question about focusing

[minniemouse22]

Just received my new 35mm 1.8 and I've been experimenting a little. I was taking pictures of my children and I was wondering how I an fix the focus on their eyes? OR, general area where their eyes would be through my view finder (center of camera kinda thing). Nikon d500. Thanks!

 

[kathyt]

Have you been taking pictures thus far and not achieving focus? If so, show us an example. Also, please tell me you have went to your cameras manual first.

 

[The_Traveler]

Just received my new 35mm 1.8 and I've been experimenting a little. I was taking pictures of my children and I was wondering how I an fix the focus on their eyes? Nikon d500. Thanks!

What do you mean by 'fix the focus on their eyes?'

 

[minniemouse22]

Just received my new 35mm 1.8 and I've been experimenting a little. I was taking pictures of my children and I was wondering how I an fix the focus on their eyes? Nikon d500. Thanks!

What do you mean by 'fix the focus on their eyes?'

As in, when I push the button, it doesn't focus on their foot in the left corner or the flower on their shirt. I want the focus to be fixed dead center when I look through my view finder.

 

[o hey tyler]

As in, when I push the button, it doesn't focus on their foot in the left corner or the flower on their shirt. I want the focus to be fixed dead center when I look through my view finder.

Change your focus point to only the center focus point. Boom. Problem solved.

 

[minniemouse22]

As in, when I push the button, it doesn't focus on their foot in the left corner or the flower on their shirt. I want the focus to be fixed dead center when I look through my view finder.

Change your focus point to only the center focus point. Boom. Problem solved.

thanks! I just got it. Silly me.

 

[KmH]

Your D5000 has 3 auto focus modes - AF-S, AF-C, AF-A - PLUS 4 focus area modes - Single point, Dynamic area, Auto area, 3D-tracking. (pages 54-61 of the D5000 users manual).

The next consideration is depth-of-field (DoF) or how far from the camera the zone of acceptable sharp focus begins and ends.
How deep that zone of acceptable sharp focus (DoF) is is determined by several variable factors: the lens focal length, how far from the camera the point of focus (PoF) is, the lens aperture.

With a 35 mm prime lens the focal length stays constant and the PoF distance and the lens aperture become the main variable you can control.

So you want to take make a head shot type photo of one of your children
You pose the child so one eye is closer to the camera and you focus on that closer eye. You set the lens aperture to f/2.8.

Using an online DoF calculator, like Online Depth of Field Calculator we plug in the pertinent numbers;
Nikon D5000
Focal length - 35 mm
Selected f-stop - f/2.8
Subject distance (actually PoF distance) - 4 feet

and the calculator tells us
Depth of field
Near limit - 3.79 ft from the camera's image sensor
Far limit - 4.23 ft from the camera's image sensor
Total DoF- 0.44 ft (5.28 inches)
In front of subject - 0.21 ft (2.52 inches) (47%)
Behind subject - 0.23 ft (2.76 inches) (53%)

If you don't pay close attention and lean just 2.75 inches closer and don't re-focus, that front eye will no longer be sharply focused.

 

[minniemouse22]

Your D5000 has 3 auto focus modes - AF-S, AF-C, AF-A - PLUS 4 focus area modes - Single point, Dynamic area, Auto area, 3D-tracking. (pages 54-61 of the D5000 users manual).

The next consideration is depth-of-field (DoF) or how far from the camera the zone of acceptable sharp focus begins and ends.
How deep that zone of acceptable sharp focus (DoF) is is determined by several variable factors: the lens focal length, how far from the camera the point of focus (PoF) is, the lens aperture.

With a 35 mm prime lens the focal length stays constant and the PoF distance and the lens aperture become the main variable you can control.

So you want to take make a head shot type photo of one of your children
You pose the child so one eye is closer to the camera and you focus on that closer eye. You set the lens aperture to f/2.8.

Using an online DoF calculator, like Online Depth of Field Calculator we plug in the pertinent numbers;
Nikon D5000
Focal length - 35 mm
Selected f-stop - f/2.8
Subject distance (actually PoF distance) - 4 feet

and the calculator tells us
Depth of field
Near limit - 3.79 ft from the camera's image sensor
Far limit - 4.23 ft from the camera's image sensor
Total DoF- 0.44 ft (5.28 inches)
In front of subject - 0.21 ft (2.52 inches) (47%)
Behind subject - 0.23 ft (2.76 inches) (53%)

If you don't pay close attention and lean just 2.75 inches closer and don't re-focus, that front eye will no longer be sharply focused.

Wow, great response Keith. Thanks!