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SteveH
08-04-2006, 11:45 AM
All,
Anyone have some interesting thoughts on constructing a shutter for a barrel lens ? Im thinking ahead slightly as to what I want to use on my achromat. Granted, there's always the packard shutter; but what fun is that ??
I've seem some old shutters that resemble the one on a holga. Granted, it would be about 30x larger, but perhaps a possibility.
Im more interested in a 'studio' type of shutter; as I can always stack on ND's for 1s + exposures (efke 25 is my friend !).
The only thing Im truly worried about is vibration; which I think the holga-type of shutter may impose.

Thanks again,
Steve

Wimpler
08-04-2006, 01:45 PM
I have always wanted to attempt a shutter as in the kodakj brownie box camera (or any other) made from coke can aluminium. I suppose the holga shutter is much like it. You don't have to make it that large if you plan to shoot at small apertures... I don't think vibration would be a big problem.

SteveH
08-04-2006, 04:10 PM
Well, after doing a quick sketch, the holga type of shutter will simply be too large to be feasible. Even if I tame the lens down to f/5.6, it would still be a pretty big piece of metal.
I think my best bet would be to find an old packard, and making up an electronic solenoid assembly in place of the air bulb. This way, I can have somewhat more accurate times, and a broader range of speeds in the most used times (1/15, 1/8, 1/4, 1/2, B, T). Im not sure the packard would/should go much faster than 1/15th, nor do I think a small solenoid (the smaller the better, weight and vibration -wise) would do it.

Wimpler
08-04-2006, 04:23 PM
Maybe you could make a motor driven roller blind shutter to mount in front or behind the lens? I've been thinking about it and even did one lousy attempt but then had to much work and forgot about it... You try with a spring instead of a motor as well.

I think these shutters were called thornton pickard shutters or something... Oh yes... here... http://licm.org.uk/livingImage/Shutters-Blind.html They are the a lot like the speed graphic (I think) focal plane shutters, but using them near the lens makes even larger formats possible.

SteveH
08-04-2006, 05:32 PM
I thought about the motor idea. It would be easy to do it with a wind spring. My idea was to always have the spring in tension, with a tick mark on the wheel. Cock the shutter and let it go = instant exposure time. The purpose of the tick mark on the rotor wheel would be to stop the rotor with a small block when the opening was lined up wtih the barrel, this allowing a 'time' exposure and viewing/focusing.
The problem wtih that design is that the rotor has to be at least 2.25x the size of the largest f/stop. On a 230mm focal length lens with a 4.0 f/stop, that's a hell of a piece of brass.

JoeVanCleave
08-04-2006, 05:47 PM
Steve, a homemade shutter has been on my list of projects for some time. For my purposes, it would be used for an improvised lens box camera. The large frontal surface area of the box should provide enough room for installing a home-built shutter even as crude as a rubber band or spring powered rotating disk, with variable width pie-shaped opening. Or a horizontally sliding, spring-actuated guillotine shutter with variable width opening.

Several years ago I experimented with a gravity powered, vertically oriented guillotine shutter, using a lead weight to actuate the metal slide. I was able to measure shutter times of around 1/15th sec, but never actually put the design into practice, since a vertically falling shutter is effected by the angle at which the camera is tilted, therefore the shutter time would be modulated by the angle of the camera tilt. Hence the idea of a horizontally moving, spring-actuated shutter.

SteveH
08-05-2006, 09:51 AM
Joe,
I thought about the guillotine shutter idea as well; mainly just as a studio shutter sort of thing. My idea had 'wings' that opened up on either side of the shutter barrel, using a simple lever mounted ontop of the barrel.
Unfortunately, either way, the most simple and effective idea would still be to find a busted packard shutter, and modify it to use an electronic solenoid.
About the blind shutter; how would you set it for focusing ? Have any of you gotten a chance to actually look inside of one ?

Thanks again !

murrayatuptowngallery
08-05-2006, 10:52 AM
'blind' type, as in roller blind, or cloth focal plane shutter?

I can tell you what a Speed Graphic one looks like.

Imagine a length of opaque cloth attached to to spools (like a roll of film).

