1. ## Shallow DOF

which would be the method to get a shallow DOF? smaller aperture or faster shutter speed?

2. ## Re: Shallow DOF

smaller aperture value

3. ## Re: Shallow DOF

Originally Posted by boredphuck
which would be the method to get a shallow DOF? smaller aperture or faster shutter speed?
Faster shutter speed don't contribute to DOF

Apperture size and focal length do.

http://www.dofmaster.com/dofjs.html

4. ## Re: Shallow DOF

Distance affects the DOF too.

5. ## Re: Shallow DOF

Generally, the smaller the f-stop number, the shallower the DOF for a given distance to object.

6. ## Re: Shallow DOF

thank u guys for the help. going to play around with the settings again tonite. thanks a million again!

7. ## Re: Shallow DOF

Originally Posted by Redsun
smaller aperture value
Eh.... you have to be careful with such phrasing, else they may mistake using f11 or f16 as a smaller aperture value.

A large aperture in correlation to the lens focal length will give you a nicer blur of the background as well as foreground. Often it will mean as big as f1.4 to f1.8 for a short focal length of 50mm. As the focal length increases, you can use smaller apertures such as f5.6 or f8 to the same effect.

8. ## Re: Shallow DOF

ok. i'm abit lost liao.

9. ## Re: Shallow DOF

Small aperture means a F stop of like f/22 which means deeper DOF. Large aperture means a F stop of maybe f/2 which will give you your shallow DOF.

10. ## Re: Shallow DOF

Depth of field formulae

Hyperfocal Distance
Let f be the lens focal length, N be the lens f-number, and c be the circle of confusion for a given image format. The hyperfocal distance H is given by
H=f2/Nc

Moderate-to-large distances
Let s be the distance at which the camera is focused (the “subject distance”). When s is large in comparison with the lens focal length, the distance DN from the camera to the near limit of DOF and the distance DF from the camera to the far limit of DOF are
Dn=Hs/(H+s), Ds=Hs/(H-s)

When the subject distance is the hyperfocal distance,
Df=infinity, Dn=H/2

The depth of field Df − Dn is DOF=2Hs2/(H2-s2), etc...

Confused now? haha, just wiki DOF lah. If not go riceball to buy a few good books for your bedtime reading. Cheers

11. ## Re: Shallow DOF

i actually don't know when to use what fstop with what focal length to achieve best results.

12. ## Re: Shallow DOF

Originally Posted by boredphuck
i actually don't know when to use what fstop with what focal length to achieve best results.
The largest aperture you can get away with to maintain DOF in your shots....

13. ## Re: Shallow DOF

wheres riceball? at first i tot u ask me buy mua chee go home eat. haha.

14. ## Re: Shallow DOF

Originally Posted by zac08
Eh.... you have to be careful with such phrasing, else they may mistake using f11 or f16 as a smaller aperture value.

A large aperture in correlation to the lens focal length will give you a nicer blur of the background as well as foreground. Often it will mean as big as f1.4 to f1.8 for a short focal length of 50mm. As the focal length increases, you can use smaller apertures such as f5.6 or f8 to the same effect.
Aiyah.. you also not exactly right.. f-number is a reciprocal.. so the number is at the denominator. f/1.4 or f/11. f refers to the focal length. So the bigger the denominator, the smaller the aperture and vice versa. It's just Maths.

15. ## Re: Shallow DOF

Originally Posted by lsisaxon
Aiyah.. you also not exactly right.. f-number is a reciprocal.. so the number is at the denominator. f/1.4 or f/11. f refers to the focal length. So the bigger the denominator, the smaller the aperture and vice versa. It's just Maths.
I know... but I was hoping to reduce the confusion

16. ## Re: Shallow DOF

ahh ... so the actual effect very much still depends on the focal length regardless of the other value?

17. ## Re: Shallow DOF

it actually depend on both combination

focal length
18mm----300mm
large------small DOF

f/16------f/1.4
large-----small DOF

So a 300mm lens at f/1.4 () will give you very very narrow depth of field.
a 18mm lens at f/16 will give you large depth of field, which mean most thing will be in focus.

Still got another influence, depend on how close is the focus subject toward the lens, the closer the subject the shallower DOF.
e.g.
a subject shoot by 50mm lens f/5.6.
further---------closer
large---------small DOF

you can use the DOF calculator at the link to simulate the situation you want.
http://www.dofmaster.com/dofjs.html

18. ## Re: Shallow DOF

tat whats wad i meant. a f/5 on 2 different focal length will give very different results. i'm using a pns. no wonder i have to stick my face into the object to get a good narrow dof.

19. ## Re: Shallow DOF

Originally Posted by boredphuck
tat whats wad i meant. a f/5 on 2 different focal length will give very different results. i'm using a pns. no wonder i have to stick my face into the object to get a good narrow dof.
Its 'shallow', not 'narrow' ... DOF as the name implies is 'depth' how far into a picture is an object in focus. Not how far away from the centre of a view that its in focus.

Some picts of focusing off-centre and on-centre for comparison might make a better point.

Generally P&S can take pretty good shallow DOF pictures but only at Macro level. once you get big objects, even with a f2.8 aperture, its quite hopeless unless its some very brightly conditions. I tried with my prosumer camera, never could get it to work well with objects bigger than a pail!

20. ## Re: Shallow DOF

in order to get a shallower DOF on your lens

• zoom to the longest focal lenght
• use the biggest aperture you have
• position subject further away from the BG
• position subject closer to the camera

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