Indiana Loc: Huntington, Indiana

I read a lot trying to educate myself on the nuances of photography and equipment. A reoccurring reality on lens reviews is that not all lenses are equal, that is, they do not all test the same. Some test as sharp, while others test as having flawed sharpness. These reviews are generally by professional photographers with years of experience and testing skill sets. My question then becomes: Can I as a consumer have a lens tested by a "certified tester" prior to purchase (either new or used lens) that will give me assurance of lens sharpness and perhaps other measurements of a quality product. In reading reviews of lenses in particular, I frequently read a response like, "this is the third lens I tested, the other two were sent back because of sharpness issues with the lens." So the question becomes, "Can a dealer provide this service as a part of the purchase process, and/or is there a independent certified tester or organization that can provide this service within the 30 day return policy of most dealers? I am not interested in being the tester myself since I am not qualified. A reasonable fee for this service is expected. Looking forward to your response. Thanks

CHG_CANON Loc: the Windy City

Put simply - no

You can find reviewers who try "science" such as DxOMark taking pictures of black lines on charts in a lab. You can find reviewers that perform their own standardized tests as well as provide real-life usage reviews such as Ken Rockwell and Bryan Carnathan (The-Digital-Picture.com). You can recognize the design and manufacturing processes for all the major lens vendors have all improved in consistency of product, both through striving for excellence and competition for excellence.

But the individual lens you receive? No one can (will) pre-certify your exact copy relative to any others of the same model nor against the competition other than general observations from their own unique copies. The lenses either tested (via sampling) within accepted tolerances or they're not packaged for sale.

lamiaceae Loc: San Luis Obispo County, CA

Actually there is virtually no such thing as a bad lens today. The problems you speak of are due to slight issues with the autofocus system of a lens-camera system. Lenses are manufactured to operate on a multitude of different models of camera bodies. Also the electrical contacts for all the electronics in lenses for autofocus and vibration control or anti-shake are subject to dirt or oils on the contacts that may cause problems. If manually focused all lenses made in probably the last 70 years are great. To test as you imply would mean on an optical bench and you would need to test the entire system of specific lens and specific camera body to find discernible differences. And again that would likely only pertain to auto use. Yes, there are some poorer lens designs out there but when you are speaking of a model you can read about what few lenses to avoid in reviews, your own independent testing would be pointless.

Bottom line, the issues are generally with the electronics and mechanics in the lens not the focusing system. So lenses would have to be tested on your camera to find "tuning" issues. A camera shop, if you can find one, could test a lens, though probably not accurately, but what of most cameras and lenses that are sold in big box stores or on the Web?

ken_stern Loc: Yorba Linda, Ca

Thank God --- Great answer
I did not want to be the 1st to respond ---
Without a camera the best you can certify any lens for is as -- in my opinion only -- a DOOR STOP !!
Start with FORMAT -- Then come up with a Manufacture / Brand Name --- Then ask your question --
The answer still remains NO -- But you will at least get lots & lots of certified opinions

E.L.. Shapiro Loc: Ottawa, Ontario Canada

Many decades ago, when I was studying photography in an academic environment, OPTICS was a required course of study. There were volumes- books written about lens ABERRATIONS. Theses are , let's say, flaws defects, irregularities in lenses that can causes a lack of sharpness, various distortions and basically causes our photographs not appear exactly as our eyes see things. The more scientifically inclined folks around here might take me to task in that this explanation is an oversimplification. Theses abberations are not necessarily quality control failures rather they phenomena that are intrinsic in all lenses to various degrees. FYI- just to name a few; comma, , spherical and chromatic aberrations, curvature of field, barrel and pincushion distortion and more.

The good news is that advanced optical design and engineering has minimized many of theses issues but the still exists in certain lenses. Most lenses preform best at certain f/stops and zoom lenses may not work a peak performance at all focal-lengths. Most macro lenses work better at closeup distances.

Some of theses issues are not easily detectable, in our photographs, to the naked eye, especially if the are not enlarged to a great degree. Some of the reviews that appear in photo magazine and online are the result of lens testing under laboratory conditions- sometimes know as optical bench testing. Lenses are focused on special targets that reveal resolution factors at various distances, apertures and focal length settings. Nowadays the resulting readouts my be obtained by electronic instrumentation.

Other reviews may be more subjective, such as are reports by photographer using theses lenses in the field. Unfortunately, some of theses may be advertising hype.

As others here have alluded to, it is highly unlikely that you will end up with a "lemon" of a lens from a major manufacturer and a reputable dealer. The manufacturer's guarantee should cover any optical or mechanical defect and a reliable dealer will make the appropriate refund or exchange if you are dissatisfied with any product. Of course you should test any newly purchased lens promptly and make certain that any issue is reported within the specified time limit.

Yes! There are lenses that are superior to others. Some are "faster", meaning that they have wider apertures that can work well under dim lighting conditions. Others have apochromatic correction and their imagery can be enlarged to mural proportions with little or no loss of sharpness with all colors in perfect focus without "fringing". As a commercial photographer, I have lenses that cost many thousands of dollars and do perform exceedingly well, however, many of my images will appear on billboards or displayed in very large proportions. For my own personal photography around the house, at family events and on vacations- I have a few so-called "kit lenses"- just regular consumer stuff and they do just fine. Those personal images will never see anything larger that an 11X14 print or a screen image on my computer.You lens purchases should be based on you specific needs and what kind of photography you mostly do. Tell us what you are into and you will get a plethora of suggestions.