Part way into the roll, followig an opening-free 'leader' of shutter fabric, analogous to, say, 'exposure 1 or 2 ', there is a rectangular slot cut in the fabric, and supported with a thin metal band to keep it from fraying ,etc. A little bit further into the roll, say exposure 4, is another slot, wider than the first. They are spaced by a bit more than the width of one exposure, say rough guess (actually no idea) 6" for a 5" film window. The continues to almost the end of the fabric, where there is a giant opening that will expose the entire sheet of film at once...same size as back of camera. Thsi is I guess the 'T' setting. I believe there is no 'B' as it isn't practical with th emovement of such a shutter. After the full opening is another final length of slot-free fabric that covers the film plane.

The whole thing is wound up so that at maximum tension, the first slot whizzes by the film plane, with the shortest opening and highest winding tension resulting in a very fast shutter speed (1/1000 on Speed Graphic). I think the narrowest slot on my 4x5 SG shutter is about 1/8" long.

I don't know the exact spacing, but there is enough between slot openings so that the film plane is covered again after each shutter firing.

Say you wind it all the way to 1/1000 and fire it. Some of the tension is unwound, and it's actually cocked & ready for the next slower speed (actually ,there is a high/low switch so the speeds are stagggered every other speed, I think in the following order 1/1000, 1/250, 1/60, flip the switch and 1/500, 1/125, 1/30) appear in the window indicator.

After firing at 1/1000, if you want another shot at 1/1000, you have to rewind the shutter to full tension.

To focus, or use a lens with its own shutter, or do long exposures you use T and fire the shutter so it stays open.

To totally release the shutter tension you fure it as many times as necessary to get all the way wound back up...say 1/1000, 1/250, 1/160, T, end.

Greg_E
08-05-2006, 11:51 AM
Mamiya does something similar with the older 645 cameras, but it uses two shutter curtains and fires them in a timed fashion to produce the correct traveling slit to expose the film. They work great until they need service, then they are almost always a write off. Sounds like the Speedgraphic would be easier to service than the Mamiya.

SteveH
08-05-2006, 03:48 PM
All,
I think a curtain would be too complex/too delicate of a shutter idea to start out with, and to mount in front of a lens. I am thinking of a falling leaf sort of shutter, that shouldn't be too large.
We'll see what the sketch looks like; then hopefully you all can tell me what you think.

-Steve

Jim Jones
08-05-2006, 10:02 PM
I bought a new shutter about 40 years ago in Japan intended to mount on the front of a barrel lens. It works like the Speed Graphic shutter Murray described, except it has only one slot. Varying the shutter tension varies the exposure from about 1/30 to 1/90 second. Of course it also has provisions for time exposure. Such a shutter could perhaps be improvised from an old Speed Graphic or other focal plane shutter press camera, or made from scratch. Adapting or fabricating these shutters is far easier than the more common two-curtain focal plane shutters.

ImageMaker
08-07-2006, 11:29 PM
I'll take your word on whether that'll work -- I can't see the magic smoke in that drawing, so I'm lost. ;)

I don't know if you'll be able to get the Packard mechanism to go faster than the 1/15 "instant" speed, however; the shutter consists of a pair of biggish, relatively heavy leaves that pivot at one edge, so they open like a wedge and then reclose, and I think 1/15 is about as fast as the shutter's internal mechanism can open and close those leaves. Nice, accurate slower speeds, however, would be a very welcome thing with a Packard. You can, BTW, buy new Packard shutters that are built with a solenoid to be fired by a number of different voltages; I don't know if they're any faster than the pneumatic variety, but they can use a smaller hole in the standard or lens board (wires instead of a tube) and are more convenient to control with electronics (like what you're working on here).

moot
08-08-2006, 01:17 AM
I started to answer you earlier today but ran out of time, and I see you've changed your circuit from the earlier post.

It took me some head-scratching to figure out what you are up to here. The connection from the relay back to the timing network was puzzling, but now I see that the rotary switch disconnects the timing network from +9 (disabling the timer) and connects +9V to the relay, giving you the "bulb" function you wanted. I think that will work (pretty creative, really). There is one problem, though. It looks to me like the diode on pin 3 is backwards. The way it is, when the 555 output is high the diode is reverse-biased and no current will flow. Worse, when you select the "bulb" function, current from the 9V supply flows through the diode (now forward-biased) into pin 3 which in that condition is a saturated transistor straight to ground. The result would be fatal to the diode and the 555. Incidentally, as you may have figured out, the way the "bulb" button was connected in the earlier circuit would have fried the 555 output in very much the same way.

