Metering?

[rowingbum]

Here are three shots I made today. This may seem like a dumb question, but why is the focus limited to such a narrow circle? BTW...I am taking the Nikon school in early Feb. These shots were made with a Nikkor 18-200 and SB-900.
Thanks,
David

[ChristopherCoy]

I can't see the exif, but apertures like 2.8 to 8 have shallow depth of fields.

Check out the book "Understanding Exposure" for a full explanation.

[WarrenG]

David,

At first glance it does not appear to be a metering issue, but rather as Chris mentioned, it looks like an aperture issue. Posting the exif information would be helpful... but remember as a general rule of thumb, lenses are their sharpest stopped down 2 stops and at the middle of their zoom range and conversely, at their worst "wide open" and zoomed all the way out. With that said, try stopping down, and adjusting your distance from the subject to accomodate the above statement and see if it improves the shot? The lens you are using is not likely to give you stunning bokeh but you can accomodate for that in post if need be, albeit a little time consuming.

W

[humminboid]

Your pixes are sharp and beautifully exposed. Nikon Matrix metering is the best!

It is a depth of field..not a "problem", but a fact. You have a BEAUTIFUL , capable lens. Cherish it!

Your depth of field is too shallow to encompass the whole subject.

Depth of field extends at a 90 degree angle to the lens axis. (across the way the lens is pointed)

It extends from ~1/3 in front of the subject to about 2/3 behind.

It is governed by four things only, which are based in the laws of physics.

1. Focal length of the lens: Wide angle lens= more depth of field; Telephoto lens= shallow depth of field.

2. F/stop: This is often confusing, and seemingly backwards, but that's photography. Learn it, and it will serve you well.
Large f/stop (small number, like f/4 means a bigger hole in the lens diaphragm)will give shallow dof, and lets in more light.

A "small" f/stop, which is designated by a larger number, like f/22, means a smaller hole in the lens' diaphragm, and that gives more dof, as well as letting in less light.
There is a technical reason for all that, which is not anything you will need to remember, and that is: the f/stop designation is a fraction of the ideal f/stop of f/1.
F/11 is 1/11th of the illusive (and expen$ive) f/1.

Stuff like this doesn't happen very often in photo, thank goodness!


3. Distance from the subject: The closer you are, the shallower is the depth of field.

4. The distance focused upon: same thing; close=-less dof, far= more.

I don't know what your distance or f/stop was, but, you could extend the dof by stopping down, or backing off. To do that, you might have to use a tripod, or increase your sensitivity. Probably a combination would work best.

Enjoy your Nikon School!