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Author Topic: How do you test a lens at a store?  (Read 5244 times)

bholliman

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How do you test a lens at a store?
« on: January 20, 2013, 10:34:28 PM »
I'm planning to pick up a 135mm L lens this weekend at a nearby brick and mortar retailer.  I'm looking for some recommendations about how to test the lens for AF, sharpness in the store?  Anything else I should be looking for?

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How do you test a lens at a store?
« on: January 20, 2013, 10:34:28 PM »

RMC33

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Re: How do you test a lens at a store?
« Reply #1 on: January 21, 2013, 12:06:57 AM »
I do the lens at -20 -15 -10 -5 0 +5 +10 +15 +20 AFMA and compare them at home to get an idea. If they are not too busy they let me auto AFMA in store with my laptop. The store I frequent used to let you take the lens out for the day or two if you had a CC but they don't anymore. If these are not an option just use the zoom feature on your screen and take bunch of shots.

Mt Spokane Photography

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Re: How do you test a lens at a store?
« Reply #2 on: January 21, 2013, 12:16:51 AM »
You can't! 
 
You might find obvious flaws like gross decentering or complete failure to autofocus, but checking a lens for sharpness requires a careful setup, several shots at each aperture on a sturdy tripod.
 
Most good stores will let you return a lens if it is defective, but unless you have lens testing experience, its likely that you will never find a issue without knowledge and test experience.
 
The good news is that lenses are seldom defective, its pretty rare, but it does happen.  There is a normal range of tolerances for sharpness, and the same with bodies.  So, even if you think you have found a issue, it can be the camera body.

knifez

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Re: How do you test a lens at a store?
« Reply #3 on: January 21, 2013, 01:37:07 AM »
I like to grab the canon box the lens came in, which has one side printed with little black text on a white background, angle it 45 degrees to the lens, and focus on a letter using the centre point in camera. If the letter is sharp, and not the text in front or behind it, then I like to think the lens is more or less good there in terms of not front & back focusing. The sharpness across the frame and all I guess you'll have to check later with more serious pixel peeping at home. :)

Check all the switches and aperture blades and focus too. I had a dodgy samyang once where the manual aperture ring didn't work and the blades were stuck in one position.
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Marsu42

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Re: How do you test a lens at a store?
« Reply #4 on: January 21, 2013, 02:09:07 AM »
I like to grab the canon box the lens came in, which has one side printed with little black text on a white background, angle it 45 degrees to the lens, and focus on a letter using the centre point in camera. If the letter is sharp, and not the text in front or behind it, then I like to think the lens is more or less good there in terms of not front & back focusing.

+ you could do a quick test for decentering and relative sharpness: Print a EIA1956 chart, glue it to a cardboard and shoot it in the store with your camera lying on a bag or something in live view with mirror lockup and 2 sec timer @med iso and @med aperture like f5.6- then compare if the edges and sides look the same.

I admit I didn't do that yet myself because I would have thought it'd be not practical - but after doing such a test at home I know it's really quick. With my first mail order 17-40L copy I immediately saw decentering and returned it, 2nd is was much better.

If they have some time and are nice they might even let you try 2-3 copies of the lens, even with this EIA1956 mini-setup differences should be visible - and if not they probably aren't large enough to return the lens even after careful inspection @home.

AvTvM

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Re: How do you test a lens at a store?
« Reply #5 on: January 21, 2013, 04:24:58 AM »
i don´t test at all in stores.
all stores in my area suck.

i order a copy at amazon, test it at home and if it´s bad i send it back.
 
returning a lens to amazon is much more hassle free then arguing with a clerk.

+1 ... exactly!

Why would one try to test a lens in a store when it is done so much easier and better at home.

bholliman

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Re: How do you test a lens at a store?
« Reply #6 on: January 21, 2013, 05:46:52 AM »
Thanks for the input!

I'll print a chart and shoot that along with the lens box at 45 degrees and see how much more they will let me get away with in-store.  My experience with AMFA is pretty limited, but I've been working on it.  I'm using Neuro's article at TDP as a guideline and doing the manual setup now.

All of my other bodies and lenses have been purchased on-line.  I've purchased a number of accessories at this store and they have always been very helpful and cooperative.  The last time I was there the assistant manager said he would match B&H pricing on bodies and lenses, so that made me decide to start purchasing those there.  Definately nice to be able to physically inspect things like tripods, ball heads, bags, etc. before you buy.  So, I felt I needed to support them with some of my larger dollar purchases.
Bodies:  6D, EOS-M (22/2 and 18-55)
Lenses: Rokinon 14mm 2.8, 35mm 2.0 IS, 85mm 1.8, 100mm 2.8L IS Macro, 135mm 2.0L, 24-70mm 2.8L II, 70-200mm 2.8L IS II, Extenders: EF 1.4xIII, EF 2xIII ; Flash: ST-E3-RT, 600EX-RT (x3)

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Re: How do you test a lens at a store?
« Reply #6 on: January 21, 2013, 05:46:52 AM »

Marsu42

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Re: How do you test a lens at a store?
« Reply #7 on: January 21, 2013, 11:03:50 AM »

returning a lens to amazon is much more hassle free then arguing with a clerk.

