Digital moviemaking-got the book but could use some elaboration and clarrification

[Ryan Wachter]

Ok it talks about lighting with minidv to give it a film look, but a few things in here it would be nice if I had the author around to clarrify. I was hoping someone where would be willing to throw me thier email address who has knowledge on the subject so i annoy them with my stupid questions.

EXAMPLE

TEXT-you can use the shutter to control the amount of light without chaning your f stop or adding nuetral density filters. Each consecutive exposure time is cutting down or increasing the amount of light enterin the camera by one f stop, which means that it is effectively halving or doubling the exposure.

As I mentioned before the object is to find an f stop that allows you to create depth in your composition (start at f/4) and then use that stop to shoot your entire scene.

Ok so f.4 is a fairly big iris and so there will be a smaller dof which will give it some depth and not make it so 2d i believe it was he is saying but what should I be using to adjust for brightness?

Also it says using a ND filter to bring down the stop a few to make you have to light better for the scene and stop any white wash from occuring is a good idea. I know the agdvx100 has a built in 1/8th ND is that too dark to use indoor for that purpose?

thanks for your help guys.

[Rob Lohman]

The best way is to simply do tests yourself. Whether or not you
can change the shutter speed basically depends on if you have
moving objects in frame or are moving the camera. Because if you
are then how the motion will look will change (dramatically) when
you change the footage. Usually you don't want to mix different
shutter speeds in one movie unless it is for a certain type of effect
or special scene.

Most people shoot at 1/50 (PAL) or 1/60 (NTSC) and adjust other
parameters.

Usually an ND filter is too much for indoor shooting, unless you
have lights setup. If you set the shutter at 1/60 you can probably
open up the iris to f4 or lower with ease (due to relative low light
levels), so that shouldn't be any problem if you want a smaller
depth of field. Keep in mind that if you want a real small DoF you
will have to zoom in as well which can be nearly impossible
indoors.

When outdoors you can add screwon ND filters for example to
lower the light levels and thus allow you to further open the iris.

Do some tests and you will easily see what will work in a given
situation and what will not.

[Ryan Wachter]

Thank you for your help.
As far as shutter speed Ill be using the 24p mode on the agdvx100.

As for indoors I do plan to obviously use lights. Now the books lists the different ND filters as ND0.1 ND0.6 and ND0.9 now I dont know exactly what the ratio is these numbers are using but I was wondering if the built in ND filter on the agdvx100 listed as ND 1/8th on the side of the camera coinsides with any of the ones I listed above....as in maybe its just two ways of saying the same filter?

Thanks again
Ryan

[Rob Lohman]

What has 24p to do with shutter speed?

I'm not into the numbers. I basically see what works and run
with that. Sorry. I'm hoping someone else will come in to answer
your "numbers" question.

[Ryan Wachter]

24p is the shutter speed. 24 frames per second. I mean its the shutter speed as far as digital goes.

[Rob Lohman]

No it is not. 24p is the framerate. In digital video camera's the
shutter is completely unrelated to the frame rate and vice versa.

24p is 24 progressive frames per second. If you want to shoot
that at 1/30 or 1/60 go right ahead.

[Ryan Wachter]

now were talking....so whats the point of a shutter on a digital camera if it doesnt affect the speed at which each picture is taken? What can and does the shutter speed on a minidv do?

[Rob Lohman]

It does affect the "speed" at which a picture is taken since it
blocks out the CCD's from light (although electronically) during
certain periods and opens them up in the other periods. As with
a film camera shutter the signature of the (especially moving)
objects that are being recorded will change.

So a shutter of 1/12 or 1/25 will have more "motion blur" on
moving objects in the frame than a shutter of 1/50 or 1/100 will
have. The higher you go the crispier the image gets when
movement is concerned.

The difference with a film camera is that it isn't tied into the frame-
rate. This wouldn't be possible (at this point in time) since the
current con-/prosumer CCD's block don't allow for variable timings
to get the different frame rates. The DV format also only supports
30 (dropframe) or 25 fps and nothing else.

Keep in mind that the shutter in video camera's is electronic,
not a physical shutter!

[Ryan Wachter]

So shutter speed on a minidv will only affect the motion and not the light because digital doesnt need time to expose....but isnt 24p considered changing the shutter speed on a digital camera? I understand it all has to run at the 30p 60i frame rate, so isnt it just a technicality to not call it a frame rate?

[Rob Lohman]

I don't know how it works on a digital camera (if you mean a
digital still camera). Yes, the light level does change when
adjusting shutter speeds which I would guess the digital
algorithm is providing as well (I'm not 100% sure on how this
all works technically).

The chips are being read out at 60/50 fields per second, that's
what the framerate means in this case.