Are their "good" and "bad" copies of lenses?

How big the tolerance range allowed depends on the company,price of the item,etc...but there is always slight differences with anything produced in quantity.

That said,I can't recall ever returning a lens because I thought it was a bad copy.But I have seen differences in sharpness when comparing a lens I've owned with the same lens owned by a friend.

Regards,

Robert

robert614 wrote:

How big the tolerance range allowed depends on the company,price of the item,etc...but there is always slight differences with anything produced in quantity.

That said,I can't recall ever returning a lens because I thought it was a bad copy.But I have seen differences in sharpness when comparing a lens I've owned with the same lens owned by a friend.

Regards,

Robert

+1

same here, robert, i own about 13-14 canon "L" lenses, 2 zeiss, and 1 sigma 150mm f2.8 macro lenses. none has been off in any way that i can put my finger on, right out of the box! so, if that is the case and this copy variation is true, at least one of my lenses should have been off in focus or something else. so far, i am not believing in this copy variation myth others' mileage may differ! happy zooming.

No text.

Graham Meale wrote:

I've never returned a lens, and have always been happy. This means either ...

1. I've been lucky
2. I'm not fussy enough
3. The variation between lenses is not enough to lose sleep over.

Not sure which.

#1 with a little bit of #2 (and of course some #3 on average)

but believe me you would've returned the first 17-40L I got!

And I've seen differences between copies of this and that that are enough to reasonable be able to tell the copies apart.

Mostly it's not too bad, but some designs have higher tolerance requirements than others and just in general if you get one of the lesser copies and one of the very better, you can definitely see the difference.

Yes, there are good and bad copies in my experience.  My theory is that the manufacturers have calculated that it is better for their bottom line (and also for the average buyer's bottom line) if  buyers do the quality control.  This lowers the price of lenses and keeps the average buyer, who isn't knowledgeable enough or fussy enough to detect small differences, happier. This often leaves more demanding buyers frustrated.

Apparently, Canon (and presumably other manufacturers) allow for a little imperfection here and adjust this via a setting on both camera and lenses. In Canon's case think this is a scale that runs from +5 to -5 with L lenses and 1-series bodies requiring a setting of no more than +/-2, but it's been a while since I discussed this with CPS and I might have the numbers wrong. The sum of the two values then provides an adjustment bias to the focussing mechanism that should correct the error(s) and bring things back into spec.

Where this comes unstuck is when you have a lens and body that are individually within acceptable tolerance, but in combination are beyond the ability of the system to correct, for instance a body with a setting of +2 and a non-L lens with a setting of +4 (which is the issue I had - CPS replaced the lens which fixed the problem). This is why you'll sometimes see issues with a lens having focussing issues on one body but not another, and why people often send both lens(es) and body in when they are having lens recalibrations done.

Andy

The best answer I've seen on this subject:

http://www.lensrentals.com/blog/2008/12/this-lens-is-soft-and-other-myths

In short, it's not just the lens, but lens + camera combination that can make all the difference. For sufficiently high resolutions, the manufacturing tolerances of both can come into play.

bruxi wrote:

Of course there are.

That is why Lens Rentals tests several lenses and does not just get the same result with each.

When buying a second hand lens it is even more of a lottery as you never know if a lens has been dropped or abused or whatever.

I think some more expensive lenses may well have less sample variation but I think there will be variation with even the best.

Then again, the same probably applies to cameras but no one ever mentions this.

And of course, the sample variation between photographers is FAR greater.

So while the answer is undoubtedly yes, the chances of getting a lens that is not within the manufacturers standards and unusable is very slim.