Building a Sinar Handy from non-Sinar parts

[Paul Droluk]

Uli - currently, both Schneider and Rodenstock build to a tolerance of +/- 0.5mm for the FFD specified. I have no data for Nikon or Fuji. In any case, the Fotoman HFM provides +/- 1mm of internal adjustment capability (Schneider & Rodenstock HFM's provide +/- 0.5mm) to compensate for the allowable manufacturing tolerance. From our experience calibrating MANY lenses, all of the makers most usually deviate on the longer (+) side of the stated FFD... probably due to stack-up. Regarding the use of a pre-marked or un-marked HFM, a pre-marked mount includes an accurate DOF scale for the focal length being mounted... a distinct asset.

GPS - HFM's from every maker are accurate (out of the box) for infinity focus with a given lens ONLY on a pot-luck basis... maybe 10% of the time. The reason is that every lens is different... even within a single production run. For this reason you must always find or verify infinity focus anyway. Assuming the components have been manufactured within tolerance, the final "calibration" of the HFM becomes the last fine tuning step in the "Harmonizing" effort.

Determining the exact length for each component of the assembly is not that difficult as long as you have precise measurements (see my earlier posting). Maintaining Parallelism across muliple components on the other hand is more difficult. However assuming one uses quality machine tools and proper machining practice, acceptable parrallelism is quite acheivable.

[GPS]

GPS - HFM's from every maker are accurate (out of the box) for infinity focus with a given lens ONLY on a pot-luck basis... maybe 10% of the time. The reason is that every lens is different... even within a single production run. For this reason you must always find or verify infinity focus anyway. Assuming the components have been manufactured within tolerance, the final "calibration" of the HFM becomes the last fine tuning step in the "Harmonizing" effort. ...

Yes, I know it. That's why I use a construction that allows me to fine tune the lens both on distance and the parallelism. In imagination it's always just "I put this there and that's it" but the devil is in details...

[Uli Mayer]

IMO, neither knowledge of focal length tolerances (+/-1% in the past or +/- 0.5mm today) nor statistical trends are of much help here. My rule is simple: If one does not know the lens' exact f.l. or its precise FFD ( within fractions of a millimeter) one should build for the shortest f.l. or FFD tolerated by the manufacturer - and accept that "infinity" might finally not coincide with the helical mount's zero-position. Better some draw than filing! You may call this approach less than perfect but at least it's "error-friendly".
Having the "infinity" mark at the mount's end position would certainly complicate calculation and actual building (and make the doubtful use of shims and spacers almost obligatory).

My approach does not rule out adding a home-made DOF scale or a pair of DOF marks for the most frequently used stop. But as I stick to the rules published by Harold Merklinger, I can do without.

[GPS]

Better some draw than filling? Even better is - adjusting! And no, shims or spacers are not obligatory for adjusting...

[Uli Mayer]

GPS,
you wrote: "I use a construction that allows me to fine tune the lens both on distance and the parallelism."

Could you be a bit more specific about this construction or do you want to keep it as a secret?

[Ed K.]

Hi Frank!

You could make a wooden body spacer and then sand or, better yet, mill it down.

I have made many wooden box cameras, and I have a 65mm Angulon version that works great with FIXED focus and F22. The only trouble though is that hand-held shots are seldom practical once the center filter is added. That said, using DR5 processed HP5 is one way to get enough speed to make it practical. I use a shim washer for closeup range of 6-50 ft., and no shim for 25 ft to infinity. The results are quite sharp and nice. You could make a wooden body to accept your sinar parts in a jiffy. The flange to film plane distance stated by Schneider is .75mm different than Schneider specs for my particular Technica 65mm. Best to start with the recommended distance and then check it somehow first.

As to the Chinese helicals, I have one made for 90mm, which is not a Fotoman. Unfortunately, it won't fit my 90mm 5.6 Fujinon because the rear element is too large. I bought it from a non-Fotoman supplier. Be sure to watch out - make sure that they have one that will fit your particular lens!

At the moment, I have a Fotoman 90mm mount on order, one that is supposed to fit my Fujinon SWD 90 / 5.6. My plan is to use it in combo with my Gowland architectural/scenic/aerial so that I have Grafloc back, rise and fall, aerial handles, and the Fotoman helical all in one package, and of course, f 5.6 in a pinch. I can let you know how it came out if you like - the parts should be here soon.

Cost-wise, and time-wise, the Fotoman camera itself looks just right if you don't care about Grafloc items such as the Horseman 6x12 back, or if you don't care about rise and fall. By combining the Gowland and the Fotoman parts, I get what I need, but the price starts to climb pretty fast.

One good thing about building some wooden box cameras is that it lets you find out how you like the idea. I ended up loving it - so I'm getting the rest of it done.

Good luck on your projects!!!

[GPS]

GPS,
you wrote: "I use a construction that allows me to fine tune the lens both on distance and the parallelism."

Could you be a bit more specific about this construction or do you want to keep it as a secret?

This specific construction is indeed my secret ;-) ... but as a consolation I can tell you that there are many other different ways of adjusting the lens board correctly. One of them is even known to all of us, I dare to say... (now it starts to be interesting, doesn't it?) And it doesn't need any filling or shims or a spacer either! If you don't know at least this method... uhm, then take out your view camera and look at it. No shims, no spacer, no filling, yet - adjusting. And not the only way of adjusting, as I said... ;-)

[Uli Mayer]

GPS,
with or without your kind permission I'll answer in my mothertongue in order to prevent further misunderstandings:

Du kannst dir deine Arroganz - "as a consolation I can tell you" .."If you don't know at least ..." - dahin stecken, wo du das Geheimnis ( das Sekret ) deiner Konstruktion bewahrst.

[Daniel Unkefer]

Norma Sinar Handy Final Version by Nokton48, on Flickr

Made from Sinar and Non-Sinar parts