If you turn the diode around, it is now forward-biased when the 555 output is high so current can flow through the relay. When you select the "bulb" function, the diode is now reverse-biased to block current from toasting the 555 output transistor. The smoke will remain inside where it belongs . :)

A couple of other points. There should be a diode like a 1N4001 across the relay coil (cathode connected to positive so it's reverse-biased) to absorb the reverse voltage "kick" from the coil when the relay turns off. I think your earlier circuit had one. Also, the earlier version had one more pullup resistor and a protection diode on the trigger. You can probably live without the diode but I think the trigger will be more reliable with the second pullup on the button side of the capacitor.

I am curious as to the nature of the relay. Is the relay you have shown actually the solenoid on the shutter, or is it just being used as a switch to control that solenoid? I'm also curious as to what sort of battery supply you are planning to use.

moot
08-08-2006, 01:09 PM
The output looks OK now.

The resistor you added to the trigger should be a pull-up, so connect the capacitor directly to the switch contact as you had it. The resistor then goes from that connection to +9V. The idea is that it provides a solid source to keep that side of the capacitor high when the trigger button isn't pressed. Without it, the trigger might work but it might also be flaky.

If you need more current for the solenoid (watch out for power dissipation limits of the 555), instead of using a relay as a switch use a driver transistor. With a relay you have another coil sucking power from your battery, whereas with a driver transistor it is just a switch. I did a quick search and found a page that has some info that might be helpful.

http://www1.jaycar.com.au/images_uploaded/relaydrv.pdf

The lower figure on the linked page that shows the 555 is not using it as a timer so I'd ignore that. The upper figure showing the driver transistors is what I'm referring to. The transistor numbers they mention are European, so if you're a yank you need to get something similar.

SteveH
08-08-2006, 02:33 PM
Moot,
Thanks again, I have since revised the design to reflect the change. I'll check out the link you supplied. Right now Im just going to try to get the circuit to flash an LED - at least that way I know I did something right :D

Thanks again,

SteveH
08-08-2006, 06:15 PM
Ok....
So I couldn't get my hands on a bread board, but I did find a gridded PCB. I revised the plans (yet again !), and instead of using a resistor pack, I installed a bank of potentimeters. This way, I can dial in the speeds better.
I assembled everything, but I goofed some where. When I hit the button, I get voltage from the output, but it never turns off. Perhaps I need an actual load (and not just the multimeter ?). I either need to ground the out put (which will imediately turn the circuit off), or disconnect the battery.
Attached files http://f295.f295.org/uploads/shutter_timer_1979.jpg (http://f295.f295.org/uploads/shutter_timer_1979.jpg)

murrayatuptowngallery
08-09-2006, 08:51 AM
I wasn't sure why D1 was needed or if a 555 has enough current capability to drive very many relays...you'd need a 'sensitive' one, and I don't mean artistic. the missing D2 was what I first thought about too.

I stopped shopping at RS - it got way too annoying -

I had to learn the part numbers, the package colors and the store layout before I went there because the employess invariably would tell me they didn't have what I was looking for. Armed with that research I could either show them where it was or get in and out before they accosted me with the standard "Duh, whatcha buildin'?"

A few years ago, you could get away with saying "...Grrr, a b_ _ b", but that isn't funny these days.

The insult, indignity and inequity in pricing sent me to mail order.

In a few days I'll scrounge up some links to shutter patents. Hopefully it hasn't been dumped from the server, but I posted instructions here once on searching the USPTO website. Earl was the only one who commented. It's useful but not friendly.

SteveH
08-09-2006, 11:54 AM
Murray,
Thanks ! Ya, S**Tshack just about sums it up. The pieces should be here tomorrow or friday, so we'll see what happens.

