Chroma - Lasercut Acrylic 4x5 Field Camera

stevelmx5 said:
Alright stranger, long time no speak. I've still got all of your dev kit and scanner here :0). We need to catch up soon, maybe we can meet up to test this build out?
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Now, that sounds like a plan mate! I have been gazing longingly at my poor Rollei & 4x5 with the hope that I can escape to actually take some pictures soon haha. I'll give you a shout towards the end of next week once this work is out of the way & we will definitely arrange to meet up. No worries at all on still having the dev kit & scanner, am happy they are getting some use - I have new developer & fixer here if you need it in the meantime. Would definitely be good to catch up very soon mate, I look forward to it (y)
 
Here are some Pre-assembly pictures;

The three main components, chassis with focus rail, rear standard and front standard

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Front standard with lens board

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This is the 'flat-packed' layout when the camera is disassembled for packing. The nearest things I had to show the size were DVD cases :0) (once the bellows are attached, they will be fixed between the rear and front standards)

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stevelmx5 said:
I've just assembled camera to see how heavy it is. With everything, including the focusing rail, but without the bellows, it's 1015g so I'm happy with that. It's slightly heavier than the Intrepid which is listed as 900g but I've still got options to lighten it further by removing some of the material from the bed and back. I'll wait until it's all assembled with the bolts etc and weigh it again before I think about reducing the weight. The rear 6mm part could be cut down considerably as it's basically creating a frame around the DDS to give it some extra grip.

Whilst it's slightly heavier than the Intrepid, I also think I could assemble one for lower cost meaning it could be cheaper to buy :0)
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Any intermediate plies could be heavily drilled/cut to remove extraneous material...
 
Nod said:
Any intermediate plies could be heavily drilled/cut to remove extraneous material...
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Thanks, good thinking. Once they're all sandwiched and bonded they won't be going anywhere. I'll definitely remove some of the corner areas on the 2x3mm parts holding the rotating disk. I think those, combined with the rear panel being slimmed down will make a big difference.
 
The front standard is now assembled and drying overnight, along with the lens board frame.

I'm really starting to like this build :0)

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I've been looking at the parts and I can definitely finesse their shape to shave some weight off but I think for now I'm going to build it as it is to make sure I like the overall handling before looking to reduce the weight.

Oh, and another thing.....look no hands!!

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Who needs brackets to hold a DDS in place anyway. I haven't got the extra surround mounted there either so it will be even more secure.
 
How does the density of acrylic compare with the MDF? I'd have assumed it was lower, so the final build should be lighter anyway? However, saving weight without sacrificing strength has to be a good thing; you'll thank yourself for it when lugging it up a hill somewhere! ;)
 
ChrisR said:
How does the density of acrylic compare with the MDF? I'd have assumed it was lower, so the final build should be lighter anyway? However, saving weight without sacrificing strength has to be a good thing; you'll thank yourself for it when lugging it up a hill somewhere! ;)
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I'm not sure to be honest although you're probably right that it is slightly lighter than MDF. I was chatting with my friend who's letting me use the laser cutter earlier. We were taking about marketability of a camera like this and costs and I started coming around to the idea of sealing then spraying the MDF to see how it looks as well as making an Acrylic version. MDF is much cheaper as a material and is probably less flexible along its' face. Also, MDF can be sanded easily to round off the edges whereas Acrylic is a much 'harder' edged material.

I'm not sure what to do long term. My main priority is to get one camera up and running and see how it is to use. To do that I'm going to need a lens, a DDS and ground glass!
 
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Acrylic is quite a lot more dense than MDF - 1180kg/m3 compared to 600-800kg/m3. The downside of MDF is that it's very fractious once damaged, especially at the edges. It just disintegrates. Acrylic tends to splinter and crack with edge impacts, but is more resilient than MDF (bigger hit needed to damage it). MDF is also pretty bad when it gets wet, and a coating is the only means of protection unless you can impregnate it with something. Acrylic is inherently untroubled by water.

I'd consider acrylic and look into some serious lightening - you'd be surprised at just how much material can be removed while retaining the required stiffness, etc. I've done a few lightening jobs, usually aluminium, and getting the mass down to half has often been readily doable. Not sure how much can be removed from this, because it needs some bits to be light tight, but the laminated structure should be conducive to making hollow areas.
 
