Photo of 30mm fisheye courtesy of D. St. Denny - Thanks!!!

Lens Resolution Tests
by Fernando Carello


Related Links:
Lens Resolution
Lens Testing in The Backyard by Jim Bullock
Lens Testing Tips

I thought it was fun and interesting to pit 35mm, 6x4.5 and 6x6 lenses one against another...

Test was done with following cameras:


The lenses I tested for 35mm were:

(Of course an M42->Y/C mount adapter was used when needed)


For 6x4.5 I tested:


Finally, 6x6 lenses were:

Film was a Fuji Provia 100F, instead of some ultra-high res BW film, because I also wanted to notice if there were color casts or chroma aberrations. Cameras were screwed on a serious tripod (Manfrotto 144 + 055 head); center column was not extended, and I used self-timer on PentaconSix and Yashica (not available on the Pentax, where I used a cable release) to shoot the shutter, both to eliminate finger-induced vibrations and because, with self-timer engaged, the Pentacon Six and the Yashica lock up the mirror before shooting: another anti-vibrations measure. Focal plane was parallel to test surface (portion of a terrace wall). Focus was as accurate as I could get; but depth of field was more than adequate to compensate for minimal focus issues

I used a self-made test target laser-printed at 600 dpi on high-quality coated paper. Target was vaguely inspired from USAF MTF targets, was composed by horizontal and vertical lines arranged in "L" shapes.

The whole test took three weekends; as a result, I improved the test chart during the period, and this ended up having different charts for different lenses. Sorry for that, but anyway, only the maximum resolution test was affected by this change (i.e., for the Sonnar 180 I used a chart that topped at 60 lp/mm).

I inspected the slides on the lightbox, with a custom-made (with telescope eyepieces) 30x loupe, and with a 40x microscope. I double-checked every slide with each instrument.

Missing values are due to skipped tests (time constraint), except for missing "F/11 Border" value for the Arsat 30, that was due to a tree shadow temporary dropped on border targets, so that it was too much difficult to read them on the slide.

Tests of 6x4.5 and 6x6 lenses were not useable at apertures wider than F/5.6 because both cameras have 1/1000s as their fastest speed: under sunlight, slides resulted too clear for targets to be reliably recognizeable (I didn't have ND filters at hand).

How did I evaluate "Extinction frequency"?

It's the maximum spatial frequency at which test target pattern was still (if barely) distinguishable, both for the vertical pattern and for the horizontal pattern. That means, on the next target it was impossible to recognize the line pairs.

By the way, I noticed that for the smallest targets (70 lp/mm and finer), film grain was a serious limiting factor.

 
F/4
F/5.6
F/8
F/11
F/16
F/22
Notes
  35mm lenses
Center
Edge
Center
Edge
Center
Edge
Center
Edge
Center
Edge
Center
Edge
Zeiss Jena 20/2.8 MC
60-65
54
75
75
60
60
75
75
75
60
60
45
 Chart max was 75 lp/mm
Very good overall contrast
Contrast drop and chroma at edges
Vivitar 28/2.8
60
54-60
54-60
54-60
60
60
60
65-70
60
60
60
50
 Chart max was 75 lp/mm
Heavy barrel distortion
Yashica ML 50/1.9
50
40
n/a
n/a
54
54
n/a
n/a
n/a
n/a
n/a
n/a
 Chart max was 54 lp/mm
Yashica ML 50/2
54
60
60
75
70
75
75
75
75
60
n/a
n/a
 Chart max was 75 lp/mm
Very good contrast
Industar 50/2.8 Macro
50
40
n/a
n/a
40
50
n/a
n/a
n/a
n/a
n/a
n/a
 Chart max was 54 lp/mm
Jupiter-9 85/2
> 60
50
n/a
n/a
50
40
n/a
n/a
n/a
n/a
n/a
n/a
 Chart max was 60 lp/mm
Chroma at edges
Tamron 200/3.5
40
30
n/a
n/a
40
40
n/a
n/a
n/a
n/a
n/a
n/a
 Chart max was 60 lp/mm
Contrast not so good. May be defective
S-M-C Takumar 200/4 screw
40
30
n/a
n/a
50
40
n/a
n/a
n/a
n/a
n/a
n/a
 Chart max was 60 lp/mm
S-M-C Takumar 300/4 screw
50
40
n/a
n/a
60
30-35
n/a
n/a
n/a
n/a
n/a
n/a
 Chart max was 60 lp/mm
Very good contrast
Chroma at borders
May suffer from slight adapter misalignment
  6x4.5 lenses  
Pentax SMC-A 35/3.5
76
63
> 76
63-65
> 76
63-65
> 76
63-65
> 76
63-65
63-65
55
 Chart max was 76 lp/mm
Very good contrast
Limited by film grain and test chart
Pentax SMC-A 150/3.5
63
63
76
63
55
63
63
63
63
63
55
55
 Chart max was 76 lp/mm
  6x6 lenses  
Arsat 30/3.5 MC
n/a
n/a
> 70
35
> 70
35
> 70
n/a
> 70
40
> 70
35
 Chart max was 70 lp/mm
Very good contrast
Fisheye distortion made difficult reading values reliably, but should be in the ballpark
Mir-26b 45/3.5
n/a
n/a
52
30-32
70
40
57-65
40
70
35
52-57
35
 Chart max was 70 lp/mm
Contrast not so good
Chroma at edges
Zeiss Jena Flektogon 50/4 MC
n/a
n/a
70
50
70
50
> 70
50-57
> 70
57
60-65
57
 Chart max was 70 lp/mm
Very good contrast
Zeiss Jena Biometar 80/2.8 SC
n/a
n/a
30
30
n/a
n/a
45-50
30
n/a
n/a
n/a
n/a
 Chart max was 60 lp/mm
Volna-3 80/2.8 MC
n/a
n/a
60
35-40
n/a
n/a
50-60
45-50
n/a
n/a
n/a
n/a
 Chart max was 60 lp/mm
Vega-28b 120/2.8 MC
n/a
n/a
> 70
35
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
 Chart max was 70 lp/mm
Zeiss Jena Sonnar 180/2.8 MC
n/a
n/a
> 60
60
60
50
45
50
35
45
n/a
n/a
 Chart max was 60 lp/mm


I leave conclusions to readers; as for me, I was impressed by the performances of the Flektogon 20/2.8 for 35mm, the Arsat 30/3.5 and Flektogon 50/4 for 6x6, and the Pentax 35/3.5 for 6x4.5.

I didn't expected such good performances from retrofocus wideangles, let alone a 6x6 fisheye!

I found the Pentax 35/3.5 to be much better than I was expecting after reading Photodo's MTF charts. This glass is outstanding! Shows excellent color reproduction, too.

I was somehow disappointed by telephoto performances; but given that the target chart was relatively near the camera, longest telephotos were forced near their minimum focus distance, so this may have impaired their performances a bit. Still, I was expecting more from the mighty Sonnar 180/2.8 MC!

[Ed. note: many thanks to Fernando Carello for sharing these test approaches and results with us!!!]

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