I'm often asked about my opinion on camera selection, i.e. "What camera should I buy?". That's a really hard question to answer because it all depends on what you want to do with the camera. Today a more narrow question was asked that's a little easier to discuss, and that is: "What are the advantages of a dSLR over a point-and-shoot camera?". Since my reply ran on a bit, I thought it would make a good blog topic, so here you go... Professional lenses often go as low as F1.8 or F1.2. Many less
expensive hobbyist lenses go to F4 or F2.8. If you can find an F2.8
lens I'd go for it. Zoom lens quality is also judged by the ability
to use that low aperture regardless of whether you're on wide angle or
zoomed way in, say F2.8 at 24mm and also F2.8 when zooomed to 70mm.
Less expensive lenses have variable minimum aperture so they might be
at F2.8 at 24mm but only able to open up to F5.6 at 70mm. Portraiture
is often best when using mid-range zoom lenses cover at least 80mm to
130mm. When using those longer focal lengths the smaller F number
becomes more pronounced, making the subject appear to be sharp with
the background out of focus. Wider lenses like 10 to 50mm don't make
good portrait lenses because they introduce distortion that is not
flattering to people's faces, and its harder to produce a good shallow
DOF (meaning the background and foreground will be more in focus even
at low F numbers).
The first advantage that comes to mind for reasons why to get a dSLR
is that the lenses are interchangeable. Often, lenses are worth more
than the camera body for good reason, but sometimes you can find good
inexpensive ones.
There are several factors that make a lens good. The most interesting
reason is that the well built ones have a very wide aperture, which is
the F number. The lower the number, the wider the aperture, the
larger the opening. This is important because wide apertures produce
shallow depth of field (DOF). Shallow DOF causes the subject to be in
sharp focus but other things in the foreground or in the background
bcome blurry and abstract. The lower the number, the more blurry
other things become. This makes for a more artistic photograph. Bright
items that are blurry typically produce a distinct pattern known as
bokeh, and this is considered desirable in much photography.
Another advantage of wide apertures is that they are better able to
shoot good images in darker places without using a flash. For
example, by increasing the ISO to a higher number (say 400 or 800) and
opnening to F2.8 or 1.8, you can shoot in a dark church without using
flash at all, giving you the ability to capture the scene the way your
eyes see it naturally. By not using the flash you're better able to
be more discreet by not drawing attention to yourself and not annoying
people around you. The downside of a dSLR is that the shutter is
audible. If its very quiet then people around you will hear the
shutter's click-clack.
Here's some examples of bokeh and shallow DOF
Lens interchangeability is pretty useful to optimize for diffierent
situations. There may be times when you're in a narrow space like a
small kitchen. With a dSLR you can put on a wide angle lens (say
10-22mm) and be able to take group photos from just 3 or 4 feet away.
Then you head off to a soccer game and you put on a 100-300mm F4 lens
instead so that you can take a photo of your kid in the middle of the
soccer field and get them to stand out from everyone around them.
Professional lenses are made of higher quality metal in weather proof
housings, but you can find good lenses that have plastic housings
instead for less money. Sometimes that's all you need. I have
several lenses that cost $2000 each, but I also have other lenses I
like just as much that cost $75 to $300.
Digital point-n-shoot cameras are really increasing in quality all the
time, and there are some that approach the quality of a dSLR (but
don't have interchangeable lenses). For example the Canon G11 is a
p-n-s that pros use as an secondary or backup camera since it can shoot RAW.
The ability to shoot RAW images is also a very important decision in a camera
purchase. Using RAW is a little like being able to re-take a photo
after you've taken it. It captures so much information that later
using a program like Adobe Photoshop or Lightroom if you discover the photo
is too dark or too bright or too something, you have the ability to
rescue or change the image to be the way you want it to be *without*
losing image quality. When you're done correcting the color or exposure, you can export RAW as your favorite format for the web or for print such as JPG or TIF. P-n-S camera often shoot only JPG (but sometimes
TIF), and those image times don't contain as much information as RAW,
so if you want to correct the exposure in a very unique photo, you're
probably out of luck because the image will automatically lose quality when you attempt to correct it.
There's other advantages to shooting dSLR over a point-n-shoot, but I
think lens selection and RAW images are two of the most important
reasons to use one.
#1 by Matt Williams on 11/24/09 - 11:29 AM
I think the biggest disadvantage to the dSLR is the size and lack of portability. My wife can`t put in her purse for short outings or whatever.
#2 by Sherry on 12/9/09 - 11:38 AM