</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (David A. Goldfarb @ Oct 2 2002, 07:47 AM)</td></tr><tr><td id='QUOTE'>Well, a 24"/f:11 lens needs to be at least 2.18" in diameter plus a little room for the flange, and the maximum iris on an Ilex #4, according to this chart:
is 1.730", turning the lens into an f:14 lens, presuming that the lens and shutter can be machined to fit (probably can, but ask Mr. Grimes). So you lose about half a stop, but you get a smaller, lighter shutter.
What I've done is to take the Ilex#5 shutter that came with my 10" WF Ektar, and I've had an adapter made so that by removing the cells for the Ektar, I can mount my 12" Dagor or my 19" Apo-Artar onto the front of the same shutter. The shutter is big enough to work in this way without causing any vignetting with these particular lenses, it means I have fewer shutters to maintain and more consistent shutter speeds from one lens to the next, and that's only one big shutter/lensboard combination in my pack for three lenses. The downsides are that if that shutter fails in the field, there are three lenses I can't use (hasn't happened yet!, and it takes slightly longer to switch lenses if I have to swap out the cells for the Ektar to put on the 12" or the 19".
Personally, I'd hold out for a #5 shutter, if you think you might want to use other barrel lenses on the same shutter. If not, go for a #4. Mr. Grimes often can provide refurbished Ilex, Alphax, and Betax shutters himself at reasonable prices. Have you asked if he has what you need in stock?</td></tr></table><span id='postcolor'>
I just got a nice #4 betax off of ebay for 35$. #5 shutters are very expensive (as far as I have seen). Another candidate would be a fujinon C 600, it is a 11.5 lens and takes a 67mm filter, and I would bet it would fit in a #4. I am not sure if you can pick this up in a barrel lens. I would be happy with any ~600mm dialyte that is coated and fit this shutter.
Also, I discovered something on my last vacation. Single action shutters are very desirable if you are taking long exposures and need to shut the shutter when the wind blows. Recocking a shutter several times is tedius and you might move the camera.