Chroma - Lasercut Acrylic 4x5 Field Camera

This is just getting cooler and cooler.

Silly question time.

Would it be possible or worth it to make a plate holder for a medium format camera?

E.G. Bronica SQ

Funnily enough....

As the back is interchangeable, the only limitation is what I can build so I’d already sketching up mounts for a standard rollfilm back and am also putting together a brand new 6x12 back :0)
 
Funnily enough....

As the back is interchangeable, the only limitation is what I can build so I’d already sketching up mounts for a standard rollfilm back and am also putting together a brand new 6x12 back :0)

Oh! 6 x 12.... sounds interesting :D
 
Oh! 6 x 12.... sounds interesting :D

It’s early stages at the moment because there’s more priority on testing my new Bellows material. After folding the latest set of bellows at 11:30 last night and weighing them down, I’ve just checked them and am really happy with the result. The material is lightweight, flexible and, more importantly, is completely light tight with only one layer of material.

The only sticking point is that the supplier I’ve spoken to only carries black and white in stock. They can get pretty much any colour I want but would only supply them in full (100m!) rolls. Whilst I’m hoping for a successful campaign/sales going forwards, I’m not sure I’ll need 100m at a time of the various colours.
 
Yeahhh I like the sound of this too!

Glad you like the sound of it and I’m not just a bit nuts! I’m not going to get any actual parts cut for the next 2 weeks while we’re here in Orlando (got to our room an hour ago!) but I did draw up the layers required for the 6x12 back while I was on the plane. It’s a pretty rough draft but I reckon I should be able to make it work.

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You’ll all be glad to know that I’ve come well prepared with film as well as my digital kit :0)

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Sony A7 with FE 50/1.8 (AF), OM Zuiko 35/3.5 shift and OM Zuiko 24/2.8 (thanks Paul!)

Olympus 35RC - 2 rolls of Velvia 100F and 1 roll of Cinestill 800T

Instax Mini Neo 90 with 40 sheets of film

I reckon that should cover me [emoji1303]
 
Sony A7 with FE 50/1.8 (AF), OM Zuiko 35/3.5 shift and OM Zuiko 24/2.8 (thanks Paul!)

Olympus 35RC - 2 rolls of Velvia 100F and 1 roll of Cinestill 800T

Instax Mini Neo 90 with 40 sheets of film

I reckon that should cover me [emoji1303]


:thinking: Where's the 4x5?
 
:thinking: Where's the 4x5?

I get enough abuse from my wife bringing 3 cameras. I reckon I’d have a challenge walking if I’d packed a Chroma/film holders/tripod too ;0)

I was supposed to be going to Las Vegas at the end of November with work which I’d have taken a Chroma to but it was annoyingly cancelled :0(
 
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Ok, things are ramping up now for my Kickstarter release. I'm currently building 3 more Chroma's, one for myself in gloss black, one for Hamish Gill (35mmc.com) in matt black and one for Rachel Brewster-Wright (Sunny16 Podcast) in flourescent blue. Once these are complete I'll also be building some more for a few more bloggers/site owners. They all want their own but will also be reviewing/advertising them for me in return so all good :0)

I've just ordered 5 sets of ground glass/pinhole plates from the company I'm working with in Lithuania to supply them and they've asked me if I want all 4 corners cutout of the glass or just one and I'm not really sure what would be the best option? Previously I've used a solid groundglass on my Polaroid 4x5 but there wasn't any movement on those bellows so airflow wasn't an issue. However, with the Chroma, the bellows are completely airtight so I need some release but am not sure what's best. Any thoughts from the collective experts?

Cheers
Steve
 
Are you worried about launching so close to Christmas, at all? I imagine the Kickstarter-savvy lot will know what kind of impact it has on people funding their own KS goodies when there are presents to be bought too... or do you anticipate people funding on behalf of others as gifts?

Really excited to see the finished article :)
 
Are you worried about launching so close to Christmas, at all? I imagine the Kickstarter-savvy lot will know what kind of impact it has on people funding their own KS goodies when there are presents to be bought too... or do you anticipate people funding on behalf of others as gifts?

Really excited to see the finished article :)

Funnily enough I was chatting with a KS campaign manager the other day and they said about launching before Christmas sometimes being a risk. It makes sense with cash before Christmas, but I’m a bit concerned about leaving it until after Christmas and missing the current popularity of film products. I’m a little torn at the moment :0(
 
Funnily enough I was chatting with a KS campaign manager the other day and they said about launching before Christmas sometimes being a risk. It makes sense with cash before Christmas, but I’m a bit concerned about leaving it until after Christmas and missing the current popularity of film products. I’m a little torn at the moment :0(

It's a tricky decision. I think people will still be interested in a couple of months' time, but it'd be a shame to hold off now that you've got your video done and people primed to do reviews. If you hit the holiday period just right though, anyone with Christmas money to spend might suddenly find themselves with a Chroma to tempt them!
 
It's a tricky decision. I think people will still be interested in a couple of months' time, but it'd be a shame to hold off now that you've got your video done and people primed to do reviews. If you hit the holiday period just right though, anyone with Christmas money to spend might suddenly find themselves with a Chroma to tempt them!

Good point about the post holiday cash. It will probably be the last week of November before the campaign launches so it will overlap Christmas. Cheers
 
Thought I’d share a few dry assembly shots of the Chroma I’m currently building for Rachel from the Sunny16 Podcast.

