Lenses for 12x20

Hi to everybody:

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I will appreciate if someone could give me a run down on what lenses are appropiate for a 12x20 large format camera. I am looking for a 450 or 480mm; 600mm and perhaps a 350mm.

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I am interested in either new lenses or old lenses.

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Also, I was wondering what is important to look for when shopping for a 12x20 lens, is it the image of the circle or the angle of coverage?

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Best regards to all,

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Alejandro

Ya might start here:

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http://www.wisner.com/20x24lens.htm

I think that the Nikkor 360W and Fuji 600C may offer sufficient

coverage for this format. A reference for lenses covering 11x14 is <A

HREF="http://www.cs.berkeley.edu/~qtluong/photography/lf/lenses-

table11x14.html">here</A>, and some of these will cover 12x20. This

is a format I firmly intend to get into.

Don't mistake angle of coverage for angle of view.<p>If I'm not

mistaken, the image circle is directly proportional to the angle of

coverage --> if the image cirle covers the format, the angle of

coverage will cover and visa-versa.

Friend of mine have a couple of 25" f/9-256 Rodestock Apo-Ronar in

barrel for sale.

For modern lenses, Schneider G-Claron 355/9, when stopped down to f45,

will cover 12x20 with an inch or so movements in each direction. You

will be more confortable with new Fujinon 450 and 600. For old

lenses, you might want to look at Dagors. A C. P. Goerz rectagon

270/10 will also cover 12x20. Write to Carl Weese for export advices.

Hello Geoffrey:

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Where do I find Carl Weese?

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I prefer to be more confortable, so: How much movement would I have

with the Fujinon 450? (Is this the same lens as: Fujinon CM-W 450?)

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How about the Nikkor 450M, is it a suitable lens for a 12x20?

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Regards,

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Alejandro

Carl is on the forum. Check some threads about ultra large format.

That's his specialty. Maybe someone else knows his email address.

Good luck!

Alejandro,

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Check here: http://home.earthlink.net/~cweese/

Alejandro,

One of the problems to deal with in 12X20 (besides equipment size

and weight, and film cost) is finding lenses to cover the format. I

measured a 12X20 holder - the diagonal is 23" or a little more, so you

need at least that large an image circle. A larger circle is needed to

have room for movements. Go to http://www.wisner.com/lenscov.htm and

look at the column for 12X20. The numbers Mr. Wisner gives are degree

of coverage needed in order for a particular focal length to be able

to cover 12X20. Different lens designs have different degrees of

coverage.Goerz Dagors (depending on vintage) have an 87 to 90

degree of coverage (one of the reasons Dagors are highly thought of

by LF photographers). Reading down the column, a 305mm focal length is

the shortest FL that will cover. In order to have room for movements,

choosing a 14" (360mm) Dagor would be better. A 16 1/2" or 19" Dagor

would give even more coverage, but as the focal length of Dagors

increases, they become much more difficult to find (and more

expensive). If you think you may want to someday move up to 16X20

format, you can use the longer Dagors. http://www.lensrepro.com/ is

one source for older lenses like Dagors. The 450mm Nikkor (I believe)

has a coverage angle of 60 degrees. By Mr. Wisner's chart, a 60 degree

lens would need to have a FL of more than 480mm to cover 12X20, so it

doesn't look likely the Nikkor will work. Goerz Artars cover about 45

to 47 degrees - hence the common 24" (600mm) Artar doesn't look like

it should cover, although I've heard people claim it will. The next

longer Artar shown in my Goerz catalog is a 30". Do you have enough

bellows length? Protars covered a little less than Dagors - I believe

a 14" or longer Protar would work, but I'm not that familiar with

Protars. If you haven't already, look at all the Q&A part of Mr.

Wisner's site, including the archive of older questions. Also

http://hv.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=004BTg

and http://hv.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=0004YH

Hi, Alejandro - First off, I would start with one lens and see how

it goes, then add others if the need arises. In my opinion - for

many reasons - the banquet formats are at their best with wider

lenses.

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Regarding coverage, ignore those who say that, IN THEORY, this or

that lens won't cover. Get it from the horse's mouth. Having said

that, I can state that the 14" f/7.7 Goerz Dagor will cover the

format with some (but not a lot) of movement. (And for most

landscapes you won't need a lot of movement - just a little rear tilt

for DOF, which doesn't eat up coverage.) Sharp, high contrast - I

recommend it as a good "wide" 12x20 lens. Patrick Alt - who repairs

these big cameras for a living and knows what he's talking about -

says the Nikon 450M covers the format, and he recommends that lens.

(There was a piece in View Camera by him about this a couple of years

ago.)

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The critical specification you are looking for is Image Circle, and

in 12x20 the magic number is 585mm as an absolute minimum. Realize

that most manufacturers list the circle of full illumination (i.e. NO

mechanical vignetting) at f/16 or f/22, therefore these numbers are

very conservative. You will usually shoot 12x20 at f/64, and will

find many lenses that will cover even they are not "supposed" to.

Listen to those with practical experience, or get the seller to give

you a return privilage if the lens doesn't work for your format.

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Good luck!

Hi Alejandro,

Try to look up this shop in Holland, they have a G-Claron 477/6,5 ,

don't know the price, I saw it today. You have to write them because

they won't have it on the site.

http://www.fotoabro.nl

Good luck

Andrea Milano

D'oh! the URL didn't take!

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http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1215556743

This isn't the shopping forum, but I have an absolutely mint

Rodenstock Klimsch APO ROnar 800 mm in barrel for sale that will have

no problem covering. Its big and heavy, but won't cost you even

close to what those others will cost, and it will perform. kevin

Mark Parsons refers to an article in "View Camera" where Patrick Alt

recommends the 450mm Nikkor for 12X20. Mark (or anyone) can you look

at the article and see if Mr. Alt goes into any detail on amount of

coverage? Also, I agree with your point the "on paper" coverage may be

less than what you get on film. If the upper corners of your image are

sky, and the sharpness isn't perfect, will anyone notice? The great

thing about newsgroups is having access to the real world experience

of other people.

In answer to your question about 19" Dagors, they sell for $1800-

2100, and are hard but not very hard to find. Expect to add some $

to put one into an Ilex #5 shutter, unless it already is or you don't

mind using it in a barrel. I recently bought a 19" Dagor from

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http://www.photomall.com/gelens.htm

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This place, Glennview Camera, still has one more listed in their

inventory, and seemed perfectly pleasant to deal with. I'm having SK

Grimes put it in an Ilex 5, which I also bought from Glennview. Lens

and Repro occasionally has these lenses, and just sold one, I believe.

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Good luck,

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Nathan