Chroma - Lasercut Acrylic 4x5 Field Camera

Forgot to add, this is the swing movement;

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With the gearing setup it will take a few rotations of the rotary encoder to turn the lens board or front standard 45 degrees so it should give very good accuracy. I'll also program the return point to full 'zero' so I can return the tilt or swing back to 0 automatically so there's no need to look at markings etc.

This is an example of a rotary encoder being used with a stepper (skip to 10:15 to see it being used);

View: https://youtu.be/e5p7wGEC0Xc
 
Thanks Trevor. After a few duff starts (the pleasure of 3D printing) I've now got the trial lens board/surround printed in one piece to test along with the gears/axles for the steppers. The main right angle standard is printing now so should hopefully be done by tomorrow afternoon.

After stripping down an old CD Rom drive for parts I think I've found an ideal setup for motorised shift! The laser on a CD/DVD is moved forwards/backwards along a pair of 85mm long stainless steel bars with a small but strong stepper motor using an archimedes spiral type layout. After removing the whole frame and disassembling the laser I think it may be strong enough to move the whole front standard left/right and give around 25mm of movement either way. It's not going to deliver a massive range but should be enough for most standard lenses. With it being a simple frame it won't add a lot of weight which will mean the rise/fall mechanism won't have to work too hard!
 
The main standard is nearly finished, 4 hours to go :0)

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It's green because that's the only filament I've got at the moment!

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The test lens board and gears/axles have printed well, just need to open out the holes in the gears/board slightly before bonding them together.

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I've also ordered a set of stepper motors and rotary encoders so should have them next week. I'll prepare the standard and code before they arrive.
 
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:0)

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I haven't got a traditional field camera to compare weight, but the front standard/lens board/gears are pretty light so I'm hopeful that the basic steppers I'm fitting will be fine;

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The standard is obviously pretty chunky to give enough room to embed the steppers but I'm tempted to modify the design so it steps out for the motor mounts then comes back in for the rest to make it slimmer. As a first build I'm more concerned about the functionality though for now!
 
If I'm going to motorise the front standard, I'll need some way of controlling it :0)

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The two halves of the controller can rotate independently. I'll hold the left half in my left hand and move the joystick with my thumb. The Joystick has 2 axes to control Rise/Fall and Shift.

The right half of controller can be twisted forwards/backwards to control lens Tilt. It can then be clicked inwards (to the left) to return tilt to 0 degrees automatically.

The small knob fitted to right side of controller is used to control lens swing and will be turned using my right index finger and thumb. Again, it can be clicked inwards to return swing to 0 degrees.

These will be connected via cable to a pair of Arduino Pro Trinket boards mounted under the base of the camera with 5v lipo batteries which will translate the movements to the 4 stepper motors controlling the standard.

It looks complicated but it's only 50mm diameter so should fit in my hands easily without being too small. The idea is that I can change the various movements without taking my eyes off the groundglass.

Video showing movements here;

https://www.flickr.com/gp/stevelloyd/bgcb50
 
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Another update to the motorised standard. I've re-drawn the main body and shortened it by rotating both steppers around the gears to move them nearer to the corner point. I've also used a diagonal pattern to build in some cutouts without losing rigidity. As well as making the standard smaller/lighter, this also reduces the time it takes to print to around 13 hours.

https://flic.kr/p/QGkbRU

https://flic.kr/p/PtmLfu

I've also written both Arduino sketches for controlling the four steppers. One sketch uses two rotary encoders to turn two steppers. When the encoders are pressed, their stepper returns to its' start point. These will be used for Tilt/Swing. The other sketch uses a small 4-way analogue joystick to control the other two steppers. Forwards/backwards will control Rise and Left/Right will do Shift.

Now I just need to figure out how to fit it all in...
 
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Needs a bit of 'finessing' because the tolerances are a bit tight but I like the shape overall. I decided to mount the joystick just back from the surface then I'll cover the workings when I trim the whole remote in leather/alcantara.

Also, I'm going to unsolder the pins from the boards and use wires direct to reduce the footprint. The board on the right will be rotated 180 degrees once I've cleaned up the print.
 
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Erm, time for a slight (complete) redesign of the main standard.


I haven't been happy with the rise/fall mechanism all along, as the scissor lift added too much bulk and would never be fully stable which defeats the object of setting exact angles for the standard. I've spent the last couple of days going over loads of different ideas and came to the conclusion that one of my first ideas would probably be the best!


