Chroma - Lasercut Acrylic 4x5 Field Camera

mothdust said:
I agree with Chris - it doesn't really link to the Chroma name very much - if you'd not said it was a colour wheel, my first though would have been "target" instead. Maybe more of a fragmented design (something like http://www.harding.edu/gclayton/imagesglc/munsell3d.jpg)?
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Thanks Charlotte. That link isn't working from my phone but I think I know what you mean. My original idea was a segmented colour wheel (like a pie chart), rather than the target design but I liked the target one when it's actually got colour on it (which doesn't work well on an engraved piece of plastic!)

https://www.google.co.uk/search?q=c..._AUICSgB&biw=375&bih=591#imgrc=I_rUnawualUwHM:
 
Sorry, I think I messed it up by putting a bracket on the end, this might work: http://www.harding.edu/gclayton/imagesglc/munsell3d.jpg

Are you planning on offering cameras in custom colours, or settling on one colour scheme? If so, maybe the fact that it comes in bright colours (as opposed to wood and brass) might be a signifier in itself, of the Chroma name. Just a thought, though :)
 
mothdust said:
Sorry, I think I messed it up by putting a bracket on the end, this might work: http://www.harding.edu/gclayton/imagesglc/munsell3d.jpg

Are you planning on offering cameras in custom colours, or settling on one colour scheme? If so, maybe the fact that it comes in bright colours (as opposed to wood and brass) might be a signifier in itself, of the Chroma name. Just a thought, though :)
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That's better, although it looks more like the European Parliament ;0)

I'm planning on offering the camera/bellows in a selection of colours so every camera is unique. Maybe you're right that this, along with the name, is enough. I don't want it to look like an advertising board!

I did briefly look at embedding an electroluminescent panel into the ground glass cover to illuminate a printed logo but decided that's a step too far, even for me!

I may just print a vinyl logo and stick it to the ground glass cover. Minimal cost and small logo but would tie into the brand. I'll have a think :0)
 
stevelmx5 said:
I did briefly look at embedding an electroluminescent panel into the ground glass cover to illuminate a printed logo but decided that's a step too far, even for me!
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How about a series of LEDs (let's say red, orange, yellow, green, blue and white) that light up in sequence to reveal the CHROMA logo... :whistle:
 
Or a printed label for customers to stick on IF they want to?
 
Nod said:
How about a series of LEDs (let's say red, orange, yellow, green, blue and white) that light up in sequence to reveal the CHROMA logo... :whistle:
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Without saying too much....it's funny you should say that....

https://www.adafruit.com/product/1643

I could program that to circle round the colours but I reckon that's a bit too much for what's a purely mechanical camera :0)
 
stevelmx5 said:
Without saying too much....it's funny you should say that....

https://www.adafruit.com/product/1643

I could program that to circle round the colours but I reckon that's a bit too much for what's a purely mechanical camera :0)
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Would it be possible to make suck a thing extremely cheaply and have it as part of the inner packaging of the beast - starting automatically when the box is opened and running until the battery goes flat? Again, not 100% serious (but I rarely am!)

stevelmx5 said:
This is probably the better idea :0)
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However, some of my less silly ideas are almost good! :p
 
Nod said:
Would it be possible to make suck a thing extremely cheaply and have it as part of the inner packaging of the beast - starting automatically when the box is opened and running until the battery goes flat? Again, not 100% serious (but I rarely am!)



