How to Evaluate a New Lens? (Sort of Disappointed with the 16-70)

Started 7 months ago | Discussions thread
Ynos
Regular MemberPosts: 182
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Re: How to Evaluate a New Lens? (Sort of Disappointed with the 16-70)
In reply to CameraCarl, 7 months ago

CameraCarl wrote:

I just received a new Sony/Zeiss 16-70mm lens which I bought because I was not happy with the corner and edge sharpness of my kit 16-50 on my NEX-6. Today I went out and shot several hundred images to compare the two lenses. I used a tripod, OSS off, and the self timer to photograph both a large building and a large bookshelf. I took photos at 16, 24, 28, 35, and 50mm at apertures from f4 to f11. I'm comparing both jpegs and RAW images (with lens corrections applied) in Lightroom 5 side by side at 100%.

The results seem to be all over the place. Both lenses seem to be equally sharp in the center. At some focal lengths and apertures, the 16-70 is better at the edges and corners. At other focal lengths and apertures, the 16-50 is better at the edges and corners. What is surprising is that the 16-70 does not knock my socks off in image quality. In daylight (how I tested it today, both outdoors and indoors) I can see the 16-70 has a slight edge in contrast and color, but in the matter of sharpness, there is no clear superiority. I'm still sorting through all the images and will post some comparisons tomorrow, both in this thread and in my gallery. Meanwhile I'm wondering if I am not evaluating the 16-70 properly since I was expecting a lot more from it for $1000. Any suggestions how to evaluate a new lens?

I would print a test chart and some text or put a high detail map with pictures and text, put it on a wall and increase distance between camera on a tripod at least up to 3m to avoid field curvature. Turn OSS off, do Manual Focusing and do focus bracketing if you can - then chose sharpest picture to compare. You have L 24-105 lens as well judging from your gear signature - compare your shots with this lens if possible. Both are zooms of same effective range and constant f4. Then evaluate step by step - corners, edges, midline, center, look at photos and text clarity.

Alternatively, you can print a test chart and manually focus on same part of chart using first center part of lens and then each of 4 corners. Compare them. If corners are equally slightly worse than center - all is good. If one side is worse - there may be a slight decentering. Again judging from how blurred corners are or how hazed they are - you can get an idea how your lens performs. It's a long process and not easy.

My opinion is that people just over expect or expect too much from a zoom. 16-70 is a nice zoom, but it is not much different from 16-50 or 18-55 or any other NEX zoom. Difference is not going to knock your socks off. Try to look at this zoom as more convenient zoom with wider range and constant f4 compared to kit zoom. Better contrast maybe due to T* coating, less flair and so on. But it won't be as sharp as some descent primes can be. It won't be like E24Z or FE55 or Otus or old Zeiss ZM lenses. No. i think if that zoom's price was $599 nobody would complain. People tend to overestimate it due to high price. If 1 car costs 3 times more than the other - it won't drive 3 times faster. Maybe slightly faster. Mostly differences will be in comfort, build, reliability, extra features etc. Same with 16-70 vs kit lenses.

P.S. that is exactly why I created a thread about DxO testing 16-70. Because I knew many people will be dissapointed by having too high expectations. Sometimes reasonable, sometimes not. People will be dissapointed with AF, with 16-70 and so on. What needs to be done - is to better advertise or at least better review a6000 with good explanations of what this camera can do and where its limitations are, including compatible lenses that really keep up to speed of AF. We (users) need that info. Not everyone is a pro and it's not necessary to get the truth only by buying camera and testing it inside out. Otherwise there are going to be lot's of returns (and we already had some threads about returns). Same with 16-70 - sooner the DxO will test it - sooner people will get some idea where this zoom sits and what to expect from it. Let's say it will get score of 16 on A6000 - that means slightly higher than kit zooms, but lower than almost any prime. People will not hold unrealistic hopes and will settle down happily knowing that they got what they wanted. IMHO knowledge and better tests and reviews will never hurt. BTW, a good manual explaining all settings in detail would be nice too (for A6000).

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