Monday, August 31, 2009

Test Pentax SMC f1.8/85mm vs. Ultra Achromatic Takumar f4.5/85mm

Here a quick test, Pentax SMC Takumar 1.8/85mm vs Ultra Achromatic Takumar 4.5/85mm to see how that might perform. That SMC lens is said to be the sharpest Pentax ever made for that focal length.

You'll find left the SMC, right the UAT 85mm. [click on image to see a larger one]

1) Cushion on my balcony, shot at f8.

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2) Plantane trees about 5 meters from my balcony, shot fully open (different DOF due to f1.8 vs f4.5)

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The UAT behaves not too bad considering, but already the SMC outshines it ....

At (nearly) infinity, it starts to look different though since the UAT was designed for close work - tile roof ca 25 meters away, my "standard test" object, shot also at f8

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that latter one I usually use to determine the amount of CA on teh black white transitions.

Well, here at about infinity, the UAT clearly looses in terms of sharpness and contrast against the SMC 85mm lens!

But bear in mind, the UAT was made to record from 220nm to ca 1100nm without CA (UV to NIR) i.e. without focus shift and for that it keeps up with its rival excellently (which only does visible light)!!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site