Review: Minolta MD 50 mm f/2 (MD-III)

The MD 50 mm f/2 with 49 mm filter thread is the slowest non-macro standard prime produced by Minolta. The lens is less common than it’s slightly faster f/1.7 counterpart which served as a kit lens in the Minolta SR system for many decades. It’s also one of the most inexpensive SR lenses you can buy. But in this case, the price doesn’t tell you much about its qualities.

The lens is compact and pleasantly light, focus is very smooth and handling on a NEX-5T is excellent. Although it is constructed of many more plastic parts than preceding Minolta designs, tolerances are tight and the build quality is high. Due to great contrast wide open, focus peaking works perfectly at any aperture as long as light is sufficient. The latter cannot be said for many of the faster standard primes. The effective focal length of 76 mm on APS-C cameras renders the MD f/2 a nice “fire and forget” short tele prime for every day use.

For further details on the lens like weight and dimensions, have a look at its entry in the Minolta SR mount lens database.


Condition of my copy

Optics: Good. No scratches, minimal dust and a slight haze behind the first or second element from the front.

Mechanics: Excellent. Uniform and very smooth focus, aperture clean and fast.

Exterior: Excellent. Some marks on the mount, otherwise like new.


Optical performance on NEX-5N / 5T

Notice: There was a slight asymmetry in the test shots with the left side being slightly softer and showing astigmatism (horizontal lines are rendered sharper than vertical ones) and haze not present in the right half of the images. It is therefore likely that other copies of this lens show a better corner performance than the test shots suggest.

The lens shows good sharpness already open at f/2 with slight softness, minimal haze and some astigmatism in the corners (see notice above). Central sharpness increases to very good levels at f/2.8, but the corners stay softer. Stopping down to f/4 further increases sharpness to excellent levels in the center and good to very good in the corners. The latter improve once more when going to f/5.6, where the center stays unchanged (excellent). At f/8, the overall sharpness is reduced a tiny bit, either due to diffraction or from slight misfocusing. Diffraction becomes more evident at f/11, increases softness at f/16 and blurs the image at f/22.

There is hardly any evidence of lateral chromatic aberrations even at 200% magnification. An outstanding performance for an achromatic lens.

Vignetting is about 3/4 of a stop at f/2, very low at f/2.8 and disappears by f/4. The lens also exhibits a practically irrelevant pincushion distortion of less than 0.2%. The effective T-stop at f/2 is approximately T2.3 (-0.4 EV), which is not impressive.

Compared to the similarly priced MD 50 mm f/1.7, the 50 mm f/2 is a surprisingly potent opponent. It is visibly sharper in the center up to f/4, shows even less CAs and only slightly stronger vignetting. Corner performance is roughly equal in both lenses, as far as I can tell from the copies I have tested. The faster MD 50 mm f/1.4 is obviously ahead of the f/2 in terms of speed, but not in many other aspects: It shows minimally lower central sharpness up to f/5.6, small but visible CAs and more haze in the outer image region at large apertures. The f/1.4 demonstrates better corner performance, though, which might be due to weaker field curvature. Overall, the MD-III 50 mm f/2 is a refreshingly unproblematic, compact, light and sharp lens which can be had for the price of two Big Macs. You really can’t go wrong with this one!


Test charts

The following images are pixel-level crops from the test chart. They may appear scaled in your browser window. Click on them to view the crops in full size and cycle through them easily. For more info on the test setup, visit the details page.



Test chart overview

(Cropped areas marked in orange)



MD 50 mm f/2 @ f/2.0



MD 50 mm f/2 @ f/2.8



MD 50 mm f/2 @ f/4.0



MD 50 mm f/2 @ f/5.6



MD 50 mm f/2 @ f/8.0



MD 50 mm f/2 @ f/11



MD 50 mm f/2 @ f/16



MD 50 mm f/2 @ f/22


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