On the DVfilm website it "highly recommends" using a 1/50 shutter if blowing up to film under it's DVX100 section. I don't see how this could ruin a "film-look" as such. Films often use slow or fast shutter speeds for particular purposes. Wouldn't the DVX simply be simulating the same thing? The camera is running at 24 frames anyways, it doesn't change that. Any thoughts on this, or the rest of their recommendations would be appreciated.
Shutter to think
- Thread starter Zot
- Start date
Re: Shutter to think
Hi Zot!
I'm not sure if I understand your question but here's my take on this issue- Film is projected at 24fps using a 180 degree shutter so in effect,the normal shutter speed is 1/48th of a second.The 1/50 setting is the closest to 1/48 hence the recommendation.
Hi Zot!
I'm not sure if I understand your question but here's my take on this issue- Film is projected at 24fps using a 180 degree shutter so in effect,the normal shutter speed is 1/48th of a second.The 1/50 setting is the closest to 1/48 hence the recommendation.
Barry_Green
Moderator
Re: Shutter to think
That recommendation is probably a holdover from the interlaced camera days. When using a 60i camera, if you used a faster shutter speed than 1/60th, it could make for very ugly motion artifacts in the transfer.
Many film cameras use a 180-degree shutter, but a lot of them don't. Some use a 172.8-degree shutter, which gives a 1/50th exposure. I have an old B&H Filmo that has something like a 216-degree shutter, for a 1/40th exposure time. And I've got a Konvas here somewhere that has a 150-degree shutter (I think the K-3 does as well) and I believe that delivers approximately 1/60th exposure. I think the Eyemo was 150-degrees as well. And the CP16 comes in four flavors: the CP16/A is 180 degrees, and most CP16/R's are 156-degrees, but the early models were 144 degrees and the last ones were 170 degrees. Auricon TVT's were 144 degrees. 144 is nice because it produces a precise 1/60th for sync'ing with TV's in your shots.
So 180-degrees is a good starting point but not an immutable law. I've shot with the DVX in 24P at 1/60th, 1/50th (which is "shutter off" mode), 1/48th, 1/36th, and most recently at 1/30th. No matter how you go, it'll look like film, and it will transfer to film just fine.
That recommendation is probably a holdover from the interlaced camera days. When using a 60i camera, if you used a faster shutter speed than 1/60th, it could make for very ugly motion artifacts in the transfer.
Many film cameras use a 180-degree shutter, but a lot of them don't. Some use a 172.8-degree shutter, which gives a 1/50th exposure. I have an old B&H Filmo that has something like a 216-degree shutter, for a 1/40th exposure time. And I've got a Konvas here somewhere that has a 150-degree shutter (I think the K-3 does as well) and I believe that delivers approximately 1/60th exposure. I think the Eyemo was 150-degrees as well. And the CP16 comes in four flavors: the CP16/A is 180 degrees, and most CP16/R's are 156-degrees, but the early models were 144 degrees and the last ones were 170 degrees. Auricon TVT's were 144 degrees. 144 is nice because it produces a precise 1/60th for sync'ing with TV's in your shots.
So 180-degrees is a good starting point but not an immutable law. I've shot with the DVX in 24P at 1/60th, 1/50th (which is "shutter off" mode), 1/48th, 1/36th, and most recently at 1/30th. No matter how you go, it'll look like film, and it will transfer to film just fine.
Re: Shutter to think
Considering many of the scenes in Saving Private Ryan (and many other recent films) were shot on 35mm with a 15 degree shutter angle (that probably equates to around 1/600th of a second) it really just comes down to an aesthetic choice to achieve certain looks. I shoot rap videos with a 45 degree shutter all the time - it seems to be the "in" look right now.
Just be aware that as you increase your shutter speed, slow down on your pans. The "stroby" look can really upset some viewers (physically)
Considering many of the scenes in Saving Private Ryan (and many other recent films) were shot on 35mm with a 15 degree shutter angle (that probably equates to around 1/600th of a second) it really just comes down to an aesthetic choice to achieve certain looks. I shoot rap videos with a 45 degree shutter all the time - it seems to be the "in" look right now.
