What is shutter angle ?

[kunal2]

Hi folks has anyone wonder how they are able to capture both actors and cityscapes at night in some movies also arial shots where you see an helicopter enters the frame and below there is luminous skycrapers and buildings,I've noticed that these movie scene are crystal clear and noise free,I've tried to do it in still cameras,but it is quite tough,either you use a wide open lens and slow shutter or use higher sensitive film,but I have heard that in cine cameras it has something to do with shutter angle,i've tried to understand the theory but quite complicated,does someone have a clarification about all this,i would b grateful if you could post a link or clearer explanations.

THANKS
KUNAL


(excuse my english not use to speak)

[Nojoy]

Here is a link to a fellow landsman who used Renderman and increased his shutter angle to get the desired motion blur in Renderman. See the left hand side mid way down the page it deals with the subject shortly. If i find more information on the subject ill let you know. The effect you're describing above I beleive is usually always done in post with use of compositors and keys, rotoscoping, camera tracking etc. and than dealing with each layer on its own until the perfect result is achieved.

http://www.maxschoenherr.de/animation/Maya/RendermanForMaya/rendermanMotionBlur.htm

[kunal2]

Yes i do agree with you Nojoy,most of these scenes are composited nowadays,but there are those which are purely photography,i mean a 35 mm movie camera are able to a fairly lit foreground scene + the illuminated cityscape in the backgound,as a photographer myself ,I must use a very slow shutter speed to be able to capture a night scene,You will excuse me,coz I am assuming you understand a bit of photography

[Nojoy]

Well I do actually, I own a Dynax 5D wich I mainly use for my textures. I looked heavily into the shutter speed and Fstop Issue to really understand it. After viewing 4 DVD's from L**da.com and Video2B**** covering the subject Digital Photography, I actually finally feel like I know what Im doing but still far from a pro. I understand Shutter Speed, but on Shutter Angle I only found the info I provided above. For me the angle only makes sense in the way the light hits the cmos chip on the camera, but what the shutter does there makes no sense to me. Shutter speed is obvious (the speed the lid lets light through to the chip) ISO aswell (sensitivity of the chip itself back in the old days it was the films sensitivity and usually written on the box) wich is also of importance when shooting at night as you stated above. For night scenes I photograph, I usually use Minoltas low key modus wich works great in dark scenes. I guess I just didnt understand the question due to the word angle in your thread and thinking it was more maya specific, setting wise. Sorry not a pro yet there only ambitious amature. Hope you find what youre looking 4 and if you do so let me know ;)

[laxman]

if youre talking video, then I know that they use software like lustre to change the brightness and contrast of individual objects in a scene. For a photo they probably use photoshop. I'm not too sure if a straight photo can give you clear contrast of a person on a dark background because the situation is similar to photos of the earth. The reason you never see any stars in satellite photos of the earth is because the earth is several hundred time brighter than the star so they have to use a fast shutter speed so they don't over expose the film but the light from the stars doesn't have time to register.

Changeing the shutter angle will affect the amount of exposure to the film if you have a rotary disc shutter but I don't see how it will help get the contrast you need. Check this out, it might help:

http://en.wikipedia.org/wiki/Shutter_angle

[Nojoy]

Thanks laxman, very nice info on that page, I have now a clearer view ;)
Very intresting subject. These shutters seem to be used heavily in war movies such as James Ryan. It basically lets light through to the next frame without closing the shutter. Very few cams have it they stated and usually its adjusted manually with a special tool. Thanks again laxman awesome link.

[laxman]

wiki is the best isn't it:)

[kunal2]

Thx a lot guys it was vey kind of you all for sharing some info,I admit it was very helpful :yes :yes