X360 and Anti Aliasing?

[Simon F]

Isn't shutter time dependent on exposure, and thus on light conditions? Like, dark scenes need a longer exposure time to capture enough light, and thus a longer shutter time? It sure goes like this with photography, and even though movies tend to compensate for this with a lot of extra artificial lighting, I'd think that the dependency remains...

On a stills camera, yes that can be the case, but my understanding is that with the movie cameras they simply use the aperture and/or filters to control the exposure.

 

[Simon F]

Try it for yourself and you will see that this isn't always the case. A decent upscaling can help smooth the aliasing out a bit, you can see this effect simply by resizing a screenshot with an image editing program like Photoshop.

No it won't. That's equivalent to undersamping an image even more!

Sow's ear != silk purse.

It would be nice to have a Simon in every forum, may we clone you?

There is a 50% clone but her typing skills are currently limited to things like "GGFFFFFFHHHHHHH" and her spoken vocubulary isn't much greater (although "chair" is an exciting new addition). I think you'll just have to put up with me.

 

[Simon F]

Most 16-35mm film is shot with a 180 degree shutter which equals 1/48 of second @ 24FPS in video camera terms. This is done because motion film cameras have a rotating shutter that needs to be opened and closed up to several thousands of times a minute, unlike a SLR still camera which would have a shutter failure after shoting a few minutes at 24fps.

Another reason is that there has to be time to advance the film one frame ready for the next shot. If the shutter is open for longer periods, then the film has less time to be moved and hence would require greater accelerations -> much greater forces -> shredded film everywhere!

(This has been discussed before on B3D (here and here)- the "rolling loop" technology helps but still requires time when the shutter must be closed)

There are also different types of shutter speeds, for example a 90 degree shutter, like in the fight scenes in gladiator, gives a more jerky feeling since there is less motion blur between the frames.

Which backs up the assertion that we need temporal antialiasing for the movie/video/game to look natural.

 

[Shifty Geezer]

Okay, thanks for the info guys. That means for a film look w need 1/48th second moblur as standard. From what moblur I've seen it's a lot more than this, but I guess there aren't offical figures.