Ideas for Auto Focus Enlargers not historical crap

[Tin Can]

I am losing vision. Focusing an enlarger is now nearly impossible.

Next week I get my bionic Cataract lenses lasered to clean off scars. Maybe...

I have a 35mm Leitz Focomat V-35. It works well, once set up, but one still needs to zero each frame. It does 'follow focus', meaning once focused it can change print size in focus. Kodak made them long ago.
Read this.

I think rangefinder focus could work on LF enlargers, maybe with some modern sensors. I follow this robotics toy supplier.

Isn't it about time we make new enlargers with improvements?

The 10X10 chassis superstructure is not a problem. Focus is. At least fo me.

All ideas welcome.

[Bob Salomon]

Electronic autofocus enlargers do work, once calibrated to the specific lens. I used the Kaiser 69 ones but have also sold various ones including the 10 x 10” Homerichs. They all worked!

I also owned the Durst L900 as well as the Focomat llC. They were both mechanical cam focus units and the Durst was more accurate. But it was 69.

[Drew Wiley]

Easy nowadays with little stepper motors and second-hand track attached to the column. The trickiest part would be finding an accurate enough compatible distance laser. It would be extremely helpful to establish a friendship with a local machinist with this kind of background. Since I retired, I no longer have an inside track with laser manufacturers, but all kinds of stuff
gets recycled from industrial usage. An alternate method would be to rig a super-duper grain magnifier based on video, which you can examine of a large screen. Edmund Scientific (commercial division) might give you some clues. I actually have a grain-magnifying TELESCOPE set up on my tallest enlarger, using Edmund components; but it probably wouldn't work well with cataracts. Something with a bigger max aperture might. You can search for "Close-focusing Telescopes". Hopefully your personal vision tune-up will help a lot. Or there are no doubt second-hand digital cameras that could be linked to a big viewing screen, and be mounted synchronous with the neg carrier plane. Durst has a carrier with a conspicuous crosshair on the edge
of the carrier, which can be precisely adjusted to the film emulsion plane itself, and is highly visible compared to film grain itself. Even two identical glass carriers could achieve this purpose - one with the real image, the other with a big X across the diagonals.

[Tin Can]

What about a system similar to a graphic range finder light but with lasers?

Done that.

It does work well.

[Tin Can]

Drew I know it's possible.

Feedback loop.

DSLR coupling.

Need actual workers.

[ic-racer]

A five-dollar Nikon N55 body may give excellent results as a 'focus finder'; it had Nikons state-of-the-art autofocus for the time with a 'focus confirmation' dot for non-autofocus lenses or looking through a grain focuser.

I also think Canon EOS has manual focus confirmation beep. In that case put camera with no lens on the baseboard at same focal level as your easel. Camera should beep when focus is achieved.

[Mark Sampson]

I recall, from my earliest days in photography, a Durst that focused by a split-image projected on the baseboard. It was two colors of light that converged. But I may be dreaming of that... some years later I used a Leitz Reprovit II for slide copies- it had a rack-over system. You focused with a bright projected image and then racked over the Leica M body to make exposures. Probably impractical for an LF adaptation. At Kodak we had a couple of Omega D3 autofocus 4x5 enlargers, but didn't use the autofocus mechanism. Might not one of those be made to work, adjusting the cam for the appropriate modern enlarging lens?

[Drew Wiley]

I posted on a different thread today a comment about Durst autofocus enlargers. They've very expensive, quite fussy, and require dedicated carriers. Not a realistic solution in this case.

[LabRat]

One thing that could be considered is that when an image is in focus, it is not only sharp, but the contrast is highest, so if 2 sensors read 2 density steps, it could compare contrast at different focus settings and tell which is highest... You would have to roll past the focus point, but the unit would learn that reference point...

Some AF camera systems work by comparison of contrast areas... You probably have to allow a system to see the difference, especially in lower light, flat lighting scenes...

I thought of a focusing aid for cameras & enlargers long ago as film photography was on the wane, so a smaller and smaller market, so I gave up hope...

I hope your vision gets better, Randy...

Steve K

[MrFujicaman]

My first 4X5 enlarger was an old Federal 450. There was a built in focusing target built into the negative carrier. I find myself wishing my Beseler had that feature...