Back in the NEX-7 days, the Sigma 30mm EX DN was my most-used lens. Now that I use the A7, I couldn’t help but wonder: how would a 45mm like the Minolta MD Rokkor-X compare? The plastic Sigma lens on the smaller NEX-7 body feels almost weightless. With more metal content and a metal adapter, the old Minolta on the larger A7 feels more substantial but not overwhelmingly so. The pairings differ by half a pound (17 vs 25 ounces). NEX-7 w/ Sigma 30mm A7 w/ Minolta 45mm by Jeff Addicott, on Flickr The Minolta gives you the old-school manual lens experience while the Sigma has the sometimes-annoying focus-by-wire setup with a focus ring that sticks if you squeeze it too tightly. But of course you get autofocus. There are a few scenarios in which the Sigma will render more detail than the Minolta. In particular: wide open in the corners. By f/5.6 the Minolta catches up in the general region, but the extreme corner remains a just tad soft, even at f/11. Sigma 30mm f/2.8 EX DN on NEX-7 vs Minolta MD Rokkor-X 45mm 1:2 on A7 by Jeff Addicott, on Flickr Most of the time, the Minolta has little trouble rendering slightly cleaner detail at the pixel level. This is very consistent with my other comparisons, pitting the NEX-7 against the A7 – full frame has a slight but undeniable advantage. (In my experience, only an especially cheap lens - like my DeJur 35/2.8 - will fail to come out ahead most of the time on full-frame while only the very best optics come close to bridging the gap on APS-C at optimal settings.) Sigma 30mm f/2.8 EX DN on NEX-7 vs Minolta MD Rokkor-X 45mm 1:2 on A7 by Jeff Addicott, on Flickr Subject isolation is no contest. With f/2.8 on the smaller format, the Sigma 30mm always did seem a bit workmanlike in this department. The faster (f/2) Minolta on the larger format yields a 2 ½ stop advantage! Sigma 30mm f/2.8 EX DN on NEX-7 vs Minolta MD Rokkor-X 45mm 1:2 on A7 by Jeff Addicott, on Flickr But it’s not all gravy for the Minolta. Minimum focus distance is 2 feet versus 1 foot for the Sigma. (Closer than most old non-macro normal lenses.) Also: flare. The Sigma has modern coatings and generally fares pretty well with the sun in or near the frame. The old Minolta? Not so much. Sigma 30mm f/2.8 EX DN on NEX-7 vs Minolta MD Rokkor-X 45mm 1:2 on A7 by Jeff Addicott, on Flickr The Minolta 45mm seems to have a slight sickly yellowish tint - definitely not the best example of those legendary Minolta Colors. Calibrating both systems with the WB card evens things out, but with the Sigma 30mm I never felt a need to. Sigma 30mm f/2.8 EX DN on NEX-7 vs Minolta MD Rokkor-X 45mm 1:2 on A7 by Jeff Addicott, on Flickr So, at the end of the day, does the Minolta 45mm recapture my old Sigma 30 experience? Not really. The thing is, on the NEX-7, the Sigma 30mm is one of the best performers and the best values in a normal prime – I preferred it quite a bit over the 28-35mm legacy lenses I tried. The A7 is a completely different story. It works splendidly with just about any normal-range legacy prime, so good options could not be more numerous. The Minolta 45mm seems frankly outclassed by other “nifty fifties” I already use. For general use and landscapes, I much prefer my Leitz Summicron-R 50mm. (Something about the colors, the performance at all apertures and the overall character – you can really feel the absence of compromise.) For low light and/or extra isolation, there’s my Minolta MC 50/1.4 or the Canon FL 55/1.2. Minolta MD Rokkor-X 45mm 1:2 vs Leitz Summicron-R 1:2/50 by Jeff Addicott, on Flickr The Minolta 45mm does have a certain size/price allure but in my opinion there are better performers to be had for not much more cost or heft. (Hint: I’d rather head out the door with the Olympus OM Zuiko 50/1.8, which has the exact same adapted size.) I guess that extra 5mm of width didn't sway me.