Longest tele for a Crown Graphic?

[dsphotog]

What is the longest focal length lens that fits on a 4x5 Crown?
I have a 250 Tele Optar, and would like more reach.

Thanks,
David Silva
Modesto, Ca

[Leigh]

Move the front standard as far away from the film as it will go.

Measure the distance from the front of the lensboard to the film plane.

That's the longest lens focal length that will focus at infinity (approximately*). Of course it won't focus on anything closer (disregarding depth of field).

One other possibility (I've never seen this done but it sounds reasonable):
Make an extension to move the film holder back from its normal position by 100mm. This would permit you to mount a 350mm lens and still have some useful focusing movement, although the near focus limit would not be as close as you would expect for the lens.

The Graphic cameras have a pretty short throw to start with, so your focus range won't be very large with the 250mm, and worse yet with a 350mm.

- Leigh

* two sources of error:
1) Lens focal length is actually measured from the rear node to the film plane, and the rear node position varies from one lens design to another.
2) The true focal length may differ from the value engraved on the lens, possibly by as much as 10%.

[Jack Dahlgren]

Move the front standard as far away from the film as it will go.

Measure the distance from the front of the lensboard to the film plane.

That's the longest lens focal length that will focus at infinity (approximately*). Of course it won't focus on anything closer (disregarding depth of field).

One other possibility (I've never seen this done but it sounds reasonable):
Make an extension to move the film holder back from its normal position by 100mm. This would permit you to mount a 350mm lens and still have some useful focusing movement, although the near focus limit would not be as close as you would expect for the lens.

The Graphic cameras have a pretty short throw to start with, so your focus range won't be very large with the 250mm, and worse yet with a 350mm.

- Leigh

* two sources of error:
1) Lens focal length is actually measured from the rear node to the film plane, and the rear node position varies from one lens design to another.
2) The true focal length may differ from the value engraved on the lens, possibly by as much as 10%.

You can go longer than the limits that Leigh implies with a telephoto design. They are covered pretty well here:
http://www.largeformatphotography.info/lenses-long.html

Tele lenses are designed to require less extension as you know, but I think you will run out of room with anything longer than 360mm.

[dsphotog]

Good info, I would also like to hear what specific lenses folks are using/have used, and the joys/pitfalls of said lenses.

[Leigh]

You can go longer than the limits that Leigh implies with a telephoto design.
That's what I said in my Sources of Error #1.

Regardless of what the flange focal distance is for a 350mm lens, you still must move it forward by 350mm to achieve a 1:1 reproduction ratio. Farther subject distances require less extension, but the lens design does not change the amount of extension required.

- Leigh

[Jack Dahlgren]

That's what I said in my Sources of Error #1.

Regardless of what the flange focal distance is for a 350mm lens, you still must move it forward by 350mm to achieve a 1:1 reproduction ratio. Farther subject distances require less extension, but the lens design does not change the amount of extension required.

- Leigh

What was that Mr. Nonsequiteur?
I think there are few on the planet who would consider the use of a 350mm lens on a crown graphic in order to achieve a 1:1 reproduction ratio. I know I never did. Fortunately you are of made of such rare insight!

[Leigh]

I think there are few on the planet who would consider the use of a 350mm lens on a crown graphic in order to achieve a 1:1 reproduction ratio.
I was establishing the limits of movement for a 350mm lens, with infinity focus and 1:1 being the appropriate values. It makes no difference what camera it's mounted on.

The lens extension required for any normal subject will fall between those two values.

I was attempting to point out nicely that your statement: "Tele lenses are designed to require less extension..." was wrong. Lens design can change the flange focal distance of the lens, which controls the distance of the rear element from the film when focused at infinity, but it cannot in any way change the extension required to focus at closer distances.

I realize you don't understand basic optics. Why don't you ask questions rather than making stupid statements?

- Leigh

[dsphotog]

In addition to the limits of the bellows extention,(I don't do many closeups) it also has to fit the smallish lens board, that eliminates a lot of 360's, frequently on #3 shutters.
I'm just looking for opinions/experiences others have re specific optics compatable with the Crown camera.

Thanks

[Vaughn]

Hi Dave, with the 250mm tele at infinity what is the distance from the film plane to the lens board -- and how much more bellows do you have after that?

I have a 15" Wollie tele (about 380mm) on a Technica board on my desk at work. If I have time tomorrow, I'll slip it on a camera and measure the film-to-lens board distance...should be able to do it. I have been wondering about that for awhile anyway -- one tends to do that when one has such a lovely industrial-looking sort of lens on one's desk for awhile!

I have not heard much about the lens or the quality of the image it makes (sharpness and contrast).

It may be on a Technica I board, so I may not be able to quickly check it out on a camera (our Technica I is checked out by a student right now.) Anyway, I'll see tomorrow.

