Tamron sells a 6-year warranty, Sigma sells reach and coatings, Viltrox puts a USB port on the mount for firmware updates. That port answers the real risk.
Viltrox
Why we like it
Tamron
Why we like it
Sigma
Why we like it
OM System
Why we like it
Sigma
Why we like it| Product | Rank | Brand | Best For | Score |
|---|---|---|---|---|
| VILTROX 85mm F/1.8 F1.8 Mark II STM Full-... | #1 | Viltrox | Best Overall | 9.8 |
| Tamron 70-300mm F/4.5-6.3 Di III RXD for ... | #2 | Tamron | Best Warranty | 9.6 |
| Sigma 150-600mm 5-6.3 Contemporary DG OS ... | #3 | Sigma | Best Reach | 9.4 |
| OM SYSTEM Olympus M.Zuiko Digital ED 12-4... | #4 | OM System | Best Weather Sealing | 9.3 |
| Sigma 16mm f/1.4 DC DN Contemporary Lens ... | #5 | Sigma | Best Value | 9.1 |
Buyer checklist
Every figure below is the manufacturer's own, read off the live Amazon.com listings including the detail tables, and these five brands publish properly: element and group counts, minimum focusing distances in both metric and imperial, magnification ratios, filter thread sizes, coatings and weather sealing. The Amazon detail tables remain unusable, giving a 300mm focal length as 30 centimetres, an 85mm as 8.5 centimetres, and in one case a fixed focal length of 51.47 metres, so we worked from the bullets throughout. What we organised the comparison around is what each brand offers that the camera maker does not, because that is the actual decision: a third-party lens is chosen over an own-brand one for warranty, for reach at a price, for updatable firmware, or for a mount that several manufacturers share. We have also stated where image stabilisation is absent, since two of these five have none and the listings bury that in a field rather than a bullet. Nothing here was mounted or tested by us.
That the camera maker changes something and the lens stops working properly. Third-party manufacturers reverse-engineer the communication between body and lens, so a firmware update to your camera can in principle break autofocus or aperture control on a lens that worked fine the day before. In practice this is uncommon and usually fixed, but the fix has to reach the lens. That is exactly why the Viltrox 85mm's microUSB port on its rear mount is a more meaningful feature than it sounds: you can update the lens yourself. Lenses without that port depend on the manufacturer offering a service update, or on nothing going wrong.
Because the expensive parts of an own-brand super-telephoto are the ones they choose not to match: fluorite or exotic glass, the fastest focus motors, professional weather sealing and a constant wide aperture. Sigma's 150-600mm Contemporary reaches 600mm at f/6.3 with optical stabilisation and a water and oil repellent front coating for a fraction of an own-brand 600mm prime, and the compromise is aperture and focus speed rather than reach. For daylight wildlife and sport that trade is usually the right one; for low light or fast action it is where the price difference shows.
Yes, and it is the most underrated thing about the system. Micro Four Thirds is an open standard shared by OM System, formerly Olympus, and Panasonic, so a lens made for the mount works on bodies from multiple manufacturers without anyone reverse-engineering anything. The OM System 12-40mm f/2.8 PRO II in this guide states mounting for Olympus, OM System and Panasonic alike. That removes the compatibility risk that applies to every other lens on this page, which is a genuine structural advantage rather than a marketing point.