Archive for the ‘shutter’ Category

Run&Gun Shooting with Fast Shutter, then Deshake and Add Motion Blur in Post

Tuesday, July 16th, 2013

Like the title says (providing you have time for post-production), it is sensible to do Run&Gun Shooting with Fast Shutter, then Deshake and Add Motion Blur in Post.

In Summary:

  • For a bumpy aircraft flight, I shot with 1/50 second shutter and stabilized it in post.  The inevitable result, though more pleasing than the non-deshaken footage, exhibited shimmering effects due to motion blur on the various objects in the frame.
  • The shimmering could of course have been vastly reduced by shooting with a much faster shutter-speed.  One reason I didn’t was to avoid the staccato “Saving Private Ryan” look.  However I now realize that a convincing motion blur can (at least in theory, until I test it) be artificially introduced in post, following the de-shaking.
  • Some options exist for artificially introducing motion blur in post:
    • (Some degree of risk: Not perfect, but the imperfections might not necessarily be noticeable, or at least they may be less so than if not following this overall path).
    • RE:Vision Effects’ plug-in ReelSmart Motion Blur (RSMB).
      • Convenient, as it is a plug in for Premiere as well as After Effects (and various NLES/Tools).
    • After Effects’ Time Warp plugin (even if not warping time) has a Motion Blur function.
    • Comparison between them:
        • Time Warp works, but painfully-slowly.
        • RSMB is very-much faster.
        • Sometimes they get fooled when a motion-vector suddenly changes, leading to odd artefacts, though possibly not too noticeable in a changing/moving image.
  • Tips for reducing the problem at shoot-stage:
    • Shoot with elbows on a bean-bag.
    • If camera has rolling-shutter effect, then some cameras reduce this more when you increase the framerate than when you decrease the shutter angle by equivalent amount.
  • Potential methods for removing blur from the original footage, by deconvolution:

In Detail:

I shot a flight in an aeroplane (a Tristar) as a passenger that happened to have a camera (A Sony Z1)  as opposed to a proper production.  I used the Z1 because it had a (small) CCD sensor, thereby avoiding the rolling-shutter effect associated with most (not all) CMOS-sensor cameras.

Lazily, I left it at its default setting of 1/50 second.  I had a vague idea that I didn’t want a fast-shutter staccato “Saving Private Ryan” look, but that’s as far as my thinking went.  Instead of increasing shutter-speed, I applied the Z1’s built-in ND filters so I could keep keep its iris reasonably wide, so as to obtain the shallowest focus possible (with this small-sensor camera), especially to try to defocus as much as possible the inevitable muck on the passenger windows.  I had no particular plan, I was just being a tourist…

But of course, once I got back to the editing, grander plans (belatedly) came to mind: I would string some kind of video together as an entertaining souvenir for the (transient) passengers, staff (one of whom was changing his job) and of course myself.  I found some “little stories”, a “little drama”, a “celebratory ending”, and royalty-free music that was great accompaniment.

One of the first jobs was to stabilize it.  For that I used Gunnar Thalin’s Deshaker plugin for VirtualDub.   Following this, the pictures were smooth and drifting like I wanted them to be, but marred by occasional shimmering of individual objects (like houses below) that had motion-blurred at the sensor stage, prior to deshaking.

If only I had used a faster shutter…  but then it would have got that staccato look I didn’t want.  Or would it?  It occurred to me that some kind of motion-estimation-based post production technique might be able to substitute motion blur (at a stage after the deshaking).

Time for a Web-Search:

  • Google:[fast shutter stabilize motion blur]
      • “Question”:
        • – I get some blurring/shimmering in frames where the camera shakes the most.
      • Response:
        • What you see is probably motion blur, i.e. motion occuring within a frame. This is present in the source video too, but it doesn’t become distracting until Deshaker has removed the motion between the frames.
        • To get rid of this effect you need to use a faster shutter speed while filming. How fast it needs to be depends on the camera and the amount of shake. For a camera with built-in stabilizer, I’d recommend at least 1/200 sec, or so. (Faster if it doesn’t have built-in stabilizer.)
      • Title: Skip the ND (Neutral Density) Filter and add your motion blur back in post
      • One way to add motion-blur in post is RE:Vision Effects’ plug-in ReelSmart Motion Blur (RSMB).
        • This plug-in, designed mainly for 3D graphics artists who need to add blur to their rendered objects, tracks vectors frame-to-frame and generates the appropriate blurs and streaks to mimic actual motion blur.
        • It can be used in two modes: RSMB (basic) and RSMBPro (advanced).  I have only used the basic mode because it has been satisfactory for my needs.
        • Simply drag the plug-in to your clips in your timeline and drop. That’s really about it.  If you want to tweak, there are only two parameters in basic mode:
          • Motion Blur Amount: simulates different shutter speeds.  Since cinema is universally shot with a 1/48 shutter, and this is the default setting of the plug-in, you should really just leave this alone unless going for a special look
          • Motion Sensitivity: adjusts how much the warping reacts to motion.  I’ve found that reducing the sensitivity helps reduce warping artifacts in scenes with intense motion, but in my tests it handled almost all motion well when set at .5 or 50%.
        • Is it flawless? No.  If you freeze-frame some shots, you can see warping where the foreground and background mesh in weird ways. But these artifacts are hardly noticeable when played back a regular speed.
        • The main caveat to using this plug-in is increased render time.  So I would recommend applying it as a final step before rendering for output.  But don’t apply it to all your clips as a compound clip, or even worse as a rendered movie file, because then it will try to warp your different shots together, resulting in some very strange artifacts.
      • Question:
        • we are planning to shoot from the bed of a pickup truck.
        • I am aware that the rental of either a gyro or steadicam rig would be ideal, but the budget is limited and the rental situation here in Idaho is less than ideal.
        • So instead we have rigged a kind of “ghetto fabbed” large cinesadle for our tripod to be loosely ratchet strapped on top of in the truck bed (to reduce vibration), then we will stabilize in CS6 warp stabilizer.
        • My questions is:
          • What do you guys think of 4k 24 VS 3k 48?
          • Currently we have been using a shutter of 192 for 24 and a shutter of 384 for 48, any suggestions here?
      • Reply:
        • your shutter speeds are a bit high. You might get the Private Ryan strobing effect. Have you run any tests?
      • Reply:
        • We have done some testing at 4k, not yet at 3k. What would you think of as an ideal shutter? The problem we have been running into is the motion blur caused by movement/vibration, causing the shots at a more standard shutter speed to look much softer.
        • We have done some testing at 4k, not yet at 3k. What would you think of as an ideal shutter? The problem we have been running into is the motion blur caused by movement/vibration, causing the shots at a more standard shutter speed to look much softer.
      • Reply:
        • Testing testing testing!!!
        • We are doing a similar shoot, except shooting out the front window, ie, driver’s POV on some rough roads.
        • We built a bungee rig with straps through the windows and the camera hanging for the bungees, we tried a steadycam arm on a combo shorty stand, and other goofy looking gadgets.
        • So far the best was going handheld with elbows propped on a padded 2×4. Fortunatly for us, the client wanted smoother and we will be renting one of these
        • $1200 a week i think we were quoted. Maybe we can shoot some other fun stuff the rest of the week!
        • I guess I would err on the side of fast shutters than slow, the stabilize will look better with less motion blur. In our tests, it messed up on the sharp bumps where there was a lot of movement between frames, the motion blur made it a little goofy looking.
      • Reply:
        • The RE:Vision plugin works pretty good in most cases – I agree that it’s better to sacrifice motion blur if there’s ANY plan for post stabilization, and just fake it on the stabilized footage.
        • 48fps is only gonna give you the effect of slower motorcycles when played back at 24, so I would say shoot at 4k to give the stabilization/post blurring process more data to work with (and a wider shot w/less of a cropped sensor). Also, use a lens w/IS.
          • {I assume that means Image Optical Stabilization)
        • All that said, I got some great shots of some electric motorcycles six years ago from a truck bed on a dirt road using a steadicam… (actually a cheap rental Glidecam). It’s easy to operate since you’re just sitting/kneeling there, so you don’t need to hire an experienced operator.
      • Reply:
        • Increase framerate and cushion the camera with bungies or lock the camera hard to the car. Then remove frames in post and stabilize. the upped framrate will get you around rolling shutter in a way the shutter will not. So better to shoot 48fps 360 than 24fps 180.?
          • {Well I’d never have thought of that, good tip.  This is a RED camera forum, but maybe applies to some other cameras also?}
      • Reply:
        • First, partially deflate the tires on the pickup – especially the rear wheels. That will remove most of the vibration.
        • Next, keep the camera lower to the bed – the higher you are, the more “sway” introduced. If you have ever tried to shoot from the back of a truck standing up, you know that stability is lacking – it will fight you.
        • If you want to be clever and build a rig:
          • Mount a high hat in the middle of a piece of plywood.
          • Drill a series of holes at the edge of the plywood.
          • Mount some drilled rails along the top of each side panel of the bed (use the rectangular holes as gravity mounting points)
          • Install numerous high strength rubber straps / cords between the rail holes and plywood holes.
          • Result: a floating camera platform. The rubber straps will absorb a lot of the vibration.
        • Downside is it tracks with the level of the bed – so as the truck takes a corner, the platform tilts.   Then again, a tripod will do the same thing.
        • So, another approach is to construct a floating mount suspended from an overhead rail. With a bit of practice, you can keep the horizon level in a turn. Again, heavy duty rubber to take the load and absorb vibration.
        • If you are able to get a Steadicam or Tyler mount w/gyro, best place to position yourself is sitting down on the tailgate.
      • Reply:
      • Potential methods for removing blur from the original footage, by deconvolution:
      • Matlab algorithms (downloadable)