Nomad Z said:
Acrylic is quite a lot more dense than MDF - 1180kg/m3 compared to 600-800kg/m3. The downside of MDF is that it's very fractious once damaged, especially at the edges. It just disintegrates. Acrylic tends to splinter and crack with edge impacts, but is more resilient than MDF (bigger hit needed to damage it). MDF is also pretty bad when it gets wet, and a coating is the only means of protection unless you can impregnate it with something. Acrylic is inherently untroubled by water.

I'd consider acrylic and look into some serious lightening - you'd be surprised at just how much material can be removed while retaining the required stiffness, etc. I've done a few lightening jobs, usually aluminium, and getting the mass down to half has often been readily doable. Not sure how much can be removed from this, because it needs some bits to be light tight, but the laminated structure should be conducive to making hollow areas.
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Thanks for the stats on density, very interesting. I fully agree about the limitations of MDF so it's something to weigh up the cons against the few pros. An alternative is to use birch ply like Intrepid use for their cameras. Whilst it will create splinters if it's left Raw, a few coats of varnish will deal with that.

Before I make any decisions on materials, I'm working on lightening the design and have already removed a considerable amount of material from the rotating pieces. I think I've removed enough of the rear standard to make some weight savings without compromising the strength or light-tightness at the same time.
 
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moomike said:
Now, that sounds like a plan mate! I have been gazing longingly at my poor Rollei & 4x5 with the hope that I can escape to actually take some pictures soon haha. I'll give you a shout towards the end of next week once this work is out of the way & we will definitely arrange to meet up. No worries at all on still having the dev kit & scanner, am happy they are getting some use - I have new developer & fixer here if you need it in the meantime. Would definitely be good to catch up very soon mate, I look forward to it (y)
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Awesome mate. Now the weather's getting better we might actually manage to shoot some film :0)
 
First draft ideas for the weight reduction;

Weight Saving 2.jpg

Weight Saving 2b.jpg

I may have trimmed too much material from the frontmost 6mm piece. Until I build the bellows and test their fit I won't know for sure so I won't cut any other parts until I can test with the bellows attached for light-tightness.
 
mothdust said:
Love seeing the progress of this build!
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Thanks Charlotte. Building cameras via threads like this really helps me too because of the invaluable input from everyone. Whilst I started this as a camera for myself, it's developed into something I'd like to think has a wider market so hopefully I can deliver something good.

I've decided to build the first camera using the original parts I already have cut then I'll build a second lightened version afterwards.
 
If the holes near the corners of the green and blue parts in your drawing take any load, I'd be tempted to leave a bit of material between them and the surround of the big hole in the middle. I reckon the peace of mind might be worth more than the oz or 2 of weight saving. Not that it's a hugely portable piece of kit anyway!
 
Nod said:
If the holes near the corners of the green and blue parts in your drawing take any load, I'd be tempted to leave a bit of material between them and the surround of the big hole in the middle. I reckon the peace of mind might be worth more than the oz or 2 of weight saving. Not that it's a hugely portable piece of kit anyway!
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Good thinking but they're actually only holding the magnets that lock the rotating back in place so should be ok.
 
I carried on assembling my layers today and fitted the rotating back. After fitting a magnet in each corner I've found that I'm either ridiculously weak or I really don't need that many magnets :0).

After removing two of the magnets from the rear standards (opposite corners), I've now got a strong enough grip without it being nearly impossible to move so I'll take that as a happy medium!
 
steveo_mcg said:
Fantastic!
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I forgot to add the bit where I'm never making another set in my life...

Although saying that, using the changing bag material was a 100 times better than the last attempt I made using alcantara. It moves really well and should contract nicely on the camera too.

I'm just wondering now if I should embed magnets into the front/rear frames so it locks in place but can be removed too without using clips or bonding it permanently. I need to do some testing.
 
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I shouldn't say this but.... will you ever want bag bellows?

Repair/replacement might be easier with magnets or clips.
 
StephenM said:
I shouldn't say this but.... will you ever want bag bellows?

Repair/replacement might be easier with magnets or clips.
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That was along the same thinking as me really. Also, this camera is my mk1, I'm going to be building updated versions with changes I've made to the design as I've gone along so I don't want to be making bellows for each one if I've stuck them to the frame.

