Aperture Av mode in DSLR photography simple tutorial

Camera: Canon

Model: Canon EOS 5D Mark II

ISO: 800

Exposure: 1/40 sec

Aperture: 1.8

Focal Length: 50mm

Flash Used: No

Aperture? f stops? wide aperture? Depth of Field? Bokeh? i have been asked several times to explain what the big deal really is about apertures and shooting with Av mode on a DSLR or compact cameras. and so here is a simple tutorial explaining this ....

Aperture : is the opening or hole which controls the amount of light entering the lens. and please remember a large aperture means smallest f number like f 1.2, f 1.4, f 1.8, f 2.8 . its inversely proportional. ALWAYS. and similarly a narrow aperture means large f number like f 8 to f 22.

what and why are they useful?

most useful in photography as it conveys what exactly u what u want to convey or highlight or focus in a photo.

f 1.2

Model: Canon EOS 5D Mark II

ISO: 100

Exposure: 1/3200 sec

Aperture: 1.2

Focal Length: 50mm

Flash Used: No

see the photo above of sweet potato crop growing in my farm. i have used my 50 mm f 1.2 L lens. at such a wide aperture, i have focused only in the middle of the frame while the sides are totally out of focus and blur.... the out of focus and blur background is called 'bokeh' .

now watch closely as i increase the f no 

f 2.8

Model: Canon EOS 5D Mark II

ISO: 100

Exposure: 1/640 sec

Aperture: 2.8

Focal Length: 50mm

Flash Used: No

here the centre of the frame is still in focus and narrowing the aperture from 1.2 to 2.8 brings a lot more detail in focus. 

f 10

Model: Canon EOS 5D Mark II

ISO: 100

Exposure: 1/50 sec

Aperture: 10.0

Focal Length: 50mm

Flash Used: No

now this final photo , one can clearly see a lot more detail like backgrounds also coming into focus. 

and all i did was get a narrow aperture to bring the entire scene in focus.

aperture settings or Av is really awesome where u can choose what needs to be in focus, and how much of a scene needs to be in focus. getting the perfect background blur or 'bokeh' can be achieved with some decent gear but the lens is really what matters most and how wide the aperture really is. and since these wide aperture lens allow a lot more light to enter, due to its wide opening, the images are crispy and sharper and the bokeh just melts away like 'fine cheese'

some more examples of f 2.8 with background blurs using EF 70 to 200 mm f 2.8 L IS USM glass

Model: Canon EOS 5D Mark II

ISO: 160

Exposure: 1/160 sec

Aperture: 2.8

Focal Length: 160mm

Flash Used: No

Model: Canon EOS 5D Mark II

ISO: 100

Exposure: 1/60 sec

Aperture: 2.8

Focal Length: 70mm

Flash Used: No

Model: Canon EOS 5D Mark II

ISO: 100

Exposure: 1/4000 sec

Aperture: 2.8

Focal Length: 200mm

Flash Used: No

happy clicking and if u still dont understand... DIE!!!