However, some of my less silly ideas are almost good! :p
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I like your thinking @Nod, happy to over complicate things like I do ;0)

Adafruit sell an all in one board called a circuit playground that combines a 10 unit neopixel ring (programmable leds in a circle), along with a selection of sensors like light, sounds, accelerometer and microphone. Unfortunately. The light sensor only senses lumens up to 1000 otherwise I'd be building it in as a light meter!

https://learn.adafruit.com/circuit-playground-lesson-number-0/intro
 
mothdust said:
An LF camera with a light meter? Be still, my beating heart!
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I've already been looking at miniature Android devices so I could embed one and use a light meter app :0) Obviously I could just use the phone that's in my pocket or, radical I know, a handheld light meter but where's the fun in that?
 
stevelmx5 said:
I've already been looking at miniature Android devices so I could embed one and use a light meter app :0) Obviously I could just use the phone that's in my pocket or, radical I know, a handheld light meter but where's the fun in that?
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I mean, I have a light meter app on my phone too... but if there's a possibility to over-complicate something... :p
 
What about off-the-ground-glass metering, maybe a touch sensitive ground glass so you could point to an area and get a meter reading? I mean, if you REALLY want to over-complicate things...:wacky:
 
stevelmx5 said:
The light sensor only senses lumens up to 1000 otherwise I'd be building it in as a light meter!
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I bet that a gentleman of your experience and ingenuity could put a more sensitive sensor on it and use the Circuit Playground as the meter part using the standard (as supplied in the kit IIRC) pinhole - red led for 1s, orange for 2, yellow for 4 etc....

However, IMO the simplicity of the basic design of the Chroma camera itself needs no further gimmick than being built from a relatively modern material (in funky colours!)
 
ChrisR said:
What about off-the-ground-glass metering, maybe a touch sensitive ground glass so you could point to an area and get a meter reading? I mean, if you REALLY want to over-complicate things...:wacky:
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Funnily enough....

Well, I haven't actually built it but I've spent some time thinking about how I could possibly integrate AF with a touch panel and motorised helicoid. After that, I vowed never to drink again ;0)
 
ChrisR said:
What about off-the-ground-glass metering, maybe a touch sensitive ground glass so you could point to an area and get a meter reading? I mean, if you REALLY want to over-complicate things...:wacky:
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Well, the first part is (or was) achieveable. I have the necessary probe for my Lunasix meter to enable me to take measurements directly from the ground glass. I think other people made them specifically for some LF cameras - probably Sinar.

On a different tack, given that the bellows are short, the focal lengths of lenses used must be short too; and given that short focal length lenses have narrow depth of focus (depth of field - how much you can move the subject backwards and forwards and still get a sharp image; depth of focus - how much you can move the film backwards and forwards and still get a sharp image) how easy will it be to ensure parallelism when needed? Mike Walker's wide angle cameras have fixed backs to address this point.
 
StephenM said:
Well, the first part is (or was) achieveable. I have the necessary probe for my Lunasix meter to enable me to take measurements directly from the ground glass. I think other people made them specifically for some LF cameras - probably Sinar.

On a different tack, given that the bellows are short, the focal lengths of lenses used must be short too; and given that short focal length lenses have narrow depth of focus (depth of field - how much you can move the subject backwards and forwards and still get a sharp image; depth of focus - how much you can move the film backwards and forwards and still get a sharp image) how easy will it be to ensure parallelism when needed? Mike Walker's wide angle cameras have fixed backs to address this point.
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When you say, fixed back, do you mean the rear standard or the actual film back? If it's the standard, mine is fixed at 90 degrees too and all movements are controlled by the front standard. There are embedded magnets to act as click stops to indicate zero rise/fall and zero tilt. There are also line markers cut into the rubber base layer to indicate zero swing. Finally, there are simple notches cut into the base of the front standard to indicate zero shift.
 
The rear standard is fixed; the film back (as is usual) can be removed and swapped for landscape/portrait or a roll film back). So long as yours is accurately parallel etc. that should be fine. You said that the maximum bellows extension is 260 degrees (or was it 270?), what's the minimum as the camera seems geared (or not, as the case may be :D) to wide angle lenses?
 
