Epic Stills from Motion (My First Epic Shoot)

[Mark Allen]

I just got a job to direct a short film from which stills will be pulled for an advertising campaign. It shoots May 1 and I'm really hoping my Epic (or an Epic) will be in my hands for it.

My question is this: If I'm shooting with a normal 180 degree shutter and pulling stills - there will be an abnormal amount of motion blur on the frames for still photography, correct? Would I need to plan to re-run certain scenes with a very tight shutter in order to pull clean stills? (This is assuming there is a little bit of natural life motion in the shot.)

 

[J Davis]

@RED - can the HDRx stream have a faster shutter (for stills) so you don't need to repeat the take?

 

[Martin Weiss]

Well, you'd get 1/50th of a second exposure, when shooting 25fps.

So, it really depends on the amount of movement you have.

The good thing is, it will be rather quick to swap from motion to stills mode on the Epic.

 

[Martin Weiss]

@RED - can the HDRx™ stream have a faster shutter (for stills) so you don't need to repeat the take?

Faster shutter, yes, but the shadows will be very dark. the HDRx stream is there to protect the highlights.

 

[Alexander Ibrahim]

You can use HDRx to meet this need.

HDRx works by abusing electronic shutter and taking advantage of EPIC's fast processing rates.

From a user perspective HDRx works by setting how many stops of "highlight protection" you want.

What it does behind the scenes is just record two images from the same exposure.

So, if you are set to record at 180° shutter and want +3 stops of protection, the camera records a frame at 1/384 shutter and a frame at 1/48 shutter.

So, you set the camera for the 180° shutter. Let's say you've chosen to expose motion at t/4. You actually light for t/11.

Now... your standard footage is 3 stops overexposed, but the HDRx highlight stream is correctly exposed.

This little abuse of the system turns your standard footage into "lowlight protection." Of course in this case, we really want to use it as "motion blur protection" because we will be satisfied with the exposures of the HDRx stream.

So the question is what shutter are you going to need to capture your subjects motion cleanly for stills? I expect that for most subject motion you'd be happy using this technique at +1 or +2 stops.

There are tons of choices you could make. I'd be inclined to at least test 360° shutter with HDRx at +3 stops which, if lit appropriately, should allow you dial in any motion blur you want in post.

 

[D Fuller]

You can use HDRx™™ to meet this need.

HDRx™™ works by abusing electronic shutter and taking advantage of EPIC's fast processing rates.

From a user perspective HDRx™™ works by setting how many stops of "highlight protection" you want.

What it does behind the scenes is just record two images from the same exposure.

So, if you are set to record at 180° shutter and want +3 stops of protection, the camera records a frame at 1/384 shutter and a frame at 1/48 shutter.

So, you set the camera for the 180° shutter. Let's say you've chosen to expose motion at t/4. You actually light for t/11.

Now... your standard footage is 3 stops overexposed, but the HDRx™™ highlight stream is correctly exposed.

This little abuse of the system turns your standard footage into "lowlight protection." Of course in this case, we really want to use it as "motion blur protection" because we will be satisfied with the exposures of the HDRx™™ stream.

So the question is what shutter are you going to need to capture your subjects motion cleanly for stills? I expect that for most subject motion you'd be happy using this technique at +1 or +2 stops.

There are tons of choices you could make. I'd be inclined to at least test 360° shutter with HDRx™™ at +3 stops which, if lit appropriately, should allow you dial in any motion blur you want in post.

Are you sure about this? I might be off base, but it seems like a lot of conjecture about what might be possible.

 

[Jannard]

You can use HDRx™ to meet this need.

HDRx™ works by abusing electronic shutter and taking advantage of EPIC's fast processing rates.

From a user perspective HDRx™ works by setting how many stops of "highlight protection" you want.

What it does behind the scenes is just record two images from the same exposure.

So, if you are set to record at 180° shutter and want +3 stops of protection, the camera records a frame at 1/384 shutter and a frame at 1/48 shutter.

So, you set the camera for the 180° shutter. Let's say you've chosen to expose motion at t/4. You actually light for t/11.

