Do you "test" your lens after purchase?

davidc502 wrote in post #16467411
"It 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. "

I totally agree, however, I do like to know where the flaws are so I can take them into account when shooting. I know I can live with them because I also know there is no perfect lens, even a $2500 lens. I definitely don't agree with the sentiment that "I spend $2k on a lens, it should be perfect". No lens is 'perfect'. Some come close to being perfect for a particular application, but there is always trade-offs.

DreDaze wrote in post #16467421
i usually just take pictures with it...the only time i do 'test' shot type things is when i feel like i'm missing shots...and a quick tripod mounted test usually establishes that i was the problem...

^^^ That. Pretty much

Just got my camera this afternoon. Pretty overcast so I will test it tomorrow.

What should my expectations be?

Every image I shoot I look at it at 100% to see how sharp it is.

Should I expect my text shots to be sharp at f2.8, throughout the zoom range?

Or should I just be happy if it is sharper than my version I of this lens at f2.8?

Just curious. How many lenses have you sent back due to lack of sharpness?

Thanks for all the feedback.

Alan

Check to see if it is acceptible to you. And from what I have heard, yes, it should be sharper than your mk1. My 24mm needed MFA. It didn't seem very sharp even when stopping down a bit. When manual focused I knew I could get nice crisp photos with it. After a little MFA I've got it performing great. If you walk around for a while and review your pics and they seem soft or OOF check the lens with MF and see if it produces a sharp photo. If so, then run some micro focus adjustments to get it bang on. If it can't produce sharp acceptable pictures, then return for another.

I've never sent a lens back because most of my lenses were bought 2nd hand, those people do all the leg work in finding a sharp copy. I just reap the benefits of buying cheaper and getting a sharp lens. Of the lenses I've bought new (8-15L, 24L II, 40mm) I have been very pleased with them. The 24mm needed a little MFA but nothing more.

ahender wrote in post #16469973
Should I expect my text shots to be sharp at f2.8, throughout the zoom range?

Or should I just be happy if it is sharper than my version I of this lens at f2.8?

The problem is how do you know what 'sharp' is? I don't mean to be flippant, but honestly except for an 'expert' I think it is quite difficult to see if a lens is 'sharp' or as sharp as you think it should be without comparing with something. Obviously if it is way off, but that will be obvious.

So yes, I would compare with your mk I and although I don't have this lens, from everything I have read I would expect it to be sharper at all f-stops and FL's. If it were softer of about the same, I would order another to make sure it was not my mk I that was out of the ordinary and then return one - I realize that is extra expense.

Honestly though I haven't seen many/anyone complain about this lens, and if there was a likely issue, I think we would have heard a lot about it. So if for whatever reason you think it is not up to par, I would make sure it is not you (use tripod + manual focusing).

Personally, I just make sure it's focussing pretty close to where it should be (where I placed the AF point in the viewfinder) at a few different focus distances, and call it quits at that. And don't get too stressed if it's a touch out in weird lighting conditions, such a fluoro lighting. Everything I shoot is 3 dimensional, so I will never expect the whole subject to be in perfect focus, or be 100% perfectly sharp

I mount it and go out for a couple hours. If the pictures look good, I'm good. I've not bought a lens that I've ever had to test yet. I'm with DC fan in that real world testing is what matters.....

First thing I test for is decentering. My experience is that focus issues can be corrected by AFMA or sending it in, but repair centers rarely take the effort to take apart a lens to correct decentering, saying that its "within spec" no matter how bad, so the only option is to return it for a refund within the return period.

DC Fan wrote in post #16467205
The best way to "test" a lens is to use it for the purpose for which it was purchased. A couple of weeks' extensive use will answer all questions. Only real-world exercise will reveal any equipment's strengths and weaknesses (and the photographer's limits as well).

It's useful to note that photo equipment performs best when used to capture images of real three-dimensional subjects.

I partially disagree. While what you say is generally true, it only takes a few minutes to test a lens and determine if a new purchase is decentered, or back or front focusing. Why wait for a few days or weeks of use to confirm it one way or the other when a quick test can give you the result within 10 minutes of opening the box. Of course there are also other issues a lens can have, but decentering and the focus plane are two of the most common problems and the easiest to confirm.

mwsilver wrote in post #16472007
I partially disagree. While what you say is generally true, it only takes a few minutes to test a lens and determine if a new purchase is decentered, or back or front focusing. Why wait for a few days or weeks of use to confirm it one way or the other when a quick test can give you the result within 10 minutes of opening the box. Of course there are also other issues a lens can have, but decentering and the focus plane are two of the most common problems and the easiest to confirm.

