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View Full Version : how to simulate effects of a fish eye lens?

cubizmo
08-02-2004, 06:49 PM
Hi everyone!
Does anyone know about some software or a possibility in cinema to accurately apply fisheye-effects to a scene? I am talking about the characteristical bent lines on both the left and the right vertical edge of the pictures, while the middle-placed lines are perfectly vertical. The effect I would like to achieve can be seen here: http://www.cgarchitect.com/gallery/image_spotlight.asp?galleryID=11687
I tried to let the cam look trough a self-built lens, but the effect was not the one I was hoping for. I would be very happy if anyoune could help me out on this topic. I also could imagine to build a system of lenses in front of the virtual camera (just like in a real photo-lens), but even though I do some amateur photography, I don't know the exact refraction values or the thicknesses of every singel lens-part in a fish-eye. Also a accurate sketch or a blue print of a lens is hard to find on the net...

Thank you for helping me up, and nice warm greetings from Vienna!
Aleksandar
Per-Anders
08-02-2004, 07:27 PM
two easy ways. (a) put a sphere in front of the camera, and give it a transparent material (i.e. nothing apart from transparency selected, and 100% transparent) then up the ior to change how much curvature you get. or (b) flip the camera and put a sphere in front of it, put a 100% reflective material on it (i.e. reflection checked, and nothing else checked). squash and stretch towards or away from teh camera to modify the distortion.
cubizmo
08-02-2004, 07:44 PM
Thank you very much, I will try this immediately....

nice greetings
Aleks
Lil_Mick
08-02-2004, 08:12 PM
or just bend the image in a 2d program like Combustion or After Effects. That would save on render time over raytracing in a 3d program.

~J
cubizmo
08-03-2004, 11:19 AM
To be honest, first I played with the thought to do so. Yet I am not sure, if this would result in a correct picture afterwards. Please correct me if I am wrong, my idea was basically that I would have to render the picture a fair bit wider, because the outermost points (vertical middle) are wider and more far away then on my normal rendering. Then my outer edges (upper left/right corners, lower left/right corners) have to be distorted horizontally into the picture middle. The problem that could happen here, is that objects that are nearer to the lens would have the same distortion factor as objects that are further behind, but have almost the same relative distance from the vertical or horizontal border of the picture... Maybe I could render in a few layers, e.g. objects that are x distance away from my lens, then objects with the distance x+y, and so on. Then import the pictures into my 2D-program, and bend them layerwise one by one.

I know, this sounds a bit overrated and too much fuss for one picture, but I have in mind doing a series of different shots (nearly 50!) with a simulated fish eye, so it would be very nice to know that the solution I did choose works for every single one without hours of tweaking.

Thank you all the same, I will try both solutions and then post the results in some time to let you all see what came out.

thanks for the nice help
nice greetings from vienna
aleks
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