Re: May, 1: A new era in 3D photography?: NEW SHUTTERS


Bill G
 

sorry for my typo....
>  I felt the only sensible solution was a single LED shutter.

Of course, it's "LCD" shutter



On Sat, Aug 22, 2020 at 9:22 AM bglick97 via groups.io <bglick97=gmail.com@groups.io> wrote:
I modified the subject so it reflected shutters, as once again, we are all seeking the same holy grails, but now with sync.

Large focal plane shutters are just too mechanical from my experience, and based on John R post as well... they will create shake.  We don't want perfect sync with added blurred images.

If you want the taking rig to be hand-holdable, that is one solution.  If you only use a tripod, you can isolate a mechanical shutter on another tripod with a bellows or cover between them.  talk about cumbersome, feels like the 1800's.    You can do like they did in the old days, use a slit shutter, just pull from top to bottom... smaller slits equal faster shutter speeds.

About 10 yrs ago, when I worked diligently on this, I felt the only sensible solution was a single LED shutter...they were expensive back then.  But they had issues as well...fastest shutter speed back then was only 1/60th, maybe they are faster today... it would make a universal fix for all cameras, as they are lightweight.  Anyone following that field lately?



On Sat, Aug 22, 2020 at 7:46 AM timo@... <timo@...> wrote:
There must be some other way to control the shutter speed of a gravity shutter. All objects fall with the same acceleration regardless of weight. You could adjust the height from which it falls, since dropping it from higher up will get you a faster shutter speed.  I am trying to think of wether the exposure would be different fpr the top and bottom of the frame.

Timo

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On Aug 22, 2020, at 1:27 AM, John Rupkalvis <stereoscope3d@...> wrote:
The Sinar Norma shutter for 4x5 and 8x10 view cameras would be good to look at.  If you prefer focal plane shutters, some of the earlier sheet film cameras, like the 4x5 Speed Graphic and Graphlex cameras were fitted with these.  The problem with those was that you had to reset the shutter speed after every exposure.  Also, they were rather noisy, with a rather loud "Galump" sound every time they were fired.  Some people actually made their own, including the rather interesting double-curtain "gravity shutter" design.  The edge of the curtain was fitted with a lead weight, so triggering the shutter just allowed it to drop, the shutter speed being determined by the size and weight.  Most manufactured versions were spring-loaded.  

John A. Rupkalvis
stereoscope3d@...

Picture


On Fri, Aug 21, 2020 at 2:24 PM DaveJes1979 via groups.io <davejes1979=yahoo.com@groups.io> wrote:
I realize we have discussed this before, but for newcomers it should be noted that  "perfect synch" is achievable by the use of a common external shutter.  While there are stand-alone shutter devices on the market, I doubt that any of them would be large enough to cover the lenses of two mirrorless cameras (although I might be wrong on that).

So that means one would likely be looking at a DIY project.  While I am a man of many mechanical talents, my expertise ends where the electronic hardware and software begin.  So I was never able to get the concept off of the drawing board.

On the mechanical side, the important trick is getting a fast-acting shutter mechanism that doesn't induce vibration to the camera.  That's a little tricky since an external shutter will have to move ~1.5" across the front of the lenses, on the order of 10 milliseconds or better.  The best candidate would be either a roller blind type shutter or a rotary shutter.  These are old-timey shutter types that aren't in use anymore, but they work.  For maximum flexibility in interaxial, one really needs to go with the roller blind design.  And it ought to be a double roller blind, so that there is a first and second curtain.

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