Helicoids for custom build

abruzzi · Jan 8, 2025

Light Capture said:
39mm extension will likely cause vignetting. 3d printing a lens board with a cone that attaches directly to the helicoid is a solution for this.
Ideally, helicoid should be as shallow as possible.

you're probably correct, but we'll see. Part of the challenge with this is I also have to deal with the ergonomics. If the board I 3d print is too sloped/cone shaped handholding may become challenging. I also have to figure how to mount a shutter release that is easy to use while gripping the camera. If it does vignette the extension may be useful if I want to do a second, longer lens. I was originally thinking a Fujinon-A 180 or a 150 Xenar, but when I started measuring out what a long lens like that would look like, I realized why every 35mm in the world uses a telephoto design for their 100mm and longer (probably 85 as well?). I have a 180mm Tele-Arton that came with my baby technika that I hardly use. That lens has a very prominant rear element that can probably clear a 39mm extension.

Light Capture · Jan 8, 2025

abruzzi said:
you're probably correct, but we'll see. Part of the challenge with this is I also have to deal with the ergonomics. If the board I 3d print is too sloped/cone shaped handholding may become challenging. I also have to figure how to mount a shutter release that is easy to use while gripping the camera. If it does vignette the extension may be useful if I want to do a second, longer lens. I was originally thinking a Fujinon-A 180 or a 150 Xenar, but when I started measuring out what a long lens like that would look like, I realized why every 35mm in the world uses a telephoto design for their 100mm and longer (probably 85 as well?). I have a 180mm Tele-Arton that came with my baby technika that I hardly use. That lens has a very prominant rear element that can probably clear a 39mm extension.

You can easily integrate or make separately a hollow grip to bolt on the side of the cone and feed the cable release through it. That's what I use on some of my cameras.

MTGseattle · Jan 8, 2025

I sourced two adapters from this person for my modified Holga Pan 120.

CUSTOM PHOTO TOOLS

customphototools.com

I too am searching for some type of grip/platform that will let me retain a cable release. My issue seems to be that I want a right-hand grip and almost everything is left hand. I found a couple of loose platforms that look promising and a vintage Kalt universal grip that seems to be ambi-dextrous. I also thought about mangling a smallrig cage and sourcing a wood nato grip. In the smallrig lineup, I think the only thing appropriate for the HolgaPan might be Fuji GFX stuff.

I'll figure something out.

abruzzi · Jan 8, 2025

MTGseattle said:
I sourced two adapters from this person for my modified Holga Pan 120.

CUSTOM PHOTO TOOLS

customphototools.com

yeah, I've used him for #00 to #0 adapters. I have something like 5 lenses in Compur #00 shutters, and his adapters make it easy to mount them in #0 lens boards.

r_a_feldman · Jan 8, 2025

Do you have a local camera store with a bargain bin of cheap lenses? They can be a good source of helicoids.

abruzzi · Jan 9, 2025

r_a_feldman said:
Do you have a local camera store with a bargain bin of cheap lenses? They can be a good source of helicoids.

yeah, sadly in a city of 200k, our only camera shop is Best Buy.

MTGseattle · Jan 10, 2025

ebay my friend, as much as it pains me ebay and/or stumbling over gear through interpersonal netwoks.

abruzzi · Jan 21, 2025

I received the pieces from eBay. The M65 mounting flange looks like it will barely fit, so I need to start measuring and designing a 3D model. Right now I have a Symmar-S 100mm ƒ5.6 in place for testing, but I have a range of lenses I could use. The first challenge is getting the lens as close to infinity as possible. I've found that with 3D printing the models shrink a tiny bit when hardening. I had to add .2mm to the lens board holes in the boards I designed for my Toho. So if I can design it so the flange is at 100mm or 101mm. The lens is at infinity at 99.1mm, so expecting it to shring a bit, then possiblly shim the lens to exactly infinity (fortunately for their other cameras, horseman made a ground glass that fits the 6x9 graflok mounts. So I can do my best measuring, but the final settings will be inspected on the glass.)

I wonder if anyone know a source for copal #0 shims? Not for lens elements, but between the lensboard and the shutter. Alternatively, I could ship it at the M65 mount, but I expect copal shims are easier to find, and they don't need holes drilled.

ags2mikon · Jan 21, 2025

I bought some shims on ebay a year or two ago that I used to synchronize 2 lenses to use the same infinity stops that were very close but not close enough.

ags2mikon · Jan 21, 2025

Here is an auction number for some shims that can get you started. 315660857554

blee1996 · Jan 22, 2025

ags2mikon said:
Here is an auction number for some shims that can get you started. 315660857554

Search did not return any results. Can you provide the link or at least a screenshot? I don't think that is against the forum rules. Thanks!

