08-28-2011, 08:40 AM
I haven't tried the 55-300, but I hear it's AF is very slow. If the lens is intended for wildlife or sports photography, then this should be a deal-breaker.
As for the Tamron vs. the Sigma, I much prefer the Tamron - CA and all. The Tamron at 300/5.6 is simply much sharper than the Sigma. The following comparison is with a Pentax K10D:
![[Image: post-4674-1206830799.jpg]](http://d-spot.co.il/forum/uploads/monthly_03_2008/post-4674-1206830799.jpg)
To me the Tamron (on the left) is much sharper. More so when comparing corner crops. When it comes to corner sharpness at 300mm, the Sigma at 11 can't match the Tamron at 5.6.
![[Image: post-4674-1206832229.jpg]](http://d-spot.co.il/forum/uploads/monthly_03_2008/post-4674-1206832229.jpg)
![[Image: post-4674-1206832389.jpg]](http://d-spot.co.il/forum/uploads/monthly_03_2008/post-4674-1206832389.jpg)
Photozone's own tests of these lenses show a similar difference.
As for the Tamron vs. the Sigma, I much prefer the Tamron - CA and all. The Tamron at 300/5.6 is simply much sharper than the Sigma. The following comparison is with a Pentax K10D:
To me the Tamron (on the left) is much sharper. More so when comparing corner crops. When it comes to corner sharpness at 300mm, the Sigma at 11 can't match the Tamron at 5.6.
Photozone's own tests of these lenses show a similar difference.