Large shutter design - help for project

[Steven Tribe]

Earlyphotography.co.uk has a new section on early front-mounted shutters which might inspire the DIY gene!
Writing with experience of Luk, Grundner, Guerry, Copal-sinar and T-P type shutters, there just isn't anything that works at less than 1/60th. Focal plane shutters mounted at the rear, on a solid "box" structure and near the tripod mount, like the speed graflex do achieve much better speeds than this.

[m1tch]

I would need a faster shutter speed rather than a slower one, I don't want to stop the lens down too much as I would be wanting to get some bokeh with portraits, I guess I could shoot in subdued light, I never thought I would have an issue with the lens and the paper negative being too fast lol.

What would be the affect of using an ND filter but shooting wide open? The lens would actually be too large for the speed graphic to handle I think lol I will check the dimentions but I don't think the front standard is wide enough.

I do actually have an unusual camera coming soon with a LUC shutter which I might use for a portrait camera instead - think it shoots 1/4 plate, perhaps I should simply stop the lens down and use an easy to make spring loaded shutter with a fixed speed?

This could be interesting:

http://www.earlyphotography.co.uk/si...ry_S36.html#S6

Ah, also the single blade return shutter sounds interesting:

Band loaded guillotine shutter, when the shutter fires and oncovers the lens it dislodges the band which then allows the guillotine to drop back recovering the lens.

[m1tch]

I have just taken apart the front of one of my project plastic cameras (Vivitar PN2011) to look at the simple shutter arrangement.

It is basically a pivoted flap where a spring loaded notch is pushed against one end of the pivot, once the notch is past the pivot the flap then springs back to the rest position.

Seems quite simple, just need to work out how I would set and trigger it lol even cheap cameras seem to have fairly complex workings!

Edit - ok I think I see whats happening now:

The spring loaded notch is rotated back to sit against a ledge of the shutter, when the shutter release is pressed it moves the surface that the spring loaded notch is resting against, this then knocks the shutter blade on the way past and about 75% though its full travel is is past the end of the shutter blade which then springs back due to the spring tension.

I will have a look at simplfying this design slightly (the shutter is cocked on film advance), I am glad I rememebered that camera, seems a bit simpler than some of the other shutters I have seen lol

I could still go with a horizontal band powered guillotine though, thats fairly easy but its much more bulky.

[jb7]

I don't think you mentioned the design of the lens- or lenses- surely that would have an influence on the size of the shutter needed? For example, if its a rear mounted meniscus type, then you could get away with a much smaller front of lens shutter- whether guillotine or other...

[m1tch]

The front and rear elements are the same size, optical element diameters are either 110mm or 80mm (the 2 different lenses I am building), with the 80mm element lens the focal length will be at around 70mm which is basically both standards together on the camera. I would need a front mounted shutter for that, however could fit a rear mounted shutter on the larger 110mm element diameter lens.

[jb7]

The front and rear elements are the same size, optical element diameters are either 110mm or 80mm (the 2 different lenses I am building), with the 80mm element lens the focal length will be at around 70mm which is basically both standards together on the camera. I would need a front mounted shutter for that, however could fit a rear mounted shutter on the larger 110mm element diameter lens.

If you're building the lens yourself, could you place the shutter in the centre of the lens, where it's meant to be? Everything would be a lot smaller, even a Guillotine shutter...

[m1tch]

If you're building the lens yourself, could you place the shutter in the centre of the lens, where it's meant to be? Everything would be a lot smaller, even a Guillotine shutter...

I will be using waterhouse stops in the centre, I would need to have the shutter cover the whole diameter of the lens though so it would be the same size where ever I put it.

[jb7]

... "it would be the same size where ever I put it."

Not sure that's entirely true, but I won't argue it...

There should be space for waterhouse stops as well as a guillotine or other shutter, depending on design, but I'll let you get on with it...

[IanG]

I have a Norka shutter I bought through this forum, they are easy to replicate, Gandolfi posted a thread here..

For higher speed I'd modify a TP shutter, these are normally 1/15 to 1/90 but they did sell high speed versions the only difference is the slit width, there's a big variation in sizes available, as the image below shows.



It would be possible to make something similar.

Ian

[DrTang]

buy a baby speed

saw that sucker in half


use just the back part as a shutter