The Kiron 28 mm f/2.0 is a very fast wide angle lens produced for different mounts by Kino Precision under their own brand Kiron. A lens with identical specs was also manufactured by Kino Precision for Vivitar.
The lens feels balanced on the NEX-5T and handles very nice. Focus is a little stiff, but smooth and uniform. The Kiron’s effective focal length of 43 mm on APS-C is often praised to be even closer to the viewing characteristics of the human eye than typical 50 mm “normal” lenses. The fast f/2.0 maximum aperture should be seen as an emergency stop for regular shots, though, as there’s heavy blooming going on in contrasty situations. But this may also be an advantage, if you’re specifically looking for that soft and glowy performance many appreciate in vintage lenses.
For the Kiron 28 mm f/2.0 I’ve created lens correction profiles, which are available for download.
Condition of my copy
Optics: Excellent. No scratches and practically no dust.
Mechanics: Very good. Smooth but slightly stiff focus, aperture clean and fast. Oddly, the aperture ring ball bearing is missing about 8 of maybe 50 balls which poses no problem but makes the lens rattle when turned.
Exterior: Excellent. Only slight signs of use on the mount.
Optical performance on NEX-5N / 5T
f/2 is hazy and slightly soft with medium contrast. At f/2.8, the haze is nearly gone and contrast improves visibly while sharpness is still only acceptable. Corner performance makes a big leap forward at f/4 and the lens starts to sharpen up, reaching close to good levels in the center. The latter further improves to a solid “good” rating at f/5.6 and f/8. From f/11 on, diffraction softens the image again. It becomes really evident at f/16.
Chromatic aberrations are visible at f/2 but not too obtrusive due to the haze. Heavy red and cyan CAs become clear at f/2.8 and grow further as the lens is stopped down. All in all, one of the worse CA performances I have seen. Luckily, the CAs present in a form that is easy to correct in post processing.
Vignetting is about 1/2 stop at f/2 and is gone by f/2.8. The effective T-stop at f/2.0 is approximately T2.3 (-0.4 EV), which is okay. The lens also shows a medium barrel distortion of -1.2%.
In conclusion, this 28 mm f/2 performs very similar to the Kiron made Vivitar 24 mm f/2, especially CA-wise. Luckily, sharpness is slightly higher and distortion a little lower in the 28 mm. Minolta’s excellent MD 28mm f/2.8 is ahead of the Kiron 28 mm in terms of sharpness, corner performance and especially CAs at every aperture. It’s also much less prone to flare – another weakness of the Kiron lens. In exchange, the latter is one full f-stop faster. Don’t get me wrong – the 28 mm f/2 will still deliver good results. But it’s best suited for shots in dim lighting conditions, where the CAs are less likely to become evident and critical sharpness is not your key concern. Further, it doesn’t hurt to pair it with a generous lens hood.
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