View Full Version : Packard/Thornton Pickard vignette ?
02-02-2010, 02:14 AM
Say I had a lens or two with 110mm / 4.33" rear elements and I wanted a shutter for film shooting would a Packard with a 4.5" aperture be ideal or would it vignette the image (especially when stopped down) due to it being mounted a little further away from the element itself ?
I can see this issue either by it being installed on the front and extended out on the lens hood or mounted inside the camera with the distance taken up by the mounting flange and lens board - or can you mount them on the outside of the lens board and then the lens directly to the shutter ?
Both lenses are of the design that doesn't extend past the mounting flange...
Perhaps a 5" or larger would be a better choice ?
I'm keen on the Packard as I understand you can get flash sync but I guess the same logic/question could apply to roller blind shutters ?
02-02-2010, 07:52 AM
The Packard is slimmer than the TP, and mounts by being screwed onto a piece of wood from the back - usually behind the lens, but there is nothing that would say you couldn't mont the entire assembly then in front of the lens. If the shutter is only a short distance behind the lens and the opening is larger than the back element, I don't see a problem. Stopped down would be less of a problem, not more, since the actual opening through which your image is projected on the film is then much smaller than the 110mm wide element. You don't say what "being mounted a little further away from the element itself" actually entails, however so there might be a problem if you have it set back far enough...
02-02-2010, 08:53 AM
Nick, I have both types, my Thornton Pickard shutter works fine with a Wray lens designed to cover 8”x5” which is approx 12”/300mm FL, and covers that format without vignetting, and I think would be just OK with an 8” lens on 5”x4”.
All the Thornton Pickard/lens combinations I've seen tended to be longer focal length Portrait lenses.
However the Packard shutter as Whitey says can be fitted closer to the rear elements and I can use almost any lens from my 151mm f16 WA Ross (Protar) lens upwards on my 10x8 cameras with no issues. But in your case a 5” shutter would give a better safety margin, but in practice a 4½”
might be fine as your only covering 5”x4”.
02-02-2010, 05:17 PM
I'm covering up to 11x14" - and with the arrival of my new jobo that can do 16x20" I'm shopping for holders! And there's always those pesky Collodion chems to find, sky and skill is the limit to size there...
If I look through the lens at an angle using my eye to simulate the extremes of the film plane I can already see the aperture progressively turning into a sort of 'truncated oval' when fully open (what is the correct term?) - If I use a cardboard cut out hole to simulate a Packard I can see it make this truncated oval even more truncated, so I'm just losing a little at the edges which is to be expected. When I stop down I get a complete circle across the full 'frame' but at the extremes the cardboard cut out when it affects the aperture visually now cuts into it a lot faster (than simply the rear element barrel or lens hood does on the other side)
Obvious stuff I guess ...
My question is more how far I should hold my cardboard cut out from the lens to simulate the shutter ? Which is the same question as how do they mount ?
02-02-2010, 07:13 PM
Covering ULF at 1:1 and not afraid of a little swirl I might add...
Its a Dallmeyer 4A and a Voightlander 'slightly longer than the 4A'
You dont want to drop these lenses on your feet
02-03-2010, 03:38 AM
Nick, a Packard shutter's blades can be the less than 1/4" plus the thickness of the lens board from the lens flange, so that's more than close enough with long focus lenses.
So try a card cut out at 1/2" that gives a good margin for error.