Re: Slip on focal plane shutter
This is a very old idea and probably covered by scores of 19th C patents. Problems are variable friction (changes in temperature and moisture/dirt/polishing on the friction surfaces) and acceleration (the terminal velocity is reached after a few meters - the top half of the lens get longer exposure than the bottom half). A certain amount of weight in the slide would help reliability. If I make one, I would use a set of strips (very much like a set of Waterhouse stops) with different slot widths rather than fiddling around with adjustments.
Re: Slip on focal plane shutter
Steven, yes it is an old idea and from my research it worked quite well then. Even Mathew Brady use one. As far as variable exposure is concerned, it is unnoticeable in the end results. If the unit is used vertical there is enough tolerance to void friction. Weight is no concern here. The slides are heavy enough to be constant. I have tried several versions and this one works best. I am working on a similar ideal that is controlled by an electronic timer that will be quite a bit smaller in size and weight. My first ideal was to use several slides with openings to correspond with the basic speeds, but that idea soon vanished when the cost was considered. I made one shutter for a 5 3/16" lens and the shutter was quite large, which led me to designing a smaller version. It will take a couple of months to get this one going. The guillotine shutters have all been large in size and heavy, which has been an inconvenience to the user. I try to make mine as light as possible, (4.5oz for the small one) If you have looked at the photos taken with these units you may agree that it's not bad for the cost. My original idea was to make something affordable and durable and accurate for the guys that had no other option and wanted to use a faster film. All ideals are appreciated.
Re: Slip on focal plane shutter
I just spent this weekend with Ron and a few other great guys photographing in Kentucky and I got to see Ron's shutter first hand, it works great, attached is a photo he took of us with it.
Re: Slip on focal plane shutter
Quote:
Originally Posted by
Tintype Bob
I just spent this weekend with Ron and a few other great guys photographing in Kentucky and I got to see Ron's shutter first hand, it works great, attached is a photo he took of us with it.
Good to see another image showing that this works so well. As Ron says, its an older concept but it works very well.
I finally got the mounting finished on the coated Cooke lens mentioned and hope to post some images after using it (and Ron's shutter) this weekend ...give me a couple days after the weekend for develop and print 8x10 contacts.
Re: Slip on focal plane shutter
If you'd like to see what Ron's shutter does on that huge lens (10+ pound coated Cooke 5+ inch diameter objective) you can see examples at:
All on Tmax 400 (TMY) 1/8 second shutter speed 5.6(wide open with soft setting just under halfway so its somewhat diffuse) - available light in Goldfield, Nevada, county courthouse -- at the Jim Galli/Per Volquartz Tonopah workshop
(model: Per Volquartz)
http://www.apug.org/forums/members/d...t-set-2-5.html
(model: Jim Galli)
http://www.apug.org/forums/members/d...-sec-f5-6.html
(model: Harlan Chapman)
http://www.apug.org/forums/members/d...nted-scan.html
These are just negative scans, inverted -- the negatives are outstanding and Ron's shutter performed flawlessly.
Re: Slip on focal plane shutter
Anybody knows how to get hold of Ron? I have sent inquiry to both of his email accounts and have yet received any reply. I am interested in an adjustable device for lenses with 3" to 5 1/4" front diameters and a Lees filter slot attached.
Re: Slip on focal plane shutter
Here's an image of the 8x10 camera, Ron's shutter on the THH Cooke Lens. Note the "Kentucky Shutter Release"(clothes pin)...it worked well.
This is the camera/lens/shutter that I used to make the images in post #76 on this thread.
Don
Slip on focal plane shutter
A waistcoat slip as I know and seen is a white curved slip of fabric around 2" wide that is attached to the opening of the waistcoat so that it protrudes out around 1/4-1/2" like in the pic I posted and is attached using 6 buttons two at the back, two both sides of the fronts.
Re: Slip on focal plane shutter
Chromacameras and Custom Camera Building CCB anounced an arduino_driven shutter. No news yet
Re: Slip on focal plane shutter
Quote:
Originally Posted by
europanorama
Chromacameras and Custom Camera Building CCB anounced an arduino_driven shutter. No news yet
Focal plane?