... but it takes a week (well, for me it did with my 17-40L) so if there is a store with a good price I'd still buy it there because return is faster and after the first returned lens the clerk is probably more open to let people have a quick test with another copy because it's his hassle, too.

Don Haines

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Re: How do you test a lens at a store?
« Reply #8 on: January 21, 2013, 11:54:53 AM »
Remember the thread a few days ago about the fellow who orders a 5D3 and when it arrives there is flooring peices inside it?  Step 1 - Open the box and make sure that everything that is supposed to be there is there......

Good physical inspection, see if anything feels abnormaly loose or tight.... shake it gently and listen for things loose inside the lens... an extra screw is NOT a bonus..... Look through the lens from both ends and verify that it is clean and no scratches on the elements.

Take a bunch of pictures through the zoom range and the apeture range and look for anything grossly wrong.... If you have a comparable lens, bring it in and compare it by taking pictures of signs, text, whatever, and see how it compares to a known lens. For example, if you were looking at a 100L and had a 24-105.... and all the reviews tell you that that the 100 is sharper..... compare them in store and if it isn'[t sharper ask to try another copy.

this is about as far as you can go in store, detailed and precise testing is best left up to when you get home.
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TrumpetPower!

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Re: How do you test a lens at a store?
« Reply #9 on: January 21, 2013, 12:27:52 PM »
If it's a brand-new lens, don't bother. Just buy it. If you're not happy with it after AFMA adjustments, return it.

If it's a used lens, find the proverbial brick wall -- almost all storefronts have one somewhere, maybe the parking lot or the receiving dock or whatever. Take a picture using the best technique you can and make sure there's nothing obviously worng. You're looking for problems, not for perfection. While you're at it, try autofocusing on the cars as they're zooming past. If the lens basically tracks and everything is in the ballpark, then go for it.

If your analysis is any more rigorous than that, then your testing needs to be equally rigorous. You probably shouldn't be buying used in the first place, and you should instead be buying a half-dozen lenses and returning all but one -- and the company you're buying from should know up front that that's what you're doing so they can charge accordingly. You should also have a damned good test rig, not just some dollar bills taped to the wall.

But, mostly, you shouldn't worry. Just buy from somewhere with a good return policy, just as you'd buy anything else, and only return things that are obviously problematic.

Do you try out a half-dozen coffeemakers before buying just the right one? Washing machines? Telephones? Camera bodies? Flashes? When was the last time you measured a flash in store not only with a calibrated flashmeter but with a spectrophotometer to make sure it'll expose properly and not give an unexpected color cast? A flash with voltage problems will screw up your photos at least as much as a lens with alignment problems.

Lenses aren't so fundamentally different from anything else you buy that you should treat them any differently.

Cheers,

b&

cliffwang

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Re: How do you test a lens at a store?
« Reply #10 on: January 21, 2013, 12:30:21 PM »
i don´t test at all in stores.
all stores in my area suck.

i order a copy at amazon, test it at home and if it´s bad i send it back.
 
returning a lens to amazon is much more hassle free then arguing with a clerk.

+1 ... exactly!

Why would one try to test a lens in a store when it is done so much easier and better at home.

+1

I also like to buy online.  Nowadays returning/exchanging is so easy and free.
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Re: How do you test a lens at a store?
« Reply #11 on: January 21, 2013, 01:22:27 PM »
Ever since I got hooked to photography, I've only ever "tested" 4 lenses (if I can call it testing).
1. Sigma 17-50 f/2.8 (non-OS)
2. Sigma 10-20mm f/4-5.6
3. Tamron 90mm f/2.8
4. Tokina 11-16mm f/2.8
... all I did to test was mount it on my DSLR, take some shots, check for any fungus or specks etc ... the first tamron 90mm I "tested" had some funny shreds of metal shavings or something like that inside the lens. Some people say they test to check if there front focus, back focus issues etc, but I always found myself not having enough time/experience to check it at a store with the limited amount of time I get at the store or maybe it is just excitment of buying a news lens, I never got to "test" anything other than fungs or other foreign objects in the lens or if it is rattling etc.
Ever since I sold off all those 4 lenses, I buy all my cameras and lenses online (only B&H or Amazon Japan) ... so far Ive never had any problem with any of them ... now the only things I buy from the local stores are tripods, ball heads & camera bags.
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Re: How do you test a lens at a store?
« Reply #12 on: January 22, 2013, 05:45:52 AM »

Rienzphotoz

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Re: How do you test a lens at a store?
« Reply #13 on: January 22, 2013, 09:12:08 AM »
hire first...
Huh? How does that help? ... if he hires a lens he will know that hired lens is good or not ... but what about the brand new lens he is going to buy? unless you are suggesting that he buy that hired lens, instead of a new one.
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Re: How do you test a lens at a store?
« Reply #14 on: January 22, 2013, 09:23:05 AM »
A Sniff test should be sufficient. :|

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Re: How do you test a lens at a store?
« Reply #14 on: January 22, 2013, 09:23:05 AM »