So I ran across this interesting article while browsing lens reviews, day-dreaming about that Canon 70-200mm and other things. The author seems to run a lens rental site, but his post is quite informative and not sales oriented at all. It's some interesting food for thought, if you've ever wondered about quality control in terms of lenses and bodies. I'd be interested any thoughts about the quality of his research. Is he another Ken Rockwell or not? LensRentals.com - "This lens is soft" and other FACTS

Excerpt:
Can we just have the summary first, in case we don’t want to read all this?
Sure. I’m going to conclude that some lenses have intrinsic problems that make them bad even when properly focused (yeah, I know you already know that). I’m also going to conclude that some cameras bodies have intrinsic problems that make many lenses bad on that body despite accurate autofocus (yeah, a few of you knew that, too). Then I’ll talk about what kind of things can cause those problems and speculate at length about “bad batches”, “bad cameras” and what it all means for the photographers, gearheads, and pixel-peepers among us (yes, those are three different, if somewhat overlapping, groups).

Some outside information.
We have the privilege of working fairly closely with some excellent reviewers and testers, and get to discuss their results with them. But everything I’ll be mentioning here is available for you to read from the original source and I’ll link to their articles. But full disclosure first: Lensrentals furnishes some lenses for testing to both SLRGear and to Lloyd Chambers and have advertised on Diglloyd, SLRGear and TheDigitalPicture We’re rather picky in who we tend to associate with and have, in all three cases, chosen to affiliate with these guys because we respect the work they do. But I think the internet these days is way too full of business relationships that aren’t mentioned by bloggers and writers, so I want to make sure I mention these. Now on to their observations:

  • Lens variation isn’t always random.
  • Camera body variation also occurs.
  • Its not just major manufacturer’s lenses
  • Lets take a logical look at the manufacturing process[...]


Best quote:
Its is a bad time to be a pixel-peeper. If you look closely enough on a high resolution full-frame camera, chances are you’ll find some minor flaw with every lens you own. If you go through 13 copies and get one that’s just perfect, remember to never, ever upgrade your camera body, because it probably won’t be perfect on the next one. That’s just how it is: manufacturing processes are not up to the lens design and sensor resolution we have at the moment. Put on your Batman undies and cope with it. Or shoot with a Holga for a while and get over it. And stop looking at 100% images on your monitor: not only will it make you go blind, 50% screen resolution is more resolution than your printer can reproduce anyway. Unless you print billboards designed to be viewed from 5 feet away.