Comparison shots between "L" series and stock lens

[number41]

Having an argument at work with a non-photographer with him saying that expensive lenses and the stock lenses make no difference. I'm trying to tell him that expensive lenses are sharper, etc but he doesn't believe me!

Having only the stock lens, I cannot take any comparison shots so is it possible someone could point me to a website with comparison shots or could someone post a few comparisons between the quality please?

Wouldnt mind seeing the difference myself tbh as I'm saving for a new lens at the moment!!

 

[number41]

Basically they have no idea what they're talking about.

Here is a test I did when I got my 17-40L F4
All tests were carried out on a Tripod, using the Mirror Lock-up custom function and the Self Timer swtiched on - purely to minimise any chance of blur. If the lens has Image Stabilisation (IS) then this was turned off. The Images were shot as Large Fine JPEGs at ISO 100 on a Canon 20D set to Parameter 2 (No in camera sharpening etc), Auto White Balance and 100% center crops taken straight from the camera.

Cheers for that! Quite a difference isnt it For those asking, I was talking about the 18-55mm stock lens with the 350D kit

 

[number41]

From looking at that comparison site seems if you "step down" the F value then they look quite similar. I'm still trying to figure out what step down means however!! Whatever it means I like it lol