Big Mike's BM-SLY420NK-K2 420-800mm
The 420-1600mm zoom range and constant f/8.3 aperture offer extreme reach in a lightweight 989g body, but the lens is entirely manual focus with no electronic communication. Its F-mount compatibility spans a wide range of Nikon DSLRs, making it a low-cost entry point for super-telephoto photography. This lens is best for budget-conscious Nikon DSLR users who are comfortable with manual focus and want to experiment with long-distance wildlife or sports shots in good light.
Snapshot
What owners think
How owner sentiment changed over time
ExclusiveBased on when customers actually wrote their reviews - so you can see whether early praise held up.
The proof
Performance
Specifications
Full Specifications
Optics
| Type | Telephoto |
| Focal Length Min | 420 |
| Focal Length Max | 800 |
Aperture
| Max Aperture | f/8.3 |
| Min Aperture | f/8.3 |
| Constant | No |
Build
| Mount | Nikon F |
| Weight | 1.0 kg / 2.2 lbs |
AF & Stabilization
| AF Type | manual focus only |
| Stabilization | Yes |
Focus
| Min Focus Distance | 420 |
vs Competition
| Spec | Big Mike's BM-SLY420NK-K2 420-800mm | Tamron Di III VC 28-300mm f/4-7.1 VXD | Sigma Contemporary 18-50mm f/2.8 DC DN | Nikon NIKKOR Z 17-28mm f/2.8 | Panasonic Leica DG Vario-Elmarit H-ES12035 | Sony E 18-135mm f/3.5-5.6 OSS |
|---|---|---|---|---|---|---|
| Focal Length | 420-800mm | 28-300mm | 18-50mm | 17-28mm | 12-35mm | 18-135mm |
| Max Aperture | f/8.3 | f/4 | f/2.8 | f/2.8 | f/2.8 | f/3.5 |
| Mount | Nikon F | Sony E | Sony E | Nikon Z | Micro Four Thirds | Sony E |
| Stabilization | true | true | false | false | true | true |
| Weather Sealed | false | true | true | true | true | false |
| Weight (g) | 989 | 590 | 290 | 450 | 306 | 326 |
| AF Type | manual focus only | VXD linear motor | stepping motor | Stepping Motor | Autofocus | Linear motor |
| Lens Type | telephoto | zoom | zoom | zoom | zoom | zoom |
| Compare | Compare | Compare | Compare | Compare |
| Product | AF | Bokeh | Build | Macro | Optical | Aperture | User Sentiment | Versatility | Social Proof | Stabilization |
|---|---|---|---|---|---|---|---|---|---|---|
| Big Mike's BM-SLY420NK-K2 420-800mm | 13.3 | 47.9 | 6.1 | 62 | 20.2 | 49.8 | 3.7 | 69.8 | 64 | 82.4 |
| Tamron Di III VC 28-300mm f/4-7.1 VXD Compare | 98 | 78.2 | 65.1 | 85.8 | 96.7 | 66.3 | 91.2 | 97.7 | 55 | 82.4 |
| Sigma Contemporary 18-50mm f/2.8 DC DN Compare | 86.9 | 82.1 | 86.1 | 91.7 | 82.2 | 84.2 | 80.9 | 78.6 | 89.6 | 36.8 |
| Nikon NIKKOR Z 17-28mm f/2.8 Compare | 86.9 | 87.3 | 75.2 | 85.8 | 88.2 | 84.2 | 91.2 | 68 | 69.1 | 36.8 |
| Panasonic Leica DG Vario-Elmarit H-ES12035 Compare | 53.9 | 82.1 | 85.4 | 51 | 86.5 | 84.2 | 63.7 | 80.6 | 85.1 | 96.9 |
| Sony E 18-135mm f/3.5-5.6 OSS Compare | 98 | 75.7 | 72.5 | 40.3 | 78.5 | 77.6 | 44.7 | 95.8 | 89.6 | 82.4 |