SteveH
08-09-2006, 02:05 PM
A success of sorts.
I came hom e for lunch today to find my package from mouser (!!). I didn't pay for next day shipping, but it arrived here anyway.
I tossed a quick circuit together, using a 100k pot in the place of the switched packs. I used this basic idea here:
http://www.kpsec.freeuk.com/breadb.htm
Just to get the blood flowing a bit :D

Soooo...Tonight will be the big trial.

Keeping my fingers crossed.....

-Steve

SteveH
08-09-2006, 04:51 PM
A complete success.
The circuit works like a charm. I have it on a plug-in breadboard at the moment, so its not the cleanest looking thing in the world, but it works ! Im going to transfer it over to a PCB tomorrow or Friday.
As it sits now, I do not have the selector switch and resistor banks installed on the breadboard...Just a 10k pot. I've been able to get some rough times of 1/4-3s; but that is with a 100uf cap (which, isn't the most stable thing). I have a 1uf cap that will replace that on the PCB, and I'll just start off the resistor bank with an extra resistor.
Anyway, some quick photos. Attached files http://f295.f295.org/uploads/timer_pic_2_4984.jpg (http://f295.f295.org/uploads/timer_pic_2_4984.jpg)

SteveH
08-09-2006, 04:52 PM
And in action:

Attached files http://f295.f295.org/uploads/timer_pic_3_9170.jpg (http://f295.f295.org/uploads/timer_pic_3_9170.jpg)

ben_s
08-09-2006, 07:14 PM
Looks like it's going well.
I've been looking at home made shutters myself recently;
I think I have worked out a useable shutter design similar to a Copal, but driven by a solenoid and electronics rather than a spring mech.
So far, I have the input stroke down to 8mm, just about within the range of small (ish) solenoids.
I'm working on a more compact version at the moment.
I'm planning to make at least one if costs aren't prohibitive. - Would anyone be interested in one?

SteveH
08-09-2006, 08:40 PM
Ben,
Do you have the electronic control worked out yet ? The design I outlined will control from milliseconds (in reality, the mechanical max speed of your shutter), up to about 10mins or so. The only limitation that I would impose is that I wouldn't recomend anything longer than say...1m as the caps would start to show their inaccuricies.
To change my design to suit your needs, use the following equation:

t=.1.1(RxC)

What sort of design are you up to ? A leaf type ? If so, where are you going to be getting materials for the leaves ? Also, what size shutter are you going for ?

ben_s
08-10-2006, 07:33 PM
I already have a controller built for another project that will work. it's 555 based and has a range of between about 1/4sec to several minutes, with the current resistor pack. - this could be changed to generate "standard times, though.
See this thread for more details and a pic:
http://www.f295.org/DIYforum/cgi-bin/forum/Blah.pl?b-misEquip/m-1150231036/s-all/


The design I've provisionally gone for is very much like a standard Copal type.
At present, the clear aperture is an arbitary 30mm. I don't actually have an LF shutter myself, so I'm not sure of the dimentions required.
If I actually make it, however, I'll definately get a proper measurement and lens thread(s) on it.

I was planning to have the leaves laser cut from spring steel, if it didn't cost too much. - This is why I asked if there was any interest from anyone else, as I may have to have a full sheet of material lasered, which would probably be rather expensive for a one-off single unit build.

Although for a test rigup, I could probably use hacked up floppy disk shutters, and a simplified leaf outline, to facilitate cutting with tinsnips.
I have a contact with a Biglia 6-axis CNC lathe, who could make the main body and mechanism of the shutter (for this, I was planning on using Aluminium, or possibly Brass).
If anyone was interested, I would probably be able to have multiple units machined at less cost than several 1-offs.
The solenoid would probably be an off -the -shelf part

It's all very much in the air at the moment, but I'd be interested to hear your (or anyone else's) views on the idea.

Attached is an exploded concept pic. The solenoid drive would be attached to the little lever. (suitably redesigned to be actuated by a solenoid, of course) Attached files http://f295.f295.org/uploads/shutter_idea_7255.jpg (http://f295.f295.org/uploads/shutter_idea_7255.jpg)

Greg_E
08-10-2006, 08:43 PM
If you use Aluminum, you might want to anodize it. A good quality spring steel might be a better choice.


http://www.smallparts.com might have what you need.