Just be aware that as you increase your shutter speed, slow down on your pans. The "stroby" look can really upset some viewers (physically)
Re: Shutter to think
Yeah, I think both ends of the shutter range have nice uses. I like the high shutter speed look of the Ridley Scott or Private Ryan look. Also the beautiful and creative cinematography of the the Wong-kar-Wai movies like "Chungking Express" that use a very low shutter speed to turn action sequences into impressionistic blurs. Doing handheld with a low shutter may sound like a mess, but I think they really make it look great. His cinematographer is Christopher Doyle. This guy is genius...I think so anyways.
Oh and thanks everybody for the help! It sounds like the suggestion is recommended if you want a "standard" look, or if you are using an 60i camera.
Yeah, I think both ends of the shutter range have nice uses. I like the high shutter speed look of the Ridley Scott or Private Ryan look. Also the beautiful and creative cinematography of the the Wong-kar-Wai movies like "Chungking Express" that use a very low shutter speed to turn action sequences into impressionistic blurs. Doing handheld with a low shutter may sound like a mess, but I think they really make it look great. His cinematographer is Christopher Doyle. This guy is genius...I think so anyways.
Oh and thanks everybody for the help! It sounds like the suggestion is recommended if you want a "standard" look, or if you are using an 60i camera.
J.R. Hudson
Spirit Animal
Re: Shutter to think
I thought SPR was shot using 45 to 90 degree shutters? Aggghh...
I don't get it. Shutter Speed and Shutter Angle are two diifferent things, right?
Barry!
I thought SPR was shot using 45 to 90 degree shutters? Aggghh...
I don't get it. Shutter Speed and Shutter Angle are two diifferent things, right?
Barry!
Barry_Green
Moderator
Re: Shutter to think
They are different, but shutter angle dictates what exposure time will be (there isn't really a "shutter speed" in movie film, there's exposure time).
Shutter angle is understood thusly: a film camera shutter is (typically) a flat opaque disc, with a chunk missing. The disc is of course 360 degrees, and it rotates. The chunk that is missing is what will expose the film. The size of the chunk is the shutter angle. For example, if the disc was exactly a half-circle, then the shutter angle would be 180 degrees. For a 45-degree shutter, you'd only have a small sliver of the disc exposing the light: 315 degrees of the circle would be opaque, and 45 degrees would be "open".
So, that's shutter angle. Now, to determine exposure speed, you have to know what speed the camera's running at. The faster fps of the camera, the less exposure time, and vice versa. Let's take the example of the 180-degree shutter, running at 24fps. The shutter makes one complete rotation for each frame, so at 24 frames per second, each frame will be exposed for 1/2 the time (because the shutter is half open and half opaque, 180 degrees open and 180 degrees closed) so your effective exposure time (pseudo-"shutter speed") is 1/48th of a second (again, half the disc means exposure for half the time, and half of 1/24 of a second is 1/48th of a second).
If you instead run your film camera at 60 frames per second, the exposure time would be (obviously) 1/120th of a second, because the shutter disc is spinning faster (again locked to one rotation per frame).
If you slow down to 2 frames per second, the exposure time would be 1/4 second per frame.
Now, if you change the angle, it changes exposure time: a 90-degree shutter angle will mean that only 1/4 of the shutter disc is open, with 270 degrees closed. That means that the exposure will happen for only 1/4 the amount of time. At 24fps, you'll get an exposure of 1/96th of a second. Choppier motion (because of the shorter "shutter speed") and crisper picture (because of less motion blur) yields Saving Private Ryan look. But you need a lot of light because you're exposing for such a brief amount of time.
They are different, but shutter angle dictates what exposure time will be (there isn't really a "shutter speed" in movie film, there's exposure time).
Shutter angle is understood thusly: a film camera shutter is (typically) a flat opaque disc, with a chunk missing. The disc is of course 360 degrees, and it rotates. The chunk that is missing is what will expose the film. The size of the chunk is the shutter angle. For example, if the disc was exactly a half-circle, then the shutter angle would be 180 degrees. For a 45-degree shutter, you'd only have a small sliver of the disc exposing the light: 315 degrees of the circle would be opaque, and 45 degrees would be "open".
