FORUMS: list search recent posts

"Focal Length" in Camera Settings?!

COW Forums : Adobe After Effects

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
Filip Stillerska
"Focal Length" in Camera Settings?!
on Jul 5, 2018 at 10:26:32 am

When creating a camera in Ae, you're asked to specify the "Focal Length" (either individually or as a preset). Is this referring to the specification of the lens on a (for example) DSLR-camera, or is it referring to the focal length measured in 35mm format?
Basically, I'm wondering: if I theoretically have a DSLR-lens with a text on it that says "50mm", is it the same thing as specifying "50mm" as "Focal Length" in the Camera Settings in Ae?


Return to posts index

Walter Soyka
Re: "Focal Length" in Camera Settings?!
on Jul 5, 2018 at 2:52:59 pm

Ae's cameras are meant to simulate traditional 35mm cameras. If you have a DSLR that you're trying to match, you should figure out your crop factor or 35mm equivalent.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


Return to posts index

Jim Scott
Re: "Focal Length" in Camera Settings?!
on Jul 5, 2018 at 3:08:37 pm
Last Edited By Jim Scott on Jul 5, 2018 at 3:11:31 pm

https://helpx.adobe.com/after-effects/using/cameras-lights-points-interest....

Preset
The type of camera settings you want to use. The presets are named according to focal lengths. Each preset is meant to represent the behavior of a 35mm camera with a lens of a certain focal length. Therefore, the preset also sets the Angle Of View, Zoom, Focus Distance, Focal Length, and Aperture values. The default preset is 50mm. You can also create a custom camera by specifying new values for any of the settings.

Focal Length
The distance from the film plane to the camera lens. In After Effects, the position of the camera represents the center of the lens. When you modify Focal Length, the Zoom value changes to match the perspective of a real camera. In addition, the Preset, Angle Of View, and Aperture values change accordingly.

Assuming you are using a 35mm DSLR, the answer to your last question would be "yes."



Return to posts index


Filip Stillerska
Re: "Focal Length" in Camera Settings?!
on Jul 5, 2018 at 5:41:44 pm

Thank you, Jim, and Walter, for the help! I (currently) don't have much knowledge about cameras, but this is absolutely something I will read up on (sooner or later). But how do I know if a camera is 35mm? Are most DSLR's these days 35mm (should I assume that most of the cameras that I work with are 35mm, or not)? For example, is the Canon EOS 700D a 35mm camera?


Return to posts index

Jim Scott
Re: "Focal Length" in Camera Settings?!
on Jul 5, 2018 at 9:38:10 pm

The 700D has an APS-C sensor which is smaller than a full-frame 35mm sensor. As I understand it, Canon's APS-C sensor has a crop factor, or multiplier, of 1.6x, meaning a 50mm lens on the 700D will work like an 80mm (50 x 1.6) on a 35mm camera. Since AE's camera simulates a 35mm sensor, in order to match it to a 700D with a 50mm lens set the focal length of the AE camera to 80mm.

Don't assume that most cameras you will work with are 35mm since smaller sensor cameras are cheaper and thus more common. Check the manufacturer's web site for sensor info.

Here's a helpful article:

http://www.mdavid.com.au/photography/apscversusfullframe.shtml



Return to posts index

Filip Stillerska
Re: "Focal Length" in Camera Settings?!
on Jul 6, 2018 at 1:14:15 pm

Thank you, Jim, I definitely have a better understanding now. I also read through the article you linked, however, how do I figure out the crop factor or multiplier when I'm unable to find any direct info about the crop factor or multiplier about a camera? This info seems easy to find about DSLR's, but what about film cameras? Right now I need to figure out the crop factor (multiplier) of the Panasonic HC-VXF990, but I'm unable to find any direct info about it. But I know this about the camera:
  • Focal length (equivalent of 35mm film): 4.08 - 81.6 mm
  • Image sensor format: 1/2.3"
  • Maximum aperture (wide-angle - telephoto): 1.8 - 3.6
  • Sensor type: CMOS


Is there a way for me to calculate the crop factor for this camera using these numbers (or other numbers found online)? (apologies for all of these questions, but I do really appreciate your help).


Return to posts index


Jim Scott
Re: "Focal Length" in Camera Settings?!
on Jul 6, 2018 at 3:06:55 pm

Hi Filip,

I am glad to help where I can, but I am just a hobbyist with AE myself. The info I passed along to you was about the limit of my knowledge but perhaps someone else that deals with these issues on a regular basis will chime in with some better advice. Until then, check out this Wikipedia article:

https://en.wikipedia.org/wiki/Crop_factor



Return to posts index

Walter Soyka
Re: "Focal Length" in Camera Settings?!
on Jul 6, 2018 at 4:10:21 pm

The information you showed here already expresses the focal length in 35mm equivalency:

  • Focal length (equivalent of 35mm film): 4.08 - 81.6 mm


  • Walter Soyka
    Designer & Mad Scientist at Keen Live [link]
    Motion Graphics, Widescreen Events, Presentation Design, and Consulting
    @keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


    Return to posts index

    Jim Scott
    Re: "Focal Length" in Camera Settings?!
    on Jul 6, 2018 at 6:24:40 pm

    Good eye Walter. I should have kept reading.



    Return to posts index


    Filip Stillerska
    Re: "Focal Length" in Camera Settings?!
    on Jul 7, 2018 at 9:19:14 am

    Yes, you're absolutely right Walter. I feel embarrassed that I didn't catch that myself. Thank you!


    Return to posts index

    << PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
    © 2018 CreativeCOW.net All Rights Reserved
    [TOP]