Focusing; Using Autofocus - Nikon D5100 Experience Manual

Nikon D5100 Experience
File Sizes and Maximum Burst Rate
An additional important consideration with file format choice – JPEG or NEF (RAW) – is the
size of the files and the maximum burst rate when using Continuous Shooting Mode. Using
JPEG format, the image files are going to be around 7 or 8 MB, which will allow for a lot more
images on your 8 GB or 16 GB memory card. And the time you spend transferring them plus the
space you need to store them on your computer and external hard drives will be much less. (You
are going to be storing backups in two or three separate places, right?) The highest quality and
least compressed RAW image files will be up to about 20 MB in size. That's pretty big. They
take a lot of time to transfer to your computer and take up a lot of space on your hard drives.
You will have to invest more in external hard drives to store your ever-growing image collection.
Regarding maximum burst rate, a large high quality JPEG file will allow a burst of 100
continuous images, while RAW will allow only 16 before the buffer fills up and the camera has
to stop briefly to process them, and RAW+JPEG Fine and Large will allow 10. Now keep in
mind, 16 images in a row may be more than enough to suit your needs. But if not, you may need
to use JPEG in certain situations.
Capturing and saving both NEF(RAW)+JPEG may seem like a convenient option so that you
have the RAW files to post-process but JPEG files for immediate use. But remember that you
will need memory card and hard drive space to store all of these files, and it will limit your
maximum burst rate.

Focusing

Using Autofocus

One of the essential steps in taking a successful photo is controlling where the camera focuses.
If you allow the camera to autofocus by choosing its own Focus Point(s), it typically focuses on
the closest object or human subject. This may or may not be what you want to focus on. So you
should choose where the camera focuses using the autofocus Focus Points and selecting a
specific AF point. This does not mean you have to manually focus the camera, it means you tell
the camera exactly where to autofocus. In AF-Area modes other than Auto-Area AF, you will
select the autofocus Focus Point (AF point) using the Multi Selector. The center OK Button is
used to select the center AF point.
Note: I use the term "recompose" throughout the text. By this I mean moving the camera after
you have set and locked the focus or exposure but before you click the shutter and take the
picture. This means that what you see in the viewfinder changes from when you do those first
actions to when you take the picture – you have recomposed the view you see in the viewfinder.
See Figures 19 and 20 for an example of recomposing.
To see how autofocus point selection works, first make sure the focus mode on your lens is set at
A or M/A. (If it ever seems that your camera or lens is not autofocusing, be sure to check this
switch.) Press the i Button twice and navigate to the Focus Mode setting (Figure 16). Change it
to AF-S for Single-servo AF (Figure 17). Return to the Information Display Screen, navigate to
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