So, that's shutter angle. Now, to determine exposure speed, you have to know what speed the camera's running at. The faster fps of the camera, the less exposure time, and vice versa. Let's take the example of the 180-degree shutter, running at 24fps. The shutter makes one complete rotation for each frame, so at 24 frames per second, each frame will be exposed for 1/2 the time (because the shutter is half open and half opaque, 180 degrees open and 180 degrees closed) so your effective exposure time (pseudo-"shutter speed") is 1/48th of a second (again, half the disc means exposure for half the time, and half of 1/24 of a second is 1/48th of a second).
If you instead run your film camera at 60 frames per second, the exposure time would be (obviously) 1/120th of a second, because the shutter disc is spinning faster (again locked to one rotation per frame).
If you slow down to 2 frames per second, the exposure time would be 1/4 second per frame.
Now, if you change the angle, it changes exposure time: a 90-degree shutter angle will mean that only 1/4 of the shutter disc is open, with 270 degrees closed. That means that the exposure will happen for only 1/4 the amount of time. At 24fps, you'll get an exposure of 1/96th of a second. Choppier motion (because of the shorter "shutter speed") and crisper picture (because of less motion blur) yields Saving Private Ryan look. But you need a lot of light because you're exposing for such a brief amount of time.
Re: Shutter to think
I believe the formula is:
Exposure time = (shutter angle) / (360 * fps)
So 1/48 = 180 / (360*24)
or
1/192 = 45 / (360*24)
or
1/96 = 180 / (360*48)
or
1/48 = 90 / (360*12)
Sorry for all those examples, I was sort of checking myself. That seems to be the right formula.
As for the DVFilm recommendation, I'm guessing that they're dealing with some unknowledgeble people and mean more that 1/50 will give you the normal "film look" so that people don't end up with a narrow shutter look "by accident" and get upset about it.
Chungking Express' amazing scenes were shot at slow framerates with, to my knowledge, a normal shutter. The footage was however step-printed, doubling or tripling frames to maintain proper speed. So perhaps it was shot at 8 fps and each frame was printed 3 times. I feel like it was either that or 12 fps with each frame printed twice. It is a great look.
Will
I believe the formula is:
Exposure time = (shutter angle) / (360 * fps)
So 1/48 = 180 / (360*24)
or
1/192 = 45 / (360*24)
or
1/96 = 180 / (360*48)
or
1/48 = 90 / (360*12)
Sorry for all those examples, I was sort of checking myself. That seems to be the right formula.
As for the DVFilm recommendation, I'm guessing that they're dealing with some unknowledgeble people and mean more that 1/50 will give you the normal "film look" so that people don't end up with a narrow shutter look "by accident" and get upset about it.
Chungking Express' amazing scenes were shot at slow framerates with, to my knowledge, a normal shutter. The footage was however step-printed, doubling or tripling frames to maintain proper speed. So perhaps it was shot at 8 fps and each frame was printed 3 times. I feel like it was either that or 12 fps with each frame printed twice. It is a great look.
Will
Re: Shutter to think
I can't find my American Cinematographer with SPR in it right now, but I'm pretty sure I remember that Kaminski used various shutter angles from 15 to 90 degrees. I also remember that he used uncoated lenses for that halo effect, and had Panavision modify one camera to put the gate movement out of sync with the shutter to create the vertical "streak" in some shots. It must be nice to have the budget to ask Panavision to break a camera for your production!
As far as the terms shutter angle vs. shutter speed - they are just different terms used in motion film and video/still photography (respectively) to describe the same thing: EXPOSURE TIME PER FRAME.
In video & still photography, the 1/x second simply describes the exact amount of time the exposure of each frame takes to complete. Thus 1/50th of a second will have twice as much motion blur as 1/100th of a second exposure. In video, there are no physical moving parts, so you can also have the shutter stay "open" for the duration of 1 frame (1/24th in the case of the DVX or similar 24P cameras.)
