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KarlF
4-Mar-2012, 19:18
Dear colleagues,

I am looking for a lens with a shutter that has the shortest depth of field. The quality of the lens is not very important to me.

To phrase it differently, if we were to restrict ourselves to the 300mm - 450mm range , do you know of a lens with a widest aperture as these FL ? I am looking for specific lens names.

Best,
Karl

Ben Syverson
4-Mar-2012, 19:25
Shortest depth of field? As in least depth of field? Just choose the longest, fastest lens you can find.

If you want the opposite, choose the opposite: shortest lens, stopped down.

If you don't care about image quality, choose a pinhole. Infinite depth of field.

Mark Sawyer
4-Mar-2012, 19:26
Remember that movements on a view camera can also simulate short depth of field.

Jason Greenberg Motamedi
4-Mar-2012, 19:56
Just play with any of the online DOF calculators and figure it out. I would imagine that the differences between a 19" lens and longer, say a 800mm Nikkor telephoto, is pretty negligible; with a subject 10 feet away at f9 you have the DOF of a fraction of an inch.

Daniel Stone
4-Mar-2012, 20:39
try one of these:

Oscillo-Paragon 75mm F/1.9

I'm not sure of exact coverage, but I don't think its much...

like this:

http://www.ebay.com/itm/OSCILLO-PARAGON-3-Inch-75mm-1-0-85X-cine-lens-75-f1-9-TEKTRONIX-/180834604590?pt=Camera_Lenses&hash=item2a1a95162e

-Dan

benrains
4-Mar-2012, 21:19
I am looking for a lens with a shutter that has the shortest depth of field. The quality of the lens is not very important to me.

To phrase it differently, if we were to restrict ourselves to the 300mm - 450mm range , do you know of a lens with a widest aperture as these FL ? I am looking for specific lens names.


I doubt you'll find one with a modern built in shutter in the 300-450mm (12in to 18in) focal length range, but you'll want to consider older barrel lenses. Some of the Wollensak lines like the Verito (f/4) and the Vitax (f/3.8) did come with a studio shutter option, but that shutter is more limited in their design than modern ones. There are wide range of Wollensak lenses at f/4.5 in the Velostigmat (later Raptar) line, some of which came in Betax shutters. For the really fast lenses you'll have to consider the older Petzval designs with the fastest being around f/3 like the Dallmeyer B series. You'll have to add your own shutter though.

Hugo Zhang
4-Mar-2012, 21:23
Without a shutter, this is the one:

http://www.ebay.com/itm/RARE-Taylor-Hobson-12-1-2-inch-F-1-5-lens-Cooke-Optics-fast-lens-317-mm-FL-/110835484356?pt=LH_DefaultDomain_0&hash=item19ce4f46c4

Paul Fitzgerald
4-Mar-2012, 21:24
KarlF,

DOF will be equal to (apparent aperture/focus distance) so you would need to find the largest shutter (Compound #5). Any of the lenses in a #5 Compound will have virtually the same DOF wide open at the same distance.

Have fun with the hunt.

Leigh
4-Mar-2012, 21:33
I doubt you'll find one with a modern built in shutter in the 300-450mm (12in to 18in) focal length range...
Huh? There are lots of them.

My database shows:
nine 300mm lenses with apertures from f/5.6,
six 360mm lenses from f/6.5,
one 400mm f/8, and
two 450mm from f/9. All of these are in modern Copal shutters.

There are probably others since I don't have all the Schneider lenses in the database.

- Leigh

benrains
4-Mar-2012, 21:40
Huh? There are lots of them.

My database shows:
nine 300mm lenses with apertures from f/5.6,
six 360mm lenses from f/6.5,
one 400mm f/8, and
two 450mm from f/9. All of these are in modern Copal shutters.

There are probably others since I don't have all the Schneider lenses in the database.


I'd assumed (maybe incorrectly) that he was after something a bit more exotic than the run-of-the-mill modern offerings which max out at around f/5.6.

