Chroma - Lasercut Acrylic 4x5 Field Camera

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stevelmx5
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I’m still working with Jason Lane on the new holders, but it’s looking like setup cost and flexibility of size is pushing us towards acrylic holders rather than moulded ABS. For anyone else waiting for Chroma cameras, the holder assembly is going to be outsourced, so it doesn’t mean taking up camera build time!

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I cut the first 8x10 holder yesterday....it’s huge! I won’t get this bonded together until my adhesive arrives on Monday, but I’m happy with the dry fit. Whilst both the 4x5 and 8x10 holders I’ve cut (and the 5x7 I’ve got drawn up) are designed for glass plates, they can also be used for sheet film with simple slot in spacer plates so they’re multi-use.

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I’ve also just finished/shipped the blue Chroma, now onto another green one :0)

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Just been out for an hour or two with the Chroma, first outing after @stevelmx5 stiffened the spring and re-glued the base. This time I did remember how to close it up without tearing it apart! I'm still finding it a very difficult process. Getting the lens board in place is a major hassle (just doesn't seem to want to go down that last half millimetre on one side), and I also struggle to get the film holder in and out after focusing. When it's in landscape orientation the Graflock plate thingy on the top doesn't want to sit "out", and the one on the bottom is difficult to grip being just near the camera base.

This time I used my new dark cloth, which I'm beginning to think was a mistake. It's just a large, heavy square of cloth, red on one side and black on the other. There's nothing to grip the camera anywhere, it just sort of flops about. I agree it makes focusing easier, and I handled the dark slides with the cloth over the camera (over the lens, too, I discovered when I went to the front to take the shot!). I did previously order a black XXXXL T-shirt off the evil bay, but it never turned up, so I thought maybe I should get a "proper" dark cloth. But since it was £25 rather than £80 or so, I suspect I didn't succeed. I might try it one more time, and if not easier maybe sell and have another T-shirt attempt.

This was really two test shots to see if I can still remember how to use it, and in particular avoid dark slide light leaks.
 
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This time I used my new dark cloth, which I'm beginning to think was a mistake. It's just a large, heavy square of cloth, red on one side and black on the other. There's nothing to grip the camera anywhere, it just sort of flops about. I agree it makes focusing easier, and I handled the dark slides with the cloth over the camera (over the lens, too, I discovered when I went to the front to take the shot!). I did previously order a black XXXXL T-shirt off the evil bay, but it never turned up, so I thought maybe I should get a "proper" dark cloth. But since it was £25 rather than £80 or so, I suspect I didn't succeed. I might try it one more time, and if not easier maybe sell and have another T-shirt attempt.
Chris with his new dark cloth... :D

dark cloth.JPG
 
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Just been out for an hour or two with the Chroma, first outing after @stevelmx5 stiffened the spring and re-glued the base. This time I did remember how to close it up without tearing it apart! I'm still finding it a very difficult process. Getting the lens board in place is a major hassle (just doesn't seem to want to go down that last half millimetre on one side), and I also struggle to get the film holder in and out after focusing. When it's in landscape orientation the Graflock plate thingy on the top doesn't want to sit "out", and the one on the bottom is difficult to grip being just near the camera base.

This time I used my new dark cloth, which I'm beginning to think was a mistake. It's just a large, heavy square of cloth, red on one side and black on the other. There's nothing to grip the camera anywhere, it just sort of flops about. I agree it makes focusing easier, and I handled the dark slides with the cloth over the camera (over the lens, too, I discovered when I went to the front to take the shot!). I did previously order a black XXXXL T-shirt off the evil bay, but it never turned up, so I thought maybe I should get a "proper" dark cloth. But since it was £25 rather than £80 or so, I suspect I didn't succeed. I might try it one more time, and if not easier maybe sell and have another T-shirt attempt.

This was really two test shots to see if I can still remember how to use it, and in particular avoid dark slide light leaks.
Hi Chris. Sorry you’re having some issues with your Chroma. Going through each one;

1) Lens board fit - acrylic sheet has some tolerance +/- by a few tenths of a mm which could be causing the front standard frame to pinch the lens board slightly. I also add a rubber inlay for grip which could be adding to the tolerance. There are a couple of options, firstly you could back off the bottom screw on the front of the standard frame slightly . This will give a little bit of extra space and can be done with an allan key. If you don’t want to do that, you could take some fine sandpaper (or an emery board) and file the rubber slightly at the bottom of the front standard where the lens board slots in. I would guess that it’s slightly too tight in the centre (where the screw is) so start there.

