Shutter Speed stop down V.S. ND

[Will Keir]

What's the difference between using shutter speed to stop light down vs NDs?

Am I loosing image quality with a still shot of the sun using shutter speed at 1/8000th as opposed to
stacking my neutral density filters? It's so easy, there must be a disadvantage?

I'd like to keep my aperture at T5.6 to get the best performance (sharpness) out of my lens. I know for motion different
shutter speeds are discernible but a still landscape with the occasional bird, a mountain landscape...

Thanks in advance for some clarification on this one.

 

[Bob Gundu]

If you're asking about stills, the shutter approach is better as you eliminate a filter, and the image will have less motion blur. But for motion, you will typically not want strobey video with high shutter. Unless you shoot slow motion where higher shutter looks nice for a crisp look.

 

[Michael Romano]

With stills, you can avoid ND in almost any situation by way of shutter. I use that all the time, especially since I like less motion blur as a personal taste. Set to manual, f5.6, your preferred ISO and then adjust shutter to control exposure. With my nikon digital stills I have also found I can underexpose vastly and recover it in raw so even in lower light situations I keep the shutter speed as high as possible. At some point, you'll have to slow it down, open up and push ISO, it is inevitable in near dark scenarios.

 

[ericyoung]

Apart from motion blur reduction, stopping down increases your depth of field, which depending on your framing and shot intentions, may or may not be the effect you want.

 

[David Kuhn]

If you've got the light, then still imaging at short shutter timing does not cost you any image quality (fewer filters are better in general). However, even for still imaging... sometimes you want to induce some motion blur (taking pictures of a waterfall... blurred water motion gives it an artistic look). For motion imaging it looks like ND's are probably the most important filters you can own - jerky motion just doesn't look good.

 

[Björn Benckert]

When you lower exposure time remember to check so your blackshade is still within limits.

As stated here ND will give you less exposure at the same motion blur and aperture. For example if you want to shoot wide open in bright daylight.
Higher Fstops gives you more focus depth so adjusting the Fstop to get to the right exposure also changes your depth of field.
Changing the shutter gives less motion blur. Normal for filming is 180deg or half the fps. But personally I think without the motion mount RED and most digital cameras gets an ugly/to much motion blur at 180 deg, a film camera used 180 deg as normal but it also "faded" it's motion blur and film 180 deg motion blur looks far less than digital as the digital cameras are perfectly linear when it comes to motion blur. So for that reason I like about 100 deg shutter. But then again if it's not much motion in the shot and the camera is not moving much then anything between 360 and 1 deg is usable.

I'm quite surprised that a lot of really high end DP's do not utilize the 360 shutter of these cameras. I was on a really big shoot and we where doing a dusk shot and the DP got furious that he would not get the shot in time before it was too dark and he wanted to swap from his anamophics to superspeeds to get enough light. The shot in question was a fixed shot of a house with the door opening slowly...

In his stress I walked up to him, as a VFXsup, which is not always (and espeically in this case) not the most popular thing to do, and told him that we should open the door half as fast and shoot it @ 12fps 360 shutter and then he would gain 2 stops... First he looked at me with evil eyes but shortly after he bought me beer. So I think I got his mind onto somthing. Lol.

 

[David Mullen ASC]

These shutter tricks are fine when nothing is moving or hardly moving -- but if we're talking about MOTION pictures, that is rarely the case.

 

[Stephen Williams]

::

There is a very precise time given on the letter so my money is on somebody having dobbed you in to the council.
Probably a neighbour fed up with all the random non official bags being dumped in the bin.

You could try TiMow's approach and see what happens. If they have evidence against you ( photo if you depositing the bag, address on an item in the bag) then they should provide it in response to your query.

In future remember to only use the official bags.

I'm quite surprised that a lot of really high end DP's do not utilize the 360 shutter of these cameras. I was on a really big shoot and we where doing a dusk shot and the DP got furious that he would not get the shot in time before it was too dark and he wanted to swap from his anamophics to superspeeds to get enough light. The shot in question was a fixed shot of a house with the door opening slowly...