Canon C300 – Great Reviews & Posts

Thursday, December 1st, 2011

The Canon C300 is of interest to me as a potential “workhorse” video camera (replacing my current EX3) for both cinematic projects and live events (incidentally, after having written that sentence, I reassuringly found the same phrase uttered by Philip Bloom, so hopefully I’m on the right track here).

Cinematic projects in particular can benefit from more controllable DOF and both can benefit from light sensitivity, while the live events (indoor or outdoor) in particular can benefit from latitude.  Of course these things are handy in general, but those are the occasions when I’ve felt they were lacking in the past.

The C300 addresses most things, apart from lack of 10-bit output.  Hopefully I could trade-up to that in a couple-or-three years’ time when Canon upgrade to that.  And investing in “glass” (lenses) for it is probably a better investment than external recorders (buy or hire) for my current EX3.  The price stings a bit though, so I won’t just leap into it.  I’ll definitely begin by hiring/renting.

My Canon C300 research-in-earnest begins here with a (great) review I initially heard about (via private IOV forum).  That’s the UK’s Institute of videography by the way.  Here:

The following thread at DvInfo includes rolling-shutter-provoking tests (flash, jerk-motion):

The main points about the camera (for me at least, and not in this particular order) are:

  • Ergonomics / practicalities:
    • Better (some say) than the F3.
    • Weatherproof, sensor-cooling
    • ND Filters (three) in-camera
      • Seems fairly unique in this kind of camera
    • Handy proper buttons for Zebra, Peaking, Magnified views.
    • LCD and button-panel orientate in various directions.
    • Fits on a standard DSLR rig.
      • But Zacuto supply a tailored rig.  CVP are among its agents.
      • And there’s Redrock’s inspiringly-named UltraCage.
    • Solid construction, feel and mounting threads, better than “single central bolt” like many cameras have.
    • Wi-fi adaptor transmits a low frame rate version to your computer. If the lens is set to autofocus, you can actually change the focus remotely.
      • Wifi controller is an additional item – not part of the basic package
    • Battery lasts 5 hours
  • Sensor
    • Latitude (recordable, depending on settings):
      • Quoted as “13+ stops in the field”
      • But there is uncertainty over this, since apparently <<Canon thinks that with their Canon-Log color space, the camera allows “800% overexposure… which translates to …an Exposure Latitude of 12 f-stops.” Graeme Nattress of Red disagrees.>>>
    • Less noise, moire and jello than 5D Mk.2 etc.
      • Noise & moire reduction largely result from 4K sensor + DSP to HD.
        • Moire tends to result from significant interpolation inherent in less dense sensors
    • The “less noise” hence less need for low fstops (coupled with smaller sensor than 5D) means greater DOF (the antithesis of the 5D).
      • Greater DOF is preferable at times, for practical as well as aesthetic reasons (when you want to see the background).
  • Lens Mount
    • Camera comes in two lens-mount varieties, not interchangeable:
      • EF-Mount for Canon lenses (ordinaire & “CN-E”).  This is the one for mortals like me.
        • Permits iris to be controlled via dials on camera.
        • Greater available selection of lenses (also usable on stills cameras) e.g.:
          • Telephoto: “EF 70-200mm f/2.8L USM” telephoto zoom lens and tilt-shift lenses.
          • Macro: “EF 100mm f/2.8L Macro IS USM” (article photos include an image of ants)
          • Fisheye: “EF 8-15mm f/4L Fisheye USM”
          • TiltShift: “TS-E 90mm f/2.8”
        • Image Stabilisation (IS) is reported to be good e.g. with the Canon L 70-200mm F2.8 IS Version II
      • PL-Mount: More for movie professionals.
  • Recording:
    • Resolution: HD 1080p & 720p
    • Frame-rates: variable 1 to 30 fps in 1080p mode, and 1 to 60 fps in 720p mode, 1 fps increments.  Also time-lapse and stop-motion/claymation (latter is several frames per “click”).
      • But, like F3 (and unlike FS100), overcranking requires dropping to 720p
    • It can also shoot 50i and 60i (interlaced), useful for deriving 50p and 60p in post.  Historically (e.g. for DV or HDV (Z1) footage), I have done this using freeware (AviSynth and its TDeint filter) for this, but Apple Compressor and other alternatives exist too.  Stu Maschwitz apparently covers this topic in his book << The DV Rebel’s Guide>>
    • Gamma: includes Canon’s Log Gamma.  LCD & V/F display flat and corrected.
    • Audio: uncompressed 16-bit audio at 48 khz (info from FAQ).
  • Recording format:
    • Compact Flash (over 5 hours for a 128GB card)
    • MPEG-2 Long GOP 4:2:2 MXF codec with a constant bit rate of 50 megabits/sec.
      • Philip Bloom says “It is the bare minimum for HD acquisition, but it at least reaches it.”.
      • Sample recording (MXF as stated) is available here (according to here).
      • {Does MPEG-2 imply 8-bit?}
        • Yes.  That is highlighted in several other sites e.g. this and this.  Some believe (rightly or wrongly) that this limitation is a “corporate rather than technical” decision, and a future generation will have 10-bit.
      • {What of the Log Gamma? 8-bit (is it ?) would limit its usefulness or not?}
        • Opinions differ.  Obviously the extent to which it matters depends on the scene.  Some views and image comparisons are here, for 10, 8 and even 7 bits.
          • At that link, one poster suggests dithering as a work-around to reduce banding (from any camera): adjust camera to give noise then (in post) use a good noise-reduction plugin.
      • The only Super-35 sensor camera in its price category (as of fall, 2011) that records 4:2:2 color sampling on-board.
  • Ports:
    • XLR (via clip-on monitor assembly?)
    • Time code, Genlock, HD/SD-SDI and HDMI
      • {But how many bits? 10 (as I’d hope) or still only 8?}
        • Only 8-bits, surprisingly.  It is reported that: “SDI output (is) limited to 8-bit 4:2:2”
  • Monitoring
    • RGB histogram, vectorscope and an Edge monitor (focussing)