+1

You get a new lens, you go out and shoot 50-60 photos under most possible conditions. They don't have to be art... Test AF, sharpness, decentering. All you need is a brick wall...

If you suspect any problems, take it home, put it on a tripod and do specific tests to investigate/document the problem.

I do a very thorough check with new and used equipment. I just got another 70-200 II two weeks ago and it failed... So I exchanged it and got another which is great.

I usually first shine a bright light down the lens, check for any abnormal debris or scratches on the elements.

I wiggle/move the focus and zoom rings, make sure there is no excessive play or weird noises.

Check centering quality of the lens, make sure it is sharp top/bottom and left to right. (Trust me, you would be suprised how bad they can be...)

Check IS function (if applicable). That 70-200 II that failed was due to this, along with a zoom ring that had 1mm of slack back and forth before it moved the zooming elements. Sloppy. The IS just wiggled back and forth and would not settle.

Check sharpness from each end of zoom range, make sure all looks good.


Usually that about covers it for me.

Tested my lens this morning shooting a wine bottle. Right now, just focusing on the center of the image.

My version I lens is sharper than the new version II lens at f/2.8 200.

Both images are single point, autofocus, tripod mounted, shutter release.

Manual focus on the version II lens was sharp.

Also, all the autofocus shots with the version II lens had the horizontal lines bowed upward. Was not the case with the manual focus shot with the same lens. Have no idea what would cause that. You can see it in the sample.

Plan to use this with my 1D mkIIn camera so not available to tweak the lens.

The images below were shot with my 7D. Same result with the 1D.

Alan

MakisM1 wrote in post #16472026
+1

You get a new lens, you go out and shoot 50-60 photos under most possible conditions. They don't have to be art... Test AF, sharpness, decentering. All you need is a brick wall...

If you suspect any problems, take it home, put it on a tripod and do specific tests to investigate/document the problem.

Lensrentals.com has a very good primer on testing for decentering.

http://www.lensrentals​.com …technique-gets-a-makeover

It includes an image of the Zeiss Siemens Star Chart. The chart can be purchased, but you can also right click and download the image and print it out at fairly high resolution on 8.5x11 photopaper or enlarge it and view it on screen. Following the easy directions in the link I was able to quickly identify that my first copy of my Sigma 30mm f/1.4 was badly decentered to the upper right. I knew there was an issue but the test let me immediately identify it. I sent it back to B&H and tested the second copy as soon as it arrived. The new copy did not suffer from decentering. I also checked out my Canon 15-85 for decentering since there were reports of this problem in some reviews. My copy does not exhibit this problem. Since this testing literally takes no more than 5 minutes tops, I fail to understand why anyone would not want to perform it immediately on a brand new lens rather than figure it out over time.

DC Fan wrote in post #16467205
The best way to "test" a lens is to use it for the purpose for which it was purchased. A couple of weeks' extensive use will answer all questions. Only real-world exercise will reveal any equipment's strengths and weaknesses (and the photographer's limits as well).

It's useful to note that photo equipment performs best when used to capture images of real three-dimensional subjects.

Sorry disagree.

Let's say your lens is decentered in the upper right corner. If all u shoot are landscapes and people most likely u will never notice this problem because u never position a textural element that is intended to be in focus in that position.

Would u want canon repair centers to test your lenses only by going outside and shooting random stuff? No? Then why would u test that way?

Xyclopx wrote in post #16472589
Sorry disagree.

Let's say your lens is decentered in the upper right corner. If all u shoot are landscapes and people most likely u will never notice this problem because u never position a textural element that is intended to be in focus in that position.

Would u want canon repair centers to test your lenses only by going outside and shooting random stuff? No? Then why would u test that way?

If all I shoot doesn't bring it into play then I don't care. Period.

I have a Sigma 30 that I love. It's never let me down in real world use. On a lark I decided to "test" it in the way that a lot of the folks on this forum suggest.

It failed miserably.

So I put it on my camera and kept on shooting and getting the great results I had been getting all along.