a maquette and a shutter update...

so, first of all, the bad news. an LCD shutter is unfeasable for several reasons: they aren't clear enough when open, or dark enough when closed, and worse, because the light would be hitting it at all angles, some would leak through anyway. Which Brings me to the first real hitch in the design:

I need a mechanical (moving parts) shutter.

I was hoping to avoid this. It's an extra complication. There's a reason most camera manufacturers were proud of their super-awesome focal plane shutters- they're wonders of technology, little testaments to how awesome your engineering department is. There's no way I'm going to design one of these, it's way out of my league. Which means I need to find a commercial source. This is where I turn to you, internet. Where can I buy a single focal plane shutter in 35mm format? Electronic, quartz timed, the whole bit. I'll worry about sound dampening after I worry about having one that works.

And in other news, while I'm ruminating on the electronics design, I've been mocking up a few different body shapes. The first was a really simple box in the dimensions I gave in that first post, 5x1.5x3in. I didn't like that though, and so I made this new one, shown at the top alongside my M4 for size comparison. Yes, I like big dorky grips. And while it might get a little wider, and a touch deeper (I didn't maesure the depth, so it's a bit off), it won't get any taller. Honest. And the dorky grip? probably going to be smaller, molded. I'm still not convinced I shouldn't make the first prototype out of some really nice wood, but the sheetmetal is fast to bend a shape from, and less messy.

chip news...

So I've narrowed it down to two sensors- probably the IBIS-14000 from Cypress or the FTF-5033 from Dalsa. I like the Dalsa more- it has better fill factor, it's a newer design, and their spec sheet indicates that there's little problem with incident angles because it doesn't have microlenses. Also, you get a few more megapixels for your buck.

And in other chip news, I've found an ADC (analog to digital converter) that fits the bill- the LTC-2203 from Linear Technology. 25msps, 16 bit, 225mw of funkin'.

Other thoughts: Should I go ahead and design custom logic, or find a DSP that does what I need? Basically, the sensor sends voltages to the ADC, and the ADC spits out a datastream that should go to some high-speed ram (I'm thinking I should get a 1Gb chip, just to be excessive). Then that data needs to get written to a flash card/chip (and I'm on the fence right now as to what kind of storage to use, removable or not. Depends really on what is easier to implement). I have a feeling this kind of thing is already commercially available. No need to reinvent the wheel, and that part of the imaging chain has almost nothing to do with how the final image looks- once it's bits, it's bits, and it's not going to change.

I've decided I might need a shutter, too. I think it might be possible to get away without a mechanical one, though. If I can find one in approxamately the right size, there are those near-opaque LCDs that would be good. It only has to be 99.902% opaque to get a clean readout from a 1/2000th exposure. Which I think is doable... can't seem to find specs on any lcd's, though. it'll happen, and I'll keep you all posted.

Some ideas

So, with the broad strokes of the electronics out of the way, the broad strokes of everything else still need to be taken care of. I'm partial to cameras with handgrips on the front, molded shapes, so I'm thinking that's going to be in my design. The box I put the machine in won't really matter, though, as the electronics should be small enough to fit in just about any shape you want them to. I might even make mine out of mahogany or titanium or something else interesting.

There's control: you need to be able to control shutter and iso in the field. What else? It's a RAW only machine, and it writes to internal flash. So, what controls do we need? Apeture is on the lenses. I suppose a switch for single/continuous drive would be handy. I'm not going to bother with a screen, so no menu interface, no zoom/playback buttons. There isn't any modality, even: there's a apeture priority position on the shutter speed dial, and the rest is manual. simple is better. I think that's it. there's probably something easy I'm missing.

Batteries: I'm thinking 3-4 AAs, and then I'll have the option of rechargeables or disposables. and I'll be able to power it anywhere.

that's all for now. more later.

so here's the block diagram I've been promising. old skool, ink on paper. no need to back that up.



still a lot of work to go.

Welcome!

First Post! This is the home of the Open Source Camera Project. Code, designs, everything will be available freely under creative commons and gpl.

It seems to me that thus far there has been a lot of work on the software side in gaining control of our images, and almost none on the hardware side. No choice of sensors, no open architectures for using different sensors, zero interoperability of lenses, etc, etc. I'd like to change that. So, I'm building a camera from scratch, and documenting all the steps. If people are so inclined, they can take what I've done (when I'm done) and run with it, to make their own camera.


The broad outlines of the camera are:

Rangefinder focusing, M-mount
overall size less than 33x75x140mm (dhw)
Sensor: 36x24mm +/-.2mm
12+mp
Black and White or Color
Socketed sensor (user removable/replacable)
16 bit
Shutter: In-sensor electronic
frame rate: 3+fps
Wifi+bluetooth connectivity
20gb built in memory