wide angle lens for 12x20 format

[Lewis Lauring]

I need help in choosing and finding a wide angle lens, 14" range for a 12x20 cam era to be used for landscape photography, to include infinity in focus. I am tol d that the Schneider G-Claron 355/9 covers the format stopped down but is this a t 1:1 or at infinity? At infinity focus, what will be the image circle? How much movement will the Goerz dagor 14"/7.7 allow? Are there other lenses I should co nsider? Thanks Lewis Lauring

[Pete Andrews]

Your 12 by 20" format has a massive diagonal of over 590mm. You haven't got a prayer of covering it with a 355mm normal angle lens, and neither the Dagor nor the G-Claron are wide-angle lenses by any means. See the post 8 down from this.

[Chad Jarvis]

At 14" focal length you'll need a lens with an angle of coverage of just about 80 degrees... which leaves no room for movement. I know that the Zeiss Protar Vs (fives) have an angle of coverage of right around 105 degrees (in barrel, slightly less if mounted in a shutter), which should be just the ticket. And you get the added bonus of a highly corrected convertible lens.

[Struan Gray]

The LF home page associated with this forum has some useful lists of lens coverage (Click on 'about' on the main page and follow the obvious link). Michael Gudzinowicz has also recently posted some other lists which include older barrel lenses to the usenet group rec.photo.equipment.large-format: you can retrieve them at www.dejanews.com.

The consensus on usenet seemed to be that older 14" Dagors would cover 12x20 but modern formulations wouldn't. The 360 Fujinon-W seems to be a universal recommendation as a modern lens that will cover the format with a little room for movements and a wider than normal angle of view.

[Chris Partti]

Glen Evans has some info on lenses to cover 12x20 (that is, the ones he's selling) on his web site (www.photomall.com/gevcam.htm) and Wisner has a page on lenses that cover 20x24 (www.wisner.com/20x24lens.htm). Collectively, these might give you some useful info.

[Steve_571]

I use my 355 g-Claron on 7x17 (at infinity) with no problems what so ever, and I know of one photographer that uses the 355 G-Claron on his 12x20. I only saw him use it up to middle distances, but he was using tilt (if I recall correctly). 355's are abundantly available used, and most likely if you weren't happy it is easily re-sold. I would say try it.

Steve

[Mark_437]

Lewis - I shoot on 12x20 with a 14" Goerz f/7.7 Dagor. I love this lens on this format - my favotite 4x5 lens is the 90mm and a 14" (360mm) lens on 20" wide film has the same horizontal angle of view. Although my particular lens is uncoated, Dagors inherently have good contrast due to their construction (only 4 air-to-glass surfaces). You don't get a lot of extra coverage with the 14" Dagor, but enough for slight movements and (more importantly) enough to use a filter without vignetting. (Realizing, of course, that most of your pictures will be taken at f/64.) The lack of coverage has never been a problem for me with landscapes. My camera (Korona) has front tilt and rise/fall (no front swings) and a bit of rear tilt and swing. The only movements I really use are moderate rear tilts, which I prefer to front tilts because 1) they don't eat up any coverage, and 2) I like the slight foreground exaggeration - it adds to the near/far 3-D effect.

I haven't personally used the 355mm G-Claron so I'll avoid the curse of the web and refrain from making unfounded conjecture based on third-hand hearsay. Some of the sources mentioned in the other replies seem like good bets for reliable info.

Have fun with your big camera, and if you have any questions feel free to e-mail me offlist.

Cheers!

[Lewis Lauring]

Thanks to you'all in providing great and useful information. This website is really fantastic. In the few short weeks that I have been visiting the site, I have significantly added to my photographic knowledge. What a tremendous resource. Now all I have to do is make an expensive decision between the Dagor and Fujinon. Lewis Lauring

[Carl Weese]

Lewis,

The 355 G-Claron works wonderfully for 12x20 format: it's my usual lens with this camera. The G-Claron design gains enormous coverage over the published stats as it is stopped down to f/45 or farther. At 45, you've got at least 3/4" of rise/fall available. No objectionable light falloff either.---Carl

[SAShruby]

Lewis,

The 355 G-Claron works wonderfully for 12x20 format: it's my usual lens with this camera. The G-Claron design gains enormous coverage over the published stats as it is stopped down to f/45 or farther. At 45, you've got at least 3/4" of rise/fall available. No objectionable light falloff either.---Carl

I disagree. This weekend I did a 8x20 picture with 355 G-claron (orange filter) on sunny day, I've got a significant falloff. According to my calcucation by densitometer almost full stop between center and corners. With distance, center is 355mm from nodal point, corners are 448mm from nodal point, approximately 25% further than center of the filmholder.

