Telephoto lens for large format camera.

[Bobby Ironsights]

Hey there, do they make telephoto lenses for large format cameras?

I'm wondering, because I've been thinking about doing astrophotography, where grain is a major issue because of the long exposure times, and often, the large enlargement scales.

So, a good size of lens is 1600mm for a 35mm.

What sort of equivalent do you guys think I could get/cobble together for 4x5?

Do they make/could I use a teleconverter?

What about making use of one of those aero lenses?

Thanks for your time,
Bobby.

[Peter K]

Telephoto lenses for LF where made up to 1000 mm like the Tele-Xenar 1:8/ 1000mm. Process lenses where made up to 1200 mm but only with f/12 diaphragm. Together with a tele-converter the aperture will go down to f/22 at best.

So aero lenses are a good choice. The aperture of objectives of this type do not usually exceed F/5. And such a lens is heavy.

In any case the camera has to be mounted in such a way the compensation of earth rotation is possible.

Peter K

[Dan Fromm]

Bobby, not to be patronizing or anything, but there are reasons why the longer the camera the shorter, relative to format, the lenses used tend to be. Size, weight, extension.

If you're willing to deal with those problems, look on eBay at least once a week for aerial camera lenses. Coupla weeks ago a 900/4 sold for > $US 4k.

The French Atomic Energy Commission used a couple of 2500/12.5 lenses at Mururoa (spelling?). These were heliar type process lenses, needed a loooong camera.

[Walter Calahan]

This is too short for what you're thinking, but it is an example of using an Military Aero-style lens for a telescope.

http://cgi.ebay.com/Kodak-Aero-Ektar...QQcmdZViewItem

I do see much longer glass for sale on eBay that has been removed from Military cameras. 36" and 54" f/5.6 and f/8.0 lenses that could be rig for your needs.

Or as suggested above, a very large process lenses will do the trick, but they are not as bright as the Aero style.

This one is out of my price range, and you'll only have a few hours to bid on it:

http://cgi.ebay.com/Rodenstock-Apo-R...QQcmdZViewItem

[Gene McCluney]

In general true "telephoto"lenses designed for 4x5, mounted in leaf-shutter have been made to about 800mm. A telephoto design lens does not require as much bellows draw as a the same focal length lens in a "standard" design, thus, for example, on a press camera such as a Crown Graphic, in standard lenses you can use up to about a 210mm with a fairly wide focus range, but anything greater in focal length will just about not focus, even at infinity. To get around this, telephoto design lenses were provided which focus within the bellows draw limits of the average 4x5 camera. You will find brands such as Fuji, Nikon, Komura, Schneider, Wollensak all with telephoto lenses, but these are seldom longer than 500mm, a few 800mm, perhaps a 1000mm.
Not really ultra-telephoto at all when you consider the negative format.

[Ralph Barker]

One thing to remember is that the object size on film will remain constant based on the focal length of the lens or telescope being used. The rule of thumb for the moon, for example, is about 1mm of image size per 100mm of lens focal length. So, with a 1000mm lens, one would have a 10mm moon on film, regardless of format. Thus, unless one is doing wide field images, going to 4x5 really doesn't do much for solving the enlargement factor problem.

Additionally, most (affordable) very long lenses for photography tend to be pretty soft. As a result, the astrophotography images can be pretty disappointing. Military lenses originally used fo surveillance purposes are probably better in that respect, but are often still limited in focal length.

[Rakesh Malik]

You'd probably be better off getting a small (6-inch) Maksutov-Cassegrain if you want to do planetary imaging, a medium-sized, aprochromatic triplet refractor if you want to do super-sharp wide-field imaging, or a larger (10 inches+) Maksutov-Cassegrain if you want to image faint, deep-space objects like nebulae.

You'll definitely need an equatorial mount with a motor, and for really deep space objects, either use multiple exposures and stack them or go for an autoguider.

And whatever you get, make sure that carrying capacity isn't a problem. A 10-inch Celestron Mak-Cass with a GEM, tripod, motor drive, and counterweights can easily exceed 200 pounds.

For lunar photography, you could get away with a Takahashi Sky 90 and your regular photo tripod; you don't need particularly long exposures to photograph the moon

[Bobby Ironsights]

Alrighty, I've decided to put this on the back burner for awhile, but I've discovered an astronomy club in my area.

When I regain interest, I think I might attend a few meetings, hobnob awhile, show off a few prints, maybe give a few out...see what comes.

From what I've seen, astronomy is as expensive a hobby as photography, and I'm just really intent on getting a couple good shots of gibbous moon, so instead of killing myself financially, I should team up with somebody local.

[venchka]

Alrighty, I've decided to put this on the back burner for awhile, but I've discovered an astronomy club in my area.

When I regain interest, I think I might attend a few meetings, hobnob awhile, show off a few prints, maybe give a few out...see what comes.

From what I've seen, astronomy is as expensive a hobby as photography, and I'm just really intent on getting a couple good shots of gibbous moon, so instead of killing myself financially, I should team up with somebody local.

Astronomy far exceeds photography. I know people who have built backyard planetaruims. I don't think the building cost as much as the hardware inside. And they have cameras to record their viewing.

A friend of mine has on the last few evenings used the following to record the comet currently visible over Texas and probably elsehwere: Canon 600/4.0 lens, 1.4 TC, 2.0 TC and Canon ID Mk III body. Effective focal length: 600 * 1.4 * 2.0 * 1.3 = 2184 mm. He has all this hardware mounted on a Gitzo 55xx tripod with a Wimberly Sidekick head. He gets a wiggle every now & then.

[George Stewart]

Here is my idea of LF astrophotography: http://www.superwasp.org/ I think the same if not better could be achieved by using a single fast lens and stitching the images together. Keeping LF film flat durning several hour exposures would be difficult.

You might be interested in this LF astrograph taking 12x12 plates (note the 8x10 camera on top of the whole thing: http://www.library.gatech.edu/barnard/ A more detailed description of the astrograph and lenses can be found here: http://www.library.gatech.edu/barnard/intro1.html