Large format shutter options.

[Boscoe]

So I have been interested in 8x10 for a while but I was first getting my 4x5 camera built until a friend came across a lens used for laser cutting/etching. It's made by Rodenstock and has a focal length printed on it at 635mm - it has nothing else other than a serial number that returns no information. The front element diameter is about 140mm so estimating aperture at around f4.5 which is phenomenal at this focal length! It's such an amazing lens I have decided to bring my 8x10 project forward but I need a shutter with an opening approximately 75mm diameter. I'm interested in building one so I was wondering if someone could point me in the direction of some others who have attempted something similar? I'm an electronic engineer so was thinking of a couple of spring loaded blades that would move out of then in front of the aperture all controlled via solenoids and an electronic system for controlling shutter speed. Good idea?

Thanks
Boscoe

PS If anyone's interested I can post some pictures of the lens and I may be able to get a second which I can sell.

[Steven Tribe]

There are plenty of already designed shutters which can do the job!

Mechanical leaf shutters are not so suitable for the 6" diameter opening, though. Think front mounted focal plane shutters and rear mounted Grundner shutters (pneumatic).

[Dan Fromm]

See http://www.suaudeau.eu/memo/pratique/Les_obturateurs_centraux.html for a table of shutters and sizes. The largest shutters available that offer timed speeds are Compound #5 and Ilex #5. Both have maximum apertures ~ 65 mm in diameter.

Packard shutters are available used and new (http://www.packardshutter.com/). Experienced users say that with practice repeatable speeds between 1 second and ~ 1/20 second can be obtained.

[Jac@stafford.net]

Did you test whether the lens is suitable to a camera? Does it have some strange chromatic qualities? Does it have an aperture? I'm guessing not because it is an F-Theta scanning lens. Here is some data. Someone smarter than me could tell us more.

117424

The url for full resolution is: http://www.digoliardi.net/f-theta.jpg

[Boscoe]

I haven't tested it however I have no way of doing so really. I have projected my window onto my wall with it in my room to inspect the coverage and it will easily do 8x10 if not larger. Thanks for the other help guys.

[DrTang]

I have an Ilex Ilexpo which is similar to a packard shutter.. and it has a 4" opening

[c.d.ewen]

Boscoe:

Could you tell us why you consider the lens "amazing"? Is it perhaps faster than the common 24" process lenses that many of us use?

If you think an Ilex 5 could be useful, you might check eBay for an Electronic Ilex 5. They're usually cheaper than ordinary Ilex 5's. I've seen schematics online for controlling them, and as an electronic engineer, you should be able to make it work.

Charley

[Tin Can]

Earlier this year I played with operating a 4-1/2" Packard shutter with robot parts from http://www.pololu.com/ Cheap to play, but found the shutter speed acheivable with RC servo controllers slower than a standard Packard squeeze bulb and hose. I used an IOS app for shutter speed checking. I have a thread here in DIY about it. Look it up.

I now use bulb and hose and have installed a microswitch on my Packards for flash sync.

The wheel was already invented.

[Boscoe]

Boscoe:

Could you tell us why you consider the lens "amazing"? Is it perhaps faster than the common 24" process lenses that many of us use?

If you think an Ilex 5 could be useful, you might check eBay for an Electronic Ilex 5. They're usually cheaper than ordinary Ilex 5's. I've seen schematics online for controlling them, and as an electronic engineer, you should be able to make it work.

Charley

I only say amazing for it's shear size - I'm used to 4x5 150mm lenses etc, this one dwarfs them.

Thanks I'll keep looking on that however I can't seem to find much info on them.

[EdSawyer]

I have a nice aerial lens leaf shutter that is approx 3" diameter. It's a fairchild night shutter, I believe. It is electronic but also has manual controlability. If you are interested, I can part with it cheap, like $50 or so. It works fine, I have tested it.

Ed

[Boscoe]

Sounds great Ed. Could you post some pictures? Would you ship to the UK?

[Jac@stafford.net]

I only say amazing for it's shear size - I'm used to 4x5 150mm lenses etc, this one dwarfs them.

Thanks I'll keep looking on that however I can't seem to find much info on them.

Info on the shutter or the lens? If you mean the lens, then this post should tell you a lot. Below.
http://www.largeformatphotography.info/forum/showthread.php?114568-Large-format-shutter-options&p=1148351&viewfull=1#post1148351

[Boscoe]

Info on the shutter or the lens? If you mean the lens, then this post should tell you a lot. Below.
http://www.largeformatphotography.info/forum/showthread.php?114568-Large-format-shutter-options&p=1148351&viewfull=1#post1148351

I am a little naive, could you tell me how this tells me about the lens?

I did mean the shutter however I would like to know more about the lens.

[Jac@stafford.net]

I am a little naive, could you tell me how this tells me about the lens?

I did mean the shutter however I would like to know more about the lens.

I will (try to) leave this to Dan Fromm because he is smarter than I.

[Dan Fromm]

Boscoe, in post #4 in this thread Jac posted specs for a 635 mm Rodenstock f-theta lens that seems much like yours. You might want to read this: http://specialoptics.com/pdf/wp_scanning_lens_theory.pdf

I'm not sure that f-theta lenses, if that's what yours is, are well-suited for use as taking lenses. If you're lucky, Bob Salomon will notice this discussion and give you good advice.

[Boscoe]

It is a F Theta lens. By reading that it seems it will have built in barrel distortion?

I'll see if I can contact Bob Saloman if he has experience.

[Kevin J. Kolosky]

I don't think you could do any better than to adapt a sinar shutter to the camera you are building. the reason is that almost any lens can, with various means, be jury rigged to work with that shutter, and it doesn't have to be using some fancy machining or fitting either. You just have to get the lens a very short distance from the shutter blades for it to work.