[Dave Wooten]

I would suggest one take a look at the web site of Carl Weese. :)

[Really Big Cameras]

I disagree. This weekend I did a 8x20 picture with 355 G-claron (orange filter) on sunny day, I've got a significant falloff. According to my calcucation by densitometer almost full stop between center and corners.

Actually, I'm surprised that's all the fall-off you measured. The C Claron is a standard design (no tiling entrance pupil like the Biogon and derivatives like the Super Angulon, Grandagon, Fujinon SW and Nikkor SW). So, the theoretical best case fall-off will be cos^4. For a 355mm lens in the corners of an 8x20 negative, that works out to about 1 1/3stops. Of course, that assumes you are focused at infinity (the worst case scenario). As you focus closer the angle theta decreases and so does the fall-off.

For a modern wide angle with a tilting entrance pupil the fall-off closely follows cos^3. However, the longest lens of this type I know of is the 300mm Fujinon SW. If such a lens did exist in the 355mm focal length, the fall-off in the corner of an 8x20 negative would be just under 1 stop.

Of course, how much anyone would notice this is a matter of personal sensitivity. I personally don't find fall-off of 1 1/3 stops objectionable on high contrast color transparency film. Once the fall-off gets up around 1½ stops on Velvia, I reach for the center filter. On lower contrast black and white materials, my person sensitivity to fall-off is less.

Every lens has fall-off. The wider the lens, the more the fall-off. The tilting entrance pupil design of many modern wide angles lenses helps reduce this fall-off, but doesn't come close to eliminating it. Even center filters are not designed to give totally even illumination. They are typically designed to reduce the fall-off to a tolerable level for most people. If you've got a stop of fall-off corner-to-corner, most people wouldn't find that offensive. In fact, unless you have a VERY even toned subject (white geese in a snowstorm), most people won't even notice.

Kerry Thalmann
Really Big Cameras

[Really Big Cameras]

I would suggest one take a look at the web site of Carl Weese. :)

And, the key comment by Carl in this thread was:

"No objectionable light falloff either."

Not, no measurable fall-off.

There is a significant difference between these two statements.

Kerry Thalmann
Really Big Cameras

[Jorge Gasteazoro]

I disagree. This weekend I did a 8x20 picture with 355 G-claron (orange filter) on sunny day, I've got a significant falloff. According to my calcucation by densitometer almost full stop between center and corners. With distance, center is 355mm from nodal point, corners are 448mm from nodal point, approximately 25% further than center of the filmholder.

SAS.... buddy, this is a thread from the year 2000.. :)

PS. Don't know what you didi, I use a 355 frequently in my 12x20 and see no fall off...are you sure your filter ring did not cause vignetting?

[SAShruby]

I know Jorge, :D, but I searched for G-Claron fall off thread and I found this one. I didn't want to start new thread.
You know, you got it. This is it! I just realized it, (blushing). I stopped lens to f11 only for fast exposure. Aaaach.

I gotta check it out if I had full circle in my corner! Highly likely not :(

[imageshooter]

I have a nuArc 8-1/4" F8 Process Lens that came along with a Sinar P 4x5 with Digital shutter. This lens is mounted on a small thick board 4" square. As I am brand new to LF photography I do not have clue about what the camera's previous owner used it for. It doesn't have shutter speeds, and doesn't seem to be able to talk to the Digital Shutter. Any feedback will be appreciated.

Richard

[Archphoto]

I think that if you want to use this lens you will have to put it onto a Sinar lensboard.
And no, this lens will never be able to talk to this shutter, but is there a need for it ?
As long as you can set the shutterspeed on the shutter you could give it a try.

Peter

PS would it not have been wiser to start a new thread ???

[imageshooter]

Thanks for the reply Peter. As I am new at this stuff I just thought you jumped in and started asking Qs. I just went to the top of the page and saw the new posting button.

Thanks for the tip off

Richard