# Thread: How DoF is affected by the 3 rules

1. ## How DoF is affected by the 3 rules

Hi all,

I read on books and on some articles, about how apertures affects Depth of Field (DoF). The rules that I know:

1) The Focal length of lengths affect DoF
2) The distance of subject affects DoF
3) The aperture size affects DoF

Of course we can remember the rules by memorising them, but what I like to really understand how the 3 rules above applies, in a layman explanation, or even in a graphical diagram.

Can anyone enlighten or point to me any site where I can read more? Thanks!!

2. ## Re: How DoF is affected by the 3 rules

Originally Posted by Sun_Of_The_Beach
Hi all,

I read on books and on some articles, about how apertures affects Depth of Field (DoF). The rules that I know:

1) The Focal length of lengths affect DoF
2) The distance of subject affects DoF
3) The aperture size affects DoF

Of course we can remember the rules by memorising them, but what I like to really understand how the 3 rules above applies, in a layman explanation, or even in a graphical diagram.

Can anyone enlighten or point to me any site where I can read more? Thanks!!
why read when you can go out, shoot and learn at the same time? Practise practise practise

3. ## Re: How DoF is affected by the 3 rules

Originally Posted by foxtwo
why read when you can go out, shoot and learn at the same time? Practise practise practise

In army, must learn the thoery before go for actual range mah....same here, want to understand the actual concept, so that when I shoot, can appreciate more.

4. ## Re: How DoF is affected by the 3 rules

Try the library or the HWM Megaguide (can browse at local bookstores first) - got some good illustrations or borrow from seanlim..

5. ## Re: How DoF is affected by the 3 rules

http://www.dpreview.com/learn/?/Glos...f_Field_01.htm

and perhaps u might want to do some experiments at home.
i was intrigued at such things when i first got my camera!

6. ## Re: How DoF is affected by the 3 rules

Originally Posted by Sun_Of_The_Beach
In army, must learn the thoery before go for actual range mah....same here, want to understand the actual concept, so that when I shoot, can appreciate more.
The difference is, when you shoot in range, you might hurt someone if you don't apply some fundamental theories. But for cameras, you won't anyone when you shoot "wrongly". And often, the best way to learn is through mistakes, and seeing the results for youself.

If you really want theoretical, yet simple explanation, check this out.

8. ## Re: How DoF is affected by the 3 rules

I agree - go out with your camera and test what difference these three variables make.

Choose a subject, set camera up on tripod and shoot at different apertures (I would just change by a complete stop i.e. f4, f5.6, f8, etc... each time). Then try a different focal length repeat and try at different distances to subject. In my opinion this is the only way to learn this.

Not only is distance to subject important but probably more importantly, it's the ratio of distance to subject: distance to background. If this is high (1:20) then you will get a very blurred background, even at a small aperture. If you are close to your subject but everything else is at a similar distance (e.g. shooting a wall face on) then you might not see the actual shallowness of the DOF.

9. ## Re: How DoF is affected by the 3 rules

Thanks guys!! The info helps!!

10. ## Re: How DoF is affected by the 3 rules

Originally Posted by blive
Try the library or the HWM Megaguide (can browse at local bookstores first) - got some good illustrations or borrow from seanlim..
aiyo say my name?

11. ## Re: How DoF is affected by the 3 rules

Less DOF:
Focal length - longer
Distance to subject - closer
Aperture - bigger

More DOF:
Focal length - shorter
Distance to subject - farther
Aperture - smaller

12. ## Re: How DoF is affected by the 3 rules

wah seanlim kena again.

yeah. go practice la. in the end, u wont even be memorising thiose rules. it will become 2nd nature to you when you shoot

13. ## Re: How DoF is affected by the 3 rules

...nvm lar tio kena also for gd cause

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