An actual filmmaking question...

[twister!]

Wow ilpostino - that's a tough question, but I like it!

Here goes: it's all to do with things called 'circles of confusion' (thankfully nothing to do with Phil Collins and Genesis) which happen in our eyes as well as in the lenses of cameras - these are the areas that are out of focus (ie confused).

Circles of confusion are formed by light rays passing through the lens tube. The size of a circle of confusion is proportional to the amount of light that can pass through it. This means that smaller circles of confusion will be formed if less light can pass through. As we all know controlling how much light comes through the lens is controlled by the aperture value.

I hear you say 'but why does light passing through a lens cause circles of confusion?' I don't know - but it does.

I do like this serious stuff, as opposed to endless talk of zombies (shhh - hope that doesn't start anyone off on a rant).

How about a thread concerning 'What's the meaning of life'?

[ilpostino]

Thanks guys, I didn't realise that the aperture had the effect of controlling the portion of the lens used, I just thought it was only for increasing/decreasing the amount of light captured. I nearly entered my own circle of confusion when reading your replies though.

Makes more sense now.


As for the meaning of life, I once heard someone say that religion was answer to the unanswerable i.e. the meaning of life.



[This message has been edited by ilpostino (edited July 26, 2001).]

[eddie]

oops, I mean the OPPOSITE of what you want to acheive!
If you want to *increase* your depth of field (phew Im getting bored of this!) you need a SMALLER aperature, so you need to flood loads of light on your subject and use a f stop of 8 or higher.
If you want to *decrease* your depth of field then you need a wider aperature, and so less light (perhaps a filter will help)

Filters REDUCE the amount of light getting into the camera and nearly always need you to *open* up the aperature a stop or two.

Mind you I read somewhere that super8 cameras are pretty seriously limited as to the amount of depth of field altering they can do, simply because the frame size is so small - it requires a certain type of lens.....and so on - can of worms anyone?

blah blah blah, I hope you sort it out.

[twister!]

That's true - someone once said 'if God did not exist then it would be necessary to invent him' which logically speaking is what indeed happen - the concept of a creator is just that - a series of thoughts in the human mind.

I think it was Wittgenstein that said the problems of philosophy and the question 'what is the meaning of life' all stem from a problem of language (ie if we did not have language then that question would not exist and we wouldn't have spent thousands of years trying to answer it - very interesting.

I think Wittgenstein was right - we have created the problem for ourselves and thinking about it just sends us mad - as eventually happened to many of the great philosophers...

[eddie]

to be honest I dont think its something to worry about. Just knowing it works is enough.
If you want to know more then probably the internet isnt the right place to find out.
(Its too complicated!)
You need to do a course in photography optics or something.

The meaning of life?
'To measure the circumference of a circle you can start at any point.'

Most circles add up to 42.

[machead]

I couldn't be arsed to read most of the responses so I may be repeating someone elses reply.
Try altering your focus point,depth of field works on the principle that 1/3 infront of the focus point will be sharp and 2/3 behind will also be sharp.
So try focusing beyond the nearest point which you wish to be sharp.
There are some charts that give you DOF data lens data blah blah blah to help.

also using a wide angle lens can increase your DOF.

I hope this answers your question as opposewd to create a debate about 'what depth of field is?'

also stopping your lens down and choosing a longer shutter spead will increase your depth of field.NO ARGUEMENTS PLEASE THAT"S A FACT!!!!