Custom engraving on the removable back as well as the pinhole size, focal length and aperture (these parts have black backing when it’s complete for light tightness);

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Quick assembly to check alignment before removing the protective covering;

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Protective covering removed (except the base)

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Look at the extension on that... (the front standard isn’t twice the size of the body really, just the iPhone distortion!)

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Just bloody stupidly excited :banana:

Me too [emoji3]

I know it’s been a long time coming but I’m glad I’ve gone through the various designs to get to this one. I’ve made the front standard much more rigid this time which removes any of the wobble I had with the previous versions.

Also, using the rivnuts to bolt the main sections is so much neater and quicker at the same time.
 
It’s looking awesome Steve.
 
Thanks Steve. It was seeing your camera that gave me the idea of doing a 6x12 back so cheers [emoji1303]

I had originally planned to put the lens on a Holga Wide pinhole 6x12. I still think one of those would make a good 6x12 film back with a minimum amount of modification.


Steve.
 
I had originally planned to put the lens on a Holga Wide pinhole 6x12. I still think one of those would make a good 6x12 film back with a minimum amount of modification.


Steve.

Randy from Holgamods uses them with LF lenses to build exactly that. The only issue is the limited supply of them hence building from scratch being a better option long term.
 
Pinholes and groundglass have arrived from Lithuania :0). Obviously, an opaque Chroma won’t show the metal plate through it (or the back of the adhesive block sheet on the rear side for light blocking)!

I’m not going to be building Chromas in transparent acrylic as the laser seems to have issues cutting it for some reason so this is a one off!

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I’ve also cut the remaining sheets for it, including the black top plate for the focus bed. I’ve engraved common distances for when the bed is fully retracted as a quick reference guide.

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I'm happy to report that my final bellows assembly materials and design are the best ones yet. It's now a single layer of external material with internal ribs cut from a heavy duty vinyl and is completely light tight (obviously!) and very flexible. Total weight, including the front and rear acrylic plates, is 131g so I'm happy with that.

For the time being I'm only going to be building them in black as I'm working with a few suppliers to find alternative colours. However, one supplier I've been in contact with can only supply the material in multiple colours by 100mx1.5m rolls so I reckon that might be more than I need seeing as one set of bellows only needs 1x1.5m of material :D The bellows are user-replaceable so could be swapped out for different colours down the line if I do choose to offer them.
 
Ongoing assembly process. I’ve found a few places where holes need to be slightly bigger (to allow me to fit the rivnuts through) and I’ve also moved away from embedded threads on the lens board surround to reduce assembly time. It will need a slight change to the bellows front plate so I haven’t bonded that yet.

I’ve bonded the Bellows to the rear plate and bolted it to the rear standard to clamp it. By doing this, I don’t need to have loads of clamps and clips to hold the Bellows to the rear plate while it dries. It also keeps it completely square with the body.

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Front standard fully assembled with countersunk bolts and rivnuts. I wasn’t happy with the alignment on the front plates of the lens board so I haven’t fitted those yet. I also need to bond four suede pieces inside the The frame runners so the rise/fall is cushioned.

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The bed is now countersunk and bolted together. I’m waiting for M5 rivnuts before I bond the sliding bed layers together but it’s ready for the uprights.

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I delivered my first Chroma to another photographer last night and, apart from never using "flourescent blue" acrylic again, it went well :0) I'd added extra light seals to the front and rear standards to block unwanted light but found that the acrylic manages to bend light around corners :confused: After a bit of adjustment of the seals and several rounds of swearing at 11pm (it's being used on a commission in Birmingham today!..) it's good to go.

My main findings from the completed Chroma are;

1) Never use flourescent acrylic again...

2) Remove the build complexity of the front standard to simplify its assembly and use

3) Swap out the sliding foot that the front standard is bolted through and replace it with several fixed position threads on the focusing bed. There's 0.5mm of play on each side of the foot from where it was cut out of the surround piece that's used as the focus rail. On its own that's not a problem but when I add the wide front standard, the extra torque means that there's some wobble even when fully tightened which isn't ideal

4) Use metal 90 degree brackets to bolt the rear standard to the camera bed because the current acrylic brackets are a potential weak point when the camera is folded.

5) Use smaller magnets to secure the ground glass holder. On previous builds I've used four 5x5mm magents on the rear standard and six on the ground glass (it's moved between two positions). For this build I swapped to four 10x5mm magnets on the rear standard and six on the ground glass and they're ridiculously strong!

Overall, no major changes needed but they will all add up to improve the complete handling/assembly.
 
Looks good to me Steve, very professional. My only comment (and I'll be honest, it's just nitpicking) is that you say its been 2 years in the making but the Peaks meet was only last September. :)
I am very excited and I'm especially excited about the 6x12 back, I love a pano me :D
 
Looks good to me Steve, very professional. My only comment (and I'll be honest, it's just nitpicking) is that you say its been 2 years in the making but the Peaks meet was only last September. :)
I am very excited and I'm especially excited about the 6x12 back, I love a pano me :D

That’s a very good point Andy. I was sure it was 2 years ago but I’ve just looked at the first design on Flickr and it was Sept 2016! Good spot, I’ll change it now [emoji1303]
 
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