More links:

Other Misc. Links:

Fast Shutter Speeds for Action Scenes

Sunday, December 19th, 2010

For action scenes like fast ski-ing, what shutter speed is best?

EX3 Shooting-Mode & Shutter Effects on Exposure

Friday, December 17th, 2010

The traditional degree of motion blur, broadly consistent with what the eye normally experiences, is obtained by using around 1/50 sec shutter (no problem in practice for shutter speeds 1/48-1/60).  What shutter setting (mode /value combination) can best achieve this for different shooting modes, e.g. 25p, 50i, 50p ?  I am no expert on this but from my web-search I assume the following:

  • For progressive modes around 25-30p, where light level allows, use Shutter On.
    • But for double-rate progressive (50p-60p),  use shutter-off.
  • For interlaced modes or double-rate progressive or for low light situations, use Shutter Off.
    • In interlaced modes, Shutter Off is equivalent to 1/50 or 1/60 (depending if 50i or 60i)
  • Warning about Angles: in Interlaced modes, “180 shutter” acts more like a 135 shutter.
    • The “Angles” option is really aimed at film veterans, who by definition only use progressive.


Shutter Speeds – progressive (24p,25p,50p) and interlaced (50i)

Friday, December 17th, 2010

On an EX3, what’s best for indoor shots of lectures etc?

  • Normally film runs at 24fps, with a 180° shutter – which is 1/48th second.
    • Hence for 25 fps, ideally use 1/50 second, or nearest available match to this.
    • Uncertainty: For 50i, each field is at 25fps, so presumably still use 1/50 second ?  Depends on how camera works?
  • For a shot of someone talking, it would be hard to see the difference between a 1/48th shutter time and a 1/60th shutter time.
  • To avoid (conventional) light flicker, frame rate should divide by integer into twice the power frequency.
    • EX3 has no 1/50 shutter speed, at least when specified by Time – nearest equivalent is 1/60.  This may risk some degree of light-flickering in 50Hz mains countries.
  • For 1080i50
    • Initially, used “No Shutter”, to maximize exposure with least Gain.  But gave noticeable motion-blur.
  • For 50p or 25p
    • 1/50 or nearest equivalent (on EX3 is 1/60)
  • For 50i, opinions vary:
    • UseEX3’s nearest equivalent time-based shutter time of 1/60
    • Use 180 degrees (assumes this angle relates to frames-per-second, namely 25fps for each frame – but is this valid when interlaced)
    • Use No-Shutter (assumes 50i shoots each field alternately, at 50fps, hence no-shutter is inherently 1/50 – but is that assumption true?)