SteveH
08-10-2006, 08:52 PM
Ben,
What are you going to be using this shutter on ? Sorry, I haven't gotten a chance to go back through all the threads yet - Im new here :D .
As for your shutter, it looks pretty good. I take it you are going to use electronic control to open/close the shutter. If you're going to be needing a semi-standard size, why not chop a factory shutter ? You can find non-working ones CHEAP.
I would use Aluminum over brass for weight purposes.....Obviously for a mechanism, the lighter the better. Also, have you looked at the brass prices lately ? I hope I cut my lens barrel right the first time - because if not - it'll be an alum monster, not a brass beauty.
Have you put any thought into your solenoid ? For my project, I need one that will give me 1" of throw. Obviously, a plunger type would be best - but all of the ones I have found thus far with a 1" throw have been monsters. I may have to use a rotary type with a larger wheel on the end, affixed to a shaft (ala locomotive style). Being as I don't need much force, I should be able to get away with a very small solenoid.
As for a relay, check out mouser #653-G5B-1-DC5. If you run your 555 circuit off of 9vdc, you'll get about 5.7vdc out of pin 3, with a max of about 100mA. That relay has a draw of 72mA @ 5vdc, and it is rated to switch 3A @ 120vac.

ben_s
08-11-2006, 05:22 AM
Greg; I was planning on using laser cut spring steel for the actual thing - I just mentioned Ali as a temporary experimental material - Cutting spring steel with tinsnips tends to take more metal off the tinsnips than the stock ;)

Steve; I picked up an Arca-swiss 5x4 monorail as scrap a while back, and I want to get it fixed up.
Making a shutter looks interesting.
On the Solenoid front, I'm planning to use something standard off the shelf. On the current design, I only need about 8mm of drive. I can fine tune this by varying the lever length.
I might hack a "real" shutter, although finding somewhere to attach the solenoid is likely to be difficult.
If I can get one really cheap, I might have a look at this option.

The relay in my controller is my standard "does-everything" relay.
It suits me down to the ground - physically small, sensitive 12V coil which fires easilly directly from a 555 run at 9v, but a lot of punch on the switch side -DPDT, 250V@16A. ;D
Suffice to say that with the current PCB layout, the board would melt before the relay even started sweating ;)

SteveH
08-11-2006, 07:30 AM
Ben,
If you were to hack an OLD two leaf shutter, there is a point at the bottom of the assembly where the two leaves meet. This point is pushed up/down to open/close the leaves. If you had a solenoid that gave you 3mm or so of throw, it would work fine.
The only problem that you may have with doing this, is that the old shutters usually aren't the correct size for modern glass. Also, I wouldn't push a two leaf shutter past say...1/50th (although my old pronto goes to 1/100th). But again, at those speeds, I don't think a regular solenoid will be able to keep up either.
If you want to take a look at the guts of one of those old shutters, let me know, as I have an old AGFA sitting around.

Wimpler
08-11-2006, 07:36 AM
If you don't need a large shutter, I can't imaginbe anything easier then taking the shutter elements out of an argus C3 and replace the uhm.... rather crappy timing mechanism with yours. The argi are extremely easy to open up, and because the actual parts are not at all fragile, even an argus in horrible condition will be ok to be used for parts. A clear aperture of 30mm will certainly not be big enough for all large format lenses.

I think a shutter like this would be interesting to make a 6x9 view camera (with a home made lens). When stopped down to about F32 and with ISO 50 rollfilm, all conditions should be OK with a shutter like this. Also, at f32 most aberations of "lower quality" lenses shouldn't matter much. To test you might want to take a lens out of one of the none focussing crappy single plastic element polaroids. From memory I'd guess they have a focal length of about 110mm which is fine for 6x9.

Using existing lenses is not a good idea I think believe because of the need to mount them to the shutter with correct spacing. Also, because of the "slow" maximum shutter speed you need to stop down quite a bit.

I think you could sell a simple lens (either single element, 3 element, or symmetrical design) in a simple shutter in surpringly large quantities if you can keep the production cost down. If you ask $150 for lens + shutter you'd still be the cheapest new solution on the market. Better older lenses are available second hand, but buying second hand is always a bet, especially on older lenses and shutters...