Vaughn

PS -- just did a little research -- seems like others have used them on Speed/SLR/Crown Graphics, needs 10 to 12 inches of bellows, and people seem to like the image quality. Might be worth your while to check on it further. People also mention how big and heavy it is. I guess it is -- I am too use to lenses for 8x10!

http://www.apug.org/forums/forum44/48331-wollensak-raptar-15-inch-f5-6-lens.html

[john biskupski]

Take a look at "graflex.org/helpboard/viewtopic.php?t=5128" on the Graflex site. I understand the 15" Tele-Optar (or Raptar) was designed to work, at least at infinity, with all Graphic cameras, the Crowns/Speeds with 12-1/2" or 13-1/2" bellows, and the Graphic view which had longer bellows extension.

[Dan Fromm]

Second John's advice, the 15" Wolly tele was the longest standard issue lens for 4x5 Graphics, is recommended for Crown and Speed. They were sold in barrel and in shutter.

[rjmeyer314]

I don't have a Crown Graphic, but I do have a Super Graphic. I have one of the 15" Wollensak TeleOptars (in shutter). It will work on my camera, but it has to be focus on the ground glass. I have found one of the correct cams, but the range finder still doesn't focus properly with that cam. I also have a 20" B&L aerial lens on an extended lens board that will work on my Speed Graphics. It requires a home-made support stand inserted between the camera and the tripod to take some of the stress off the front lens standard. I have seen similar tricks used to allow the use of up to 40" lenses on Speed Graphics. I once came across a monstrous homemade box camera at a swap meet that was really just a 36" process lens and a Speed Graphic focal plane shutter back, no bellows. I should have brought it, it was only $40.

[Ivan J. Eberle]

Some of us won't be deterred by a lack of 1:1 focus, but would be much more interested in how much extension the 15" Raptar telephoto design requires to focus down into the head-and-shoulders portraiture magnification ratio. Is this within the range of a 4x5 Crown/Super Graphic?

[Frank Petronio]

There are "Sports" extended Speed Graphics that took really long lenses, you see them once in a while on eBay and they aren't that expensive. But at that point you might just as well use a cheap old Sinar or monorail since they're not going to fold up nice and compact.

[Jim Michael]

I own a Schneider 240 Tele Xenar. The infinity focus is about 152 mm from flange to film. A 300 mm extension doesn't provide 1:1 but a 480 extension provides quite a bit larger than 1:1, so the 1:1 point is somewhere in between.

[Paul Fitzgerald]

"Some of us won't be deterred by a lack of 1:1 focus, but would be much more interested in how much extension the 15" Raptar telephoto design requires to focus down into the head-and-shoulders portraiture magnification ratio. Is this within the range of a 4x5 Crown/Super Graphic?"

You're asking a horse to climb a tree here but the 15" Tele-Raptar should focus down to 7 feet on a SpeedGraphic, more than close enough for a head-and-shoulders. portrait.

[Leigh]

I own a Schneider 240 Tele Xenar. The infinity focus is about 152 mm from flange to film. A 300 mm extension doesn't provide 1:1 but a 480 extension provides quite a bit larger than 1:1, so the 1:1 point is somewhere in between.
Hi Jim,

Unfortunately the term "extension" can have two different meanings.

1) The distance from the film to the lens when focused; and
2) The distance the lens must move forward from its infinity focus position to focus on a closer subject.

The value of #1 depends on the position of the rear nodal point of the lens, which may or may not be known. In your case it would be 88mm forward* of the lensboard (240 - 152 = 88).

The value of #2 can be calculated from the equation 1/SD + 1/FD = 1/FL where SD is the subject distance, FD is the film distance, and FL is the lens focal length. The 1:1 reproduction ratio provides a convenient example, since in this case SD = FD. Solving the equation yields:
1/SD = 1/FD, so 1/SD + 1/FD = 2/FD
2/FD = 1/FL, and cross-multiplying we get
FD = 2FL, so the lens must be extended forward from its infinity focus position by a distance equal to its focal length.

Using this same equation to answer your question...
Suppose you want to focus on an object ten feet away (10 feet = 3000mm) with your 240mm lens.
1/3000 + 1/FD = 1/240
1/FD = 1/240 - 1/3000 = 1/261 approximately, so FD = 261mm. The lens needs to be 261mm from the film to focus at 10 feet.

At infinity the lens is 152mm from the film, so the required extension is 261 - 152 = 109mm. That's the distance the lensboard must move to focus at 10 feet.

- Leigh

*nb
The front and rear nodal points are theoretical positions that are used when designing a lens. They can be anywhere. The front node is the point to which all incoming rays appear to converge. The rear node is the point from which all exiting rays appear to emanate. In telephoto designs it's customary for the rear node to be in front of the front node. :eek:

[banjo]

OK All
I just though that I would get here on this one. what I have is a Schneider-Kreuznach
Tele-Xenar 36cm //360mm. I put my bellows all the way out locket down on my 3x4
speed this make my focus at 6' 4" but on the 3x4 a good head-and-shoulders portraiture
need to be all most 8' away but i don't get a one to one !!!

banjo