Thread size for Kodak Ektar 8 1/2" f/6.3 lens?

[Hugo Zhang]

I have a Dallmeyer 9" F/6.3 Anastigmat Wide Angle lens in barrel and I want to find a shutter for it. Very hard to find one. Does anybody have a Ektar 8 1/2" f/6.3 lens and measure the shutter/lens thread for me?

Thanks.
Hugo

Note: Not promising at all. I have just found out somewhere on the net saying Ektar 8 1/2" f/6.3 lens has a mounting hole of 54mm. My Dallmeyer has a thread of 56mm.

Any other shutter ideas?

[adelorenzo]

I have an 8.5 inch Commercial Ektar, the shutter is an Ilex 3 which would be too small for you according to SK Grimes (http://www.skgrimes.com/library/used-obsolete-discontinued-shutters/ilex).

Packard shutters can be adapted to just about any lens but are kind of clunky. Ditto for a DIY guillotine shutter (http://www.largeformatphotography.info/guillotine-shutter/guillotine-shutter-construction.html).

[Roger Hesketh]

Hugo the thread size for shutter on the Commercial Ektar 6.3 is 42.5 mm it is a No 3 Acme Synchro. So no joy their. I need to have a bit of a root about but I may be able to suggest a cost effective soluution to your problem.


Roger

Found it.

88307


A size 6 Luc shutter is a perfect fit on your lens. Indeed it was the original equipment that would have been fitted to your lens. It's listed in the same Dallmeyer catalogue.

[Hugo Zhang]

Wow Roger,

Is it a direct fit? How do you like this lens and where did you find this shutter?

Thanks.
Hugo

[Roger Hesketh]

Clearly the penny has not dropped. Compare the serial numbers on your lens and on the picture I posted. I liked the lens fine and the only reason I don't still own it is I do not have a camera big enough to use it on. The largest camera I currently have is only 10x12. Though I do have a Deardorff 11x14 back which I may consider using at some time in the future I do not think I will ever use anything larger. and I have an 8" Cooke series VIIb which will cover that just if I need it to.

I have been looking to see if I have another size 6 Luc. I have managed to find a couple of 4's which is no use Not keen to sell my only Size 6 but would consider lending it to you until you can find one to get for yourself.

Having said that I would not look to shutter it that way anyway. Their is a more elegant solution which I had planned to use myself and that is to use large roller blind shutter and mount the lens in front of that.

The problem you have is unless you are careful in looking to shutter this lens you will get mechanical vignetting which will restrict coverage. Which lets face it is the reason you bought the lens in the first place. These lenses were never mounted in shutters for that reason. Nor is their space between the elements to mount a shutter. Actually your lens is not too bad in that respect. From memory I think you have a quarter of an inch or more between the internal elements. Room for an iris and shutter blades. So it is doable That is not the case with some of the shorter Dallmeyer and Cooke Series VIIb versions of this lens the internal elements are just too close together and your lens is just a scaled up version of those.

Front mounting the lens in front of a shutter has the potential to restrict coverage. Cutting off marginal rays unless you are mounting across a largish hole. I front mount a number of the shorter versions of this lens in front of an Compur shutter. It has an adapter which is mounted to the shutter into which the lenses can screw. I have a bunch of wide angle Cookes an Dallmeyers of different focal lengths and fortunately they all have the same thread size so one shutter serves for them all. I have focal lengths between 2 and 5 inches shuttered that way but can also use them in barrel if I should wish on cameras with focal plane shutters.

Incidentally despite what the V.M. may say I can detect no discernible difference in use between Cooke Series VIIb's and Dallmeyer Wide Angle Anastigmats that are of similar age . I also am not aware of any vignetting due to mechanical cutoff of rays due to front mounting but and it is a big but in use on the plate sizes that I am using them on I am not utilising anywhere near the full coverage of the lenses. Mechanical vignetting and cut off may be occurring.that I am unaware of.

I would not risk it with your lens.

I would front mount it across a roller blind shutter with a wide opening. The one I was was going to use had a 3 inch opening , had six shutter speeds and even had a PC flash sync socket. So in using a roller blind shutter you do not necessarily lose any convenience or reliability in use compared to using a newer shutter. One half turn opens the shutter for focusing, another half turn cocks it. Trip the shutter and repeat if necessary.

To mount the lens to the shutter all you have to do is drill a hole the size of your flange in a piece of ply that is big enough to cover the hole in the front face of the shutter. Screw your flange to it. Screw the piece of ply to the shutter casing and then screw the shutter to a lens board that has a suitably sized hole.

Half an hours work Problem solved. Job done. The shutters are not expensive because many do not appreciate the benefits of using them.

Have fun with it. Glad it has found a good home and you appreciate it's qualities sufficiently to want to shutter it. As I say the the only reason I parted with it is I do not have a use for a 9" lens with 100 degree coverage and if you are not going to play with something it is better to pass it on to someone who will. Well I suppose being skint and needing the cash had something to do with it as well.

[Hugo Zhang]

Roger,

I guess I bought the lens from you. :) This is the first Dallmeyer Anastigmat lens whose images on the ground glass at wide open is so different from any other lenses I have. I can't focus at f/6.3 and things are spinning crazy in the center like image edges of a Petzval lens. Stop down to f/11-16, I could get some interesting soft images with glowing highlight. Only the front lens behaves this way and I can use the front cell with my Packard shutter as a long lens.

I agree with you that lenses with extreme wide angle like this one will not work well in shutters.

Thank you for your tip about the roll blind shutter. My Packard shutter does the same thing.

Hugo