Now... your standard footage is 3 stops overexposed, but the HDRx™ highlight stream is correctly exposed.

This little abuse of the system turns your standard footage into "lowlight protection." Of course in this case, we really want to use it as "motion blur protection" because we will be satisfied with the exposures of the HDRx™ stream.

So the question is what shutter are you going to need to capture your subjects motion cleanly for stills? I expect that for most subject motion you'd be happy using this technique at +1 or +2 stops.

There are tons of choices you could make. I'd be inclined to at least test 360° shutter with HDRx™ at +3 stops which, if lit appropriately, should allow you dial in any motion blur you want in post.

Actually, just the opposite. Light for the "Normal" exposure and the "under" exposure handles the highlights. Your description of how it actually works is only partially correct.

Jim

 

[J Davis]

Actually, just the opposite. Light for the "Normal" exposure and the "under" exposure handles the highlights. Your description of how it actually works is only partially correct.

Jim

But can the two streams be used for another purpose ?

Can they both be set to the same exposure but different shutter.
This way the video can remain at 180 degree for motion and the x stream can be used for fast shutter stills so we don't have to make a second take?

If this can be done ... there's a new marketing angle for you Jim.

 

[J Davis]

Actually ... the use of the two streams at different shutter (one for video one for stills)
in sports applications is huge ...

 

[Mark Andersen]

But can the two streams be used for another purpose ?

Can they both be set to the same exposure but different shutter.
This way the video can remain at 180 degree for motion and the x stream can be used for fast shutter stills so we don't have to make a second take?

If this can be done ... there's a new marketing angle for you Jim.

Nice idea, but you can only have one aperture. So if one stream has a higher shutter speed the exposures won't be the same. Maybe you could use a stereo rig, one for stills and one for motion.

I know if I'm going to pull stills I just ramp up the shutter to 1/96 or 1/192. I know my motion gets a little choppy, but that's the best way to insure sharper frames. On the other hand your idea could work if you upped the exposure of then highlight protected stream in post, but you would introduce some noise.

 

[J Davis]

Nice idea, but you can only have one aperture. So if one stream has a higher shutter speed the exposures won't be the same.

Dowp! (not thinking)
Would an iso shift to compensate work?

 

[Jason Sinclair]

You can do an iso change in post anyhow.

 

[Alexander Ibrahim]

Actually, just the opposite. Light for the "Normal" exposure and the "under" exposure handles the highlights. Your description of how it actually works is only partially correct.

Jim

You misunderstood me Jim. You are explaining the normal HDRx operation.

That gives me great hope that I am on the right track.

I am intentionally standing your intended use of HDRx on its head... and that means working backwards.

I mean to expose the highlight protection (underexposure) correctly, so you can use it to extract correctly exposed stills that are very sharp, with very little to no motion blur.

Then you can use the "normal" stream, which will be overexposed in this use, to add back in the shadows and motion blur for the motion image application.

In other words its still HDRx, but working in an opposite way to prioritize stills over motion.

What gives me caution is your statement that my explanation of HDRx is only partially correct.

The reason I think you are manipulating the shutter to create all this is because the other elements of exposure (light level and aperture) will be out of your reach in many workflows that are very common among RED users. (PL lenses on a film set for example.)

So, I inferred that you are extracting a "fast shutter" version of the image at the same time you are taking a "normal shutter" version of the image. So, if the shutter is 1/48th and HDRx is set to +1 stop protection, then you are writing the HDRx stream by concatenating the middle of the 1/48 exposure (That is you are lopping off the first 1/192 and ignoring the last 1/192 of exposure) to leave a 1/96 exposure, thus gaining one stop of highlight data through the faster shutter.

Is that accurate enough to work with?

 

[Alexander Ibrahim]

Are you sure about this? I might be off base, but it seems like a lot of conjecture about what might be possible.

I think something very close to this is the case.

Of course I don't own an Epic, and have not tested it... so of course I am not sure in that conservative cinematographer sense.

It would be a new technique, and working outside the intended operation of HDRx.

 

[PatC]

Mark Allen. 100% depends on how and what your shooting. That being said, sharp frames can come from a 1/50th shutter.