I've now drawn a new standard that incorporates rise/fall, tilt and swing in one unit which is only 45mm deep front to back and 115mm tall. It allows for 60mm of rise/fall (+40, -20), as much tilt as the lens will allow and around 45 degrees of swing in each direction. The shift is currently set using a traditional locking bolt rather than incorporating an additional motorised element to keep the overall height down as low as possible for easy use.

Rise and fall is controlled using a threaded bar

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linear actuator. The stepper mounted to the top of the upright rotates the threaded rod which makes the plate attached to it with a captive nut move up and down. There are two 3mm steel rods inside the upright to keep the plate level. Tilt is controlled by another stepper that's attached direct to the lens board frame using a bracket to spread the weight. Swing is controlled by a third stepper mounted in the base of the upright pointing downwards.

At the moment I'm using a traditional locking bolt to fix the base of the standard to the focusing rail. Loosening the bolt will allow the base to shift up to 30mm in each direction. I haven't drawn it yet but there will be an overhang on each side of the focusing rail to stop the standard swinging when the bolt is released. I could have built in a fourth motorised axis for shift using another linear actuator but as it would add up to 70mm to the height I've decided to keep it more flush with the bed of the camera.

All of the new parts for the main standard will be lasercut from 4mm Acrylic. As well as being light, Acrylic won't flex which will keep everything aligned. This standard is completely interchangeable with the more traditional manual standard I've designed for the Acrylic 4x5 so I can test both out alongside each other.
 

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Well, here's my job for tonight. It could go really well or I could be throwing some half-folded bellows out of the window...

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And yes, I will rotate the pieces and get them in the right order before I start glueing them to the material ;0)
 
Takes a while this bellows building lark doesn't it....

I'm half way through now and have run out of glue so will have to call it a night. I'm happy with the progress so far and the alcantara I'm using is really nice to work into shape so it will only be my fault if it doesn't fold properly!

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I'll pick up another tube of Uhu tomorrow and finish off the other ribs before I start the fun job of folding.
 
Takes a while this bellows building lark doesn't it....

I'll pick up another tube of Uhu tomorrow and finish off the other ribs before I start the fun job of folding.

Good luck with that Steve!
 
Thanks Baz. I drew up the ribs to be laser cut from card but got impatient so now have to cut 120 ribs out by hand. Kind of wish I'd waited for the laser cutter now ;0)
 
Saw you post the bellows building photos on Facebook this morning, and my first thought was "that looks difficult!" Hope it works out well when you've finished! Shame you can't just 3d print them :D :LOL:
 
Thanks mate. Believe me, if I could just print them I would ;0) I'll definitely pre-cut the ribs if I do any more after this one, it gets a bit tedious cutting 30 ribs per face along with a 4mm gap between each one!
 
Thanks Steve, that's a very useful link. I've got two different sheets that need to be cut for my main 4x5 body/back and the two different front standards. One sheet of 24"x12" (4mm thick) and one 36"x24" (6mm thick). Thanks for the offer of cutting, I'll take you up on it for my next bellows.

I'll get my local company to cut the main parts for the camera though, bit much to ask from you as a favour ;0)

Cheers
 
The only problem with the bellows ribs by post option is that I would have to send them either as individual parts or in small sections. The beauty of my system was being able to laminate all of them to the cloth whilst they were held in place by the waste material.


Steve.
 
Definitely, I was planning on doing the same myself as it's a much simpler way and also maintains exact gaps. The ribs on mine are pretty much spot on but there's still a human element in getting them lined up.
 
I skimmed this thread so forgive me if this has been addressed. But I wondered why you'd use acrylic to make the camera? It's not exactly robust and breaks far to easily, I'd be looking at making it out of nice birch ply or something which will laser cut just as well?

I spend a few hours every day laser cutting acrylic parts for work stuff and repair a lot of very large format mahogany cameras and I can only foresee issues for you
 
Thanks for the suggestion. My original reason for using Acrylic was initially based around it being slightly different from the norm. I've drawn up the design to be made from layered 4/6mm sheets for strength so parts like the main base will be 12mm thick and the rotating back will be 18mm which should help with the rigidity. Alternatively, I can use the same plans to cut the pieces from any other material that's the same thickness. I did consider carbon but paying for it in 6mm sheets makes it slightly more expensive than selling my first born child so I'll stick to more mainstream materials ;0).

My first camera will be cut from MDF because it's cheep and easily available in 4/6mm sheets. Assuming the parts all fit well I'll move onto the Acrylic.

