D2X Acuisition / Tracking Issues

[jfenton]

I confirmed to myself this past weekend that there is a definite issue with my D2X and the D2X of others with the cameras ability to acquire and track a moving target (bird), be it a full 1/2 frame subject or something smaller, at medium to long distance.. I have discussed this with others well versed at this type of shooting who have shot both the D2H and now the X and have been told that they are experiencing the same issues.

This was tested using both a 300 AFSII and a 500 AFSII.


Acquisition (lock) was very difficult if not impossible at times and focus yield was substantially lower than 30%. Prior experience with the D2H yielded substantially higher yields, in the 70-80% range.

This occurs at medium to long target distance in any focus mode and in any contrast situation. It appears to be worse with targets moving towards or away, the the yield is better with targets moving parallel to the camera.

At close range....ranges of less than 40 feet, there appears to be no issue at all, at least with my particular camera.

I have contacted Nikon (someone of service prominence was contacted directly) and advised them of the issue and have been told that it will be looked into immediately.

As soon as I hear anything official, I'll post the information.

 

[DavidM]

Very interesting Jim...

I've been having a bear of a time with focusing in general on my D2x, but had assumed (up til now) that it was my lack of technique. Given that one of the main reasons I wanted this camera was to gain a better focusing system than the D100 had, I have to say that I've been frustrated so far with my tests.

I'm still not convinced that my issues aren't more related to low/poor light and the use of TCs, but I will certainly watch this thread closely to see what you find out.

 

[Joe_Lorenzini]

I had this same experience. I shot an indoor Supercross race and when the racers were closest to me I got the highest yield, when they were on the other side of the track and a much smaller target, I got a very low yield.

I too figured it was low light followed by a smaller target but I've shot this type of event before and didn't as much trash as I got this time. I'm still going to test it out more but Jim may have something here.

_/oe

 

[DiverX]

Hmmmm! I thought about this also but have not had a chance to really test it. I had some issues with birds flying at me but again have not had that many chances. I do have a bunch of days now (10 or so) off to test it out on my gear (500mm AF-S, 200-400, etc, etc) so I will be if I get the opportunity. Please keep us posted and thanks for the heads up!!

 

[jfenton]

More Info

I shot Canadian geese today...coming and going fast, slow,...you name it..I shot them.

I'll estimate that I got a 20% acceptable yield...are you ready for this one? All of the in focus shots were ones which I totally missed getting the hot reticle on the target.

I tried shooting at f9 and 11 to get a greater depth of field but it really made no discernible difference....and it slowed the shutter speed down to a point where I started to pick up motion blur.

To prove even further that is wasn't all in my head, I borrowed a D2H and shot it as well. As I was accustomed to...as long as I didn't grossly miss the shot, they were in focus.

Definitely a bug here somewhere.

 

[jfenton]

David

My original assumption was that it was due to low light..low contrast...TC's...etc.

Then I tried it with no TC in really nice bright light on things like Canadian and 4 snow geese that happened to be in the area against a deep blue sky..and the same results. About a 20% yield.

Don't get me wrong...I love the camera...they just need to get the acquisition / tracking squared away.


It's not just moving targets either. It is targets at distance.

 

[DiverX]

Re: More Info

I shot Canadian geese today...coming and going fast, slow,...you name it..I shot them.

I take it all of this was with AF-C? Did you try with AF-S? I will do same tomorrow.

Also, I want to try with "Lock-on" both "on" and "off". Maybe there is something messed up in the subroutine.

 

[Larry Gleason]

That will be something I will be taking a hard look. The Steeplechase would have been a good test but that is gone until October. I'll find something meanwhile to see if its a common issue. Most of my tracking focus as been horses and dragboats so at least those are large critters.

 

[Harry S.]

I'm glad someone brought this up. I'm having similar issues lately with the D1X and the 70-200VR. I made some shots of my wife at 200mm and she was quite far from me. It took me several attempts until the focus really locked. Firstly, when I got some shots that were not sharp I dreaded a back-focussing issue.

I am not a tech expert, but might it be that the AF sensor covers a larger area than the subject (if the subject is very small)?
Oddly enough (since it is mentioned above), I have only recently switched from AF-S to AF-C because I hated that the camera would not release if the subject is outside the AF-area and to permanently use the lock-button is a nuisance.

I wonder if someone has an explanation for this.

 

[jfenton]

Further D2X Focus Observations

First Off...

I have found the isue to occur in both AF-S and AF-C

It is occuring with Focus tracking / Lock on both on and off.

Interestingly, this is beginning to look in my small test cases to be related to AFS lenses.

I have tested both flavors of 85mm lenses (1.4 and 1.8) as well as an older 70-210 AFD push pull zoom...and they all worked substantially better than the AFS lenses I've tried.

Is anyone else able to confirm this particular observation?

 

[DavidM]

Jim -

So far I've had the following lenses on my D2x (all Nikon):

50mm 1.8
70-200mm AFS VR (with and without TC-14 and TC-17)
300mm f/4 AFS (with and without TC-14 and TC-17)
17-35mm AFS

I haven't done any controlled focus testing with these, but I believe I can say that I've had the most trouble with the two longer lenses (70-200 and 300), with the 300 being the most difficult. It's quite possible that the reason is simply related to the subject matter, but I'd really need to do more checking to know for sure.

The 300+TC14 combo works reasonably well on my D100, but my yield on the D2x has been much lower. It's also fair to say that I've had less than ideal lighting while shooting with the D2x (NC can't compare to Fla when shooting birds -- they're a lot more shy here and stick to shady areas).

I haven't had a lot of time and opportunity for shooting lately, so when I do I tend to experiment a lot with features that I haven't used before (ie. Auto ISO a couple weekends back -- not a single keeper because I was also using the 300+TC17 combo and most were wide open).

For now, I'm still willing to accept that most of my problems have been operator error as I learn about the new camera and various lens and setting combinations, but I've had enough difficulty trying to lock focus on some things that I'm starting to get suspicious.

 

[Scott Sherman]

I may have missed this but has anyone done these experiments with the 2.0 crop? If the AF sensors are only on a small part of the sensor it may be that the camera is tuned to work with this type of moving target in the crop mode at high speed. Just a guess. I am still looking for a D2x so if anyone knows of one...

 

[Joe_Lorenzini]

Hi Scott,

I used the HSC feature exclusively when I shot the race, it is a fantastic feature that I use quite a bit. I did not notice any performance difference between full size and HSC.

I've experienced this behavior mostly with the 70-200mm VR.

_/oe

 

[hans]

Jim

Seems to me that with the 17-55 dx and the 28f1.4 i've got no "soft"shots with the 70-200vr a lot especially with tracking that big doggie

I will follow this thread hope spomeone explains it

 

[MontyDog]

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[MontyDog]

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