Canon 17-55 f/2.8 or Canon 24-70 L f/2.8 to replace Tamron 17-50 f/2.8

jitteringjr wrote:

Assuming you have the non VC version of the Tamron, it is a pretty good lens in the IQ department.  The Canon 17-55 will only be a touch sharper throughout the frame.  The Sigma 17-50 will be sharper in the center but slightly softer at the corners.  The 24-70/2.8 is probably overall softer.  The new 24-70/2.8 II you will notice sharper images, but not as much as your wallet's weight would drop in buying it.

The reason to upgrade the Tammy is going to be for stabilization, faster and quieter focusing, or better build.

On the other hand, anything you replace the 75-300 with will give you noticeable IQ improvement.  Even the 55-250 will be a jump in IQ. Here are some ideas for replacing that keeping in the same budget as the 17-55 or less:

Tamron 70-300 VC, 70-200/4 non IS or the IS version, the 135/2 L, the 200/2.8 L, Sigma 70-200/2.8 OS, and the Sigma 50-150/2.8 OS.

If you want to keep to the standard focal lengths, maybe add a nice prime or two.  The Sigma 35/1.4 and the Canon 35/2 IS are both excellent standard primes for crop.  There is also the Sigma 30/1.4.  I have the older version, but there is a slightly improved Art version now.

Great advice jitteringjr!

Thank you for the honesty!

I do have the non VC version of the Tamron, and my biggest beef with it is the slow focus, and it seems to have lower image quality with indoor flash shots and cloudy days.  But that may also have been because I was shooting on full auto or P with just white balance and iso adjusted?  Maybe I'm imagining that it doesn't seem to do as much justice to the 60D body.

I have never owned a prime lens, so bear with me.  What is the advantage of a prime lens over a zoom?  Is image quality better?  With all of this advice, it's getting me thinking that I should focus my attention on replacing my 75-300, and not the Tamron?

Thanks!