Even though we ARE Nikon lovers,we are NOT affiliated with Nikon Corp. in any way.

English German French

Sign up Login
Home Forums Articles Galleries Recent Photos Contest Help Search News Workshops Shop Upgrade Membership Recommended
members
All members Wiki Contests Vouchers Apps Newsletter THE NIKONIAN™ Magazines Podcasts Fundraising

What to do? Bad lens? Bad D7000 body?

ericbowles

Atlanta, US
10552 posts

Click to send email to this author Click to send private message to this author

"RE: What to do? Bad lens? Bad D7000 body?"

ericbowles Moderator Awarded for his in-depth knowledge and high level skills in various areas, especially Landscape and Wildlife Photoghraphy Writer Ribbon awarded for for his article contributions to the community Donor Ribbon awarded for his very generous support to the Fundraising Campaign 2015 Nikonian since 25th Nov 2005
Sat 02-Feb-13 01:13 PM | edited Sat 02-Feb-13 01:23 PM by ericbowles

I know the lens has already gone back, but just a few comments for future reference.

The 50 f/1.4 should produce very sharp images, but DOF is very small wide open. That makes it easy to miss focus. But you already know that. The other issue is the 50 f/1.4 is not at it's sharpest wide open. While you should use f/1.4 for fine tuning, it really performs much better at f/2-2.8. So getting sharp images requires a different aperture than fine tuning - and your test images should be a little soft at f/1.4.

In comparison to the 18-200, the zoom has an minimum aperture of f/4 or so at 50mm. That means you are going to have a lot more DOF and many errors will be forgiven. The 18-200 may have issues at the extremes, but at 50mm it is in a focal length where it performs very well compared to any lens including the 24-70.

AF is not perfect. AF accuracy can be viewed as a relative distribution of AF errors over a number of images. If your test equipment is precise, you'll see that every time you focus using AF, the result is a little different. There should be a concentration of AF results at the best the lens can perform, but there will also be a distribution of missed focus that includes some bad misses. There is a thread somewhere here by NatGeo photographer Daniel Cox with a link to his blog. He tested the D4, D800 and D600 AF on a moving dog in great light. With the D600 he only hit focus on 54% of the images - and he thought that was quite good. The D4 hit about 70%. All of the results were better than any prior Nikon camera.
http://www.naturalexposures.com/corkboard/testing-the-nikon-d4-d800-d600-in-predictive-auto-focus/

While it did not come up here, the center sensor is the one that performs best on Nikon cameras. The surrounding cross sensors perform slightly less well, and the other sensors less accurately still. This also applies to the amount of light required wide open - the center sensor is the one that focuses at f/5.6 or f/8 and other sensors may only provide focus at f/4.

Phase detect AF is slightly less consistent and less accurate than the contrast detect AF of Live View. Live View will be better and more consistent, but it is slower - and not practical for some images. Still, Live View provides a perspective on what the lens is capable of delivering if properly fine tuned. Think of it as a baseline.

There are a wide range of AF tests for different factors. You can test to fine tune the lens. You can test for performance of phase detect focus on specific AF sensors. LensRentals.com does most of their testing with the center sensor only - other sensors are not going to be as accurate and introduce many other variables.

Stick with the 50 f/1.4 - it really is a very good lens in spite of the copy you received and issue you experienced.

Eric Bowles
Nikonians Team
My Gallery
Workshops

Nikonians membership — my most important photographic investment, after the camera

This is a hot, active topic! What to do? Bad lens? Bad D7000 body? [View all] , Omaha , Thu 31-Jan-13 01:31 AM
Subject
ID
Reply message RE: What to do? Bad lens? Bad D7000 body?
1
Reply message RE: What to do? Bad lens? Bad D7000 body?
2
Reply message RE: What to do? Bad lens? Bad D7000 body?
3
Reply message RE: What to do? Bad lens? Bad D7000 body?
5
     Reply message RE: What to do? Bad lens? Bad D7000 body?
9
Reply message RE: What to do? Bad lens? Bad D7000 body?
4
Reply message RE: What to do? Bad lens? Bad D7000 body?
6
Reply message RE: What to do? Bad lens? Bad D7000 body?
7
Reply message RE: What to do? Bad lens? Bad D7000 body?
8
Reply message RE: What to do? Bad lens? Bad D7000 body?
12
Reply message RE: What to do? Bad lens? Bad D7000 body?
10
Reply message RE: What to do? Bad lens? Bad D7000 body?
11
     Reply message RE: What to do? Bad lens? Bad D7000 body?
13
     Reply message RE: What to do? Bad lens? Bad D7000 body?
14
          Reply message RE: What to do? Bad lens? Bad D7000 body?
15
               Reply message RE: What to do? Bad lens? Bad D7000 body?
16
                    Reply message RE: What to do? Bad lens? Bad D7000 body?
17
                         Reply message RE: What to do? Bad lens? Bad D7000 body?
18
                              Reply message RE: What to do? Bad lens? Bad D7000 body?
19
     Reply message RE: What to do? Bad lens? Bad D7000 body?
26
Reply message RE: What to do? Bad lens? Bad D7000 body?
20
Reply message RE: What to do? Bad lens? Bad D7000 body?
21
Reply message RE: What to do? Bad lens? Bad D7000 body?
22
     Reply message RE: What to do? Bad lens? Bad D7000 body?
23
          Reply message RE: What to do? Bad lens? Bad D7000 body?
24
               Reply message RE: What to do? Bad lens? Bad D7000 body?
25