Glide-shots: Steady-Shot / Smooth-Deshake-Stabilize / SteadyCam

Sunday, July 25th, 2010

Which is best?   Depends on the camera, scene and shot dynamics I guess.  The same point is queried at the following thread:

Some general advice from a computer-post-savvy author: definitely use the camera’s SteadyShot:

Limitations of post

  • Stabilization necessitates motion estimation and image reconstruction, which are extremely CPU-heavy, hence really slow to execute.
  • Most stabilization apps (in post) can’t currently cope with motion-blurred edges or parallax effects (though both should be possible in principle, by deconvolution and 3D modelling both informed from multiple frames).
  • For rolling-shutter-ed footage (e.g. CMOS sensors as in Sony Exmor as in Sony XDCAM-EX e.g. EX1 & EX3), there exist options to reduce the effect (don’t expect perfection, but may suffice):

My experiences:

  • Stabilizing Tools:
    • Gunnar Thalin’s Deshaker works really well.  And it is multi-threaded, really speeds up the process.  The author says it is more intended for handheld pans etc. than fast-shaking shots from vehicles etc. (but has nevertheless seen good results in such situations).
      • The author says [] to try “to stabilize only on the most distant parts in the frames, since the moving inwards-effect is less there”.  And “you should probably increase the value for [discard motion of blocks that move > X pixels in wrong direction]. That’s to allow the blocks to move “freely” a little, since Deshaker can’t handle the “moving inwards”-effect.
      • Possibly equally applicable to other smooth/stabilize/deshake tools ?
    • Boris’s Optical/Motion Stabilizer (in Boris Red 4.3.3 on XP) is only single-threaded and I find it slower, clunkier and less intuitive than Deshaker.  Has a Smooth mode, which is like the others here, as well as a Stabilize mode (try to keep frame static, no good for motion then).  The other tools can be configured to do the same thing.
    • Mercalli in Sony Vegas has no mode for 720p50 but otherwise is pretty good and very intuitive and configurable.
    • FCP’s SmoothCam Effect worked best for a challenging clip for wobbly-hand-held camera tracking close past an object (a Formula-1 car) hence huge degree of moving-inwards effect.  The default settings worked straight away.  The result quality was way above that of the other tools.  On the other hand sometimes it’s not the best (sorry, forgot the exact situation).
  • Cameras & Shots:
    • Historically, using a TRV33 DV HandyCam indoors (hence low-light hence long shutter time):
      • Way back in the past, using a (now ancient) TRV33 DV handy-cam (which has huge sensor margin i.e. spare pixels), when I shot big zooms to lecture audience individuals (e.g. question-time) I had the camera’s steady-shot (digital, not mirror) enabled  and used Gunnar Thalin’s Deshaker (VirtualDub plugin) also.  The result was astoundingly steady.
      • The same arrangement worked OK with hand or shoulder mounted cam for walk-throughs past nearby objects (e.g. walls, people, furniture).
      • An attempt to do the same thing without steady-shot enabled on the camera resulted in seriously motion-blurred edges.
    • Now, using a Sony EX3:
      • With camera Steady-Shot set to Medium, hand-held pans and motion past nearby objects seem to acquire a positional instability, as if the camera feedback mechanism needs greater damping. Maybe the camera’s internal mirror “suspension” has to be tighter (than the TRV33 digital equivalent) because it lacks the generous pixels margin of the TRV33?  or maybe something to do with the mirror’s inertia?  Or (real-time-constrained) processing-power?
        • Experimentation is needed with the camera’s other SteadyShot modes (High, Low).
        • In the absence of more generous sensor pixel margins, I wish it could be loosened-up e.g. to allow black borders (to crop in post) so as to permit smoother rides overall.

Shutter speed effect on snowfall

Monday, February 8th, 2010

Great sequence of images tally with my general experience:


  • 1/100  looks slushy, grey and indistinct “cords” (not flakes/lumps)
  • 1/500  looks crisp – can see individual snow flakes/lumps falling

Also, from my own experience,  is best to focus on 2 metres or so away.  Focus matters since DOF small when aperture maxed as one may do to allow max shutter speed (depending on lighting conditions, most likely overcast)