In his stress I walked up to him, as a VFXsup, which is not always (and espeically in this case) not the most popular thing to do, and told him that we should open the door half as fast and shoot it @ 12fps 360 shutter and then he would gain 4 stops... First he looked at me with evil eyes but shortly after he bought me beer. So I think I got his mind onto somthing. Lol.

I think you mean 2 stops 1/4 of the light.

24 FPS to 12 FPS = 1 stop
180 degree shutter to 360 degree shutter = 1 stop

 

[Dr. Sassi]

All based on movement: two examples.

To have a short shutter speed results in an aesthetics of "Saving Private Ryan".

If the f-stop is fixed and using then a long shutter speed, while pivoting around the actor, "peels" him/her from the background, based on more motion blur of the BG.

Time is an essential tool for the final result and you should work with NDs as long as there is no other intention for the change in image aesthetic. It might confuse the audience more or less if you use time to get your exposure right, as the only reason.

There is so much more.

(The sweet spot of the lens is one criteria, another philosophy is to keep the aperture close to the eye and the resulting perception, e.g., wider open inside, smaller outside in bright sun-light. All these decisions are like the paint on the palette of a painter, and how it is combined on the canvas -- which is unveiled in the final product, and shows what kind of philosophy "you" as a Cinematographer were able to establish)

 

[Björn Benckert]

::

I think you mean 2 stops 1/4 of the light.

24 FPS to 12 FPS = 1 stop
180 degree shutter to 360 degree shutter = 1 stop

Yes, my bad 2 stops.

 

[Björn Benckert]

These shutter tricks are fine when nothing is moving or hardly moving -- but if we're talking about MOTION pictures, that is rarely the case.

We do it all the time when the milo can not move fast enough.... then the actors simply have to go down to "quarter speed acting" and we shoot them in 6.25fps with ND

It's no joke, for some stuff it works very well and everyone have far better chance to hit their que mark.

Then when telling them to do the same thing but in reverse people they usually get a bit irritated.


Also when doing moco I try to shoot 4x the wanted FPS a lot of times and do so with 360 shutter then I got enough in between frames to do motion estimated retime and also have the option to choose merge two frames to get more motion blur or use one to get less. It's a good option to use when fast pans and such are in use and you do not know if it will cause strobe on a big screen, or if part of the move needs more motion blur then the rest or such. The 360shutter is fantastic for merging two frames together and get double motion blur.. something film could never do as it's missing info between frame one and two.

 

[David Kuhn]

So here's a dumb question... using an ND and inducing blur is inherently a lossy operation, and it seems like it's one that's pretty straightforward mathematically. Why not expose for a sharp blur free image (maximize your data set) and add motion blur in post (giving you the ability to alter the amount for as long as you have your raw data). Is there something that getting blur during the shoot gives you that can't be captured digitally post with something like the AE 'Picture Motion Blur' effect?

This stuff is really fascinating, maybe because it's antithetical to how I use cameras in my day job (where we want as crisp an image as possible so it contains the most data it possibly can).

 

[Björn Benckert]

So here's a dumb question... using an ND and inducing blur is inherently a lossy operation, and it seems like it's one that's pretty straightforward mathematically. Why not expose for a sharp blur free image (maximize your data set) and add motion blur in post (giving you the ability to alter the amount for as long as you have your raw data). Is there something that getting blur during the shoot gives you that can't be captured digitally post with something like the AE 'Picture Motion Blur' effect?

The in camera motion blur is correct. The aftereffect stuff is a digital smear along motion vectors works quite well if you have CG renders with motion map but not good at all for camera imagery. Example. turn on camera. 25fps 180deg. Move your hand back and forth in front of it.... some frames will just be streaks of the hand and the background showing behind. Then if you shoot the same scene with super short shutter the computer will not recreate whats behind the sharp moving hand...


