Nikon D800 Autofocus Test Setup

Nikon D800 Autofocus Repair Testing - The Sequel

This is the third time I'm posting about the testing of my D800 autofocus system.  The first time was not long after I purchased it, just to see if it had the problem.  I found that it did have the problem, and I sent it to Nikon for repair.  When the camera came back, I tested it again.  Initially I thought it may have been fixed, but further testing showed there was still a problem.

During this time, I also purchased LensAlign and FocusTune to help me more accurately fine tune my lenses and camera, but also to help me quantify the results.  When I tested my lenses, I noticed that the recommended fine tune values for three of my five lenses was +20 (the highest possible).  This suggested to me that the actual sharpest fine tune value may be even higher than than, but the scale does not allow further adjustment.  Said another way, if the fine tune is at the maximum value, the calibration is not within spec for the camera/lens combination.  I decided to give my D800 and my Nikkor 50mm f/1.8G, Nikkor 80-200 f/2.8D, and Nikkor 24-70 f/2.8 to Nikon along with my results to see if they can fix the left autofocus problem plus calibrate the camera for the three lenses.

I finally received my camera back, and had a chance to test it with two lenses.  I tested with the 24-70 and the Nikkor 105mm f/2.8 Micro VR (this lens didn't go to Nikon).  I did not fine tune the camera and lenses before testing, this is how Nikon sent it to me.  I used the same test procedures I outlined previously, with a small twist because I now have FocusTune to help me out.  The results here are all RAW conversions (the only adjustment I made in Lightroom was to convert to grayscale).  I shot in RAW+JPG (L/Fine), I shot a manual focus control shot for each of the five focus test points tested (center, top, bottom, left right - all at the farthest AF points).  Between each autofocus test shot, I defocused away from infinity and took five shots for each focus point.  I then loaded all of the JPG files into FocusTune and for each focus point I found the SHARPEST result from the five samples, so the results here are the best shots from the group.

One thing to note, last time I sent the D800 to Nikon the work order showed "ADJ FOCUS SYSTEM" and "ADJ AUTO FOCUS OPERATION". This time, the work order had:

[box]

B2

Service Repair Rank B2

Repair

RPL O-RING

CLN CCD

FIRMWARE UPGRADE

GENERAL CHECK & CLEAN

RPR ELECTRICAL CIRCUIT

[/box]

It is worthwhile to note that I was not having any problems with my D800 outside of the autofocus system, I'm not sure why they replaced the o-ring and worked on the electrical system. I see no mention of them even looking at the autofocus system.

 

Lenses Tested

AF-S NIKKOR 50mm f/1.8G

AF-S VR Micro-NIKKOR 105mm f/2.8G IF-ED

AF-S NIKKOR 14-24mm f/2.8G ED

AF-S NIKKOR 24-70mm f/2.8G ED

 

Test Results

The grouped results for the 105mm lens, 100% crop under the autofocus sensor tested.

Nikon D800 Autofocus Test : Nikkor 105mmf/2.8 Micro VR: 105mm Results

Apologies that some of these are dark, I didn't want to make any adjustments so they are presented straight from the camera with no editing.  I don't see any major issues here, the focus system seems to be fairly consistent between all of the points.  Here is a closer look at the 105mm left side results.

Nikon D800 Autofocus Test : Nikkor 105mm f/2.8 Micro VR : 105mm L5 Detail

 

I would say this is fine, doesn't quite match the manual focus using live view and 100% zoom but I don't think phase detect AF is ever going to be as good.

The grouped results for the 24-70mm lens at 24mm.

Nikon D800 Autofocus Test : Nikkor 24-70mm f/2.8 : 24mm Results

Here, the left side AF sensor is clearly softer than the others in the group.  Here is a bigger version of just the left side results.

Nikon D800 Autofocus Test : Nikkor 24-70mm f/2.8 : 24mm L5 Detail

 

The grouped results for the 24-70mm lens at 70mm.

Nikon D800 Autofocus Test : Nikkor 24-70mmf/2.8 : 70mm Results

Once again, some softness on the left side.  Bigger version of 70mm left side results.

Nikon D800 Autofocus Test : Nikkor 24-70mmf/2.8 : 70mm L5 Detail

 

I would say it's not as bad as the 24mm left side test, however I would not say this is acceptable performance.  The lens works fine at the other focus points, here are details of the performance at the center focus point at 24mm.

Nikon D800 Autofocus Test : Nikkor 24-70 f/2.8mm : 24mm C Detail

 

The 24-70mm center focus point at 70mm.