Just a few rules of thumb: Prime (fixed focal length ) lenses generally are better performers than zooms. Really great zooms are more expensive. The proof of the pudding is in the tasting- if you like the sharpness, the color saturation (richness) and accuracy of a lens at reasonable degrees of enlargement- not to worry about too many published specifications and statistics. Use a good lens shade to avoid flare, that is a loss of contrast from stray light striking the lens.

There are some enthusiasts that are so preoccupied with equipment acquisitions and specifications that the have no time to take pictures.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

There are manufacturing differences, just like anything else, that can produce a "bad copy" - lenses in particular are not individually inspected and tested before they are packed and sent to the distributors for sale. Manufacturers use probability and statistics to predict the chance of a bad lens by testing a "representative sample" in a production run and extrapolating. A bad lens can easily occur due to poor assembly - un-centered elements, especially with ultra wide angle lenses is a fairly common problem - parts failure, glue failure (in element groups where cement is used to marry two pieces of glass, a flaw in the coating or the glass, etc etc etc. These things are complex and prone to sample variations. It has gotten much better, but it does happen. I went back and forth with Sigma on two lenses - a 10-20 DX zoom, and an 18-70 DX zoom. With the 18-70 Sigma in Ronkonkoma had to open over a dozen lenses to get one that was satisfactorily within spec. As you stated, mo dealer is equipped or willing to do anything like that.

As far as autofocus performance, and defocus (bokeh) and other optical parameters - these are all adjustable. Defocus is mechanical, AF performance is adjustable mechanically and in software. No manufacturer I know of suggests marrying a lens to a body with AF Fine tune. In fact, they all say or imply it is not necessary if everything is within spec.

jerryc41 Loc: Catskill Mts of NY

If there were such a business, I would not use it. I would be paying them money to offer their opinion, now knowing how accurate their testing was. Read the reviews, buy what you want, and it it isn't satisfactory, return it. I have never had to return anything, and I've gone through a lot of gear in the past fifty years.

John_F Loc: Minneapolis, MN

I would consider making an optical test bench. The lens will have a tripod screw hole so you could make a sliding mount gizmo. Then make a standard object with wide crossed lines from quadrille paper. Make a mount for it. A longish vee slotted board, like a 2x4, for base. Plop everything on and look thru the lens, sliding stuff to get focus, and judge from there. Don't make too big to lug to the lense store. There, instant workshop expert lens tester.

OddJobber Loc: Portland, OR

Couple problems, John. Tripod screw hole implies long lens. Most recommendations I see suggest testing/fine tuning at 25 to 40 times the mm of the lens. For a 600mm lens, you'll need a 2X4 from 49 t0 79 feet long!

Indiana Loc: Huntington, Indiana

Thanks for the response. Perhaps I have opened the door for a new dealer service, that if offered to the consumer, would set themselves aside for additional business by offering this service. I was reviewing the Tamron 150-600, Sigma 150-600, and the Nikon 200-500 for possible purchase when all these concerns appeared. Several reviewers were returning the Sigma & Tamron for issues. Since I am a Nikon loyalist having just upgraded to the 850, I will probably focus on the Nikon lens. Thanks again for your comments and valuable reflections.

OddJobber Loc: Portland, OR

Please don't say no one. There's the Oddjobber Calibration and Certification Lab. Since this is best done with the camera body that will be used, the OP should send the camera and lens to me.

Indiana Loc: Huntington, Indiana

Thanks to all the responders on the lens issue. I value your opinions and have read your responses carefully. When a lens reviewer responds by stating "I had to send the "bad" copies back" or "my copy tested poorly", it is concerning. With my advancing age and deteriorating eye sight, I am not the best judge of sharpness. Recognizing my own inadequacies, I was looking for a third party solution. Thanks again to all the responders.

latebloomer Loc: Topeka, KS

RE: Lens quality
I recently went to a two hour workshop with a Tamron representative. He said that in the production of any model of lens, there will be slight variations. For the pixel peepers it looks like the most accurate testing of a lens would be to have a significant number of lenses not provided from the manufacturer tested at the same time with the same camera body. Those of you who have had a course in statistics will understand that variations are inevitable. Even if there are significant variations, they should also be tested under the same real world conditions before drawing conclusions. In other words, testing only applies to the exact lens being tested.

kymarto Loc: Portland OR and Milan Italy

Actually no. There are quite wide variations in sharpness across the frame due to centering issues and quality control of similar model lenses. That being said, they are certified to meet certain tolerances, but differences can be noted between different exemplars, especially in the corners when viewing at large sizes.

http://www.slrgear.com/articles/variation_canon50f14/canon50f14.htm

https://wordpress.lensrentals.com/blog/2011/10/notes-on-lens-and-camera-variation/

https://www.lensrentals.com/blog/2015/06/measuring-lens-variance/

camerapapi Loc: Miami, Fl.

This is a most interesting discussion and I am going to participate warning beforehand that I am not an expert on lenses.
Like Jerry I have bought many lenses over my more than 50 years in photography. All of those lenses did they part when I did mine. I never ever had to return any lens, when lenses did not have AF and when they did have AF. I have never calibrated a lens in my entire life.
Modern lenses are excellent in quality and the more we pay the better the lens. It is only logical to assume that some variations will be normal while producing the same lens and with poor quality control those variations are going to be noticeable.
Sharpness has a lot to do with us and not always with the quality of the lens in use. I do not need to explain once again that a person without basic photographic knowledge will not do well with a professional lens.
If something does not bother me today it is sharpness. All lenses sold today come with a warranty. If the lens is not working to one's expectations it is easy to return it. As I said, I never returned one.
We should not expect more quality in a zoom than in a prime but we can expect convenience. Modern zooms are pretty good and sharp.