Another case of D2X backfocusing

Steve S · Aug 21, 2005

First, it was with the shoot of the young girl in the red dress a few weeks back, now this. I did print screens of these to show the focus area. Might be hard to see at this res, but this is a clear case of backfocusing. These are from my 2nd D2x body. My 1st one has already went in for focusing issues, and is working better now. I used AF-C, and Dynamic Focus Area, whatever it's called, the 2nd selection from the bottom on front of the camera. This body definitely has to go in for this. Now, I have to explain to the client that I need to do a reshoot, since few of the images taken are in focus. What a friggin bummmer. Your thoughts?

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ckdamascus · Aug 21, 2005

Steve S said:
First, it was with the shoot of the young girl in the red dress a few weeks back, now this. I did print screens of these to show the focus area. Might be hard to see at this res, but this is a clear case of backfocusing. These are from my 2nd D2x body. My 1st one has already went in for focusing issues, and is working better now. I used AF-C, and Dynamic Focus Area, whatever it's called, the 2nd selection from the bottom on front of the camera. This body definitely has to go in for this. Now, I have to explain to the client that I need to do a reshoot, since few of the images taken are in focus. What a friggin bummmer. Your thoughts?

Did you have lock-on enabled? Maybe you locked on to the fence behind the horse before the horse actually arrived, and it thought the horse was an obstacle, so it locked on to the fence.

I would guess predictive focus mode would guess what the moving object is and just guessed wrong, maybe that's why the 2nd image is slightly OOF.

I don't trust the focus selection you see in Nikon Capture since I heard if you do 'focus + recompose' it throws it completely off.

I try to fire a few shots at a time to hope it can lock on to the right subject. None of the additional follow up shots you did locked on?

ButchWilson · Aug 21, 2005

"clear case of backfocusing"

Looks like photographers error to me!. Wrong camera settings,wrong focal length.

Steve S · Aug 21, 2005

CSM selection a-4 "Lock On" is turned on

and no, none of the shots are in perfect focus. I do have some much more static shots that are. I was panning on tripod, btw.

biggstr6 · Aug 21, 2005

Im certainley not an expert at this stuff, but I think
those red brackets only show which sensor was used, not that that is where it was when the photo was actually taken (could have moved them before shot was taken), But in both shots looks like the area just above the red brackets is focused (background greenery).

seems like 2 possibilities to me.

1) Camera moved , Brackets off horse to bushes and the sensor picked those up.

or the sensor actually is picking up just alittle north of the brackets and locked on the bushes.

Beezle · Aug 21, 2005

In my experience, miscalibration will show up as slightly off. That is, the horse's eyes would not be in focus, but the rear of his mane would be. Something along those lines.

These look like focus was just aquired on the wrong thing. For whatever reason.

jfrancis · Aug 21, 2005

I agree that it looks like the focus has locked on to the wrong part of the image. I'm still struggling with this aspect of the D2X myself :shock: What shutter speed and aperture were used for these shots?

cknight · Aug 21, 2005

First off, I don't have a D2X, so I'm just going off of what I've read. Someone here posted a link to an article on Nikonians that gave a pretty in depth description of how the D2X focus system worked.

If I understood it right, then the dynamic focus mode doesn't really 'follow' the target from one focus zone to anther, it looks in the other zones for higher contrast objects. So if you focus on one object, and it decides there is a hight contrast object in another zone, it will focus on that.

In your first pic, there isn't much of a difference between the horse's head and the fence, so maybe it decided that the trees behind it were hight conrast.

I'm not sure I fully understand the article, and I need to reread it again, so I could easily be wrong here.

jfenton · Aug 21, 2005

Steve

Steve...

This isn't backfocus.

IMHO this is a very typical result of both the X and and the HS when the background presents a higher contrast subject than the subject does, no matter what the subject size.

I've seen this time and time agian...both with the birds I typically shoot and some horses I tried shooting at a local farm one day in a situation very similar to what you've shown.

Even the guys from Ron's Alaskan trip noted that it was nearly impossible to correctly acquire focus on a subject with a more contrasty background in moving shots.

The only thing I would have tried differently if you didn't have it set this way, would have been to use Iliah's suggestion of closest subject. I have found at times that this does work much better.