2) The Graflok plates are, annoyingly, victims of gravity in landscape orientation. For future builds down the line I’ll change their 45 degree slot for a more traditional stepped slot to prevent that. If they’re getting in the way, it might be an idea to keep a small ball of blu-tac on them so, once you’ve removed them from the ground glass, you can hold them in place until you want to fit them again?

3) Dark cloth - if you know anyone who’s handy with a sewing machine, I’d suggest stitching two strips of nylon webbing with Velcro on each end onto the inside of the top face of the dark cloth and use them to secure it to the camera using the two slots built into the main body;

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It’s a future accessory that’s on the design table now
 
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Nod

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Sorry but that bottom picture made me think of Sheev Palpatine!
 
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I’m still working with Jason Lane on the new holders, but it’s looking like setup cost and flexibility of size is pushing us towards acrylic holders rather than moulded ABS. For anyone else waiting for Chroma cameras, the holder assembly is going to be outsourced, so it doesn’t mean taking up camera build time!
Steve, any idea what the price point of the new holders will be? How do they compare to the various artisan wet plate holders around (Svedovsky, Stenopeika, Gibellini etc.?) This is an exciting time to shoot plates!
 
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Steve, any idea what the price point of the new holders will be? How do they compare to the various artisan wet plate holders around (Svedovsky, Stenopeika, Gibellini etc.?) This is an exciting time to shoot plates!
At the moment, I’m working with an injection moulding company in Norwich to finalise machining/assembly costs per holder. These may not be the final prices exactly, but I’m aiming for;

4x5 Double Plate/Sheet Holder - £50
5x7 Double Plate/Sheet Holder - £65
8x10 Double Plate/Sheet Holder - £75

4x5 reducing frame for 8x10 - £40 (will allow the 4x5 holders to be used on an 8x10 camera)

The idea is to keep them affordable and the only way to do that is to mould in volume. The plan is that the Kickstarter campaign will raise the funds to create the moulds (around £8k per mould and I’ll need 2) and manufacture a set number of first run holders. After that, the cost will be in moulding/assembly.
 
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At those prices there's no reason to not shoot plates. Look forward to the KS campaign!
Thanks, I'm glad we're looking at the right price point. Post-campaign there will also be a wet plate holder but that will be entirely laser cut I think rather than having it's own mould. I've got a few being tested at the moment so should have some results to share at some point in the next month.
 
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I’m all excited today because I’ve finally got my own complete Chroma!

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I decided to build one in a unique colour scheme so went with matte black/concrete grey with purple text on the back. It’s got the same front/rear standards as the Kickstarter cameras but I’m testing out a new bed design that uses an embedded lead screw at the back instead of the rack/pinion control at the front. The main benefits are that it’s simpler to build, offers finer control of focusing and doesn’t need a locking screw.

I need to give it a proper run out before I decide if it’s the best design going forwards but I’ll firstly be the loon carrying a large format camera around The Photography Show on Saturday :0)
 
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I’ve also just got another 4x5 dry plate holder print delivered. I’m planning on getting the various acrylic layers cut and assembled tomorrow so I can take it along with me on Saturday.

This is the first print I had made 2 weeks ago being test fitted in a Chroma back. I’ve narrowed the outer width down by 1mm now to make it a slightly less snug fit but the internals are the same. This is a printed version so there is no raised upper section on each face or raised latching section to hold it into the camera but the moulded version will have those.

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The two narrow plates between the dark slides are dual purpose. As well as being an indicator that there’s a plate loaded (the plastic plate won’t push in if there’s a glass plate inside), they also act as push plates to help unloading the glass plate. When the dark slide is removed and bottom hinged door opened, the plastic plate is pushed in which in turn pushes the glass plate 12mm towards the bottom door. This then allows you to get your finger alongside the glass plate and push it out entirely.
 

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I should be there on Saturday, so I'll look out for you. Will you be carrying any 5x4 DDSs with you?
 
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StephenM

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Fine. I'd like to have a chat...

You won't be able to miss me - I'll be the one without a camera.
 
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I like that idea!(y)

I think one of the Chamonix cameras uses a similar focusing method.
Yeah, along with a couple of other manufacturers including Intrepid's new 8x10 Mk2 (which I saw after I'd built mine :)). One of my earlier designs used a similar setup but at the time I couldn't find a supplier for a screw smaller than T8 (8mm diameter) which is the most common size as used in 3D printers etc so I shelved the idea and developed the current design. Recently I found a new supplier who now offers T3.5 lead screws which means I can embed it inside the focusing bed of the Chroma to keep it at the same dimensions it currently is.
 
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