Basic photography lesson

I’ve got a friend who has just bought a DSLR and was wanting to know how to use it. I’ve just sent him an email with some basic information based on having done some photography courses over the past year and using my camera a lot. I thought that I might as well include the information here. The information would’ve been useful for me although that’s now a guarantee that it will be useful for you.

Anyway, this is what I sent him:

If you are looking to learn how to use the camera, I’d recommend having a look at this web page: http://www.fredparker.com/ultexp1.htm. It is a pretty long read but explains a lot of concepts that I didn’t really understand.

I’d probably add a few things to it:

  1. You’ve got probably got three things that are important when taking photos: exposure, focus and composition. Focus and composition are pretty easy to understand and I can’t help you much with that.
  2. Exposure in the camera is based on three things: shutter speed, aperture and ISO. These are described quite well in the link above but I thought I’d add a bit more here. It’s possible to get the same exposure (amount of light on the sensor) with different settings. E.g, 1/100 (shutter speed) and f/16 (aperture) going to provide the same exposure as 1/200 and f/11.

The rest of this is mostly about getting the exposure right and what it means.

Each change in shutter speed, aperture and ISO is a trade-off though.

A faster shutter speed will stop fast motion but let less light in. A slower shutter speed will let more light in but might get blurry photos from shaky hands.

The aperture is really just the size of the hole that the light goes through when passing through the lens. A smaller aperture (bigger number e.g. f/22) will let less light in but will cause more of the photo to be in focus. A larger aperture (e.g. f/2.8) will let much more light in (from f/22 to f/2.8 you get 64 times as much light [I think]) but will create a much narrower depth of field (less in focus and blurry background). If you want a calculator for depth of field, have a look here: http://www.dofmaster.com/dofjs.html

ISO is the sensitivity of the sensor. If the ISO is low, you’ll need a lot of light to get the exposure right (bright day or long shutter speed or wide aperture). As the ISO increases, the sensor gets more sensitive but the photos get more grainy. Modern cameras a pretty good with the ISO so you can often push it to 3200 or 6400 and still get an acceptably good photo. With my old red camera I couldn’t really push it above about ISO 1000 before getting grainy photos.

If you put the camera into manual mode, the camera has a built-in light meter that you can rely on. There is a gauge that generally goes from -3 to +3 and shows what the camera judges the exposure to be. If the metered value is negative then there isn’t enough light and if it is positive then there is too much light. To get more light you need to lengthen the shutter speed, open the aperture wider or increase the ISO. And vice versa if you want less light.

The other thing is to change where the photo is metered from. On my camera I have three different metering modes for assessing the exposure. The camera will either assess the exposure based on the whole frame, or a spot in the centre of the frame or a larger area in the centre of the frame.

Changing where the camera assesses the exposure is useful when the light is difficult. An example of this might be where you are photographing people at the beach and there is a lot of light in the background. You might want to get the exposure right for the faces since that is probably the most important part.

I’m using the manual exposure mode quite a bit at the moment. It gets easier the more you use it. Using manual probably isn’t that important overall but I’ve found it very useful to just understand how it works and what it is doing.

After understanding all this information, the next most important thing you can do is read the camera manual. There is probably a lot in there and it is probably not that interesting but it will tell you a lot.

Hope this helps.

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