BM Premium SLY500 500mm

The BM Premium SLY500 is a dirt-cheap 500mm manual lens that can take surprisingly sharp photos if you're patient and use a tripod. But the fixed f/8 aperture, lack of autofocus, and flimsy build make it a frustrating experience for most people. Only grab this if your budget is rock-bottom and you know exactly what you're getting into.

When you nail focus, the sharpness is genuinely surprising for a lens in this price bracket. The multi-coated glass and single ED element do a decent job keeping contrast up and flare down, and the built-in stabilization helps a bit, sitting in the 83rd percentile for its class. But that's where the good news mostly ends. The fixed f/8 aperture is dim, making your viewfinder dark and forcing you to crank ISO or drop shutter speed in anything but bright sunlight. Optical quality overall lands in the 4th percentile, which tells you this isn't competing with even a budget modern zoom. The manual focus ring is your only option, and with a minimum focus distance of 33 feet, you're not getting close to anything small. The included 2x teleconverter doubles your reach to 1000mm but also magnifies every bit of shake and softness.

Stacked against the competition, the SLY500 is in a weird spot. It's not competing with the Tamron 28-75mm f/2.8 G2 or the Sigma 30mm f/1.4, those are fast, sharp, autofocus workhorses for completely different jobs. Even the Nikon Z DX 16-50mm kit lens will run circles around it for image quality and usability. The SLY500's only real selling point is raw, cheap focal length. If you need 500mm on a $150 budget, your other option is a used mirror lens or an old adapted telephoto, and this is arguably less hassle than those. But if you can spend even $300 or $400, a used Canon EF 70-300mm or a third-party 150-600mm will give you autofocus and far better optics.

You can find this lens for between $100 and $179, and for that money, you're getting a 500mm mirrorless lens with a teleconverter. That's objectively cheap. The value score of 44.4 out of 100 reflects the trade-off: you get the focal length, but you sacrifice autofocus, a usable aperture, and solid build quality. If your budget is absolutely maxed out and you just need to reach out and touch something far away, it's a viable toy. Just don't expect it to replace a real telephoto lens.

The BM Premium SLY500 is a 500mm f/8 manual telephoto lens that promises a lot of reach for very little cash. It's a fixed-aperture, manual-focus-only lens that comes with a 2x teleconverter to hit 1000mm, and it's available for Canon RF and Nikon F mounts. On paper, it sounds like a budget wildlife shooter's dream. In practice, it's a lens that demands patience, a sturdy tripod, and a willingness to wrestle with its limitations.

If you need autofocus for wildlife or sports, look elsewhere immediately. This lens will miss the shot every time. If you plan to shoot in anything but bright sunlight, the f/8 aperture will leave you with noisy, blurry images. And if you expect a lens that just works out of the box without fiddling, the poor instructions and missing adapter issues will drive you up the wall.

The BM Premium SLY500 is a niche lens for a very specific person: someone who wants to try extreme telephoto photography on a shoestring budget and is willing to live with full manual control and a steep learning curve. It's not for casual shooters, and it's definitely not for anyone who needs to capture fast-moving subjects. If you're a beginner looking to dip a toe into wildlife or moon photography without spending real lens money, and you own a sturdy tripod, it can be a fun, frustrating, and occasionally rewarding experiment.