Shallow DOF

[_dobbo_]

So I've been messing about with my D70 trying to get really shallow depth of field, and have worked out the ins and outs to a certain extent, giving me this result:



Apologies it's not an interesting subject - it just happens to be near my PC where I was playing.

Anyway hopefully someone can answer this - I'm finding that to get the really shallow DOF, I need to be at 70mm/f4.5 because at 18mm/f3.5 I don't seem to get the result I'm after. Why is that? I was under the impression that the lower f number meant more shallow DOF but not in my tests?

Thanks for any advice or to anyone who can set me straight!

>>> Edited by _dobbo_ on Tuesday 8th February 11:10

[srider]

DOF is a function of focal length, distance and aperture.

For short DOF, you can use wide aperture (i.e. lower f stop), long focal length, or short distance.

Have a play with this at with different settings to get an idea www.dofmaster.com/dofjs.html

[_dobbo_]

srider said:

www.dofmaster.com/dofjs.html

Thanks Stuart - that clears this all up a lot. I'm currently working through some books on photography but hadn't got to this yet, hence my confusion!

[V6GTO]

Conversly, it's all too easy to get too shallow a DOF with long lenses.

Martin.

[bilko2]

_dobbo_ said:

Apologies it's not an interesting subject - it just happens to be near my PC where I was playing. !

I think that's a good picture mate
Very good demonstration and not what i was expecting at all.
Nice one

[ThatPhilBrettGuy]

bilko2 said:

...Very good demonstration and not what i was expecting at all.

You were expecting the picture of a cat then?

I like it. You can't go far wrong taking pictures of crossfading mixers.

[bilko2]

ThatPhilBrettGuy said:

bilko2 said: ...Very good demonstration and not what i was expecting at all. You were expecting the picture of a cat then? I like it. You can't go far wrong taking pictures of crossfading mixers.

Don't know what i was expecting, just that i was pleasantly surprised
That lovely dust free onyx survace, The shiny chrome switches, an excellent crop or original composition and the fact that it had just the right shallow DOF for me. A very pleasing image i thought.

[_dobbo_]

Thanks for the comments - for what it's worth I spent an age polishing the surface before I took the picture - the image is as it came out of the camera, except for being resized down a bit for the web.

Funny how everyday objects can be made interesting if photographed in an interesting way - such as the cymbal someone posted the other day, and the bottle of gin!

[chrisjl]

_dobbo_ said:

...I spent an age polishing the surface before I took the picture...

You missed a bit! Just near the 'phones' label - I'd be tempted to clone that out of existance to make the pic truly perfect

[_dobbo_]

chrisjl said:

_dobbo_ said: ...I spent an age polishing the surface before I took the picture... You missed a bit! Just near the 'phones' label - I'd be tempted to clone that out of existance to make the pic truly perfect

Indeed I did! I've just looked and it seems to be a bit of paint - anyway, i've just spent 5 mins with the clone tool removing the more obvious blemishes...

Before:



After: