Archive for the ‘35mm’ Category

Matt Roberts (MBR’s) Automatic Color (Chart) Corrector

Tuesday, February 14th, 2012

How about an After Effects plugin for automatically grading any footage featuring a Gretag Macbeth color chart in-shot (e.g. at the beginning and/or end of shot)?  Matt Roberts’ new plugin, still “steaming off the press”, works in Premiere as well as After Effects, and has been tested in CS5 and CS5.5.  You simply pause on a frame featuring a color chart in-shot, place corner locators to identify that chart, and ‘Go”.  It not only fixes white balance but also adjusts for saturation and compensates for certain kinds of “color twisting” defects such as can occur in cameras.    Subsequent “expert tweaks” can then be made if preferred, e.g. 20% saturation reduction for “film look”.  The free version works in 8 bits, the paid (£50) one (in the process of being made available on works in 32 bits, multithreaded etc.  To find out more and to download it:

Example: Canon 7D Video Footage:

Canon 7D before correctionCanon 7D after correction

So what’s the point of this plugin?  Greater quality, reliability and productivity, as compared to traditional color correctors, as explained below.

Those with an eye for accurate color reproduction from video footage will be familiar with traditional tools such as 3-way color correctors and meters such as waveform monitors and vectorscopes.   All proper Non Linear Editing systems (NLE’s) have these.  Generally-speaking such tools work well, but sometimes in practice the situation can become confused when for example a subject’s “white”(assumed) shirt is in fact off-white, or when tinted light mirror-reflects off skin or results from camera filters.  Easy to understand in retrospect, but initially can cause “running round in circles” of interative adjustment and re-checking.  Furthermore, some cameras have peaks, pits, twists and ambiguities (e.g. infra-red) in their colour response that many such correctors cannot correct in a straightforward manner.   Not only can time be wasted but it is quite possible to end up with an image that “looks” right to most people but which in fact has done something inexcusable such as altering the very precise color of a corporate logo.

One way to reduce the potential fo such confusion is to incorporate a color chart in shot.  Various types exist, including Gretag Macbeth (GM) and Chroma Du Monde (CDM).  The GM card, while primarily targeted at photography, is also in widespread use for video.   That chart consists of a matrix of colored squares, one row of which represents (steps on) a grey-scale.  It also includes some near-primary colours and some approximate skin colours of a few types.  The simplest use of such a chart would be to use the grey-scale row for white balancing and the other colours for “by eye” grading/tweaking.  The more experienced will probably make use of vectorscopes etc. but that can still be a nuisanceful if not cumbersome process.

Enter Matt Roberts’ Automatic Color Corrector.  We tried it out on some footage from his own Canon 7D and from my Sony EX3, the latter fitted with a slightly green-tinted infra-red filter, on a snowy day.  We even tried it on an image (featuring such a chart, as well as a model with lots of fleshtones) on Canon’s website ?URL? for their C300 camcorder.  In all cases, the correction was achieved in seconds.  We were particularly confused as to why Canon’s web-image image was so off-colour, but it certainly was, and the Corrector fixed it.

Once again, the link:

Review/Comparisons: RED (Scarlet,Epic), Canon (5D-II, C300), F3, FS100, AF100

Thursday, December 1st, 2011

How best to get the 35mm look?  “Traditionally” the DSLRs like Canon’s 5D Mk.2 or 7D (or, at lower frame-rates, the D500).  But now the RED Scarlet and the Canon C300 have been announced (3rd November 2011).  Then there’s the AF100 (with or without hacks) and the FS100, also the Sony F3, with or without dual SDI link 10-bit recording to S-Log.

Here are some comparisons:

A particularly interesting “argument/opinion of comparison” between F3 and C300:

    • (Yes, the URL has a dot on the end)
    • <<<
    • Because (the C300 has) a great sensor with very good RGB color filters on its bayer sensor, great dynamic range, zero aliasing, crisp as hell 1080p, oversampled green channel, 14-bit processing, recording to log? 8-bit MPEG-2 is not as big of a disadvantage as people think if you feed it with awesomeness to start with
    • The F3’s sensor is perhaps not quite as good though – it doesn’t resolve full 1080p without aliasing – eg Barry’s brick wall color moire test. BTW Talking of that test… what exactly is the advantage of the 4:4:4 output on the F3 if its sensor can’t resolve 4:4:4 color detail anyway?
    • >>>
    • A demonstration of moire on the Canon 5D Mk.2

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:

Full-Frame Sensor Cameras (& Canon 5D vs 7D etc.)