A motion film camera, on the other hand, must physically advance the film after each frame is exposed. The shutter is required to "hide" the film from being exposed while the camera advances 1 frame. Most camera shutters look like a 1/2 moon - (180 degrees.) If you take the lens off of a film camera, look inside, and rotate the frame advance knob, you will see the stationary emulsion of the film for half of the rotation and the mirrored shutter the rest of the time (this is when the frame advances.) Since film shoots 24 frames per second, the result is that light only reaches the emulsion half of that time, or 1/48th of a second per frame. As Barry pointed out, many film cameras have different default shutter angles depending on the design of their intermittent movement, but most film light meters assume 180 degrees. Some film cameras also have variable shutters that can be used to achieve the different "strobe" effects described earlier. (Very useful in cereal commercials.)
The reason we use shutter angle instead of shutter "speed" in film is simply because of the mechanics involved - and it makes it easier to calculate exposures when shooting different frame rates. The math is also easier. The smaller the number of degress, the less light.
For example, 90 degrees is a loss of 1-stop, 45 degrees is 2-stops, 22.5 is 3-stops, etc. 144 degrees equals 1/60th of a second, so it can be used for reducing flicker when shooting NTSC monitors.
Since the film camera has the physical limitation of needing to advance the frame, you would never be able to achieve a 1/24th of a second shutter (or 360 degrees) without streaking the image. This is the wonderful advantage of shooting on video to achieve the effect of more motion blur than has ever been available in film.
I can't find my American Cinematographer with SPR in it right now, but I'm pretty sure I remember that Kaminski used various shutter angles from 15 to 90 degrees. I also remember that he used uncoated lenses for that halo effect, and had Panavision modify one camera to put the gate movement out of sync with the shutter to create the vertical "streak" in some shots. It must be nice to have the budget to ask Panavision to break a camera for your production!
As far as the terms shutter angle vs. shutter speed - they are just different terms used in motion film and video/still photography (respectively) to describe the same thing: EXPOSURE TIME PER FRAME.
In video & still photography, the 1/x second simply describes the exact amount of time the exposure of each frame takes to complete. Thus 1/50th of a second will have twice as much motion blur as 1/100th of a second exposure. In video, there are no physical moving parts, so you can also have the shutter stay "open" for the duration of 1 frame (1/24th in the case of the DVX or similar 24P cameras.)
A motion film camera, on the other hand, must physically advance the film after each frame is exposed. The shutter is required to "hide" the film from being exposed while the camera advances 1 frame. Most camera shutters look like a 1/2 moon - (180 degrees.) If you take the lens off of a film camera, look inside, and rotate the frame advance knob, you will see the stationary emulsion of the film for half of the rotation and the mirrored shutter the rest of the time (this is when the frame advances.) Since film shoots 24 frames per second, the result is that light only reaches the emulsion half of that time, or 1/48th of a second per frame. As Barry pointed out, many film cameras have different default shutter angles depending on the design of their intermittent movement, but most film light meters assume 180 degrees. Some film cameras also have variable shutters that can be used to achieve the different "strobe" effects described earlier. (Very useful in cereal commercials.)
The reason we use shutter angle instead of shutter "speed" in film is simply because of the mechanics involved - and it makes it easier to calculate exposures when shooting different frame rates. The math is also easier. The smaller the number of degress, the less light.
For example, 90 degrees is a loss of 1-stop, 45 degrees is 2-stops, 22.5 is 3-stops, etc. 144 degrees equals 1/60th of a second, so it can be used for reducing flicker when shooting NTSC monitors.
Since the film camera has the physical limitation of needing to advance the frame, you would never be able to achieve a 1/24th of a second shutter (or 360 degrees) without streaking the image. This is the wonderful advantage of shooting on video to achieve the effect of more motion blur than has ever been available in film.
J.R. Hudson
Spirit Animal
Re: Shutter to think
Yet another cut copy and save that I will have to read and refer to umpteen times. Thanks everyone.
Yet another cut copy and save that I will have to read and refer to umpteen times. Thanks everyone.
Re: Shutter to think
I stand corrected. I finally found the Saving Private Ryan article, and you are right -they didn't go below 45 degrees as I had thought.
Here's the link.
http://www.theasc.com/magazine/aug98/saving/index.htm
I stand corrected. I finally found the Saving Private Ryan article, and you are right -they didn't go below 45 degrees as I had thought.
Here's the link.
http://www.theasc.com/magazine/aug98/saving/index.htm