Canon 70-200mm and Sigma 28-70mm at 70mm

[zerartul]

I took 2 pictures both at 70mm with both lens. The Sigma @ 70mm seems to be wider then the Canon at 70mm. Is it common in lenses to have the same focal length across different manufacturer?

[boredphuck]

not surprising. the sigma 10-20 is also wider than the canon 10-22 if i dont remember wrongly.

[mtunlinn]

I think it is pretty normal. I had read somewhere that tamron 17-50 2.8 at 17mm is wider than canon 17-55 2.8IS.

[spartacus.ret]

zoom lenses are never made exactly to the advertised focal ranges and apertures, they are just approximate figures. like the tamron 17-50mm f/2.8 is actually a 17.36–50.37mm and f/2.74–2.93 while the sigma 18-50mm f/2.8 is actually a 19-50mm f/3 lens.

[Klose]

It's normal