Steve S · Aug 21, 2005

Here's the shooting data & more info

Nikon D2X
Focal Length: 120mm
Optimize Image:
Color Mode: Mode I (sRGB)
Long Exposure NR: Off
High ISO NR: Off
2005/08/19 09:43:39.9
Exposure Mode: Aperture Priority
White Balance: Auto
Tone Comp.: Normal
Compressed RAW (12-bit)
Metering Mode: Multi-Pattern
AF Mode: AF-C
Hue Adjustment: +3°
Image Size: Large (4288 x 2848)
1/800 sec - F/2.8
Flash Sync Mode: Not Attached
Saturation: Normal
Exposure Comp.: 0 EV
Sharpening: Normal
Lens: VR 70-200mm F/2.8 G
Sensitivity: ISO 100
Image Comment:
btw, I was in AF-C, Focus Priority, Pattern 1, Closest Subject. I swear, I had that focus reticle locked onto that animal's head. I have to go back and try again, but this time I'm going to use Single Focus Mode, instead of Dynamic AF mode.

jfenton · Aug 21, 2005

Steve

Can you say

"The focusing algorithms have some bugs in them"?

As I stated previously, this is a very typical result in this type of situation...at least with the bodies which I have shot and apparently yours as well.

Iliah · Aug 21, 2005

Dear Steve, Pattern 1 might be the problem. In case a4 is not "OFF", upper sensor can maintain focus on the background, especially because it has good contrast.

Steve S · Aug 21, 2005

OK, thnx Iliah,

Iliah said:
Dear Steve, Pattern 1 might be the problem. In case a4 is not "OFF", upper sensor can maintain focus on the background, especially because it has good contrast.

I'll certainly try Pattern 2 next time, and yes, Lock On was "ON".

SRA · Aug 21, 2005

Steve,

I had the same results when I had focus lock on. It's just a tricky shot with moving targets. Takes practice like shooting trap.

ckdamascus · Aug 22, 2005

SRA said:
Steve,

I had the same results when I had focus lock on. It's just a tricky shot with moving targets. Takes practice like shooting trap.

But, you probably do NOT want lock on enabled.

http://www.nikonians.org/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=4973&forum=DCForumID71&viewmode=threaded

D. L. Miller · Sep 9, 2005

Why is it so hard to shoot moving objects with a D2x?

I have read the books, the threads in this "cafe" and if you ask 10 people how they do it, you get 20 answers. No one seems to agree as to the correct settings. The best I have seen, is one or two people are lucky enough to get clear shots if there is no background.

I have said it so much I am sick of repeating it. With my 35mm film, I could 1. Set the shutter speed at 1x the focal length of the lens
2. Pan the subject
3. Keep the subject in the middle of the view finder
and get a very clear shot of the subject with background blur.
I did this at auto races, track meets, bike races etc and always had great pictures. I was shown how to do this by a pro when I was 12 (45 years ago) and within 5 minutes I could do it. I showed my daughter how to do it with her P&S 10 years ago and she got great results. Is digital that different?

Because of the 1.5x factor with the D2x I increased the speed to 2x of the focal length and even tried 3x and the subject is still blury. I have tried the different focus options and subprograms too.

Using my D2x, I am really fustrated, I can't even get a clear picture of children running around in my back yard.

If the subject isn't moving, I get great sharp images.

So what is the answer?
Other then a bird in the sky with no background, how does one get a clear shot of a moving object. If the sensors don't represent what is being focused, what good are they.

I have even tried to use DOF to increase my chances of a good clear shot and I have found with the D2x and any lense the DOF is much smaller than if I was using my film camera. Is that possible??

I have also found if I stop down to f/16 or more the picture quality is less then if I shoot between f/5.6 to f/ 9.0

Am I completely crazy, or is there an answer?

I love digital and I hope to find the answer to moving subjects.

Please help!!!! I am open to any solution.......

Kevin Scott · Sep 9, 2005

Dan, I'm not sure I can offer any advice but I did want to add my 2 cents. I am not doing anything special but I certainly don't seem to have any of these issues you mention. I have posted many shots in the birds & animal forums of birds in flight, with sky backgrounds, 1/2 sky & 1/2 treeline backgrounds and only busy backgrounds and don't have a problem getting the bird in focus. Granted, there are occasions where some shots in a series might be oof but generally speaking, I have no complaints in this area. I'm no expert but it sounds to me like there might be something wrong with your camera if nothing seems to work for you.