Aperture basics

[jdesigns]

Aperture is one of two ways to control the amount of light reaching the image sensor or film. There is other ways like film speed, but since this thread is about aperture, I won't go into that.

Aperture is basically how big the hole is in the lens that passes the light. They are standardized sizes like f2 and f2.8 or f22. With each increase in number (from f4 to f5.6 for example) the light reaching the film is reduced by half. Oppositely when going from f16 to f11, the amount is doubled. Does that make sense?

The other part of aperture to consider is depth of field. By using a big aperture, as in f2.8 or f2, you end up with a shallow DOF (depth of field.) Shallow DOF means that there is only a small part of the image in focus. When using a small aperture, as in f16 or f22, your DOF is increase. That means a lot of your image will be in focus. Simple, eh? :wave3:

Focal length also plays an important part of depth of field, but that is also another thread. :D


Questions? :cool:

DOF Illustration source (http://www.properproof.com/photo/DepthofFieldOverview.htm)

[Mr B]

I found when looking at the aperture numbers think of them as fractions (1/2, 1/4, 1/8). It's easier to picture the higher numbers as smaller holes.:o

[FineExampl]

I remember aperture from photography class in HS. Wish i still had one of those SLRs. I was just learning how to use it when the year ended.

[squeebug]

cool now I understand depth of field a little better. I was kinda wondering how sometimes everything was in focus and others only part was.

[callisto9]

wow, great write-up justin! thank you very much! i now am kinda getting it!

[jdesigns]

You are all welcome. I tried to make it as easy to understand as I could. :D

[Fowvay]

Nice explanation. When I purchased my FZ-20 one of the selling features was the F2.8 lens thur out the entire zoom range. Which allows for better low light zoom photos.

However now that I have had it for a while I really really miss having an F16 or F22 aperture. It ends at F8 which is just not small enough to get the depth of field I am often seaking.

I guess that's why we need multiple lenses and multiple cameras... woohoo :lol: