3k 160FPS

[Tom Chase]

So tonight I took my Dragon to shoot some slow motion test footage of a local wrestling event (actually pretty cool). I did a black shading prior at the settings I was going to shoot on; I was shooting with my Canon 35mm FD lens wide open - I was about 40 feet from the ring so I set my focus to infinity and let the Dragon do the default shutter angle in the camera. The crowd beyond the the far side of the ring looks in focus, the ring floor looks in focus but the Wrestlers and the Ref look soft (almost like they were intentionally out of focus).

So here's my question - what is the best shutter angle to use when shooting high paced slow motion - the R3D metafile says the camera had it set to 359.402 degrees. Even objects in the foreground look sharper than the fast moving Wrestlers.


Thanks.

Tommy

 

[Adam Carboni]

It really does depend on the final look you're trying to achieve, and personal tests will show you these things quickly. The short answer, however, is if you want the sharpest high speed images, shoot at an angle that is <180º. 90º is very popular in sports and action sequences.

Without getting too technical, a faster shutter (i.e. - <180º) will always render sharper individual frames, regardless of the frame rate. After all, we are simply shooting multiple still images in succession when recording motion, so it can be helpful to think of still photography methods when rationalizing shutter angles.

A 180º (normal) shutter angle would be 2X the recording frame rate. 160fps at 180º = 1/320 shutter speed.
A 360º (slower) angle will always have the same numerical denominator as the frame rate itself. 160fps at 360º = 1/160 shutter speed.
A 90º (quicker) angle will have a numerical denominator 4X the frame rate. 160fps at 90º = 1/640

Obviously, the faster the shutter speed, the sharper an individual frame will be, but the less exposure you will achieve. (This is why high speed photography requires much more light.) So, from a practical standpoint, shooting higher frame rates in available lighting conditions can be very tricky. This is where the practical meets the stylistic:
-If you want sharper images that still appear natural, stay somewhere between 90º and 180º.
-If you NEED the exposure, push it to 270º or even 360º, but be aware of the trade-offs (MORE MOTION BLUR, but may not really be a problem at some frame rates with more subdued actions)
-Footage recorded with an angle less than 90º can feel staccato and unnatural, in my opinion.

Again, none of these are steadfast rules since shutter speed is ultimately a creative tool, meant to be "messed with." I use 45º sometimes and 360º sometimes, depends on the look.

*Parting words of wisdom: black shade for your different shutter angles, ESPECIALLY when doing 12fps or less. Those long exposures get tricky and you can get bit by strange static noise if your calibration is off.*

-Adam

 

[Terry VerHaar]

Sounds like your wrestlers, who presumably were moving whereas your crowd less so and your floor not at all, were "soft" because of motion blur. A 360 degree shutter angle leaves the shutter open longer and causes you to see more motion within reach frame which is where the blur is coming from. As Adam says above, you'd be much better off shooting action with a smaller shutter angle. But, yes, that means you need more light and/or a wider aperture.

 

[Tom Chase]

Thanks guys - I hardly ever shoot slower (faster) than 96FPS, figured today would be a play day which is was - still got good shots, friends who have seen them like it.

But this info helps, I've always been been confused when doing the shutter angle - friends who have been to film school are always preaching NEVER change from 180º.

I think I'm going to start to get know high-frame rate side of the Dragon, so impressed that at 3K I can get 160 FPS and at 2K get 240.

 

[Patrick Tresch]

Could you post a R3D?

I bet that the wrestlers where also out of focus. But if you speed your footage up by factor 2X the resulting image should look like if you have shot at a shutter speed of 180° (obviously with less FPS). Does it look crips like that?

Pat

 

[Tom Chase]

I am really bad with RCX - but here is a link to a R3D snapshot.

It's straight from the camera - https://www.dropbox.com/s/mqs5njull2btk86/A001_C008_03264L.0000729F.R3D?dl=0

 

[David Battistella]

Yeah,

Looks like 360 degree shutter at 1/160. Looking at it, do you see crisper frames in between, or is it all soft like this? IT feels like the backfoucs might be out. 9>1 compression doesn't usually look this soft.

David

 

[Kyle Stryker]

Looked at your r3d and it defiantly just looks like it's out of focus. Not motion blur or even bad back focus, just out of focus.

 

[Philip Lima]

As Kyle said, you were just out of focus. Motion blur looks natural when watching video, so that's not what you're dealing with here. Setting a lens to infinity is a bad idea, never trust that. Even when you're shooting something that's really far away(like the moon), still check focus as it's often just a roll off infinity. You're also shooting with an FD lens, which by nature could have some softness to it. My advice would be to always do the zoom check for focus and leave focus assist on all the time. Never trust the marking on any lenses(unless you actually confirm with a ruler and chart).

 

[Brody_B]

Yep. Your just outta focus bruh. Never set it and forget it

 

[Brandon Shafto]

I've found my DOF Calculator to be a lifesaver.
Here's a link to free Apple apps that will help: http://appcrawlr.com/ios-apps/best-apps-hyperfocal-distance

You can find the same for Android apps as well. Just search Depth of Field apps and you'll be golden.

I also find the Cine Meter II app to be hugely useful. Every single shoot I do, I pull out my phone and use this app. It's amazing.