Chroma 679 - Medium Format System

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Steve
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Hi all,

It’s been a while since I started a new build thread, so I thought it would be good to share this one.

As my Kiev88 ate its’ own shutter ribbons a few months ago, it’s been sitting on my shelf in the workshop. I took its’ lens a while back and mounted it to my test bed Instax Wide camera with electronic global shutter;

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Whilst it doesn’t quite cover the whole sheet, it’s a step up in quality from the original lens!

Back to the ‘36’, I’ve always wanted a Hasselblad SWC, but couldn’t justify the price, and have wanted to build my own instead. I picked up a Schneider 47/5.6 a few weeks ago to use on my superwide SnapShot, and realised that I now have all the components for my own SWC-ish.

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I designed these components last night, and took them off the printer about an hour ago, so there are still some tweaks needed, but the overall system is feeling awesome already!

There are three basic components to the system, which are all interchangeable;

1) Lens/Helicoid plate - This is currently a flat 3mm acrylic plate, with my SnapShot M65 helicoid bonded to it. The plate is then secured to the main body by 4 thumbscrews for a secure mount.

2) Main body - This is 3D printed and is essentially a spacer to mount the lens the correct flange distance from the film plane. I’ve printed this one 10mm deep, which allows me to wind in the helicoid when I’m not using the camera to make it as slim as possible. The rear face of the body has 4 strong magnets embedded to secure the rear plate.

3) Rear plate - I currently have 2 rear plates. One is designed to mount flush to the face of the Kiev88 film back, and is secured using very strong industrial double sided tape (the same tape I use to secure my bellows to the end plates). The other plate is designed to mount the original Kiev ground glass/fresnel and popup surround. They both have embedded magnets and light baffles, to allow me to switch between focusing on the ground glass and exposing the film. The helicoid is also marked up at infinity, 10’, 6’ and 4’, so I can focus by distance rather than using the glass.

I should be getting a Hasselblad back tomorrow, so I can make a rear plate for that, along with an RB67 back early next week to do the same. I’m also currently printing the removable grip, which is secured to the main body with embedded rivnut mounts. The grip has a hole through the middle, to pass a shutter release cable through, along with a mount point for a neck strap. Next after that is a removable tripod mount.

As the whole camera is modular, I’m planning on designing alternative lens/helicoid plates to allow lenses from other systems, like Mamiya Press/RB too. At the moment, the lens would need to have its’ own shutter to be mounted, but I’m hoping to deal with that down the line with the new global electronic shutter I’m working on ;0)
 
Interesting. Be something to do with the spare RB67 Pro backs I've got (the ones with few interlocks)
 
Interesting, damn it Steve will you stop inventing things that I want....
 
Yup, that’s the long and the short of it :0)

Once I design additional front plates it will be possible to mix and match lenses and backs too, so you could use Mamiya Press lenses on 6x7 etc

For example an RB lens? tbh for what i'm thinking they'd be too bulky but as an alternative to my failing folding cameras this would be a lot lighter and not too much more bulk.

Just realised I've got a great little fuji 120mm which is basically normal for a 6x7. Gimme gimme.
 
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When can we expect full movements on the front standard? :)

Rubber flexible helicoid with locking struts to fix the bent position...

And you called it a 36. Doesn't that create a problem of nomenclature when you release the 35mm version?
 
When can we expect full movements on the front standard? :)

Rubber flexible helicoid with locking struts to fix the bent position...

And you called it a 36. Doesn't that create a problem of nomenclature when you release the 35mm version?

Stop it! I’m trying to build a simple system [emoji23] If you want rise/shift, buy a Technical/Classic SnapShot. If you want full movements, buy an Adventurer [emoji6]

I’ve called it the ‘36’ for now, because this one is 6x6. I might think of a more generic name before I launch it properly.
 
For example an RB lens? tbh for what i'm thinking they'd be too bulky but as an alternative to my failing folding cameras this would be a lot lighter and not too much more bulk.

Just realised I've got a great little fuji 120mm which is basically normal for a 6x7. Gimme gimme.

I’m planning on adding an RB mount front plate too. Whilst the lenses are quite bulky, the whole system would still be considerably smaller than the camera they came off [emoji6]

The 120mm sounds like a good shout though. Same requirements as the SnapShot lens boards, maximum rear element diameter of 62mm, maximum shutter size Copal 1 (or custom size up to 54mm diameter) [emoji1303]
 
In which case, "66" is more generic, as in Exakta66. Although given the usage of RB67 backs, "67" might be better.

Good luck, anyway. You're clearly always looking for a new challenge.
 
Call it the Chroma Swish since it's SWC-ish.

All it needs is a way to mount an external viewfinder. The RB67 back and a 35mm adapter for it would mean that you also mimic another 'blad - the XPan.
 
I’m planning on adding an RB mount front plate too. Whilst the lenses are quite bulky, the whole system would still be considerably smaller than the camera they came off

Plus it would get a cool name as a "42". The answer to everything is a 6x7 camera :)

I'd love a small camera to put my RB lenses on. I picked up a Goodman Zone recently which I'm hugely dissappointed with. If the latest application of blu-tack doesn't fix the light leaks, in the bin it goes.

Thread subbed :)
 
Plus it would get a cool name as a "42". The answer to everything is a 6x7 camera :)

I'd love a small camera to put my RB lenses on. I picked up a Goodman Zone recently which I'm hugely dissappointed with. If the latest application of blu-tack doesn't fix the light leaks, in the bin it goes.

