Greater Understanding

Loki

Loki

Veteran
Oki... I have been trying to teach myself all about when to use different lenses.. and the differences between digital and film lenses..

Someone correct me if I am wrong here, I am most likely not going to have access to a DP with any sort of knowledge in this area. (My DP is a fellow student.. so still learning, with much less knowledge than myself..)

Digital Cameras/Camcorders require a lens with a much smaller focal length to deliver the equivalent of a 35mm lens because of the small CCD size.. am I correct?

the DVX for instance, uses 1/3" CCDs, so technically if I were using a DVX that magically had 2/3" Chips, I would see more picture than what the 1/3" chips produce just because more of the projected light from the lens is hitting the CCD... ?

according to Panasonic the 4.5 Focal Length of the Leica-Dicomar lens is equivalent to a 32.5mm 35mm lens... because of the small sensor area, cropping occurs on the image, cropping that you will never actually see though..

I hope this makes sense and is correct. I want to rent the the P+S Technik 35mm Adapter and use the 35mm lenses from my school on it. So I am trying to get my head around the types of lenses I will need based on my sets/shots.

35mm needs bigger focal lengths than a miniDV cam to produce the same field of view.

Is my understanding up to snuff? or am I off?
 
Re: Greater Understanding

Think 'similar triangles'. To get the same angle of view (field of view) on two different lenses, the ratio of focal length and the diagonal of the frame must also be the same.

Nobody outside of Panasonic knows exactly what the diagonal of DVX 1/3" CCD is, but it seems to be about 6 mm. The diagonal of a 35mm film frame (in still camera, not film camera) is about 43.27mm. What's the 35mm equivalent of 4.5mm focal length on

The similarity is:

4.5/6 = X/43.27

Therefore, X=32.45mm

However, as I mentioned, this is for a 35mm still camera. In film cameras the frame is smaller, but there are different formats. For conventional 4:3 image, the frame is about 24x18mm, which gives you a frame diagonal of about 30mm.

Doing the same math as above, a motion picture 35mm lense of 22.5mm focal length should give you about the same field of view as 4.5mm on DVX.

This should probably go into Technical section.

Jerry
 
Re: Greater Understanding

I have a lot of other fantastic qualities, modesty being the greatest of them all!

Whether you'd like to be enlightened, educated, opinionated or simply patronized, I am your man! :P
 
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