StephenM said:
The rear standard is fixed; the film back (as is usual) can be removed and swapped for landscape/portrait or a roll film back). So long as yours is accurately parallel etc. that should be fine. You said that the maximum bellows extension is 260 degrees (or was it 270?), what's the minimum as the camera seems geared (or not, as the case may be :D) to wide angle lenses?
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Yes, my rear standard is fixed parallel to the base at 90 degrees. The minimum extension is around 40mm from the film plane. Obviously at that point there's limited movement possible due to the thickness of the bellows. A bag bellows could give a little bit of movement but it's not something I'm looking to build at the moment. However, the bellows is attached with magnetic fittings so is easily removed so could be swapped over in seconds.
 
stevelmx5 said:
I like your thinking @Nod, happy to over complicate things like I do ;0)

Adafruit sell an all in one board called a circuit playground that combines a 10 unit neopixel ring (programmable leds in a circle), along with a selection of sensors like light, sounds, accelerometer and microphone. Unfortunately. The light sensor only senses lumens up to 1000 otherwise I'd be building it in as a light meter!

https://learn.adafruit.com/circuit-playground-lesson-number-0/intro
Click to expand...
I think you might already have checked what's available from adfruit but just in case see: https://www.adafruit.com/product/439
It's also available in this country from: https://www.modmypi.com/adafruit-in...olor-photo/adafruit-digital-luminosity-sensor

I don't know anything about the Arduino but I have used a number of Raspberry Pis to do jobs around the house, programmed in C, PHP or the odd bit of Python which seems to be the coming script of choice these days.
 
Don't encourage me! I've already put together a parts list together last night using the higher sensitivity luminosity sensor (2591but am being good and keeping things sensible :0)
 
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stevelmx5 said:
Don't encourage me! I've already put together a parts list together last night using the higher sensitivity luminosity sensor (2591but am being good and keeping things sensible :0)
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Probably not, but it never stopped you before!
 
I've just been scanning back in this thread to see photos of the Chroma. Based on that, a thought (disturbing to me) occurs. The front standard appears to be rather small, and yet the bellows are short. The second implies a wide angle lens camera, and the first suggests problems.

Some years ago at Focus I looked at a (second hand) Gandolfi camera on the Linhof stand. In discussions I was told that the small throat for the lens did mean that some wide angle lenses wouldn't fit. From my own experience, the biggest lens I own is a 90mm f/5.6 which does take a little angling round to fit into my Walker. Other lenses just go through the hole no problem.

Have you looked at the physical sizes of lenses that are likely to be mounted?

Sorry - know my posts have been mainly concerned with raising difficulties, but I always look on the gloomy side because experience shows me I'm usually over optimistic (even when looking on the gloomy side).
 
My new Angulon 90 arrived with its 'faulty' shutter. When I removed the lens cells it looked like the shutter had been bathed in 3in1 oil! The shutter and aperture blades were soaking so stuck together. After learning how to disassemble a Synchro Compur P shutter I then found a couple of springs out of place and the main cocking lever return spring over stretched and disconnected. It looked like someone had just been randomly disconnecting springs :0(

I started by removing the five shutter blades and cleaning each one with lighter fluid then drying them on a microfibre cloth. Once I got them all fitted back in place, I cleaned up the aperture blades (I left them in place as they weren't so bad and are also opened/closed manually so no risk of damaging springs if they still stick slightly). After re-installing the shutter/timing/aperture mechanism I then fitted the springs back where they should be, (once I figured it out!) and folded the end of the cocking lever return spring so I could re-attach it to the arm properly.

I've now got a shutter that's cocking properly and triggering 9/10 times so there's still something sticking/catching slightly that I need to locate but the the shutter timings sound good (by ear), even the slow speed ones :0)
 
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StephenM said:
I've just been scanning back in this thread to see photos of the Chroma. Based on that, a thought (disturbing to me) occurs. The front standard appears to be rather small, and yet the bellows are short. The second implies a wide angle lens camera, and the first suggests problems.

