11x14 ultra, ultra wide....

[Don Hutton]

I was testing a circular mask on my 11x14 this week and mounted my Schneider 150mmXL. It soon became apparent that this lens has a much bigger image circle than I thought. Stopped down to f64, it appeared to cover 11x14 - that's an image circle of around 450mm - that translates into an angle of coverage of around 113 degrees - I couldn't quite believe it. So this afternoon, took my camera out and shot a sheet of film with the 150mmXL at f64 - hyperfocal focussing (which is ridiculously close on a 150) and used the Schneider 4 center filter - it covers! Not only does it cover, but it's sharp right into the corners. Now I'm going to have to find someone with a big nose to shoot with it....

[Walter Calahan]

LOL, can wait to see your nose gallery show!

[sanking]

I was testing a circular mask on my 11x14 this week and mounted my Schneider 150mmXL. It soon became apparent that this lens has a much bigger image circle than I thought. Stopped down to f64, it appeared to cover 11x14 - that's an image circle of around 450mm - that translates into an angle of coverage of around 113 degrees - I couldn't quite believe it. So this afternoon, took my camera out and shot a sheet of film with the 150mmXL at f64 - hyperfocal focussing (which is ridiculously close on a 150) and used the Schneider 4 center filter - it covers! Not only does it cover, but it's sharp right into the corners. Now I'm going to have to find someone with a big nose to shoot with it....

That is pretty amazing. Wonder if there is enough coverage for 7X17?

I am not surprised, however. I recently acquired a
Schneider 210mm SSXL and it covers 12X20 with about two full inches of movement, and tack sharp right out to the corners of the image.

Sandy King

[Don Hutton]

I would think it should cover 7x17 too - it appears to cover 11x14 even focussed out to infinity, so I would think that with hyperfocal it should easily get around 7x17. I may shoot a sheet tomorrow for a laugh.... I'm just not sure that my garden is wide enough.

[Jay M. Packer]

The lens does cover 7x17, albeit with some significant light falloff; see

http://www.mtwhitneyphoto.com/pages/Arch_Alabama_Hills.htm

Phil tells me that the center filter is mandatory for 7x17.

- J. Packer

[Brian Ellis]

"It soon became apparent that this lens has a much bigger image circle than I thought. Stopped down to f64, it appeared to cover 11x14 - that's an image circle of around 450mm - that translates into an angle of coverage of around 113 degrees - I couldn't quite believe it."

I'd suggest making some prints before deciding that you actually want to use this lens on that camera. Almost all lenses have an "image circle" and a "circle of good definition," with the former being larger than the latter. The difference varies from lens to lens and I understand that it tends to be smaller with modern lenses than with older lenses but it's still usually there to some degree. Conservative spec sheets will use the circle of good definition as the stated "image circle" even though the actual image circle is larger. The more you stop down past the aperture used by the manufacturer in defining the "image circle" the more you move out of the circle of good definition and into a part of the image circle that the manufacturer didn't use in the spec sheet because the manufacturer didn't consider images formed in that part of the circle to be acceptable. Sometimes that's fine, the lens manufacturer obviously has to make some judgements as to what's acceptable and what isn't and your standards may differ from those of the manufacturer. But when you have to stop down to f64 to cover a format my guess is that light fall-off in the corners will be so great as to be unacceptable to almost anyone.

[Don Hutton]

The point is Brian, it covered with the center filter in place, so the light fall-off is just fine - there is fall off, but less than you would think. I made an Azo contact with it this morning and while the print is not yet dry, it looks fine - very usuable, but I'm just not sure how often I would want to shoot that wide - I had a 210mmXl for a while and only have 3 prints shot with it which were keepers. As for sharpness - if it works on an Azo contact print, it will be fine for 99% of what 11x14 shooters do which is contact print.

[Brian Ellis]

"The point is Brian, it covered with the center filter in place, so the light fall-off is just fine - there is fall off, but less than you would think . . . "

I actually didn't have any specific amount of fall-off in mind. If the fall-off you see is acceptable to you that's great.

[Dan Fromm]

Brian, I'm with you.

But disputes about what coverage means exactly have been around forever. I'm thinking of disagreements between sensible people who actually take pictures with the lenses whose coverage/image quality in the corners they don't agree about, not disagreements with the characters who make exagerated claims in their listings on eBay.

Re disputes about coverage, if you want a good laugh search here for an old thread on the coverage of the 180/6.8 Dagor. It was initiated by an individual who posted as landarc.

[Richard Schlesinger]

Since I particularly favor wide lenses I have coveted the 38mm Schneider XL but concluded it wouldn't cover 4X5 in any useful manner. The posts regarding the 150 sound as if maybe, stopped down to 64 or whatever, it might. Short of buying one to find out, does anyone know what is useful coverage for the 38? My 65mm Rodenstock vignettes if moved very much, so I have thought this might well be true of the 38 Schneider.

[sanking]

I'd suggest making some prints before deciding that you actually want to use this lens on that camera. Almost all lenses have an "image circle" and a "circle of good definition," with the former being larger than the latter. The difference varies from lens to lens and I understand that it tends to be smaller with modern lenses than with older lenses but it's still usually there to some degree.

My experience with the Schneider 210mm SSXL is that coverage at the far edges of the circle of coverage is infinitely better than with older designs, Dagors for example. I have not done any actual resolution testing but just based on apparent sharpness my guess would be that the SSXL design gives at least 10-15 lppm of resolution at the very edge of coverage. This is far more than needed for contact priting, in fact would even allow enlargement of 2X or so without any apparent degradation of the image.

As for light fall-off, a 150mm lens on 7X17 or a 210mm lens on 12X20 is definitely going to need a center filter. In fact, even a 210mm or 240mm lens on 7X17 needs a center fielder IMO. I used a 210mm Super Angulon on 7X17 for a couple of years and fall-off at the corners was very great.

Sandy

[Ole Tjugen]

I've used an ancient (pre-WWII) 210mm f:6.8 Angulon on 12x16" (30x40cm) with good results. And an even older E. Busch Weitwinkel-Aplanat Ser.C No2 (150mm, pre-WWI) on 9.5x12" (24x30cm) with surprisingly good results!