The 12-35 mm for landscape.

Does this happen relatively frequently, or less often?

After I posted the prev. response I thought further. . . I think with IBIS what I was distracted with was general corner edge sharpness/blur when it occurred, not the one edge of the frame type I first expeirienced with the affordable EF 70-300, and later (rarely, but it happened) with L zooms.

I don't have any revelation to share - I was more curious as to how your experience fit into my perception of the cause.   And for that reservation about OIS deep in the back of my mind I think it's why I was anxious to see if the 5 axis IBIS could compete with a Pana lens' OIS when I first had the combination.   Since the IBIS proved reliable I haven't used OIS at all (using Pana's 12-35, 100-300, 35-100).    I suppose now with this conversation in mind I'll try some OIS/IBIS comparisons as is convenient moving forward, just for the heck of it.

If I didn't have IBIS I'd likely take the potential for this error in stride today (not that I'd be happy, but. . . ), because I've taken on the habit to frame a little wider in the field - sometimes I'll choose to off the precise framing for post, but more commonly I'll do that anticipating correcting perspective where a crop is a side effect of the correction.

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...Bob, NYC
http://www.bobtullis.com
"Well, sometimes the magic works. . . Sometimes, it doesn't." - Little Big Man
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