Greg_E
08-11-2006, 01:40 PM
Steve, how about a solenoid with a half inch of travel and a 2:1 lever to make up the difference. It could of course be scaled to make the inch of travel from a very small solenoid.

SteveH
08-11-2006, 02:15 PM
Greg,
I was thinking about that....Im actually had some plans drawn up. Or, again, using a rotating solenoid with a lever. Im not quite sure which way will work best.
Did you have a solenoid in mind ??

I haven't had any luck finding a solenoid that would seem happy on 9vdc. I might have to make up a battery pack and step it up to 12vdc...I was hoping to get away with the smaller/lighter, the better idea.

moot
08-11-2006, 03:19 PM
The relay in my controller is my standard "does-everything" relay. It suits me down to the ground - physically small, sensitive 12V coil which fires easilly directly from a 555 run at 9v, but a lot of punch on the switch side -DPDT, 250V@16A. ;D

If I missed this elsewhere I apologize, but you wouldn't happen to have a source and part number for that little jewel, would you? Sounds useful.

ben_s
08-11-2006, 06:35 PM
If I missed this elsewhere I apologize, but you wouldn't happen to have a source and part number for that little jewel, would you? Sounds useful.



Sure, It's a Schrack RTE24012. I bought a couple of hunderd on Ebay a while back.
Also a correction: its 250V 8A per pole, 16A if you common the two together.
If you can't get the Schrack, the Finder 40 series is very good too, - Similar spec, same base, but about twice as tall. The pins are wider as well, so you need bigger holes in the PCB
both are available in a wide variety of coil voltages and contact ratings
I think they are both available from RS components (www.rswww.com) - the Finder definately is.
I guess most major suppliers carry them though.

The Schrack (orange) is approx 16x13x29mm, while the Finder (blue) is 25x13x29mm Attached files http://f295.f295.org/uploads/finder_and_schrack_relays_5072.jpg (http://f295.f295.org/uploads/finder_and_schrack_relays_5072.jpg)

Greg_E
08-11-2006, 08:17 PM
http://www.omron.com/ecb/products/pry/121.html

A lot of the high end electronics that I work on use relays from them.

moot
08-12-2006, 12:58 AM
Obviousoly I don't use relays much and haven't been paying much attention to the electromechanical side of things. Lots of nice little toys that will switch gobs of amps.

JoeVanCleave
08-12-2006, 11:54 AM
I've been following this thread with some interest, as a homemade shutter could work for some potential large format projects I have in mind. Although I must admit that a mechanical design suits my philosophy better; nevertheless, I look forward to seeing how the electromechanical shutter works.

In an earlier post, SteveH indicated that he didn't have a breadboard onto which to prototype his design. I have a friend who's into amateur radio and such; he recently finished a low-power FM transmitter on a homemade breadboard.

The really neat thing about his breadboard design is that it harkens back to where the term "breadboard" originated: a large, flat wooden surface, into which electrical parts were screwed or nailed or soldered.

In the case of my friend's 'breadboard', it's really a section of 2x4 lumber, cut to size. He proceeds to first draw the schematic out on the board, giving adequate room in the drawing for the real physical dimensions of each component. Then small nails or brads are pounded into the board at each component's mounting location. He then uses wire-wrap and solder techniques to mount each component and associated connection wires to the mounting pins. The resulting completed circuit is completely functional, the components permanently mounted to the board. He even includes component labels and notations, written right into the wood with a pen.

Best of all, you don't have to disassemble the 'breadboarded' circuit because there's no need to reuse the board; lumber is cheap.

SteveH
08-13-2006, 10:15 AM
Interesting stuff Joe !
Thankfully I was able to obtain the breadboard and get the circuit assembled (as you can see in the photos). I will be transfering it over to a PCB over the week, and hopefully compact the design so that it will fit into the smallest enclisure as possible.
Im still entertaining a source/idea for the solenoid....

Thanks !

Asher_Kelman
08-14-2011, 12:18 AM
It would be great to know what happened to the project steve! Also did anyone else get inspired to build a timing circuit or find one for their own shutter or to control a Packard with a solenoid?

I myself need a timing circuit for for a Packard!

Would be so grateful to find out how others have tackled this!

Thanks in advance

Asher