Another reason for designing around Acrylic came from a mildly drunken conversation with @Carl Hall about making a transparent field camera (bar any parts that need to block light!) for a laugh.
 
lol, it's sure an easy material to work with, I've seen a transparent wet plate camera before made from red acrylic but that was a very basic affair. It'll be interesting to see what the MDF version comes out like, with some epoxy varnish on the MDF you should get a really solid camera :)
 
Thanks. I wasn't planning on the MDF version being the final material but like you say, a few good coats of varnish would finish it nicely. I designed and cut some headphone wraps before Christmas to sell and raise money for my sons' cubs group. They were cut from 4mm sheet and were pretty strong so I'm expecting the layered camera to be stronger.
 
Bellows update....They're all glued together!

After another couple of hours work tonight I've got the bellows drying overnight, ready to start the folding task tomorrow. Once I finally got all of the ribs cut and glued to the alcantara outer skin, I 'donated' a thin black t-shirt to give a slightly stretchy thin inner layer. I had a can of spray adhesive for flooring so used that to bond the inner layer to the ribs/outer. Once that was all stuck in place, I cheated a little and bonded the last edge of the whole bellows together with the pieces the correct way round instead of inside-out. I'm not using a form to hold the bellows in shape so it felt easier to glue the last edges the right way round. Touch wood, the joint is strong and square so I'm hopeful that the folding stage will go ok.

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I've cut a narrow 10mm diagonal overlap on the bottom of the bellows to join the material. The diagonal overlap was recommended on one of the guides I read to spread the extra thickness across the width of the bellows.
 
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Yes. I made the mistake of having all the joins in one place on the first bellows I made.

Have you fond that they come out a bit smaller than intended? I think the folds take up a bit more material in reality than they do in theory so I always add a bit to the dimensions now.

Thanks for the suggestion. My original reason for using Acrylic was initially based around it being slightly different from the norm.
At work, I have some 10mm thick polyethylene, available as kitchen cutting boards, which machines very well on our CNC router. I think some of it is going to become a camera!


Steve.
 
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Another reason for designing around Acrylic came from a mildly drunken conversation with @Carl Hall about making a transparent field camera (bar any parts that need to block light!) for a laugh.

Out of every post I've been tagged in on this forum, this is by far my favourite :D Some of the best ideas are born of beer fueled conversations :)
 
Yes. I made the mistake of having all the joins in one place on the first bellows I made.

Have you fond that they come out a bit smaller than intended? I think the folds take up a bit more material in reality than they do in theory so I always add a bit to the dimensions now.


At work, I have some 10mm thick polyethylene, available as kitchen cutting boards, which machines very well on our CNC router. I think some of it is going to become a camera!


Steve.

I added around 15% to the maximum bellows draw when I originally drew it up to hopefully account for the folds. I can't take credit for that though, it was in the guide I was following!

The polyethylene sounds interesting. If nothing else you'll have a wipe clean camera ;0)
 
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I added around 15% to the maximum bellows draw when I originally drew it up to hopefully account for the folds.

I was thinking more of the overall width and height. My first bellows were a very tight fit into the frame I made for them.


Steve.
 
Looks good Steve. I have one thing to throw in though. The back plate and base rail join to form an L shape. I feel this needs a small diagonal strut(s) for strength, in case it gets bumped in transport. Or make it detachable. And even then, a small 45deg strut could help lock it in place and add strength.
 
Looks good Steve. I have one thing to throw in though. The back plate and base rail join to form an L shape. I feel this needs a small diagonal strut(s) for strength, in case it gets bumped in transport. Or make it detachable. And even then, a small 45deg strut could help lock it in place and add strength.

Thanks Ian. The back plate and base interlock to form a joint but you're right about possibly adding a strut for support. I haven't drawn one in as yet because I'm thinking that an 18mm back and 12mm base with interlocking fingers will be a strong link but my main concern is flex across the vertical face. It will be easy to add a 45 degree strut into the design if I find it's not stable with the MDF version though.
 
There are lots of ways to do it. This is a primitive suggestion.

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But a round metal rod with screw threads or push in, might be nicer.
 
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I posted my bellows building method before, but here it is again: http://stevesmithphoto.webs.com/bellows.html
The laser cutter plays a big part in my method.

If you need any laser cutting done, let me know.


Steve.

Hi Steve. What material did you use for the inner/outer layers? The alcantara I'm using isn't holding the creases too well so is proving 'challenging'!

Sorry, ignore that. I've just read the part about it being a changing bag!

Cheers
 
I've just remembered that I've got a black portrait backdrop I made from what I think is Cordura which is light tight without being too thick. I'll have to dig that out tomorrow and see how well it will work.
 
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