I'm looking at 3 different lens mainly for distance shots but with a bit of Macro occasionally.
Tamron AF 70-300mm F/4-5.6
Nikon AF-S DX NIKKOR 55-300mm f/4.5-5.6G
Sigma 70-300mm f4-5.6
The bit I'm confused about is the optical zoom. I thought if they all had the same Max Focal Length that they'd have the same optical zoom. However what the spec's say is that the Tamron is 2x, the Nikon 5.5x and the Sigma 4.28.
Can someone explain why the optical zoom is so different?
Edit: Spec's got from here: Amazon comparison about half way down the page