The evolutionof lenses

Comparison of Hasselblad HC lenses and Carl Zeiss V System lenses

Hasselblad CFi100 vs. HC100When the iconic lens, the CFi100, well-known for its high per formance is compared to the HC 100mm lens, we see a good example that the design goal to have better performance at close range and equal per-formance at infinity is reached. In the close range, the HC 100mm clearly outperforms the CFi 100mm and at infinity it is difficult or even impossible to see any difference.For more info, please see the Victor 2/2008 article “The evolution of lenses”.

Tangential contrast drops and only sagittal contrast profits from stopping down

Diverging values for sagittal and tangential contrast can create distortions in the corners

At the very center of the image, the CF lens still performs great – even at short distances

CF 3.5/100 f8 1.2 m

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The HC lens shows good con- trast over most of the image circle, slightly improved by DAC

The sagittal and tangential con-trast curves stay close together; only at 40 lp/mm do they diverge

At the center, contrast would drop due to focus shift, but Ultra-Focus compensates for this effect

HC 2.2/100 f8 1.2 m

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At 1.2 m from the subject and fully open, the CF lens only shows good contrast near the center

The curves for sagittal and tan-gential contrast begin to diverge about 5 mm from the center

Within a small central area the CF lens shows excellent contrast even at 1.2 m from the subject

CF 3.5/100 f3.5 1.2 m

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Even at f3.5, the sagittal con- trast of the HC lens shows next to no drop off towards the edges

At the corners, tangential con-trast drops

In the center part of the image, the HC lens performs as well as its CF counterpart

HC 2.2/100 f3.5 1.2 m

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Hasselblad F110 vs. HC100 The following pages show a comparison between the F 110 and the HC 100. As for the comparison between the CFi 100 and the HC 100, we can see in this comparision that both lenses perform identical at infinity and that the HC 100 is clearly better at the close range. Especially near the image edge.

MTF for HC 100 at f/2,2 and infinity

MTF for F 110 at f/2 and infinity

f/2 infinity

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F 110 at f/2

HC 100 at f/2.2F 110 at f/2

HC 100 at f/2.2

As illustrated, the MTF diagrams for the two lenses are almost identical. The enlarged sections from both imag-es confirm this similarity by producing almost identical results.

Bothlensesperformidenticalinthecentreoftheimage

F 110 at f/2 The F110mm lens shows weak performance at the image edge as indicated by the MTF diagram where the curves drop quite low.

f/2,2 1:10

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MTF for HC 100 at f/2,2 and image

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f/2,4 1:10

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MTF for F 110 at f/2,4 and image

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Hasselblad F110 vs. HC100 (continued)

HC 100 at f/2.2F 110 at f/2

HC 100 at f/2.2 At the image edge, the perfor-mance of the HC 100mm lens is stilll very good.

AF system corrects for focus shift

With over- or under-corrected spherical aberration (the latter is illustrated here), rays en-tering the lens at different distances from the center don’t converge at the same point. Optimum focus shifts as the lens is stopped down. This can in some cases be a problem with manually focused lenses. In a camera, the focusing screen will only see light from an aperture of about f/3.5 to f/4. So if you are focusing using the screen but will shoot your image at wide open (e.g f/2), the focus plane will not be exactly where you intended. The AF system of the H System cameras is designed to correct for this focus shift.

Pitching the HC 4/210 against the CF 5.6/250 SA yields surprising results, given the price difference.The MTF diagrams to the right show the performance of the two lenses at f/5,6. At infinity, the MTF diagram shows that the CF 250 SA has slightly higher sharp-ness close to the image edge. At close range we see the opposite where the HC 210 performs clearly better.

The curves for the resolution of sagittal and tangential line patterns quickly diverge

Even fully open, the CF lens shows exceptionally high contrast across the whole image

CF 5.6/250 SA f5.6 infinity

Sagittal contrast is comparable; tangential contrast drops slightly beyond 20 mm

HC 4/210 f5.6 infinity

CF 5.6/250 SA f5.6 near

Contrast remains high for all spatial frequencies; only tangential contrast for 40 lp/mm suffers

HC 4/210 f5.6 near

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CF250S A f/5.6 infinity

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HC210 f/5.6 infinity

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CF250SA f/5.6 1:10

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HC210 f/5.6 1:10

Technical details

CF lenses (green) are optimized for infinity, HC/HCD lenses (blue) for more typical distances, resulting in a better correction overall and still good results at infinity

Lens optimization goals

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Hasselblad CF 250 Superachromat vs. HC210

Reading MTF charts

MTF curves represents the resolution of the lens and are plotted as a function of distance from image center to im-age corner. A high value represents high resolution and sharpness. Tangential patterns are represented by a solid line, the curves for sagittal patterns by a dashed line. For minimizing aberrations, both lines should be high and close to each other.

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11.09 - UK v1 - 80500550

H3DII lens range Over the decades, Hasselblad has worked with all the most skilled partners for designing and manufacturing lenses: Zeiss, Fujinon, Kodak, Rodenstock and Schneider. This has given Hasselblad a unique position and the knowledge on how to specify a great performing lens.

The new Hasselblad HC lenses are all designed with the most modern design and production technology. Most of the Carl Zeiss lenses are designed 20-40 years ago. Considering their great performance it was a great achievement, given the design and production tools available at that time.

Today with modern computer technology, it is clearly possible to design even better lenses. The wide range of Hasselblad HC/HCD lenses is a proof of that.

HC/HCD lens design goals• BebetterorequaltothecorrespondingZeisslens• Haveabetterperformanceinthenearfield• Bedesignedforfastautofocusdrivebutmustalso

have an instant manual focus override function• Lowstraylightlevel

www.hasselblad.com

HCD 4/28mm HC 3.5/35mm HC 3.5/50mm HC 2.8/80mm

HC 2.2/100mm HC Macro 4/120mm HC 3.2/150mm HC 4/210mm

HC 4.5/300mm HC 3.5-4.5/50-110mm HCD 4-5.6/35-90mm Aspherical

All C-type lenses from the V system with optional

CF lens adapter