Two lenses for the Hasselblad XPan camera, tested March 1999.
45mm f/4.0 Hasselblad
Specifications: (Tested values in italics)
Focal length: 45mm (43.87mm)
Maximum aperture: f/4 (f/3.95)
Construction: 8 elements in 6 groups
View angle: Diag. 52º
Minimum aperture: f/22
Focussing: 90º counterclockwise from infinity to close focus, 2 ft. 3 9/16 in.
Weight: 7 13/16oz.
Filter size: 49mm
Mount available: Hasselblad
List price: N/A
Street price: $426
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Subjective Quality Factor
|
KEY:
|
|
45mm f/4.0 Hasselblad @ 45mm
| MAG > |
6 |
8 |
12 |
17 |
22 |
| Size (in.) > |
5 x 7 |
8 x 10 |
11 x 14 |
16 x 20 |
20 x 24 |
| @ f/4.0 |
99.2 |
98.5 |
96.7 |
93.7 |
89.7 |
| @ f/5.6 |
99.6 |
99.3 |
98.5 |
97.1 |
95.1 |
| @ f/8.0 |
99.6 |
99.3 |
98.4 |
96.7 |
94.6 |
| @ f/11.0 |
99.4 |
98.9 |
97.5 |
95.1 |
92.0 |
| @ f/16.0 |
98.9 |
98.1 |
95.8 |
91.8 |
86.9 |
| @ f/22.0 |
98.2 |
96.8 |
93.0 |
86.8 |
79.5 |
Hands on: Compact lens has substantial weight for its size due to hefty metal barrel and helical, and beefy lens-mount. Excellently finished in satin-black. Rubberized focusing ring provides fine grip, as does milled aperture ring. Focusing action is very well damped and silky smooth throughout its travel. Aperture ring turns smoothly, with light but positive detents at full- and half-stop positions. White metre and yellow foot markings are quite clear, although some users may need reading glasses to decipher these small numbers. Lens has infra-red focusing correction mark, and full depth-of-field scale - a plus for a range-finder camera. The lens front does not rotate during focusing. The reversible, bayonet-mount lenshood (supplied with the kit and also available separately) works on both the lenses for the XPan.
In the lab: SQF results were excellent, and the lens showed virtually no field curvature. Resolution target results were also stellar, except for the edges at f/22, which were a little off the mark. Minimal pincushion (0.47 percent) could be seen in the standard frame format, and in the panorama format, the 0.91 percent pincushion is rated as slight. Exposure at the film plane was extremely accurate (within 1/5 stop) at every f-stop except for f/22 which was ½ stop underexposed.
At the closest focusing distance of 2 feet 3½ inches (1:13), centre and corner sharpness were excellent at all apertures, with f/8 being optimal
In the field: Test slides were very sharp and contrasty, centre to corners, at all apertures and in both formats. Corner light falloff was gone by f/5.6 in the panorama format: there was virtually no falloff at any aperture in the standard format. Flare was very well controlled at all apertures for both formats.
Conclusion: Panorama format or no panorama format, no camera is better than its lenses. And the Hasselblad XPan is well served by this optic - the numbers tell the story.
90mm f/4 Hasselblad
Specifications: (Tested values in italics)
Focal length: 90mm (87.37mm)
Maximum aperture: f/4 (f/3.97)
Construction: 9 elements in 7 groups
View angle: Diag. 27º
Minimum aperture: f/22
Focussing: 90º counterclockwise from infinity to close focus, 3 ft. 3 3/8 in.
Weight: 11 7/8oz.
Filter size: 49mm
Mount available: Hasselblad
List price: N/A
Street price: $506
|
Subjective Quality Factor
|
KEY:
|
|
90mm f/4 Hasselblad @ 90mm
| MAG > |
6 |
8 |
12 |
17 |
22 |
| Size (in.) > |
5 x 7 |
8 x 10 |
11 x 14 |
16 x 20 |
20 x 24 |
| @ f/4.0 |
98.8 |
97.9 |
95.3 |
90.9 |
85.6 |
| @ f/5.6 |
99.5 |
99.0 |
97.8 |
95.8 |
93.1 |
| @ f/8.0 |
99.4 |
99.0 |
97.7 |
95.5 |
92.6 |
| @ f/11.0 |
99.2 |
98.6 |
96.8 |
93.7 |
89.9 |
| @ f/16.0 |
98.8 |
97.9 |
95.4 |
91.2 |
86.0 |
| @ f/22.0 |
98.0 |
96.4 |
92.2 |
85.4 |
77.5 |
Hands on: All the comments for the 45mm f/4 XPan lens apply to this finely fashioned lens as well. We would add that the longer length of this lens makes it very easy to cradle-grip with the XPan, with both focusing and aperture rings within easy fingertip reach.
In the lab:SQF data was excellent, as were resolution target numbers. This lens did display high field curvature, though. It showed minimal pincushion distortion (0.46 percent) in normal format, slight pincushion distortion (0.94 percent) in the panorama format. Exposure at the film plane was extremely accurate at every aperture - within 1/10 stop.
In the field: Test slides were crisp and contrasty, centre to corners, at every aperture, in both formats. The lens showed no light falloff at all in normal framing; in panorama format, falloff was gone by f/5.6. Flare was very well controlled at every aperture in both formats.
Conclusion: The "other lens" for the XPan is also a sharp, contrasty, nearly flare-free performer.
Tested March 1999
SQF testing
This is some of what Pop Photo had to say about SQF testing in November 1990 when they were finally happy with their system.
In short, SQF is the way to relate the total of all our MTF measurements to the quality you can expect at any given print size.
Under normal conditions, a slight difference in SQF will hardly be noticeable. Experimentally, it's been shown that a difference of 10 SQF units will show a definite difference in quality level, with a difference of only 5 units producing a just noticeable difference (JND). SQFs below 50 yield unacceptable results.
SQF: making the grade
With five distinct quality levels to work with, it seeemed only natural to assign letter grades to each: A for the best, then B, C, D, and finally F for anything below 50. We added "+" grades to A - C to characterize the quality, widening the group as quality diminished, giving a full 10 units to both C and C+ grades. In our system, we broke them down this way:
99.9 - 95.0 A+
94.9 - 90.0 A
89.9 - 85.0 B+
84.9 - 80.0 B
79.9 - 70.0 C+
69.9 - 60.0 C
59.9 - 49.5 D
<49.5 F
We expanded the C and C+ categories to fit actual experience. There was little point distinguishing between a D and D+. As overall quality goes down, it is increasingly difficult to distinguish between pictures. It's easier to tell which of two good prints is sharper than it is to determine which of two prints is fuzzier.
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