Help! Tamron 28-75 vs Canon 24-105L?

On a cropped sensor, shorter focal length of say~ 17-50 (tammy 2.8 non vc) would be something to consider. I had 24-70mm L on 40D and found it too long, so I only used it on my 1DIIn (1.3x sensor). Now I have Tamron 17-50 non VC and am VERY happy with it. Matter of fact 95% of the time my 60D is equiped with 17-50 or sigma 30mm.

Hitthespot wrote in post #14242445
I got the Tamron for Christmas and traded it in on a 24-105 two weeks ago. Here is my observations.

Don't take any of these observations as an insult to the Tamron. It is a great lens, especially at half the price of the Canon. So if cost is a serious consideration you can't go wrong with it.

1. The Tamron has no Image Stabalization. I found it necessary.
2. Stopping the Tamron down one stop improved the image quality. Mine was not as sharp wide open at 2.8. I've read this is typical.
3. The Canon has better Autofocus
4. The Canon has slightly more contrast.
5. The Canon is slightly sharper.
6. The Canon is built much more solid
7. The Canon is sharp right from F4.

I took some nice shots with the Tamron in the 3 months I had it, but the Canon made so much more sense for me.

Pretty much my same findings about 5 years back. Plus the Tamron struggled to lock focus sometimes, not front to back alignment just misfocus at times.

My "walkaround" lens is the Tamron 28-75mm. I love the damn thing!
Mine is very sharp and focus speed has never been an issue.

One Comparison:
http://www.slrgear.com …uct.php/product​/49/cat/23

http://www.slrgear.com …canon24-105f4/tloader.htm

http://www.slrgear.com …uct.php/product​/49/cat/23

http://www.slrgear.com …s/tamron28-75/tloader.htm

My Tamron has always been tack sharp and fast. My niece is using it now for her doctorate work and she loves it.

In my limited testing I found the 28-75 and 24-105 pretty similar in terms of quality at f/4. I wouldn't pick one over the other solely based on image quality.

Some factors to consider are: faster focusing on the L, IS on the L, 24mm vs 28mm makes more of a difference than you think, and build quality.