-S lenses. I also use the optional J type focus screen with it.

I find the electronic rangefinder to be accurate enough that I don't have to depend on the custom focus screen when there is sufficient contrast at the point of focus.

The same can be said with my D2x/D300s.

I find Nikon autofocus and auto exposure beyond any criticism.

 

[reddesert]

The image on the right, focused by eye on the focusing screen, looks sharper further away, that is the lens was a little too close to the film, which suggests the focusing screen is a little too far away from the lens.

The camera in question is an F-801s with a removable focusing screen, the first thing I would try is reseating the screen, and looking for any obstructions or loose bits there. I don't think it's possible to install that screen the wrong way around, but that is something to check.

Although the autofocus system doesn't use the main mirror, it typically uses a second mirror hanging behind it to redirect light to the AF sensor, so the fact that the AF system is correct makes me not suspect the mirror.

 

[ic-racer]

Yes get a new camera and move on. I’m always curious so I save all my cameras and sometimes years later figure out the issue.