Schneider 47mmXL coverage test

[micah_marty1]

I'm not usually a "testy" kind of guy, but. . . .

 

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I've heard many comments over the past few years about the limited

coverage of the renowned Schneider 47mmXL lens: that it "just barely"

covers 4x5, or even that it's functional primarily for 6x12 and

smaller rollfilm formats and of little utility on 4x5. On the other

hand, my experience with this lens had indicated that appreciable

movements were possible even with 4x5 (though I usually use a 6x12

back on the camera), and I'd heard that Schneider tends to be

conservative when listing image circles.

 

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So last week I made a series of photographs with different degrees of

movement to discern at what point vignetting begins with the 47mmXL

lens and 4x5 film. My Cambo Wide camera has millimeter marks so that

as you move the geared rise or shift (you get your choice by rotating

the lens panel 90 degrees--and by rotating the camera) you can see

exactly how much movement youB re using. I don't usually go to all of

this trouble to test a lens, but this is a unique lens.

 

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The test:

 

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1. The lens is serial #14583557, manufactured (according to

Schneider's website) in late 1995. The lens is in a helical mount,

with distance- and depth-of-field markings; I don't know whether

Schneider or Cambo does the helical mounting. Other than the helical

mount and markings, I believe it is optically identical to the

unmounted versions of the 47mmXL.

 

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2. The lens was racked all the way to infinity to provide a "worst

case" measurement. (Obviously the image circle would be larger if I'd

used hyperfocal options: for instance, according to Schneider's d.o.f.

tables, everything from 2.4 feet to infinity is in focus when a 47mm

lens set at f16 is focused at 5 feet. The image circle for any lens at

the film plane would, of course, be larger at a 5-foot focus distance

than it is at the infinity focus distance used in this test.)

 

3. I set the lens at f16, probably my most commonly-used aperture with

this lens and the aperture Schneider uses in its image-circle

measurements for this lens. The image circle at the film plane would

be slightly smaller with f11, slightly larger at f22 (the lens closes

down to a minimum aperture of f32, effectively a pinhole).

 

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4. I used Kodak Readyload E100S 4x5 film in Kodak's (now-discontinued)

Readyload holder, with a diagonal of what looks to me like 153.5mm. My

Fuji Quickload 4x5 transparencies measure out almost exactly the same,

but I didn't have any unexposed Fuji film in the fridge so I didn't

use it for this test. I've never used 4x5 film holders or Polaroid, so

I don't know what the diagonal is there, but since the 4x5 lens chart

on this website lists 153.7mm as the diagonal for 4x5, I assume these

kinds of holders are around this figure also.

 

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5. I used Schneider's center filter on the lens during the test. The

rear threads of this filter are 67mm and the front are 86mm. I do not

believe this filter causes any vignetting, but I wanted it on during

the test even if it did cause vignetting because I wouldn't think of

using a full rise without it. In other words, a vignetting test of

this lens without a center filter wouldn't be a "real-world" test to

me.

 

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6. I ran the test "in both directions," i.e., rising to one side of

the lens and then inverting the camera 180 degrees and rising in the

other direction, just to be sure the lens wasn't mounted off-center on

the lens panel (it wasn't, as both sides tested identically).

 

7. I photographed a blank sky (with skyline at the bottom),

overexposing by 2 or 3 stops so I could clearly see any vignetting in

the upper corners.

 

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8. The first day I tried rises of 10, 15, and 20 mm, first in

landscape (horizontal) mode, then in portrait (vertical) mode (in both

directions; see #6 above). After seeing the results of the processed

film and estimating at what point vignetting began, the second day I

narrowed down the movements, trying 16, 17, 18, and 19mm of rise in

landscape mode, then 11, 12, 13, and 14mm of rise in portrait mode.

 

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The results:

 

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With 4x5 film (153.5 diagonal), at infinity focus and at f16, the

47mmXL lens apparently allows ~17.5mm of rise in the landscape mode

and ~12.5mm of rise in the portrait mode.

 

While this may not sound like much to those accustomed to longer focal

length lenses, in light of this lens' focal length and flange focal

distance it is quite impressive to me (the rear element is only about

an inch in front of the film plane when the lens is focused at

infinity). With such a wide-angle lens, even large objects in the

image (e.g., buildings on the Chicago skyline in my test) are often

only a few millimeters tall on the film, so 17.5 millimeters is

significant in my book.

 

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Note that I used the center filter in this test, as I have found that

this filter is advisable anytime ANY movements are used (and often

when they are not, except when handholding the camera for

street-shooting. In those cases the need for 2 extra stops of speed

often outweighs light falloff considerations). At full rise without

the center filter, it is impossible to judge vignetting even when the

center of the image is overexposed 3 or 4 stops, so great is the light

falloff at the edge of the image circle. Again, considering the

120-degree coverage of this lens, this light falloff is not

surprising.

 

I don't have a way of posting my test photos at the moment, but anyone

with questions, comments, criticisms of my test methods, or

corroborating/conflicting test results can e-mail me directly or post

their remarks here. . . .

 

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[alpshiker]

Micah, Thanks for your feedback on your tests. Very interesting. I'm glad I spent the extra money for the 47XL

instead of the Grandagon 45 I was proposed. This lens is amazing. I have used it to shoot indoors both in 6x12

and 4x5 and had plenty of rise and fall. As you mention, as little as it can look, 17 mm have huge effects with

such a short lens. David Muench in "Plateau Light" has several shots from that lens, mostly rock walls and

canyons from within. However, it is not easy to shoot without having to notice distorted objects, especially if

they are close to the camera. Squares become rectangles and circles ovals. Even if in nature, such geometric

shapes do not appear as easily, I consider the lens a speciality lens and have found few applications to it

beyond the 6x12 format so far. But I do not live in the canyons and giant cities country and in fact, this was

the kind of shots I had in mind when I purchased it!

[trevor_crone]

Micah I had similar results to you but not as accurately achieved. With a Heliopan UV filter in place I managed about 15mm horizontal rise and 10mm vertical before vignetting set-in (this is only approx. has I've not measured rise accurately).

 

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The light fall-off with this lens dosn't bother me. Has I only print b/w, areas can be "held-back" if troublesome. I photographed a scene recently which could only have been made with this lens on 4x5. Having got back as far as I could I used the fall 15/17mm front rise to include the top of a chimney of a derelict brickworks (closed from the early 1900's) on the Isle of Anglesey, North Wales. It's in situations like this when you do appreciate this lens. Prints from this neg. had slight vignetting top L/R corners which were masked off and a "burn-in" of the central sky area to balance things ups was all that was required for a pleasing image.

[pete_caluori]

Greetings,

 

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Micah, thanks for posting the results of your test!

 

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Regards,