slower shutter speed in video mode

[silverface]

is it possible to slow the shutter speed lower then  30th of a second to give the blur effect in video...?

[Andy600]

The last time I looked a circle had 360°

http://en.wikipedia.org/wiki/Shutter_speed#Cinematographic_shutter_formula

[arrinkiiii]

Maybe override the fps 

[silverface]

these replays wouldn't create blurry footage would it?

[dmilligan]

It should be completely obvious that making the shutter speed slower than 1 / fps is impossible and absurd. Think about it, if you're shooting 30 fps (the standard frame rate for video) then each individual frame canot be longer than 1/30 of a second. Otherwise the exposures would have to overlap which is impossible since there is only one sensor in the camera and it canot take two different exposures at the same time. The only way to get longer exposure time is to slow down the frame rate, which is possible with fps override, but the footage is going to either look choppy (if played back at the lowered frame rate) or appear sped up like a timelapse (if played back at a normal speed like 24 or 30 fps)

If you are trying to do some type of extreme motion blur special effect, the only way to achieve this is by blending frames in post production software. Adobe After Effects has an effect called CC Time Blend that does exactly this.

[fiveservice]

my old JVC digital videocamera has this option

[Matheus]

I know this may sound stupid, but what if we get the exposure and add it to the previous frame?

For example, we capture all frames in 1/30, in a "capture" buffer: [F1, F2, F3, F4, ...] and then, we add each of these frames exposures with the previous frames, into the buffer going to the card (output): [O1 = F1, O2 = F1 + F2, O3 = F2 + F3, O4 = F3 + F4, ...]

This way, we could lower down the shutter to a "virtual" 1/15, for example...

I'm not a ML developer, but this is my idea for what could be done (while keeping at 30fps)...

[mageye]

Incredibly complicated to do something that would best be done in post.

[dmilligan]

The only way you could do something that complicated is with hardware, there is no such hardware that I'm aware of in these cameras, thus it is impossible. You can do it in post anyway, and you will have much more control.

You have remember the absolutely huge amount of data these cameras are dealing with. To simply frame stack 2 images you are going to have to do 1920 * 1080 addition operations in 1/30th of a second (that's ~60 million operations per second, just for the addition, not to mention all the additional operations you have to do like loading values into registers, and writing out to memory, which is considerably slower). And that's only for the option to do a 2 frame stack. In post you can stack several hundred frames if you want or fade the effect in and out.  Here is an example I did to get the waterfall blur effect in AE:
https://vimeo.com/70987503

It was attempted to do a 14 > 12 bit conversion for raw video, but the cpu wasn't even fast enough to do a simple truncation like that, much less adding two or more frames.

Almost all image processing (debayering, image adjustments, curves, h264 and jpeg encoding, etc.) is done by dedicated hardware, not the cpu. The cpu's resources are extremely limited, it is used mostly for controlling the various hardware. This is how almost all embedded systems are designed that have to deal with large amounts of data. Custom hardware is cheaper to produce than some really fast general purpose processor that can handle doing the processing in software. I see so many feature requests for ML by people who seem to not understand this principle and think these cameras do everything in software (because they are used to computers, where everything is done is software, and nothing has to be 'real-time').

[steve parker]

if it is possible to shoot at 25fps i.e. 1/50th second, or 15fps i.e. 1/30th second - then why not 6fps i.e. 1/12 second [most movie cameras have this function]? steve

[dmilligan]

if it is possible to shoot at 25fps i.e. 1/50th second, or 15fps i.e. 1/30th second - then why not 6fps i.e. 1/12 second [most movie cameras have this function]? steve

yes, you can do this, use fps override, the shutter speed limit is 1 / fps

[arturochu]

i can override fps, but not the shutter, what am i doing wrong?

[steve parker]

i installed the alpha version of ML on my 5Dmk3 but the menu doesn't look anything like the mk2 version and there is no FPS override option. i've followed all instructions, watched YouTube so all very frustrating...anybody out there knows a really good link, i'll try anything to get the FPS override function !! steve

[dmilligan]

anybody out there knows a really good link, i'll try anything to get the FPS override function !! steve

maybe start here: http://wiki.magiclantern.fm/userguide#fps_override

you may need to update to a more recent build (the early alpha version don't always have everything working)

and then there's always:

[steve parker]

d.milligan
thanks for the suggestion...trust me, i've tried all this - i've also spent most of my life working with arri & panaflex movie cameras and helped fix a few bugs over the years...but this one continues to defeat me. the build version i have installed is 2012-11-08 / 15:11:43 by a1ex@thinkpad - &  i don't think there is anything more recent than this.
best, steve

[dmilligan]

the build version i have installed is 2012-11-08 / 15:11:43 by a1ex@thinkpad

you are running a build that is more than a year old, probably some type of early alpha that didn't have everything enabled, there are hundreds of more recent builds, you need to update

http://builds.magiclantern.fm/#/

[steve parker]

deep joy: i'm in - with all features - but slowing the frame rate is only any good as a creative tool if matched by slow shutter e.g. 6·25fps = 1/12th second [well, it would be if a 180º spinning shutter was involved]...earlier on in this thread you said anything slower than 1/30th was too much for the 5D processor, & CC Time Blend was the only way to achieve serious motion blur? my old sony miniDV camcorder can handle 6fps and delivers beautiful motion blur [and it's tiny in comparrison to the 5D, but then I guess it has a tiny chip]. obviously i've tried playing with the A and B values on the 5D but 1/30th seems like the end of the road? I'm much obliged for all the advice, steve.

[dmilligan]

use the low light mode in fps override, it makes the the shutter as close to 360 degrees as it can (when using fps override, the displayed shutter speed may not be correct)

[Duncan123]

Chaps , taking this in a slightly different direction and reading the posts above , I am an Astro photographer and want to shoot video but at a slow frame rate but longer exposure .
As I understand it I can go down to 1 FPS , can I make that a 0.5 sec exposure each time , or can it be greater . In reality I am looking for a slower still video and a longer image duration , any help appreciated , what are the limits ML can work with for FPS and respective exposure duration ?

[dmilligan]

http://www.magiclantern.fm/forum/index.php?topic=12523.0

[axelcine]

@dmilligan - I just love the film in #8. So impressive, and right to the point: a photographic issue presented with some of the most awfully beautiful pictures I have seen in a very long time. Jeez, you must love your camera and what she lets you do in that wonderful environment of yours.

[Duncan123]

Superb response guys .

One happy T5i owning astronomer here .

Duncan

[kikipi]

After 9 years...any news on having a slower shutter speed of 1/30?

[theBilalFakhouri]

@kikipi

We can unlock full shutter range supported by hardware from 360° to 0° in video mode (without bricking physics laws):
e.g. for 23.976 FPS: we can get shutter speeds down to 1/24 and up to 1/31K.

[Walter Schulz]

If you are asking for shutter > 360°: No.
If you are asking about slower shutter speed than 1/30 with fps below 30: Yes.