Right, time to make some bellows frames with embedded magnets.
 
i have to say i love reading up on your projects, but this one in particular is gripping! fantastic work, really appreciate you sharing this on the forum
 
niko said:
i have to say i love reading up on your projects, but this one in particular is gripping! fantastic work, really appreciate you sharing this on the forum
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Thanks. I'm actually really enjoying this build, especially as I've had the idea drawn up for so long but lost momentum on it.
 
stevelmx5 said:
Thanks. I'm actually really enjoying this build, especially as I've had the idea drawn up for so long but lost momentum on it.
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keep up the good work! long term projects can be hard to keep enthusiastic about, but this is so worth it, can wait to see the 1st complete build pics and 1st pictures from it.
 
Another update. I've got the rear bellows frame drilled along with the main body with magnets embedded.

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I've ordered a pack of 3mm thick magnets to embed into the frame as I wanted to keep it as thin/light as possible.

Also, I was thinking about flocking the face of the main rear standard to give a better seal then decided to 'steveify' it...

IMG_7866.JPG

Seeing as the mdf isn't waterproof anyway and neither am I, I've decided to make it look a bit more plush :0)
 
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Before I fit the alcantara trim I've started painting the rest of the body black to tidy it up.

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I'm using a brushed flat black as I didn't think ahead to spray the parts before assembling :0). Once the two coats on the outer edges are dry tomorrow I'll paint a thin layer on the inner faces of the rotating back to tidy that up too.
 
What about carbon fibre? Or maybe titanium... :) to keep the weight down.
 
kendo1 said:
What about carbon fibre? Or maybe titanium... :) to keep the weight down.
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Yeah, I kind of thought that seeing as I cut this version before the weight saving changes I may as well go all out to make this the classier but heavier model :0)

The tripod plate I'm fitting is heavier than the base panel so weight saving isn't really going to happen before I cut the next version.
 
ianp5a said:
That tripod plate is crying out to get 4 big holes in it, to save weight.
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Definitely! It's not really the lightest option but I needed something more substantial than just fitting a tripod bush into the mdf base and it's the first one that came up on EBay :0). With the Acrylic version, I think fitting a tripod bush with heat will give a stronger mount so I won't use the plate there.
 
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Well done with the bellows. A few questions, if I may...

How did you work out the geometry for the ribs? I can see that the widths alternate to effect the taper in the folds, but how is the overall long taper in a set of ribs worked out?
What sort of card did you use, and what thickness? And what type of glue?
Is the fabric porous, and did any glue seep through?
Is the join glued?

I'm asking because I'm considering making a bellows for a possible 10x8 camera project, which I've never done before, so I'm trying to scope out how to approach it. So far, I have a sheet of polyester blackout material that might be big enough (1.6 x 1.15m).
 
Nomad Z said:
Well done with the bellows. A few questions, if I may...

How did you work out the geometry for the ribs? I can see that the widths alternate to effect the taper in the folds, but how is the overall long taper in a set of ribs worked out?
What sort of card did you use, and what thickness? And what type of glue?
Is the fabric porous, and did any glue seep through?
Is the join glued?

I'm asking because I'm considering making a bellows for a possible 10x8 camera project, which I've never done before, so I'm trying to scope out how to approach it. So far, I have a sheet of polyester blackout material that might be big enough (1.6 x 1.15m).
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I was kindly given the ribs by Steve Smith on this forum. He laser cut them from 0.3mm thick plastic with a sheet of double sided tape on each side. The fabric I used is a film changing back. The outer layer is a smoother nylon type material which is slightly shiny, and the inner layer is a stretchy fabric. I stuck the ribs to the outer layer first using the double sided tape then stuck the inner layer using the same thing. In hindsight, I should have added spray adhesive because I don't think the double sided tape is strong enough on its own but it's holding for now.

To join each edge of the inner/outer layers, I used spray adhesive which I bought from a local shop (The Range). It's used to stick carpets/flooring down so it easily strong enough but you have to make sure that everything except the edges you want to stick is masked off as it does tend to go everywhere!
 
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And it's on a tripod :0)

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I'm not happy with the embedded threads on the lens board. I didn't have a pillar drill so had to do it by hand. The embedded thread needs an 8mm hole which only leaves 2mm each side so it's caused some de-lamination as I expected. I'll clamp it up with some glue to recover the strength but apart from that I'm happy with it.

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That looks fantastic mate. Top work.
 
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