Sigma 875205

A cheap way to double your reach on old Minolta glass, but the image quality hit is brutal. Only worth it if you find one for pocket change and know exactly what you're getting into.

What surprised us most is how much this little tube can drag down an otherwise sharp lens. Our database puts its optical quality in the bottom 20th percentile, which means you'll see a noticeable drop in sharpness and contrast. The autofocus works, but it's middling at best, and on anything but a fast prime, it'll hunt in anything less than bright sunlight. You're also losing two full stops of light, turning an f/2.8 lens into a dim f/5.6.

Stacking this up against modern glass like the Tamron Di III VC 28-300mm or the Sony E 18-135mm is almost unfair. Those are modern, optically stabilized, all-in-one zooms that run circles around this converter in terms of versatility and image quality. The Viltrox Pro AF 27mm f/1.2 is a different beast entirely, a fast prime that prioritizes sharpness and bokeh over reach. This Sigma converter is for a very specific person: someone with a cabinet full of old Minolta A-mount glass who wants to play with a doubler for less than the cost of a nice dinner.

Pricing is all over the map, from a reasonable $184 to an absurd $35,686 from some joker on Amazon. At the low end, it's a fun experiment for a Minolta shooter on a budget. Paying anything over $200 for this is a mistake. If you see a clean copy for under $200, it's a cheap thrill. Otherwise, just crop your photos.

The Sigma 2.0x APO Tele Converter is a niche piece of kit that doubles your reach for a song, but it comes with some serious strings attached. It's a dedicated doubler for old Minolta SLR glass, and finding one in good shape today is the real challenge. The one thing to know is this: you're trading image quality and light for focal length, and the hit to optical performance is significant.

If you're looking for a sharp, modern telephoto solution, this isn't it. Go get a used superzoom lens or a native teleconverter for your current mirrorless system instead. This is a vintage curiosity, not a serious tool for image quality.

The Sigma 2.0x APO Tele Converter is a relic from a different era. It does exactly what it says on the tin, but the optical penalty is steep. If you're a Minolta die-hard and find one for under $200, it's a fun way to get more reach from a fast telephoto prime. For everyone else, this is an easy pass. Modern superzoom lenses or even digital cropping on a high-megapixel body will give you better results without the hassle.