better camera's!

Blender's renderer and external renderer export

Moderators: jesterKing, stiv

Post Reply
dotblend
Posts: 36
Joined: Thu Oct 17, 2002 2:18 pm

better camera's!

Post by dotblend » Fri Jul 23, 2004 10:09 pm

i think a lot of people would like better camera's, ( I would like to)
or at least the option to change the lenses ,
fisheye with distortion!!!
the option to set real lens values!!!

this would make life so much easier!

peter "dotblend"

dotblend
Posts: 36
Joined: Thu Oct 17, 2002 2:18 pm

Post by dotblend » Fri Jul 23, 2004 10:18 pm

copied this from http://www.vrphotography.com/data/pages ... sheye.html
One can use the following formula for fisheye fov calculation:

fov = 4 * arcsin (image size/(focal length * 4))


A 35mm film frame has the following dimensions: 24.3mm x 35.8mm (43.3mm diagonal)

Thus, for a 16mm fisheye on the 35mm camera in portrait orientation:

fov(y) = 136 degrees
fov(x) = 89 degrees
fov(diagonal) = 170 degrees

Note that the image circle produced by the 16mm fisheye lens is slightly larger than the diagonal of the 35mm film frame, so Nikon's claim of 180 degree coverage may be fairly close to accurate, although the user won't necessarily see that coverage on film.




The image sensor dimensions on the Nikon D1 series cameras are smaller than the 35mm frame (which results in the effective focal length magnification). They are approximately: 15.6mm x 23.7mm (28.4mm diagonal)

Thus, the same 16mm fisheye lens on a D1x in portrait orientation yields the following fields of view:

fov(y) = 87 degrees
fov(x) = 56 degrees
fov(diagonal) = 105 degrees




The same formula can be used with the 8mm fisheye lenses. The difference is that the 8mm lenses are true fisheyes, rather than full-frame fisheyes like the 16mm. A true fisheye projects the full image circle of the lens within the frame of the camera, so you wind up with a circular image inside a dark field, rather than having the frame filled with the image. Note however that these 8mm lenses are designed to be true fisheyes for the 35mm camera format. The smaller sensors of digital cameras such as the D1 series crops part of the image circle, so it is no longer a true fisheye when used in this format.

The diameter of the image circle on an 8mm Nikkor fisheye (focused at infinity) is approximately 23mm. (Note that the actual focal length of most Nikkor 8mm fisheyes is about 8.2mm.) Thus, the circular field of view inside a 35mm film frame is about 178-180 degrees.

However, when this lens is used on a D1x with its smaller image sensor, the 23mm image circle is cropped on the short dimension to 15.6mm, yielding a fov of about 114 degrees. The resulting image is a cropped circle with 180-degree vertical coverage and 114-degree horizontal coverage (assuming portrait orientation).

One final note... the FC-E8 Fisheye Converter made by Nikon for its Coolpix line of digital cameras is often mistakenly referred to as an "8mm fisheye." It is not, but it produces a similar rendering on the Coolpix cameras to an 8mm true fisheye on a 35mm camera. As a supplemental lens adapter, it is far more limited in its optical quality, and any flaws or aberrations are magnified by the even smaller image sensors used in most Coolpix cameras. It does produce a circular image within the Coolpix frame, with a field of view between 184 and 186 degrees. Many photographers yield quite acceptable results with it. It is a foundation element of most iPIX digital capture kits.

dotblend
Posts: 36
Joined: Thu Oct 17, 2002 2:18 pm

Post by dotblend » Sat Jul 24, 2004 9:10 am

what even could be better... camera blocks

specified to your own needs
pick one out of a list, or write your own.

enough resources available...

macouno
Posts: 0
Joined: Tue Nov 18, 2003 3:37 am

Post by macouno » Wed Jul 28, 2004 6:02 pm

I agree that we'd be better off with setting the cameras in blender to actual real world milimeters, that would certainly not hurt the current workflow and would help immensly in integrating blender work with that recorded through cameras.

dotblend
Posts: 36
Joined: Thu Oct 17, 2002 2:18 pm

Post by dotblend » Wed Jul 28, 2004 6:13 pm

the current camera system is outdated, almost everything gets a overhaul... but the one thing we use for ALL renders is the camera...

major update is needed!

kitsu
Posts: 0
Joined: Sun Jun 06, 2004 8:08 am

Post by kitsu » Fri Feb 23, 2007 11:06 pm

This is still the case. I am working on an importer for motion tracking software. In the format I have information about aperture, field of view (x and y), and focal length. Meanwhile Blender only has this mysterious 'lens' value. I don't really know enough about real camera lenses to do anything fancy with real camera parameters, but I know even less about Blenders camera. Are there any plans to implement realistic camera parameters in future versions of Blender?

chipmasque
Posts: 0
Joined: Mon Aug 20, 2007 6:31 pm

Post by chipmasque » Mon Aug 20, 2007 8:38 pm

kitsu wrote:This is still the case. I am working on an importer for motion tracking software. In the format I have information about aperture, field of view (x and y), and focal length. Meanwhile Blender only has this mysterious 'lens' value. I don't really know enough about real camera lenses to do anything fancy with real camera parameters, but I know even less about Blenders camera. Are there any plans to implement realistic camera parameters in future versions of Blender?
Have you tried using the "Degrees" option ("D" button in the Lens field) to enter an FOV angle in Blender? I've been doing a number of tests to find out what the default "Lens" option value is all about (no luck yet), and in doing so, found that entering a properly calculated FOV angle gives much better results when trying to match real-world cameras.

For example, after calculating the required FOVs to match a 50mm lens imaging to a number of 35mm film formats (135 roll film (1:1.5) and motion picture in 1:1.33 and 1:1.85 aspect ratios), I get very good results using that value in Blender's "Degrees" option for its lens.

Post Reply