March 11, 2007

Photo Fun

I have no idea how to use my camera. F Stop, shutter speed, white balance; I don't really get it all. I'm sure I could learn if I felt like it, but instead I end up playing around, seeing what works, and then enhancing it in Photoshop. Here are two pictures I took of a blooming christmas cactus.



2 comments:

Anonymous said...

awesome shots, you know I love flowers
DAV

ndbutter said...

You can learn an awful lot about photography just by checking out the EXIF data of great photos on Flickr's "Interestingness" page.

The relationship between aperture and shutter speed is pretty critical, but you're a smart kid so I'm sure you can figure it out. It all has to do with how much light you're letting into the camera. If your shutter speed is long (or, "slow"), you're letting a lot of light into the camera. The advantage is that you can use slower shutter speeds to catch dimly lit areas without a flash. The disadvantage is that the slower the shutter speed, the more susceptible you are to blur (either from camera shake, or moving subjects).

Aperture tells you how wide the opening is in the lens that lets in the light. The wider your aperture (the lower the F-stop), the more light you're letting into the camera. The consequence of using a wide aperture is that you have little depth of field (DOF). That is, your subject may be in focus, but the entire background is blurred out. Many times this effect (known as "bokeh") is desirable, for example with portrait shots. However, if you were shooting a landscape shot, you'd want a much longer depth of field (higher F-stop/wider aperture). Additionally, sharpness is generally less with wide apertures.

It's important to get the ratio of aperture to shutter speed set correctly. It is for this reason that most cameras nowadays have both aperture and shutter priority modes. So for example, if you're shooting fast-moving sports action, you're probably going to want to use shutter priority mode so you can set the shutter speed fast enough so that your moving subjects won't be blurred. The camera will then choose the appropriate aperture to achieve a correctly exposed photo. Conversely, if you're shooting a still-life subject (like these flowers you shot), you can set the aperture fairly wide to get some good bokeh and possibly not have to use a flash. When in aperture priority mode, it's important to keep an eye on the shutter speed the camera is selecting for you. Anything below about 1/60" will be tough to hold still enough to not come out blurry from camera shake. That's why a tripod can be important.

Most cameras now also allow you to control the ISO settings. The ISO measures how sensitive the sensor is to light. A higher ISO setting (say 800 or 1600) is much more sensitive to light than a lower setting. This means that if you were in a dimly lit room, you could crank the ISO up higher and use a faster shutter speed and/or narrower aperture. The downside to high ISO settings is that the higher you go, the more grain and noise enters into the picture.

Most cameras also have a full manual mode that allows the user to set the shutter and aperture independently of each other. This can be used if you don't like the exposure the camera is giving you in one of the priority modes, or if you want to intentionally over or under expose a picture.

That's a real basic rundown. I suggest joining Flickr and keep shooting. It's fun stuff...