OM-Zuiko 300mm Auto-T f/4.5 Test (andrea tasselli)

Celestial hemisphere: Northern · Constellation: Ursa Minor (UMi) · Contains: The star Polaris (αUMi)

OM-Zuiko 300mm Auto-T f/4.5 Test, andrea tasselli

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OM-Zuiko 300mm Auto-T f/4.5 Test

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OM-Zuiko 300mm Auto-T f/4.5 Test

This is another workhorse of the heydays of film, with unpeccable credentials in terms of sharpness wide open, back in the day. A very light lens (weighing in at 1260 grams with lens collar attached) for its focal length which allows operations hand-held. The test with the 40D reveals a more nuanced picture (pun intended). First off, there is constant (in magnitude) 5th order coma across the whole field which is rather unusual. Here I suspect a slightly tilted component somewhere. Secondly, LCA is felt across the whole field, which was expected from this type of lens (no ED glass, modified Cooke triplet lens design), so that green reaches focus differently from red and blue. The amount is moderate in the RGB range with some significant purple halo but still well contained. Overall the lens will deliver still reasonably sharp results across the whole field (there is no sweet spot here) with average FWHM between 3 and 4 pixels albeit with, let's say, unconventional PSF.

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Astrometry.net job	5570103
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OM-Zuiko 300mm Auto-T f/4.5 Test

OM-Zuiko 300mm Auto-T f/4.5 Test

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OM-Zuiko 300mm Auto-T f/4.5 Test

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