How the aperture can massively affect your photos
Not only does the aperture determine how much light comes in through the lens, it also determines the depth of field in the image (amount of the photo which is in focus) as illustrated in the previous test.
A small (narrow) aperture (F8, F11, F16) gives good or deep depth of field where most of the image is in focus, good for landscapes, property photos etc. If you are short sighted and wear glasses, try this as an experiment…
Take off your glasses and using your index finger and thumb, make as small a hole as possible and look through it. Try to read letters in the distance and close the hole as small as possible, the letters should become clear. That is the effect of a small aperture!
On the other hand, a large or wide aperture (F4, F2.8, F1.4) gives very shallow depth of field where only what you focus on is sharp. This is a great effect for portraits or images where you really want the subject to stand out. Using the above experiment, simply open the hole in your hand and all will be blurry again.
In this next video, you can see the effects of the aperture opening and closing in real time…
Now there are exceptions to this rule and they depend on a couple of factors:
- How close is the subject you are focussing on?
- What lens are you using?
- What part of the image are you focussing on?
The closer you are to the subject you are focussing on, the shallower the depth of field will be despite using a small aperture of f11 or f16 etc. This is due to the “hyper-focal distance” effect.
Here is an example that perhaps you can try (if you have similar lenses):
Note: I am not going to provide samples because I want you to do it yourself and practice…it’s the only way to learn : )
Place an object about 4-5 feet away, set your camera on a tripod, or at least ensure you stay at the same distance when taking these shots, and focus on that object using:
- 24mm lens or focal length on a zoom (for full frame, use 16mm for cropped sensors) with an aperture of f2.8
- 100mm lens or focal length on a zoom (for full frame, use 85mm lens for cropped sensors) with aperture of f8-f11
Take the two shots above from the same distance and then zoom in on the subject. You should notice that the background blur is very similar in both shots despite using very different apertures.
Once you fully understand this, life gets a lot easier with your photography. For example, if it is a very bright day and you cannot get a small enough aperture, and you don’t have an ND filter handy to reduce the light coming in, you can simply zoom in more on the subject and blur the background that way.
The longer your focal length, the more blur you will get even at small apertures…try it.
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