Or a rabbit running behind a fence... aftereffects can not simply not keep the fence and blur the rabbit.

 

[David Kuhn]

Right... makes sense... with a long shutter you're giving up some data relative to a sharp image... but you're capturing motion data that may be happening between subsequent frames (and would be missed with a very short exposure).

 

[D Fuller]

Right... makes sense... with a long shutter you're giving up some data relative to a sharp image... but you're capturing motion data that may be happening between subsequent frames (and would be missed with a very short exposure).

Yes, and both the camera and the various subjects may all be moving at different speeds, so the amount of blur created by each would be different. In post, all you can do is one directional blur. (Maybe Flame or Nuke can do more? I'm not sure about that.)

 

[Björn Benckert]

Yes, and both the camera and the various subjects may all be moving at different speeds, so the amount of blur created by each would be different. In post, all you can do is one directional blur. (Maybe Flame or Nuke can do more? I'm not sure about that.)

There are motion estimate blurs that analyze the footage and blur the part of the footage where motion is present. But that procedure has similar issues as Twixor and all the retiming softwares. works as a charm... not so often. but some times they shine

We made a plugin for max a while back that actually was top of the line at the time, and I think they guys here actually still use it but converted to nuke. It takes any motion or depth vector maps and create a really nice dof or motion blur... but again there is artifacts.


Old web page: http://web.archive.org/web/20130218200757/http://www.syndicate.se/Default.aspx?Id=313



We

 

[Björn Benckert]

Around the table at about 30 seconds we used 360 shutter and overcranked to varispeed and go from realtime to timelapse seamlessly: https://vimeo.com/69091088

Could not be done without the 360 shutter.

 

[Dr. Sassi]

Good question. For Cineversity I have had created an "Integration 101" tutorial series (over 50 parts long), based on my multi awarded short JET (Junior ExtraTerrestrial). http://youtu.be/vtBHyYaOQ9I

"Energy-conservation" would be the best argument to do it in camera. Over-bright light that would perhaps clip (specular highlights for example) will affect the blur differently than the post blur does. It is perhaps a fine nuance.
Not everything can be blurred in post, such as layered elements, think of a car reflection (window) and the view through the glass, hard to split. I have sometimes to do it for my CG work in post to adapt to practical footage, and if I do not use floating point images, I do not get even close to what could be possible.
The next point is that you can't always retrieve if the motion is shaky or rotational, etc. Motion analysis is not bad these days, but not as far as we wish to. In other words, it needs manual attention. For a short commercial that might work, but for a feature film, this is out of reach for a normal indie production: 130,000 frames is a normal feature, talking about straight forward mathematic. ;o)

So here's a dumb question... using an ND and inducing blur is inherently a lossy operation, and it seems like it's one that's pretty straightforward mathematically. Why not expose for a sharp blur free image (maximize your data set) and add motion blur in post (giving you the ability to alter the amount for as long as you have your raw data). Is there something that getting blur during the shoot gives you that can't be captured digitally post with something like the AE 'Picture Motion Blur' effect?

This stuff is really fascinating, maybe because it's antithetical to how I use cameras in my day job (where we want as crisp an image as possible so it contains the most data it possibly can).

 

[Jeff Kilgroe]

Maybe I missed it if someone else mentioned it, but we also have to watch out for fast shutters more so on sensors with a scanning read-out (rolling shutter). The faster the shutter (exposure time), the more apparent the rolling shutter skew on moving objects.

Lengthening the shutter can be advantageous to gain a more light for motion. We have to be careful of making the exposure too long, though. That can lead to a smooth video look. On the flip side of things, with the shutter getting too fast, the lack of motion blur can leave our motion shots looking stuttery or with a very staccato look, and yes, more defined shutter skew.

 

[Will Keir]

Yes. This is true with stopping down aperture. I'm talking about shutter speed, which should not effect Depth of Field.

Apart from motion blur reduction, stopping down increases your depth of field, which depending on your framing and shot intentions, may or may not be the effect you want.