Bizarro flash shoe problem

[Dante_Stella]

Ok, Brian.

I have a Fuji G690 and a Leica Universal Viewfinder M (the monster-sized finder that does a whole bunch of focal lengths).

The Fuji has an unsprung flash shoe made of a very solid piece of metal that has a slot cut from front to back (in contrast to an ISO shoe, which has a slot made by folding over two pieces of metal toward the center of the camera).

Fuji 6x9 and 6x7 finders fit the slot and are held in place by the sideward pressure of the finder foot (they are split partway along their length and bent slightly outward). Other older feet like on Mamiya finders have springs on top that push the finder foot down into the bottom of the shoe. This all works fine.

What is not working fine is the Leica finder, which uses a tension ring lock that would normally sandwich ISO rails between the top of the finder foot and the ring (and those rails, typically being made of sheet metal, usually comply a little under tension). This finder levels perfectly on every camera with a stock ISO shoe.

But mount this finder on the Fuji, and tightening the ring (which drives the finder's foot upward into the top of the Fuji's slot) causes the finder to become un-level in relation to the camera (from the back, the left side of the finder is higher than the right). The finder's lock ring, being made of hardened aluminum, has zero give or compliance - and neither does the camera's flash shoe.

I have narrowed this problem down to an irregularity in the slot height, either somewhere on the left side or between sides. This both makes it difficult to get full tension on the lock ring and makes the left side of the finder lift up when the ring is tightened. I'm sure that the slot height was of little consequence to the factory, since it simply wasn't a surface on which viewfinders of the time really depended.

So how would Sweeney attack this one? I already thought of just leveling the finder by shimming underneath the shoe, but its three attachment points are too close together to allow a good tilt. I could conceivably shim under the Leica finder's shoe, but it has four screws (so not easy to establish a plane).


Thanks!
Dante

 

[menos]

If the shoe is the one, you see in this image from Flickr:

Flickr link here.

Your weapon of choice is a thin jeweler's file (looks like a nail polishing file).
Lock the finder, find the misalignment, file the slot in the accessory shoe and check back with the finder after each filing.

The proper way would be to disassemble the shoe and re machine the part on a milling machine or a wire eroding machine after careful adjusting alignment - a 2−4 h job.

 

[Sonnar Brian]

As Menos stated, I would be pulling out the file. I would also pull out the Nikon Bubble level and a regular bubble level to try to find the imbalance.

"I have narrowed this problem down to an irregularity in the slot height, either somewhere on the left side or between sides."

With the camera on a level surface, if you put a level across the top of the Shoe, does it show the unevenness? If you put a shoe-attached bubble level, is there a difference? If it's the left side of the shoe rail that is too high, I would try the file.

 

[Dante_Stella]

Here was the easier solution. Find a 50mm finder whose mounting was similar to the Fuji finders' method. That can be leveled by adjusting the prongs of its mounting foot. Get the tripod level, the head level, and the finder level (or as close as you can).

Since the Seculine Action Level Cross level comes with a magnetic base (shoe on top), I was able to use 3M Command adhesive to adhere the level to the left side of the finder. You obviously need to make sure that everything else is level up to that point and that the LEDs are all green when you mount the level.

But what you get is a digital bullseye that works in two orientations (unlike the one in the Leica finder, which only works in one). And because leveling is indicated by colored lights, you can do it in your peripheral vision.

The Seculine can actually be field-adjusted, so even if you can't mount it to something that is level or at a 90 degree axis to level, you could make a final system adjustment.