Thread subbed :)

I wondered why my cameras don’t use Blu-tac for light seals [emoji23]
 
Call it the Chroma Swish since it's SWC-ish.

All it needs is a way to mount an external viewfinder. The RB67 back and a 35mm adapter for it would mean that you also mimic another 'blad - the XPan.

I’ll be integrating a cold shoe mount along the way. The main body on mine is only 10mm thick, and a quick first print, so I didn’t design one in. I’ll probably add extra mount points around the body for accessories.
 
I’ve also just received a couple of sets of winding knobs from Elvis at ONDU. I’ve been working on my own 612/617 rollfilm back for the Adventurer, and was chatting to Elvis, as I really like the magnetic design on his pinhole cameras, so he sent me a few sets over to look at designing them in to my back.

Once I get to the point that I’m happy with the back, I could potentially use it on this system too, as a completely flexible option.
 
I’m planning on adding an RB mount front plate too. Whilst the lenses are quite bulky, the whole system would still be considerably smaller than the camera they came off [emoji6]

The 120mm sounds like a good shout though. Same requirements as the SnapShot lens boards, maximum rear element diameter of 62mm, maximum shutter size Copal 1 (or custom size up to 54mm diameter) [emoji1303]

Cool, sign me up for a dohicky box, a LF lens board thingy an RB lens boardy thing.
 
Cool, sign me up for a dohicky box, a LF lens board thingy an RB lens boardy thing.

Please keep it simple for us old 'uns who don't understand all this technical language :)

I can't afford any new equipment anyway.
 
If you want rise/shift, buy a Technical/Classic SnapShot.

I can recommend (y) ( even if atm I'm still "getting to grips" with mine.)
That's not a negative feedback, just that handheld LF for me is VERY strange o_O
 
So could you fashion something along the lines of a Hasselblad super wide with movements?
 
So could you fashion something along the lines of a Hasselblad super wide with movements?

To be honest. Eventually, I’d like to make a new Hasselblad Flexbody-style system, with the same range of movements, but am really enjoying this fixed version at the moment. I’ve got a roll of Foma200 in it and, bar a couple of standard issue double exposures (I really need to remember to close the shutter after composing..), I’m looking forward to seeing the results.
 
Or, and I really hesitate to suggest this in current company and venue, could you make a tilt/shift adapter to allow LF lenses to be used on a Sony a7rii (other cameras are made).

Actually, scrub that idea. If popular it would push up the prices of LF lenses, and, if people got a taste for it and started buying up the cameras as well....

I know that a tilt/shift adapter is made, but I think it's Hasselblad lenses only.
 
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Or, and I really hesitate to suggest this in current company and venue, could you make a tilt/shift adapter to allow LF lenses to be usedon a Sony a7rii (other cmeras are made).

Actually, scrub that idea. If popular it would push up the prices of LF lenses, and, if people got a taste for it and started buying up the cameras as well....

I know that a tilt/shift adapter is made, but I think it's Hasselblad lenses only.

As far as I know, there are also Canon/Nikon/Olympus mount versions too. I’d suggest speaking to someone like RAFCamera via EBay about making a custom adaptor to mount an M65 Helicoid to one of those mounts. You could then use one of my SnapShot lens boards to mount the LF lens [emoji1303]
 
Sounds tempting, especially as I have a 300mm 10x8 lens that's the size of an OM 50mm f/1.8. Thanks for the info.
 
If you google for 300mm f/9 lenses, you'll find that they are rather small. My 300mm f/9 Tessar just covers 10x8, which makes it very usable across formats.
 
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Sounds tempting, especially as I have a 300mm 10x8 lens that's the size of an OM 50mm f/1.8. Thanks for the info.
That sounds like a seriously tiny lens!
If you google for 300mm f/9 lenses, you'll find that they are rather small. My 300mm f/9 Tessar just covers 10x8, which makes it very usable across formats.
If you’re talking about the 300mm APO F/9 that I borrowed quite a while ago and then purchased one of my own then yes it is tiny and covers 10x8 reasonably well ( I forget the coverage) but for landscapes it is ample and I’ve used it for some architecture without experiencing any major problems. It’s benefits re size and weight outweigh its limited coverage for me personally. Atm I have mine on an 110mmx110mm intrepid board for use on the 5x7.

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Just checked, it has a listed image circle of 264mm @f/22

Iirc 325mm is the minimum required to cover 10x8 but I promise you that the apo lens pictured above with a 264mm IC covers the format at infinity without problems.
Obviously closer objects the coverage increases.
 
I was thinking of my Tessar 300mm f/9 which has an image circle at infinity just big enough for 10x8. But they're both about the same size.
 
I printed a quick test grip last night to get a feel for the size. I liked the overall size, but have made some changes now to integrate the tripod mount into the base, and change the path of the cable release slightly. The updated version is on the printer now.

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The grip is attached to the main body, using a pair of keyhole mounts, allowing it to be removed easily too.

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I also printed an updated ground glass frame this morning, to move the popup shade a few mm closer to the glass, to make the magnifier function properly.

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Looking at the weight, with the Schneider 47/5.6, it’s a nice comfortable balance between weight and mass. The Kiev rollfilm back is almost the same weight as the rest of the camera/lens!

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But what's with the SD card holders?
 
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