How Do You Test a New Lens?

[Kayaker72]

For those interested, after testing NINE copies, my odyssey with the 24-70 II appears to be over.

A quick recap (first three digits of the serial number):

October - December 2013 (ordered from Adorama and Amazon)

• Copy 1 (032): Clicking while operating the zoom ring
• Copy 2 (032): Clicking while operating the zoom ring
• Copy 3 (062): Had AFMA vs aperture issues at 70 mm
• Copy 4 (062): Small bubble in front element (otherwise excellent)
• Copy 5 (042): Clicking while operating the zoom ring
• Copy 6 (042): Clicking while operating the zoom ring
• Copy 7 (950): Extremely soft at 70 mm, similar AFMA issues as Copy 3
• Copy 8 (950): Perhaps an acceptable copy, but ~20% resolution drop (based on Reiken #) from f/4 to f/2.8 at 70 mm and my 24-105 was sharper (according to Reiken) at every aperture at 70 mm.

I returned all these copies. #8 may have been acceptable, but frustration was high at that point, it didn't "wow" me at 24 mm, and had the noted extreme drop at 70 mm plus my 24-105 was sharper at 70 mm and close at 24 mm and 50 mm.

June 2014 - I caught one of the 15% off a refurbished lens from the Canon Store. I decide to try it again.

• Copy 9 (961): Excellent lens.

Across the board sharper than my 24-105 mm, especially at 24 mm. Little resolution drop at 70 mm from f/4 to f/2.8.

I used the firework show in Portsmouth NH as my landscape test:
5DIII, 24-70II @ 50 mm, 8 sec, f/9, ISO 100

Small-8781 by kayaker72, on Flickr

And my neice was up a day earlier. In reviewing those photos, this lens is a keeper.