How DOES an LF Helical mount actually work?

I've only been doing photography for 30 years but before I buy a helical focusing mount to use shorter-than-90mm lenses in my Linhof Tech IV could someone offer a quick explanation of how you actually use one?

Given that the helical LOOKS like it moves the lens farther away from the film plane (instead of closer, like a recessed board) I'm guessing the front standard must be placed further back into the camera (which can be problematic on a Tech IV) before any helical-focusing can occur. Also, do you have to manually focus on infinity FIRST, to give some sort of benchmark for the helical to work from?

Since I'm still investigating ultra-wide-on-Tech-IV options, and so many users complain about Linhof recessed-board difficulties, I'm open to any user-friendly suggestions (other than 'buy another camera'...I've got too many already!) I do realize that my dropped front bed will appear in every shot but I'm going to crop it out in printing. Thanking you in advance, this forum is an amazing resource and a real class act.

Rick Olivier
New Orleans

I have a 65mm Super Angulon factory mounted in a helical mount on a Super Graphic lensboard. The Super Graphic does not have articulated bed rails, so if the lens has to be positioned on the part of the rails inside the camera body shell (as this 65mm requires) there is no way to accurately focus. Thus with the 65mm you "rough" focus on the ground glass pushing the front lens standard back and forth, then clamp it down, and do your fine focus with the helical focusing mount. Don't forget to drop the front of the camera to its "dropped" position, or you will see the front bed in the picture.

In general, for most field type cameras, a helical mount is not needed. Only for certain cameras, such as the Super Graphic and extreme wide angles such as the 65mm Super Angulon used on the Super Graphic, does the helical become a benefit.
There is no advantage (with most all cameras) focusing using a helical mount, rather than using the geared bed rails. The geared bed rails work just fine.

Then there are the cameras like Sinar Handy which don't have bellows at all. Think of a Sinar monorail camera with just a lens board + helical mount attached to the rear standard instead of a bellows.
I'm in the process of building a helical-mount lens board for hand-held use on my Sinar Norma. It is quite possible that I will end up with something hideous but it can't hurt to try.

To use a helicoid mount on a Technika the front lens standard is left inside the body and not pulled out onto the focus tracks. The helicoid has the same screw mount as a lens that is in #3 shutter so the helicoid is mounted onto a Linhof flat board with a 3 hole.

You then set the helicoid to the infinity mark and while viewing through the gg move the front standard in or out on the rails in the camera body until a point a infinity is sharp. That is the infinity position for that lens and helicoid.

Each lens must have its own helicoid so you would need one for 35, 38, 45, 47, 55, 58 and 65mm lenses, depending on which you want to use. The helicoids are not universal and both Rodenstock and Schneider makes them for their lenses. Each helicoid is marked for distance and has DOF scales on them.

There is no way that a recessed lensboard can be used with a helicoid with a Technika 45.

Linhof also makes several different recessed lensboards for lenses as short as a 45mm for use on the Technikardan. These also fit the Technika IV and later.

"so many users complain about Linhof recessed-board difficulties,"

The current Linhof recessed lensboard for the Technika IV and later models has surface mounted aperture scale, surface mounted aperture selector lever and a surface mounted press focus lever with a colored indicator that visibly indicates if the press focus is open or closed. It also has a cable release quick connector that does not use a wire like the older versions.

No owner/user is complaining about the use of this board.

"I do realize that my dropped front bed will appear in every shot but I'm going to crop it out in printing."

Your drop bed will appear in any picture with a very wide lens when your back is positioned vertically (even with full lens rise and bed drop). It will not appear in shots with the back positioned horizontally with full lens rise and bed drop.

Linhof suggest that if you do not want to have the bed in the picture when using extreme wide lenses vertically that you use leave the back in the horizontal position and tilt the camera over 90° to take a vertical shot. As most tripod heads may have a problem doing this with a Technika Linhof has offered an outrigger bracket for doing just this for several decades.