Mr Mobius Posted March 1, 2003 Share Posted March 1, 2003 Hey guys, I was wondering if there is anyway of entering the width and height of the film back in the houdini camera. The Inputs are there in the Maya camera, but I suspect that houdini camera's differ slightly. any input would be cool. cheers. Quote Link to comment Share on other sites More sharing options...
edward Posted March 2, 2003 Share Posted March 2, 2003 Try these links: http://www.odforce.net/tips/realcam.htm http://cade.scope.edu/courseware/notes/hou.../integrate.html Quote Link to comment Share on other sites More sharing options...
Mr Mobius Posted March 4, 2003 Author Share Posted March 4, 2003 Thanks edward, ive looked at this and it has really helped. cool. Although do I need maya everytime I want to do this, I mean do I always have to calculate film back as how it would come out of maya. Im not being smart here, but what happens if Maya went off the market tommorow. Im just a little comfused why there isnt an input in Houdini. Although I could be missing something. Cheers. Quote Link to comment Share on other sites More sharing options...
edward Posted March 4, 2003 Share Posted March 4, 2003 I'm confused. What exactly are you trying to do? Quote Link to comment Share on other sites More sharing options...
Mr Mobius Posted March 4, 2003 Author Share Posted March 4, 2003 oh, sorry, Im trying to do a manual match move in the view port, If I could just punch in the film back the angle of view would be pretty easy obtain by matching perspective lines. Quote Link to comment Share on other sites More sharing options...
pockets Posted March 4, 2003 Share Posted March 4, 2003 oh, sorry, Im trying to do a manual match move in the view port, If I could just punch in the film back the angle of view would be pretty easy obtain by matching perspective lines. Now I'm confused...the "filmback" is defined by your aperture and viewport/image aspect ratio. Houdini uses the horizontal aperture coupled with the XY aspect ratio of your viewport/image to define its "filmback" rather than force you to enter a lot of redundant/dependent data. For instance, to define a Super35mm "filmback" you would use the following: Aperture = 24.8921 ...I think, that's .980 inches converted to mm, Academy will be smaller X Resolution = 2048 Y Resolution = 1556 ...therefore all it needs is the horizontal measure (aperture) and the 1.316:1 aspect ratio. All this, coupled with your focal length, determines your field of view. You could write expressions that would convert a known field of view into a focal length if that data was known instead of focal length. Quote Link to comment Share on other sites More sharing options...
Mr Mobius Posted March 4, 2003 Author Share Posted March 4, 2003 hey pockets, The reason I want to input the filmback is because Im actualy working with Video, This is the way I understand it. If you had a the same size lens's on two different camera's (video) an XL1 and a Betacam. The film back on an XL1 is a third of an inch and the film back on a beta is 2 thirds on an inch, because the film backs are different then the angle of view will be different also. Therefore the lens settings you use in the viewport have to work in conjuction with the correct filmback size. Is it just a case of doing the math for the film back you use? Quote Link to comment Share on other sites More sharing options...
pockets Posted March 7, 2003 Share Posted March 7, 2003 Your "filmback" is still defined by one number, essentially, in the aperture channel. This value plus your focal length defines your field of view. You can figure out what to plug into your focal length if you know the FOV and your aperture, but you need at least two of these numbers. The aperture is the (relatively) easy one to arrive at. What you need to remember, with video in particular, is that for whatever reason the CCD size is given as a DIAGONAL measure rather than a horizontal or vertical measure, like with film. I had to figure that one out the hard way. Why did they do this? Because some fool decided to measure TVs that way? Love of the pythagorean theorem? Video engineers, man, a pox on them all. What a collection of hacks they've created. I don't have the figures in front of me but if I remember when I get home I'll grab the .hip file I made with camera setups for Super35mm, 2/3" CCD...I think 1/3" and 1/4" are in there too. I'm pretty sure I made one for an HDWF900 or DSR500, one for a GL-1 and one for another camera between the GL1 and the 2/3" cameras that should match up with the XL1. I basically wanted something I could use no matter what camera I came across. What's kooky is, even for something like the HDW-F900 HD camera, which shoots a 16:9 image, the 2/3" CCD measure is based on the actual 4:3 area of the raw CCD, since none of these cameras actually have 16:9 CCDs. Quote Link to comment Share on other sites More sharing options...
Mr Mobius Posted March 8, 2003 Author Share Posted March 8, 2003 hmm.. Strange, cos The engineer who came out to fix my TV last week seemed to be a really nice guy, we had a coffee and he never mentioned trig once, im mean they cant be all bad. Just kidding! Seriously, Thanks pockets, the .Hip file would be a real God send. Although you have cleared up alot of confusion. Cheers for the responce. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.