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How Sharp Is Sharp? |
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As a camera lens
specialist, we are often asked for advise on choosing a new or used
picture taking lens; often heard is - How Sharp Is It? |
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Bert Otten, a customer of ours and a specialist in optics has been testing various camera lenses over the years and has gone some way in answering the sharpness question. He has kindly allowed us to publish his findings: | |
Resolution of some Medium and Large Format Lenses |
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The data below
is based on measurements of resolution directly in the aerial image
behind the lens, viewed through a microscope, of a test chart. Each time
the magnification was chosen high enough so that the human eye would not
be the limiting factor. It should be stressed that resolution itself is
not sufficient information to decide on the quality of a photographic
lens. Often manufacturers optimize the optics for high contrast at the
cost of maximum resolution. That is why Modulation Transfer Functions (MTF
curves) are used more often. Yet, the results of our resolution
measurements are interesting enough to present them here, especially
combined with the subjective contrast impression, rated along a scale from
1..10; |
Lens Tested | Test Aperture | Resolution in lines / mm | Observed Contrast (1 to 10) |
---|---|---|---|
Schneider SA 47mm / 5.6 MC | f 5.6 | 320 | 8 |
Rodenstock Grandagon 65mm / 4.5 MC | f 4.5 | 400 | 7 |
Rodenstock Sironar N 150mm / 5.6 MC | f 5.6 | 300 | 8 |
Rodenstock Sironar N 150mm / 5.6 + Horseman 2x Converter | f 11 | 120 | 7 |
Hasselblad CFL 40mm / 4 T* | f 4 | 300 | 8 |
Horseman Super 65mm / 7 | f 7 | 190 | 6 |
Hasselblad CB 80mm / 2.8 T* | f 2.8 | 285 | 5 |
Hasselblad CB 80mm / 2.8 T* | f 4 | 430 | 8 |
Hasselblad CF 80mm / 2.8 T* | f 2.8 | 500 | 5 |
Hasselblad CF 80mm / 2.8 T* | f 5.6 | 320 | 7 |
Horseman Prof. 105mm / 3.5 | f 3.5 | 350 | 5 |
Hasselblad CF 150mm / 4 T* | f 4 | 170 | 8 |
Horseman Prof. 180mm / 5.6 | f 5.6 | 165 | 5 |
Fujinon T 300mm / 8 MC | f 8 | 210 | 8 |
Hasselblad C 350mm / 5.6 T* | f 5.6 | 160 | 5 |
Contax G 45mm / 2 | f 2 | 530 | 6 |
Contax G 45mm / 2 | f 4 | 450 | 8 |
Contax G 45mm / 2 | f 16 | 100 | 8 |
Canon EF 50mm / 1.4 | f 1.4 | 360 | 5 |
Sigma 105mm / 2.8 Macro | f 2.8 | 380 | 7 |
Notes:
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