5x7 camera extension - how much is needed?

Jerevan · Oct 9, 2006

Okay, this is one of those "how long is a piece of string" questions:

How much bellows extension would I need to comfortably use a 5x7 with a 210 lens, doing landscapes and the occasional portrait or still life? I am looking at the specification for a field camera and 270 mm as a maximum extension sounds a bit short to me.

I'd need 210 mm just to focus the lens at infinity and getting closer would need more than 60 mm, I suppose.

EDIT: 270 mm would be 10.6 inches to anyone who's... uhm... metrically challenged.

Nick Zentena · Oct 9, 2006

All I can say is do the math with the magnification ratios you intend to use. For landscape use it sounds fine but it's not going to handle 1:1 obviously. Also how much you need will depend on the lens. For example according to the Nikon website the 210 W needs 207mm for the flange focal distance. Other lenses may need more and some might need less.

Curt · Oct 9, 2006

600 mm would put you in the best of all worlds. My Canham 5x7 bellows extends to 25 inches and compresses down to "not much". 270mm sounds like, well, not enough. Can you tell us what camera you are looking at? If you had to you could use extensions for the lens or the back but that's pretty bad for a field camera.

David A. Goldfarb · Oct 9, 2006

Generally, lightweight field cameras have a bellows length about twice the length of a normal lens for the format, and cameras meant to be more general purpose or to double for studio use or more "deluxe" have a bellows three times the focal length of a normal lens.

By that generalization, a 5x7" camera with a 270mm bellows is something like a dedicated wideangle camera that could handle up to a normal lens (210-240mm) easily for general use, but not for macro.

seadrive · Oct 9, 2006

My 5x7 2D has 14" of draw, without the extension rail. 10.6" would be enough for landscapes and full-length portraits, I guess, but you'll need a lot more than that to do still lifes with a 210, probably 16 to 20", depending on the subject matter.

Jerevan · Oct 9, 2006

Thanks for your answers, it confirms my first thought that it was a little bit on the short side for macro and still life stuff. I am looking at an Argentum Excursor.

As I am having this camera done to my specifications, maybe I am painting myself into a corner by skimping on the extension capability?

The lenses I own at the moment are two Sinaron-N (150 and 210), a Wollensak 210 and an old brass Rodenstock Rectilinear, also 210 mm. The 150 would cover 5x7" in a pinch at f22 or f32 but I think that would be a close call and with no movements.

EDIT: Rethinking this, I see it doesn't make much sense using this camera as a macro or still life camera.

Nick Zentena · Oct 9, 2006

Depends which lens you use. The 150 would almost do 1:1 with 270mm of bellows. It would also easily cover if used for macro. It all depends.

Ole · Oct 9, 2006

I've switched from a 5x7" Linhof Technika with 600mm of bellows to a Gandolfi Traditional 5x7" with 571mm bellows. The only limitation I've found (and the only time I've needed more than 40cm too!) was when trying to use the 420mm rear half of a 240mm Symmar: The Gandolfi can't do it, the Linhof could.

The Excursor should have 400mm extension from what I can see, and that should be plenty for just about everything.

I'm thinking of a WA-optimised 8x10" camera myself, sort of like an "Architec on stereoids". 120 to 300mm extension, lots of front rise, limited rear tilt&swing. Or maybe a shortened Excursor?

BradS · Oct 9, 2006

The Math....

1/focal length = 1/object distance + 1/image distance

in this case we have focal length = 210 mm and maximum image distance is 270mm. We want to find the minimum object distance....

1/object distance = 1/focal length - 1/image distance

object distance = 1/( 1/focal length - 1/image distance)

object distance = 1/( 1/210 - 1/270) = 945mm

so, a 210mm lens with 270mm of bellows would be able to focus as close as 945mm. Probably fine for landscapes, only marginally acceptable for serious portraiture and certainly not anywhere close to acceptable for macro work.

David A. Goldfarb · Oct 9, 2006

That's an interesting bunch of cameras there. They seem to have a good range of features for wooden field cameras without getting too exotic, are fairly light in weight, and are reasonably priced. Anyone here have one?

Okay, found this thread--

(there was a url link here which no longer exists)

Amund · Oct 9, 2006

David A. Goldfarb said:
are fairly light in weight,

You must be spoiled by your Gowland Pocket views, the weight of the Argentum Excursors are sensational.

argus · Oct 9, 2006

David A. Goldfarb said:
That's an interesting bunch of cameras there. They seem to have a good range of features for wooden field cameras without getting too exotic, are fairly light in weight, and are reasonably priced. Anyone here have one?

Okay, found this thread--

(there was a url link here which no longer exists)

David,

as you noted yourself, the cameras are leightweight but all of the Excelsior models have very short maximal bellows extention.
The weight has to be saved somewhere...

The cameras look nice and are very low priced, I almost got tempted to buy one of theirs when I was informed on their existance. But I like to build my cameras myself and they tend to get better each time (not that it saves me any money, on the contrary).

G

Nick Zentena · Oct 9, 2006

Anybody actually touch one of these cameras yet? Also what are the difference between the Explorer models? All I can figure is a little longer bellows.

Peter De Smidt · Oct 9, 2006

These are nice looking cameras. I like the clean lines and natural finish. Unlike some large format cameras, it doesn't look like it belongs in a bordello.

Jerevan · Oct 10, 2006

Thank you all,

I decided to change the specifications slightly to a 300 mm maximum extension. This camera will be a basic lightweight camera for landscapes specifically, and I tend to go normal or semiwide for most of my photography so I think this will fit me well.

As to hands-on, I might be able to tell you in something about that in the near future, I hope.

5x7 camera extension - how much is needed?

Jerevan

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David A. Goldfarb

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Jerevan

5x7 camera extension - how much is needed?

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