Coverage of Super-Angulon XL: varies non-linearly with focal length?

[john wilton]

In looking for an ultra wide, I'm puzzled by the variation in angle of view. One would expect it to be the same for all focal lengths, or (typically) decrease a little with increasing focal length. But it's all over the map: 47 and 58 XLs are listed by Schneider as having identical image circles!

F/coverage at f/22 in degrees

47/120
58/110
72/115
90/110

What is happening here?

A few questions for users of these lenses:

Is Schneider's spec based on resolution within image circle that meets their spec, with a somewhat greater circle of illumination?

Does coverage noticeably increase at f/32?

I've posted a WTB 47 or 72 in the for sale forum.

[Bob Salomon]

Are you asking about angle of view or angle of coverage? One is determined by the lens formula and the latter by the film format.

At f32 you are in diffraction. That will reduce the final quality.

[Ed Bray]

72mm is not really an ultrawide on 4x5 but it is on 5x7.

My experience although limited the image circle only increases a small amount when stopped down from f22 to f32

Why would you pay 72mm XL money when for 4x5 you can get a cheaper 65mm SA MC or 75mm SA MC?

[Oren Grad]

One would expect it to be the same for all focal lengths, or (typically) decrease a little with increasing focal length.

It's true that that's a typical pattern, but it doesn't have to be that way. Particularly in a series like the SA-XL, where Schneider is pushing the envelope on coverage, it's not hard to imagine that they made different tradeoffs at each focal length to arrive at a coverage/size/weight/cost balance that they thought would be most readily marketable.

Looking at the specs for the SA-XL series, the only one that's really anomalous is the 58. A plausible explanation is that they decided that a design at that focal length that was sufficiently extreme to cover 5x7 wouldn't be saleable at the price they'd have to ask, so instead they decided to minimize size/weight/cost for a lens that would be adequate for 4x5.

Anyway, why don't you ask Schneider? Over the years, they've been very responsive to questions like this that I've asked.

[Leigh]

In an older Schneider lens catalog, those four XL lenses are shown as having two different designs, both with four groups
but with either eight or six elements. Unfortunately it does not say which design applies to which lens(es).



The 47mm and 58mm FLs are shown as covering 4x5, while the two longer ones cover 5x7. The longer ones are MUCH larger
lenses, with 100mm front diameters and 95mm filters, compared with 70mm/67mm for the two shorter ones.

A later Schneider brochure adds a 38mm to the SA-XL series, but it does not cover 4x5. The SA-XL lenses are all f/5.6.
In this brochure, all SA-XL lenses are shown as having 8 elements in 4 groups, so perhaps there was a re-design.

- Leigh

[Nathan Potter]

John, I'v posted some of my recent experiences with the 47 SA XL in your WTB thread.

Nate Potter, Austin TX. / Corea ME.

[Ed Richards]

> Why would you pay 72mm XL money when for 4x5 you can get a cheaper 65mm SA MC or 75mm SA MC?

Movements. Absolutely terrific interior architecture lens.

[john wilton]

Thanks all for the comments, insights and experiences. Leigh/Oren, a different (simpler) design does seem to explain the 58mm anomaly. Nathan, it does seem the 72 is a better choice for me. Ed B., I have 65 and 75 SAs, I want to be able to 'see' further up into a cathedral's vaulting without tilting the camera up. I suppose since I scan my negs and print quad tone, I should get over myself and just tilt the camera and fix distortion afterwards. Still, more coverage would be more elegant.

In the attached photo (St John the Divine in New York, single-coated 75mm SA with a lot of rise), "angle" runs out before really getting into the nave vaulting. (I don't mind the vignetting.)

[Leigh]

...a different (simpler) design does seem to explain the 58mm anomaly.

What anomaly?

If the lens meets the manufacturer's specifications there is no anomaly.

On what did you base the __assumption__ that the 58mm was a "simpler" design?

- Leigh

[Ed Richards]

An image with the 72. Plenty of coverage, just a dark church.