Dog (sports) Photography: focus question

[Desi]

Hi all,

I've been taking some photos of my dog at the beach. I'm pretty new to this sports type of photography, so I have a question about focus modes.

I'm trying to get a good shot of my dog creating a whole mess of sand exploding as she gets the ball. To this end, I have someone throw the ball at me and I shoot the dog as she runs at me. I shoot a nikon d800 with a 70-200 lens. Single focus point. continuous focus mode keeping my finger depressing the button as I track the dog. I've noticed that most of my shots have the dogs mid-section in focus with her face slightly out of the focal plane.

Any thoughts on getting improved focus? Again, the dog is running right at me and fairly close (15-20 feet).

Here's an example

Exploding Sand by Desi595, on Flickr

Thanks,

Desi

 

[Designer]

I couldn't read the EXIF or see the point of focus, so I'm only guessing.

Could be the DOF is too thin.

What we know: The distance is pegged at 8 feet from the camera. We know the camera and the lens, but we would need to know the aperture when you shot. We would also need to know the focal length of the shot.

 

[JacaRanda]

Hi Desi,

More depth of field would/should help (F8 maybe), and also you may try using more focus points to help as opposed to just one. Not familiar with Nikon, but maybe this video at about the 2:35 mark will help.

 

[JacaRanda]

I couldn't read the EXIF or see the point of focus, so I'm only guessing.

Could be the DOF is too thin.

What we know: The distance is pegged at 8 feet from the camera. We know the camera and the lens, but we would need to know the aperture when you shot. We would also need to know the focal length of the shot.

Went to the Flickr link - shot at F6.3 @ 200mm

 

[Desi]

200mm at f6.3. Not sure about the distance in this particular shot. f6.3 because I wanted to get the shutter speed to 1/1000. The focus point is central, the photo is cropped.

 

[astroNikon]

^^ as Designer said.
But when I look at it your shutter could be slightly too slow for the flying dirt too

We need to see your EXIF or you can tell us your Shutter,Aperture and ISO

With DOF if your aperture is wide open such as f/2.8 your DOF could be too shallow to get everything in focus. A way to understand this better is to use a DOF Calculator and on a fixed object get a measuring tape out and test your understanding.

DOF ==> Understanding Depth of Field in Photography
calculator ==> A Flexible Depth of Field Calculator


Edit - you guys are fast .... before I hit Reply lol

 

[JacaRanda]

200mm at f6.3. Not sure about the distance in this particular shot. f6.3 because I wanted to get the shutter speed to 1/1000. The focus point is central, the photo is cropped.

Because her head is whipping around, I would kick it up a notch and go with 1250 or 1600 shutter speed. Go with F8 and set auto iso.

 

[astroNikon]

I noticed the tail was blurry at the tip .. so I was thinking shutter


using the DOF calculator
Nearest Acceptable Sharpness: 5.85 meters
Furthest Acceptable Sharpness: 6.12 meters
Total Depth of Field: 0.31 meter = 1.1 foot

 

[Designer]

O.K., I plugged in your numbers and got this:

Subject distance 8 ft

Depth of field
Near limit 7.92 ft
Far limit 8.09 ft
Total 0.17 ft

In front of subject 0.08 ft (49%)
Behind subject 0.09 ft (51%)

Hyperfocal distance 689.6 ft
Circle of confusion 0.03 mm

So the DOF being 0.17 ft. means it is only 2.04 inches. TOTAL!!!!

So if the point of focus was the dog's mid-section, then the muzzle will not be in focus. Nor the tail.

Boost your ISO and stop down a bit.

 

[astroNikon]

O.K., I plugged in your numbers and got this:

Subject distance 8 ft

Depth of field
Near limit 7.92 ft
Far limit 8.09 ft
Total 0.17 ft

In front of subject 0.08 ft (49%)
Behind subject 0.09 ft (51%)

Hyperfocal distance 689.6 ft
Circle of confusion 0.03 mm

So the DOF being 0.17 ft. means it is only 2.04 inches. TOTAL!!!!

So if the point of focus was the dog's mid-section, then the muzzle will not be in focus.

Boost your ISO and stop down a bit.

his first post stated 15-20 feet distance from subject

 

[Designer]

Oh, I forgot to say:

GREAT SHOT!

 

[Designer]

his first post stated 15-20 feet distance from subject

Yes, he did, but I got the distance while trying to view the EXIF.

 

[Desi]

I think the DOF is adequate when she is moving slowly. In this setting, she is moving quite fast and it seems the cameras autofocus is not keeping up with her. I agree that stopping down would help DOF but would hurt shutter speed. I still get quite a bit of motion blur at 1/800. Not sure if there is a better strategy to keeping up with the dog. I know Nikon has a dynamic focus mode, which I haven't tried using before.

Thanks for your comment Jacaranda, Designer and AstroNikon. They are much appreciated.


Here's the dog at 1/800 second, f6.3, ISO 400, 155mm....just for fun. Different day.

Marty by Desi595, on Flickr

I'm taking her back to the beach next week to try again. Maybe just getting farther back will help with the DOF. I can't quite predict where the ball will land, but one thought I had was to focus on the ball, rather than the dog.

 

[JacaRanda]

Hmmm. Can you just go manual, set shutter 1600, aperture to F8 and auto iso?

 

[astroNikon]

his first post stated 15-20 feet distance from subject

Yes, he did, but I got the distance while trying to view the EXIF.

Yeah it is in there isn't it

• Lens ID - 162

• Image Number - 30986

• Approximate Focus Distance - 10

He's using his d800 a lot too ... 30,986 clicks