Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old Jun 15, 2010, 12:52 PM   #1
Member
 
Join Date: May 2010
Posts: 56
Default Good copy, bad copy

What's up with that? Recently I'm reading quite a few reviews for my next lens purchase, and I see some very good reviews and some very bad, complaining about bad copies of lens or whatever. Don't all lenses pass some kind of quality test?

How do I avoid a bad copy, and how do I even know if I own one?

If someone could explain all this...it'd be great.
Ishay is offline   Reply With Quote
Sponsored Links
Old Jun 15, 2010, 1:15 PM   #2
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

First, if you happen to get a bad copy of a lens, chances are it will be fairly obvious.

Second, bad copies can occur as a result of rough handling during shipping, and some lenses are more likely to be affected than others.

Third, all manufacturers have a Quality Control process where they evaluate products before they leave the factory, as well as at various steps in the production process. But sometimes, stuff just happens.

Some products, and even some manufacturers, seem to have more trouble with this than others. But there is no hard fast rule. As certain products mature, the manufacturers learn better how to avoid failures, and some of those lessons learned are applied to an entire product line. In general, new products will meet the manufacturer's specifications, and if they don't, the manufacturer will repair or replace them free of charge.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
Old Jun 15, 2010, 1:25 PM   #3
Member
 
Join Date: May 2010
Posts: 56
Default

Assuming I get a bad copy- how can I avoid being accused for it?

Seems likely that the store will go like 'you were careless' 'it's your fault' and all kinds of nasty stuff.

I'm asking all this because when on a budget you can't afford your hard earned $$ go to waste...photography isn't cheap.
Ishay is offline   Reply With Quote
Old Jun 15, 2010, 1:51 PM   #4
Senior Member
 
Join Date: Dec 2006
Location: Davenport, IA
Posts: 2,093
Default

What lens do you have in mind and what body will you be using with it?

Were those reviews from http://www.dpreview.com/lensreviews/ or http://www.lenstip.com/lenses_reviews.html or, athough not as formal the first two but useful for 4:3 folks http://www.wrotniak.net/photo/43/index.html#LENS? Or were they reviews on seller's web sites?

Basically reviews on seller web sites are variable quality due both to the inabilities and biases of those providing them at best and outright fraud at worst. I trust the first two above (though there may be more that are equal) and find, because I'm an Oly user, the third useful.

I'd also, if the info was still conflicting, ask for the opinion of the participants in the camera and/or lens forum here and at DPReview.

Getting a truly sub-par example of a good lens is fairly rare. How do you tell if that's happened? Take pictures with it and compare the results to your other lenses. Compare also 100% crops from the lens in question and your other lenses.

A. C.
ac.smith is offline   Reply With Quote
Old Jun 15, 2010, 1:52 PM   #5
Senior Member
 
shoturtle's Avatar
 
Join Date: Dec 2009
Location: Frankfurt AM
Posts: 11,348
Default

well sigma has a slight problem of front or back focus. But they do fit it for free if that is the case for 5 years.
__________________
Super Frequent Flyer, no joke. Ex Patriot and loving it.
Canon Eos 60D, T1i/500D, Eos1, Eos 630, Olympus EPL-1, and a part time Pentax K-X shooter.
shoturtle is offline   Reply With Quote
Old Jun 15, 2010, 2:37 PM   #6
Senior Member
 
Join Date: Dec 2006
Location: Davenport, IA
Posts: 2,093
Default

Quote:
Originally Posted by Ishay View Post
Assuming I get a bad copy- how can I avoid being accused for it?

Seems likely that the store will go like 'you were careless' 'it's your fault' and all kinds of nasty stuff.

I'm asking all this because when on a budget you can't afford your hard earned $$ go to waste...photography isn't cheap.
1st thing I'd do is carefully examine the lens visually looking for scratches and dings and look through the lens while turning it to make sure nothing is floating about or stuck to any of the elements. I'd listen to the lens while turning it to see if anything sounds loose. If something seems wrong at this stage then back to the store and compare it to another sample of the same lens. If the lens is good at this point I'd attach it to a body and exercise all the controls. If that's OK then start using the lens and look at the photographic results.

If at any point it unsatisfactory after its passed the visual/audible exam and someone wants to claim you abused the lens then it's on them to show you the scratch or ding that supports their case. You already know there are none. In general I agree with TCav that if the lens is really defective it will be DOA out of the box.

If it helps at all I acquired 4 new lenses within a week's time last month and all have proven good.

A. C.
ac.smith is offline   Reply With Quote
Old Jun 15, 2010, 2:52 PM   #7
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Quote:
Originally Posted by ac.smith View Post
Getting a truly sub-par example of a good lens is fairly rare.
I dunno about that... :-)

Sigma has a pretty bad reputation for problems with their lenses.

But, even more expensive Pro grade lenses from major camera manufacturers can have more QC related issues that they should. For example, here's a quote from the Canon 24-70mm f/2.8L review at photozone.de (a very respected source of lens reviews):

"The Canon EF 24-70mm f/2.8 USM L proved to be a worthy representative of the pro grade lens league ... if you can get a good sample. During the last two years four lenses has seen the lab with only one within specs - this is disappointing especially for a lens of this price class."

http://www.photozone.de/canon-eos/18...review?start=2

If you look at the "blur charts" at other review sites like http://www.slrgear.com , you'll often see minor decentering defects from lenses they test (one side softer than the other, etc.).

QC isn't what it used to be.
JimC is offline   Reply With Quote
Old Jun 15, 2010, 3:06 PM   #8
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

Quote:
Originally Posted by Ishay View Post
Assuming I get a bad copy- how can I avoid being accused for it?

Seems likely that the store will go like 'you were careless' 'it's your fault' and all kinds of nasty stuff.

I'm asking all this because when on a budget you can't afford your hard earned $$ go to waste...photography isn't cheap.
Agreed. But trust me when I say that you won't be the first person to try to return a lens to the store where you bought it. The people in the store know that stuff happens, and they aren't likely to accuse you of anything, because they want you to come back and spend more money.

That's one of the reasons you're better off buying from a local merchant. You can try it out before you leave the store, and if something happened in shipping that caused it to fail, you can catch it before you get it out the door. If the salesperson saw you take it out of the box, put it on your camera, and it didn't work, it's hard for them to say you did something wrong.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
Old Jun 15, 2010, 3:08 PM   #9
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

If you're looking for reliability data on lenses, this and it's predecessors is the best source I know of:

http://www.lensrentals.com/news/2009...repair-data-35
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
Old Jun 15, 2010, 6:18 PM   #10
Member
 
Join Date: May 2010
Posts: 56
Default

The thing is, that in my area, we don't have many 'local stores'. And the ones we have can be 40-50% more expensive than what i can get on the internet. that applies to lenses as well as to bodies.

Any practical advice on how should I get my gear?
Ishay is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 12:56 PM.