Canon 70-300 DO

[ArtyFacts]

I held the 70-300 DO and attempted to use the zoom. It was not "locked". The zoom mechanism was particularly stiff and I was wondering if that was the general result. I have a 16-35, a 28-135 and a 70-200 4.0 for comparison.

I am curious as to whether anyone has used the 70-300 DO with a 250d +4 close up lens? I use one with the 70-200 4.0L for flowers,etc. The 70-200 4.0 gets a 4.1 from photodo...

thanks,
artyfacts