© 2006 KenRockwell.com
Nikon 12 - 24
mm f/4, Tokina 12 - 24 mm f/4, Sigma 10 - 20 mm f/4 - 5.6 and Tamron
11 - 18 mm f/4.5 - 5.6.
Click an image to get it from Adorama. Also try Amazon. It helps me if you get yours at either one.
Let's drop these onto a concrete sidewalk from six feet. This is a reasonable test which ought to be a decent tradeoff between a regular drop from your hands and dropping them into Bryce Canyon. Whoops!
They use two different kinds of construction.
The Nikon and Tokina keep all of their optics inside an outer housing. The outer lens barrel is separate from all internal optical assemblies. The front and rear sections of the lens slide around inside the outer barrel as you zoom or focus. You can scrape the front of the lens on the pavement while you're hanging out of a moving minivan during a car shoot and not touch the optics. Your biggest worry dropping them is hoping not to bend the outer housing which would constrict the movement of the internal assemblies. Their housings are plastic, not metal, so they would probably bounce back or break off before they would stay bent. This is all good.
The Sigma and Tamron are conventional zooms. The front of these two lenses moves in and out as you zoom. The front of the lens is the front optical group. If you drop or drag either of these you won't so much damage the optics directly, but you are very likely to damage the alignment or precision of the zoom assembly. You easily could knock the lens out of alignment or dent or crack the zoom cams. Once you've done that you've destroyed the lens' inherent sharpness. This is why it's potentially dangerous to buy used zooms, especially if they've been in a drop test and look OK externally.
I'd suggest the Nikon or Tokina for rough use. I'd be very careful not to apply force or impact to the fronts of the Sigma or Tamron.
Drop Test Aftermath
I own my Nikon 12 - 24mm. I love you folks, but not enough to drop my favorite lens on concrete for you.
The other three were loaned to me, brand new, out of good will. I'm not going to drop them on my sidewalk either. Not that I wouldn't love to, but the store might not be so happy about it.
Made you look!