Some years ago at Focus I looked at a (second hand) Gandolfi camera on the Linhof stand. In discussions I was told that the small throat for the lens did mean that some wide angle lenses wouldn't fit. From my own experience, the biggest lens I own is a 90mm f/5.6 which does take a little angling round to fit into my Walker. Other lenses just go through the hole no problem.

Have you looked at the physical sizes of lenses that are likely to be mounted?

Sorry - know my posts have been mainly concerned with raising difficulties, but I always look on the gloomy side because experience shows me I'm usually over optimistic (even when looking on the gloomy side).
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I haven't actively done comparisons but the lens board is 94mm square and the throat is 78mm square so any lens with rear cells smaller than 78mm will fit.
 
That does actually rule out quite a few lenses. I'm assuming that I'm correctly reading the data here.
 
stevelmx5 said:
My new Angulon 90 arrived with its 'faulty' shutter. When I removed the lens cells it looked like the shutter had been bathed in 3in1 oil! The shutter and aperture blades were soaking so stuck together. After learning how to disassemble a Synchro Compur P shutter I then found a couple of springs out of place and the main cocking lever return spring over stretched and disconnected. It looked like someone had just been randomly disconnecting springs :0(

I started by removing the five shutter blades and cleaning each one with lighter fluid then drying them on a microfibre cloth. Once I got them all fitted back in place, I cleaned up the aperture blades (I left them in place as they weren't so bad and are also opened/closed manually so no risk of damaging springs if they still stick slightly). After re-installing the shutter/timing/aperture mechanism I then fitted the springs back where they should be, (once I figured it out!) and folded the end of the cocking lever return spring so I could re-attach it to the arm properly.

I've now got a shutter that's cocking properly and triggering 9/10 times so there's still something sticking/catching slightly that I need to locate but the the shutter timings sound good (by ear), even the slow speed ones :0)
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I used the Angulon 90 for about 5 years in the late 50's 60's for industrial work and interiors. You may on may not be aware, but I will repeat it anyway for other users benefit. Unlike the Super Angulon, but like many of its contemporaries it was never designed to be used anything like wide open. If you try you will be very disappointed. however stopped down at f11, or preferably smaller, it comes into its own and is beautifully sharp with excellent coverage for movements and with minimum linea distortion. The F6.8 is adequate rather than bright for focussing. I used to carry a modified pencil torch that I could place in shot while setting up and focussing to help define the limit of coverage and focus distance. I even managed to accidentally shoot the torch more than once.
 
StephenM said:
That does actually rule out quite a few lenses. I'm assuming that I'm correctly reading the data here.
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From that sheet, I'd say that these won't fit;

Super Angulon 90/5.6 XL - Rear diameter too large for bellows opening
Super Angulon 90/6.8 XL - Rear diameter too large for bellows opening
APO-Symmar 210/5.6 - Rear diameter too large for bellows opening
APO-Symmar 300/5.6 - Rear diameter too large for bellows opening & bellows extension too short
APO-Symmar 480/8.5 - Rear diameter too large for bellows opening & bellows extension too short
APO-Tele-Xenar 400/5.6 - Rear diameter too large for bellows opening & bellows extension too short
APO-Tele-Xenar 600/9 - Rear diameter too large for bellows opening & bellows extension too short
APO-Tele-Xenar 800/12 - Rear diameter too large for bellows opening & bellows extension too short
 
Right, the Synchro-Compur P shutter is smooth now but I'm still getting intermittent mis-firing and noticed that the main spring is stretched (which won't help!). I've been in touch with Miles Whitehead and am sending it down to him tomorrow to work his magic :0)

I also mounted the lens to my mark1 Chroma yesterday so I could test the coverage and was pleasantly surprised that all of my movements were covered. It was a quick and dirty test as the camera has been partially disassembled to harvest magnets but I was happy with the overall brightness of the screen too. This is a phone picture of the ground glass taken without any cover over it so it's lacking in contrast slightly (and rotated!)