MattKing · Jan 22, 2025

There is no problem with sharing links to sources for items.

ags2mikon · Jan 22, 2025

Let's try this. https://www.ebay.com/itm/3144190507...JRmy+O4ryCDGnSwljcPlXW3w==|tkp:Bk9SR4Lf--WRZQ

abruzzi · Jan 22, 2025

thanks. I'll look through them. It looks like M35 would be appropriate. That link above shows the sizes available in M35:

ags2mikon · Jan 22, 2025

I used one for a guide to also cut the black paper inter leafing from Efke sheet film with an exacto knife. I have also used the film itself as spacer material. Some of the filter data sheets from Japan are very thin yet hard.

dirkfletcher · Mar 25, 2025

abruzzi said:
I have this idea to expand out my Horseman Convertible. It may be impossible, but I think I can build a 3D model that functions like the default lens board. To start with, I'd like to build a board for a 100 or 105 normal lens. I've got several that would work well like the Nikkor 105/3.5 or Fujinon CM-W 105/5.6. The challenge--since the camera is scale focused--is to find a helicoid I could mount the lens in that is marked (or can be marked) for distance.

The one new thing I found was made by Fotoman:

Pardon Our Interruption...

What I like about this is it already has distance and DoF scales on the helicoid. I asked them what the closest focusing a 105mm helicoid and they said 1.7m, which is a bit short. I'd be happy with one meter, but so far I haven't found anything else. However I have 2 questions:

1. Does anyone have experience with the Fotoman part?
2. What other helicoids are out there that I'm missing. Due to how it will be used it needs to be able to mount a Copal #0 shutter for the lens. I've seen an expensive Rodenstock helicoid, and I know there is a user here that builds custom cameras ( @dirkfletcher ) and frequenlty outfits them with 47mm SA on a helicoid. So what is that helicoid and can it be adapted for longer lenses (the Horseman has a 62mm which is plenty wide for me, so I need a normal--105mm--and a long lens--180mm Fujinon A)

Hey there- we recently chatted about the front panel of the Convertible but I just ran across your question about helicals now.

Ironically, just this afternoon I shot a roll of film in the ‘broken…parts only’
Horseman Convertible that I’ve been working on.

I removed the 62mm lens and was able to use 10-15.5mm M42/M42 helical with a 47mm f/5.6 and keep the original front panel intact. Once the camera is done, I’ll post some proper pictures of the camera when I’m done, but I’ll share a quick shot tomorrow.

Going with a longer lens, an M58 17-31mm helical should be perfect, I’ll shoot a pic with an M58 helical for size as well.

The M65 helical might not be a good choice, it’s quite big and very heavy. It would be overkill for the convertible. I just used one on a super chunky 4x5 point and shoot with a 90mm lens, the entire camera was chunky and it was a perfect fit.

If you want to check there is a link for that project in here:

https://www.flickr.com/photos/dirkfletcher/albums/

Off to bed, more tomorrow!
Dirk

dirkfletcher · Mar 25, 2025

Here is my Horseman project so far, still needs work but thankfully I'm not traveling for the net week and a half and I'm hoping to finish it off and take it with me to the Masters.

Thankfully the M42 helical just fit into the stock board, the M58 would be larger but shouldn't be overkill. Ironically, I have a Nikkor 105mm f/3.5 in a (massive) Wista Copal #1 that I completely forgot about until I came upon these posts. I'm interested in seeing a potential nosecone come to life. A 105mm might be long for scale focus but it would be cool to give it a whirl.

Dirk

abruzzi · Mar 25, 2025

Nice! I'm glad you made some progress because I haven't. I have a lot of ~100mm lenses for 6x9 cameras. I expect I'll use a Symmar-S 100/5.6 that I have, but there are a lot of other options. I just pulled up my spreadsheet with my view camera lenses, and I have:

Kodak Wide Field Ektar ƒ:6.3 100mm
Schneider-Kreuzenach Symmar-S 5.6/100
Fujinon Fujinon-SW 1:8/105
Voigtlander Color-Skopar 1:3.5/105
Nikkor Nikkor-M 105mm 1:3.5
Schneider-Kreuzenach Xenotar 1:2.8/105
Georg Leitmeyr München Weitwinkel Anastigmat ƒ:6.8/105
Fujinon CM FUJINON-W 1:5.6/105mm

That doesn't count the six 90mm lenses and some slightly longer lenses. Some of the lenses in the list above have specific uses so I won't dedicate them to this, but the most likely will be either the Symmar-S or the Color Skopar. The Symmar-S is in a modern shutter that seems pretty accuate. The Voigtlander is in an old dial set compur that probably needs some attention.

(oddly, I've been using the Leitmeyr on a 60mp MF digital back, and it does surprisingly well. Its in a prontor shutter that seems pretty accurate--the digital backs tell you how long the shutter was open for each shot you take so it can function as a speed tester.)

Helicoids for custom build

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