Photography For Dummies : Depth Of Field

As I promised to one of my friend who's now started to shoot in manual,I will write about Depth Of Field(from this point onward I'll refer as DOF).(Spoiler : going to be a boring topic for non photographer,please scroll down and enjoy the pic but my fellow photographer friend,please read,digest and understand the concept as you will need to play with DOF in order to take control of the shot.As this is one of the element in exposure triangle please read Photography For Dummies : The Exposure Triangle

So what is Depth Of Field(DOF)??

I'll give the technical explaination 1st and later I'll come back with the one easier to understand.

Depth of field is the amount of distance between the nearest and farthest objects that appear in acceptably sharp focus in a photograph. A preferred selection Depth of field ("DOF") in a focused subject in an image can be quite subjective. Remember this, adequate selection of DOF for one situation, application may be unacceptable for another photographer. It is all a matter of personal preference when trying to determine the appropriate use of DOF to enhance an effect in a photograph. 

DOF is basically as simple as the blur effect that you either see in camera shot or photoshop(Gaussian Blur).The blur I'm referring to is the one that your  subject appear sharp but the background and/or foreground is blur.


How to achieve DOF?


You can achieve the effect by changing the the aperture value.the lower the no(the bigger the opening of the lens blade,we will called it larger aperture no)the smaller the DOF is the sharper it is,means that if you choose f1.4 and you take a close up potrait,you may get the face sharp but everything else is soft and blurry and let say you want to take a picture of something which need the background or fore ground to be sharp then bigger no(the opposite of previous example of smaller no aperture)is required.
Previously I talk about the exposure triangle right?well aperture on the other hand relate to brightness of the pic because if the f no is large(smaller on screen such as f2)more light will come in the lens and to counter it you need to increase shutter speed or decrese iso as the pic exposure might be blown out(lose details on pic)Example like the shot where the DOF is at the alien(below).
But then again photography is very subjective,some say the want it super sharp(they are known as Pixel Peeps) and some say the blown out effect bring the dreamy effect,well I personally like it because it is dreamy to me..like we are in different dimension.hahaha.
Refer to setting below where it changes as I change the aperture value to smaller value.


Make it simpler,smaller DOF(Shallow DOF) means the sharp point is smaller and the blur background is bigger..bigger DOF means the sharp area is bigger and the blur area is smaller.

You decide which aperture is for which shot.Below are the sample pic taken to make your understanding better.

Nikon 3100 // 1/200 // 50mm @ f1.4 // ISO100

This is what I meant by shallow DOF where only some part of the shot is sharp.In this case its the magic 8 ball.

Nikon 3100 // 1/200 // 50mm @ f1.4 // ISO100

In this shot Buzz lightyear become the subject and the magic 8 ball is thrown out of focus.This can be achieved by adjusting the focus ring in front of your lens.Depending whether you have motor in your body or lens or in my case manual lens,you will need to either use autofocus or manually focus the subject.

Nikon 3100 // 1/200 // 50mm @ f1.4 // ISO100

In this shot I emphasize the background which is the Alien and throw both Buzz and Magic 8 ball out of focus.

Nikon 3100 // 1/40 // 50mm @ f8 // ISO400

By changing the aperture to smaller no(in this case f8),I include both the Magic 8 ball and Buzz in the DOF but throw out the Alien out of focus.

Nikon 3100 // 1/25 // 50mm @ f16 // ISO400

And in the case you want to cover everything you will need to choose the smallest f number as possible, f32(i sugget to use anywhere between f11-f16 to avoid diffraction) but you will need to compensate the light that is lost due to smaller opening by adjusting the shutter speed or ISO or both.Btw the Alien is not that sharp because my superb manual lens can go as small as f16 only but its good enough for me because it can achieve opening as wide as f1.4 which is honestly mouth watering.lol.For the f opening please refer to the diagram below.

I hope this help some of you.I will post more Post later so keep on following.

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Photography For Dummies : Depth Of Field