IMG_8187.JPG
 
mothdust said:
An LF camera with a light meter? Be still, my beating heart!
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It's very low down the list of upgrades but I reckon a digital light meter which clips into the ground glass cover when not in use could be pretty good :0)

upload_2017-7-3_16-26-29.png

upload_2017-7-3_16-26-45.png

The white ring contains 24 neopixels which can be programmed to show any colour so it could be used as a countdown timer for exposures etc which would be chosen from within a menu using the 3 buttons below the 0.9" OLED screen in the middle. The unit is 12mm thick and holds;

0.9" OLED screen (white text on black background
Adafruit Trinket (Arduino micro controller)
350mah Lipo battery
5v Boost circuit/USB charger
High sensitivity luminosity sensor
24 x 5050 Neopixel ring

upload_2017-7-3_16-29-55.png

Technically, the hardware and software have already been combined to make a light meter by a guy who's shared the spec/coding as freeware so I wouldn't be starting from scratch although I'd have to cut/print the case. It's definitely something for the future but just a bit of a design study for the time being :0)
 
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Component breakdown;

View attachment 105330

This is what happens when I can't get on with the priority job (building the actual camera!) because the laser cutters are out of action :0( Should be back online tonight though so i'll have something later in the week.
 
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OK, is there a tiny bit of film at the edge you could get to print the actual exposure with a gizmo? I realise the aperture/shutter etc are at the other end of the camera and all manual, so it might have to depend on the user doing something...

(The Pentax MZ-S does this but I think has to be in pretty much "I control everything" mode!)

I know, Steve, a ridiculous idea... ;)
 
stevelmx5 said:
From that sheet, I'd say that these won't fit;

Super Angulon 90/5.6 XL - Rear diameter too large for bellows opening
Super Angulon 90/6.8 XL - Rear diameter too large for bellows opening
APO-Symmar 210/5.6 - Rear diameter too large for bellows opening
APO-Symmar 300/5.6 - Rear diameter too large for bellows opening & bellows extension too short
APO-Symmar 480/8.5 - Rear diameter too large for bellows opening & bellows extension too short
APO-Tele-Xenar 400/5.6 - Rear diameter too large for bellows opening & bellows extension too short
APO-Tele-Xenar 600/9 - Rear diameter too large for bellows opening & bellows extension too short
APO-Tele-Xenar 800/12 - Rear diameter too large for bellows opening & bellows extension too short
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Thats a who's who of very expensive lenses.
 
While the laser cutter is still out of action (they've gone through 3 tubes now!), I'm keeping my mind active working on the idea of a through the lens light meter. The main benefit of this is that it would take into account bellows extensions/filters etc. Obviously, I could just build it into another plate that drops into place instead of the ground glass plate like previous meters available over the counter but that would be way too simple...

I thought I'd see if I could physically embed all of the electronics into the ground glass holder, with the glass in place, so that the light sensor could swing into place to take a reading then move out of the way (like a Leica CL).

GGMeter.JPG

The OLED screen is visible on the rear face of the holder, along with 3 buttons (not drawn on here). The short 40mm long arm is connected via an acrylic rod to an arm on the inside face of the holder at 90 degrees to it. The light meter itself (green) is mounted to the end of the internal arm so that it can be swung down into the centre of the frame to take a reading;

GGMeter-Rear.JPG

GGMeter-Open.JPG

Also mounted on the inside face is the main arduino control board, battery (grey) and charge circuit (blue) although I've just realised that I need to switch the arduino and charge circuit around so I can use a micro-usb cable to charge the battery externally.

When fitted to the main camera, the only external indication of the meter is the swing arm (that folds flat into the frame) and the OLED screen.

GGMeter-In Place.JPG

The beauty of building this into the ground glass holder is that it's completely optional and has no impact on the camera build. I'll keep it on the burner for now though :0)
 
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Maybe an interlock so the s***ter can't be fired when the arm's down?
 
Oops! That should (fairly obviously!) be shutter, rather than an I where the U is...
 
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