Quick Help with my 50mm 1.4

[hipmom]

When I shoot a family portrait occasionally one person is out of focus. Why? This lens is so sharp how do I prevent that- where should I focus on a family or 4 so everyone is sharp?

[woods]

If you shoot at f1.4, there is definitively gonna be blur in your shot. Even if you aim at the eyes, the ears (for example) will probably be out of focus. I'm not a pro but people usually stay around f4. Depending on how do you set up your scene, you may be able to have a higher aperture though.

[private]

Take a look here Online Depth of Field Calculator it'll help you visualize DoF. But what might be more helpful is if youpost an example.

[Chip]

It could easily be a DOF problem. For a 50mm at ƒ1.4 and a focal length of 10 feet, the DOF is likely much less than 1 foot. So, unless you get all those faces lined up in the DOF, then at least some parts of faces will be out of focus to a certain extent.

Using 2.8 or more would give you a bit more DOF and would still blur your background nicely, and would give you more margin for error.

As to where to focus, the rough general rule is that the 1/3 of the DOF is in front of your subject, and the other 2/3 is behind your subject.

Hope this helps.

[dcclark]

Here's an important thing to know: the "sharpness" of your lens has nothing to do with your problem. It's almost certainly a depth-of-field problem, as others have noticed: when you have a large aperture (f/1.4 or f/1.8, for example), only a very few things will be in focus.

The "sharpness" of a lens is an overall quality, not something which affects individual subjects in your photos.

[wulf]

I've rewound this discussion and deleted all the posts which were part of people arguing with each other rather than sharing and explaining some answers. Yes, you can debate things but not if you are going to start throwing round words like "tiresome" and "ignorant". Play nice or not at all.

And, a question for hipmom - what aperture setting(s) were you using?

Wulf

[fletch]

Originally Posted by wulf

I've rewound this discussion and deleted all the posts [...]

Boo!

Now I'm going to have to re-type all of my helpful advice!

50mm wide aperture lenses are normally sharpest between f//4 and f/5.6. At f/5.6 with the subject 10ft away DoF will be 3 ft (assuming a Nikon Dxx or Dxxx camera). Therefore your should be able to get everyone in focus at this aperture with the added bonus of being in the lens' sweet spot for sharpness.