Monday, November 28th, 2011

I have a friend/colleague with a Canon 7D and girlfriend with 500D.  Also I am aware of “Super” (reduced size) “35mm” sensor video cameras.  I’m keeping an eye on all the options, as currently I have no 35mm etc. capability and hence limited shallow DOF and low-light capability.  And to share / compare info with those mentioned people.

Starting with Looking at Philip Bloom’s site to (routine check see what’s new there), I came across these useful links (even though they’re not all new).  I’m attracted to getting a Magic Lantern-ed second-hand 5D Mk.II for creative purposes, especially since my typical work-pattern is not that time-critical and I am reasonably fluent with frame-rate conversion where necessary. I’ll try it out on the 500D first.  The 500D can only do 30 fps at 720p (drops to 20 fps at 1080p) but its sensor is almost an inch across i.e. about double that of my existing EX3.

Incidentally, I previously covered sensor sizes and their names at  and there’s Canon’s take on it at which (oh yes) is about their new C300 camera (will cover that in a separate blog-post).

Here are the links:

    • In a nutshell, 5D has (fairly uniquely) a full “35mm” sensor, giving the ability to achieve correspondingly uniquely shallow depth of field.  But it shoots at a non-standard frame-rate of exactly 30 fps (not 29.97 fps).  This can matter e.g. when intercutting with standard 29.97 material.  On the other hand when using the camera on its own (and I guess with possible allowance for the time duration change and audio pitch change if you fiddle the metadata) it need not matter.
    • Magic Lantern firmware is available for the {original} 5D but not the 7D.
    • Meanwhile the 7D has less shallow DOF capability and slightly more noise but slightly less rolling-shutter effect and, crucially, a number of standard frame-rates.
  • Magic Lantern – unofficial extended firmware for Canon cameras like 5D
    • Magic Lantern gives many improvements to modes, metering displays (e.g. zebra & peaking) and quality (e.g. more shutter-speed choices and greater recording bitrate).  However it does not (yet?) provide additional frame-rates.
      • As of today (2011-11-28) it is reported that Magic Lantern is still not available for the 7D, though progress towards this is being made (slowly).
      • There are limitations to shooting movies on a 5D Mark II, notably the limited 12 minute recording time.
      • (An image illustrates a 5D “tooled-up” with rods, mattebox, audio box etc. to serve as an outside rig)
      • Altering frame-rates is still on the to-do list.  Hence not yet done!
    • FINALLY the full frame Canon 1DX DSLR featuring “improved video”.
    • STandard frame-rates: 24,25, 30p in full HD and 50 and 60p in 720p mode
    • Intra-frame and Inter-frame compression (H264), easing editing.
    • Single clip length of up to maximum of 29 minutes and 59 seconds (reflecting an EU tax rule {on what constitutes a stills – as opposed to video – camera} )
    • will retail body-only for around $7000!
      • {Not as cheap as the 5D Mk.II then…}
  • Canon 500D
      • {Great site, reviewing it and breaking-down the tech-specs.}
      • Thanks to its APS-C sensor size, all lenses effectively have their field of view reduced by 1.6 times.
        • {This is smaller than the 5D’s full-frame but still not bad at almost an inch wide, which I take to be about double that of my EX3’s “Half-Inch” sensor}

DSLR Lens Recommendations

Tuesday, November 22nd, 2011

I have access to a Canon DLSR and am considering getting a 35mm adaptor for my existing EX3 camera.

A colleague recommended the following lenses:

  • Canon 16-35mm f/2.8 L USM
  • 24-70mm f/2.8 L USM (~£1K)
  • 70-200mm f/2.8 L IS USM (~£1.7K)
  • 24-105mm f/4 L IS USM (~£900)
  • 50mm (fixed) f/1.8 (~£70)

35mm: Sensors & Adaptors eg Redrock M2 & M3: Quality and Relevance

Friday, November 11th, 2011

Trying to keep up my “situational awareness” in this subject area…