figuring out my camera aperture


#1

hi I have a panasonic gs 400 and it has a 1/4.7" ccd size. How do I figure out the camera aperture in inches? I want to do a matchmoving in maya but I don’t know what that ccd value mean. Thanks


#2

I have no idea how to translate this in terms of a 3D program, but the aperture is an f1.6-2.8.

This means that when the zoom is at its widest (3.3mm), the widest achieved aperture is f1.6, and when the zoom is at its longest (39.6mm) the widest achieved aperture is f2.8.

What it stops DOWN TO I have no idea - usually topping off at f16 - SOME can go to f22, but I wouldn’t count on it for this camcorder.

When recording footage, write down the zoom setting in mm, and the aperture used. Maybe this will give you what you need for matching elements with 3D.

Hope this helps-
-Lew :wink:


#3

Maya refers to the size of the imaging area as the aperture width and height - it’s also known as the filmback or sensor size. It helps to determine the correct focal length/field-of-view to use within Maya. You can get by without knowing it, as long as you know the field-of-view your using is going to give the correct perspective to match the footage shot.

It isn’t related to the iris/aperture/f-stop of a lens.

As to the original question. You can start by trying 3.92mm x 2.2mm (16:9) or 2.93mm x 2.2mm (4:3) as a starting point - that’s what www.panavision.co.nz list as the size of a 1/4" camera. Although I’d be surprised if it does work.

The user-manual for the GS400 has the focal length of the lens at 3.3–39.6mm Shoot a shot with the zoom at it’s wide and far position. Then bring the footage into Maya enter the sensor size into the aperture width/height and then change the focal length to 3.3 and 39.6. I’d also suggest shooting a distortion grid and box (of known dimensions), the distortion grid is used to remove any lens distortion from the footage and the box is handy to line up against.

Otherwise you’ll have to measure the field-of-view yourself for the near and wide focal lengths of the lens (judging by the looks of the camera it won’t have the focal lengths marked on the lens). If you know the field-of-view at a given focal it is possible to figure (using some maths) out a reasonably accurate sensor size to use within Maya.

This thread might be useful for you…

http://forums.cgsociety.org/showthread.php?f=2&t=680713


#4

thank you guys…I will try filming a box and also measure my field-of-view with different focal lenghts. This camera aperture thing is not so easy as I tought. I tought someone would come and give me the correct values right away. I wont give up until get this right…I hope to show you guys some good results soon with my matchmoving…thanks


#5

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.