Ben Syverson
4-Mar-2012, 21:44
The giant 12" Aero Ektar (ƒ/2.5) has got to have some of the shallowest depth of field at that focal length.

Leigh
4-Mar-2012, 21:52
I just ran some numbers on DoFMaster (http://dofmaster.com/dofjs.html)

for 4x5, 300mm, subject distance = 10 feet:
@ f/2.5 DoF = 0.15 feet = 1.8"
@ f/4.0 DoF = 0.24 feet = 2.9"
@ f/5.6 DoF = 0.35 feet = 4.2"

If the OP really wants minimum DoF then the Aero Ektar f/2.5 would be the best of the ones listed so far.
But it and other exotic lenses probably do not have shutters.

- Leigh

benrains
4-Mar-2012, 22:09
That link Hugo Zhang posted is for a 12.5" f/1.5 Taylor-Hobson. Since it weighs 83 lbs (37.6 kg) I'm not sure how practical it'd be. :)

Steve Hamley
4-Mar-2012, 22:12
There are uncommonly seen 360mm/36cm f:4.5 tesars (Schneider Xenars for example) in Compound #5 shutters. I also had S.K. Grimes put a 36cm f:4.5 Heliar into a Compound #5. You might post a WTB ad for a 36cm Xenar in shutter since it seems the most common of the fast lenses in shutter.

If you don't want to wait for the tessar/Xenar to appear in shutter, the more obvious choices are any of the 360mm f:5.6 plasmats like the Symmar, or a 14" f:6.3 Kodak Commercial Ektar.

Cheers, Steve

Frank Petronio
4-Mar-2012, 22:33
A 360/5.5 Schneider Tele-Xenar in a compound shutter (like I just sold for $250) does short depth-of-field on 4x5 nicely, without movements because of its telephoto design. Most of the shutters for these longer lenses will have maximum speeds of 1/125th or 1/60th (or slower in reality) so in some conditions you may need neutral density filters to reduce the amount of light.

rjmeyer314
5-Mar-2012, 07:36
There's a good discussion of depth of field at http://en.wikipedia.org/wiki/Depth_of_field. The operative formula is complicated, and I couldn't get it to paste here. In general however for a fixed distance of focus, lens aperture (set f-number) and circle of confusion size, the depth of focus goes roughly as 1/f^2, where f is the focal length of the lens. Thus, there is no particular lens that has the least depth of focus, but long focal length lenses in general tend to have shorter depths of focus. To get appreciable depth of field from most large format lenses you need to go to a very high f-number (small aperture).

Paul Ewins
5-Mar-2012, 14:35
The 300/4.5 Xenar was the one in the Compound 5, the 360/4.5 was only available in Barrel.

Mark Sawyer
5-Mar-2012, 15:11
In a conventional shutter and 300mm (anything longer needss an even bigger shutter), you're pretty much limited to f/4.5 by the shutter choke. Maybe there's an f/4, but I can't think of one...

If you can get by with a Packard shutter, there's a 300mm f/3.5 Tessar.

The most extreme that's still remotely practical (that f/1.5 Cooke is way heavy/large, and I doubt it covers 8x10), would be the 12" f/2.5 Aero Ektar that Ben mentioned. They usually have an "aircraft camera shutter", but I have no idea how to work one or what its restrictions are. A very large Packard (the back element is 4 3/4 inches across) might be the best solution. There are some equivalents to that lens too, like the 12" f/2.5 Goerz Type I.

If you lose the shutter requirement and aren't fussy about quality, the condenser lenses on an 8x10 enlarger are usually 10x10 to 12x12, and have a focal length in the 12 to 18 inch range. You could have an f/1 8x10 lens if you have a big enough front lens board...

Sevo
5-Mar-2012, 16:15
The most extreme that's still remotely practical (that f/1.5 Cooke is way heavy/large, and I doubt it covers 8x10), would be the 12" f/2.5 Aero Ektar that Ben mentioned. They usually have an "aircraft camera shutter", but I have no idea how to work one or what its restrictions are.

On-board power typically is 28V DC+200V 400Hz AC - cameras probably will only need the former.