Two years ago I chose Tamron's 28-75mm F2.8 lenses for Sony E-mount ($800) as my gear of the year. And this time around I'm choosing Tamron's 70-180mm F2.8 ($1200) for very similar reasons: It's a well-priced, quality lens that answers the needs of customers. And Tamron seems to be on a roll lately when it comes to conjuring up good glass with
Unlike its IS sibling, the Canon EF 70-200mm f/2.8L USM Lens is not fully weather-sealed - Extra caution will need to be taken in wet conditions. The 70-200 f/2.8L lens is, however, a partially weather sealed lens. A lens mount gasket is not present, but the switches, focusing ring and zoom ring have moderate dust and moisture resistance.
But f/2.8 on crop behaves like an f/4.5 lens would on full frame, so we say it is equivalent. This! The lens is always the same a 70-200 f2.8 will always be 70-200mm and f2.8. But, 70-200 looks different on a crop sensor than it does on a full frame camera.
.