Nikon D800 Autofocus Test : Nikkor 24-70mmf/2.8 : 70mm C Detail

 

Both of these are completely acceptable and would not give me any reason for concern.  However, the left side AF sensors continue to give me grief.  I'm not sure if it's the lens or the body though, because the 105mm seems to focus fine at the left side.  I'll try to test with my 50mm f/1.8G to see how it performs, and I'll post the results here when I'm finished.

 Update, April 2, 2013

The grouped results for the 14-24mm lens at 24mm, center and lower AF points are good, others soft.

Nikon D800 Autofocus Test : Nikkor 14-24mm f/2.8 : 24mm Results

 

The 14-24 @ 24mm L5 sensor detail.

Nikon D800 Autofocus Test : Nikkor 14-24mm f/2.8 : 24mm L5 Detail

 

 

The grouped results for the 50mm, again center and lower AF points are good, others soft.

Nikon D800 Autofocus Test : Nikkor 50mm f/1.8 : 50mm Results

 

50mm L5 detail, not terrible but could be better.

Nikon D800 Autofocus Test : Nikkor 50mm f/1.8 : 50mm L5 Detail

 

In general, the whole AF system seems to be a little off.  Fine tune won't fix this as the various AF points don't correlate to each other in how far out of focus they are.  If they were all equally off, fine tune could fix that.  Some, such as the center and lower (C, D2) AF point are excellent, others (such as L5) are consistently off.  If I fine tune, I'll be throwing off the good ones.

 

 

 


Nikon D800 Autofocus Test Setup

D800 Autofocus Repair Testing

[box type="info"]Update April 1, 2013: Testing after the second repair attempt by Nikon is now online here: http://photokaz.com/2013/04/nikon-d800-autofocus-repair-testing-the-sequel/[/box]

[box type="info"]Update January 20, 2013: Initial testing showed changes to the focus performance and I thought the slight softness in some shots could be fixed with fine tuning. After more testing, I could not get consistently sharp results from fine tuning. I had to set my fine tuning for the Nikkor 24-70 f/2.8 lens to +20 and that still didn't result in good performance. My AFS 50mm f/1.8 and AFD 80-200 f/2.8 lenses also had to have +20 of fine tuning. I dropped off my camera and the three lenses with Nikon last week, told them the problems and said I wanted everything repaired. I will once again post my results when I get the camera back.[/box]

[box type="info"]Update February 9, 2013: Got my camera back from Nikon, still waiting for my 24-70 lens. Some testing with the 50mm f/1.8G using FocusTune is not looking promising :([/box]

I made a previous post about the issues my Nikon D800 had with phase detect autofocus, my test charts clearly showed a problem with the left side AF sensors.  I dropped off my camera at Nikon and it came back with the following info.

[box]

B2

Service Repair Rank B2

ADJ FOCUS SYSTEM

ADJ AUTO FOCUS OPERATION

FIRMWARE UPGRADE

CLN CCD

GENERAL CHECK & CLEAN

[/box]

 

So it looks like Nikon actually did make a fix, though I have heard some people had cameras returned with B1 service repair but I'm not sure how they differ.  Today I decided to do some testing on the 'fixed' camera to see if it was any better.  Same test procedure as before, same Siemens Star test chart.  I only tested the 24-70mm f/2.8 lens as that more obviously showed the problems before.   Below you can see the results for the lens at 24mm, ISO 100.  Top row is Live View manual focus (reference), next is Live View autofocus (to test contrast detect AF), then two rows viewfinder (phase detect) autofocus tests.  The VF AF 1 is racking focus to the closest setting before letting autofocus take over, VF AF 2 was a rack to infinity.

Nikon D800 Post Fix Test - 24-70 f/2.8 @ f/2.8, ISO 100, 24mm

 

Disregard the differences in white balance, the right test chart was closer to a different set of lights. Focus should not be affected overall, and shows relatively consistent operation left, center, and right.

 

I repeated the test at 70mm but this time didn't test Live View autofocus. Here are the results.
Nikon D800 Post Fix Test - 24-70 f/2.8 @ f/2.8, ISO 100, 70mm

 

As before focus looks to be consistent, if not perfect, between the three tested points.

 

Finally, putting together my previous test charts with the updated tests shot today. Top row is Live View manual for reference, next row is the viewfinder autofocus tests before the fix and third row are the tests after the fix. This should clearly show that the fix worked. One thing to note is that the autofocus, even after the fix, is not in perfect focus however I hope that autofocus fine tune can fix that.
Nikon D800 Pre VS Post Fix Test - 24-70 f/2.8 @ f/2.8, ISO 100, 24mm