jann1033 said:
that does lead to another question...if you buy at a local store or not...will a local store let you take in your camera and actually test the lens? if , as it seems, it's kind of hit or miss with any of the lenses it would be a real pain to have to ship back and forth( not to mention the cost) so is it worth the extra you'd pay at a local place. there is a local little camera shop but i think he charges way over the normal price i can get online. also is a dodd camera nearby ( not sure is that is national or just had a bunch of stores locally)
Well, the thing is what's bad for me not necessarily bad for my (photography) teacher and what's bad for him may be a good thing for me.
Take for example. Canon 17-55 f/2.8 IS. My copy is tack sharp at f/2.8, "only" sharp at other aperture, but I will seldom take pictures with this lens at an aperture other than f/2.8, so I keep this copy. Another copy is tack sharp at f/4 but not as sharp at f/2.8 and my teacher likes to use f/4 a lot, so he keeps that copy of the lens.
Another example, Canon 17-85 f/5.6 IS. Most people are okay with the IQ of the lens. For me, I'd rather use my Sigma 18-125 without IS rather than suffer with the (to me) bad IQ.
Also about chromatic abberation. How large you're going to enlarge the pictures? Mostly 4x6 and 8x12 at the most? I've bought a Canon 24mm TS-E lens that for my purpose the CA is absolutely horrendous (I WILL only use this lens for images I'll enlarge to 20"x30"). Most people won't enlarge it to that size. Even so, they'll be content with fixing the CA using PhotoshopCS2.
So unless it's really bad (front focus, back focus, severe flare, severe CA that can be easily noticed at 5x7) you shouldn't worry about it.
I'm that picky for 2 reasons.
1. I'm crazy
2. I don't want to use post processing as much as I can.
For those reasons, I almost never buy my lens online. If I can return the item, I'll return it, if my friend should pay re-stocking fee for it, then I'll either re-imburse her re-stocking fee or I sell the item on eBay, FredMiranda or any other venues. If the lens is severely out of spec, of course, I just exchange it.
Again, honestly, how many people are as crazy as me?