Tag Archives: monitor

Why you need to sort out your post production monitoring!

One of THE most common complaints I hear, day in, day out, is: There is banding in my footage.

Before you start complaining about banding or other image artefacts ask yourself one very simply, but very important question: Do I know EXACTLY what is happening to my footage within my computer or playback system? As an example, editing on a computer your footage will be starting of at it’s native bit depth. It might then be converted to a different bit depth by the edit or grading software for manipulation. Then that new bit depth signal is passed to the computers graphic card to be displayed. At this point it will possibly be converted to another bit depth as it passes through the GPU and then it will be converted to the bit depth of the computers desktop display. From there you might be passing it down an HDMI cable where another bit depth change might be needed before it finally arrives at your monitor at goodness knows what bit depth.

The two images below are very telling. The first is a photo of a high end TV connected to my MacBook ProRetina via HDMI playing back a 10 bit ProRes file in HD. The bottom picture is exactly the same file being played back out of an Atomos Shogun via HDMI to exactly the same TV. The difference is striking to say the least. Same file, same TV, same resolution. The only difference is the top one is playing back off the computer, the lower from a proper video player. I also know from experience that if I plug in a proper video output device such as a Blackmagic Mini-monitor to the laptops Thunderbolt port I will not see the same artefacts as I do when using the computers built in HDMI.

And this is a not just a quirk of my laptop, my grading suite is exactly the same. If I use the PC’s built in HDMI the pictures suck. Lots of banding and other unwanted artefacts. Play back the same clip via a dedicated, made for video, internal PCI card such as a Decklink card and almost always all of the problems go away. If you use SDI rather than HDMI things tend to be even better.

So don’t skimp on your monitoring path if you really want to know what your footage looks like. Get a proper video card, don’t rely on the computers GPU. Get a decent monitor with an SDI input and try to avoid HDMI for any critical monitoring.

20170620_091235-1024x576 Why you need to sort out your post production monitoring!
Shot viewed on a good quality TV via HDMI from the computers built in graphics card. Notice all the banding.
20170620_091347-1024x576 Why you need to sort out your post production monitoring!
Exactly the same shot/clip as above. But this time played back over HDMI from an Atomos Shogun Flame onto the very same TV. Not how all the banding has gone.

 

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Calibrating your viewfinder or LCD.

smpte-arib-bars-sample Calibrating your viewfinder or LCD.One of the most important things to do before you shoot anything is to make sure that any monitors, viewfinders or LCD panels are accurately calibrated. The majority of modern HD cameras have built in colour bars and these are ideal for checking your monitor. On most Sony cameras you have SMPTE ARIB colour bars like the ones in the image here. Note that I have raised the black level in the image so that you can see some of the key features more clearly. If your using a LCD or OLED monitor connected via HDSDI or HDMI then the main adjustments you will have are for Contrast, Brightness and Saturation.

First set up the monitor or viewfinder so that the 100% white square is shown as peak white on the monitor. This is done by increasing the contrast control until the white box stops getting brighter on the screen. Once it reaches maximum brightness, back the contrast level down until you can just perceive the tiniest of brightness changes on the screen.

Once this is set you now use the pluge bars to set up the black level. The pluge bars are the narrow near black bars that I’ve marked as -2% +2% and +4% in the picture they are each separated by black. The -2% bar is blacker than black so we should not be able to see this. Using the brightness control adjust the screen so that you can’t see the -2% bar but can just see the +2% bar. The 4% bar should also be visible separated from the 2% bar by black.

Color is harder to set accurately. Looking at the bars, the main upper bars are 75% bars so these are fully saturated, but only at 75% luma. The 4 coloured boxes, 2 on each side, two thirds of the way down the pattern are 100% fully saturated boxes. Using the outer 100% boxes increase the saturation or colour level until the color vibrance of the outer boxes stops increasing, then back the level down again until you just perceive the color decreasing. I find this easiest to see with the blue box.

Now you should have good, well saturated looking bars on you monitor or LCD and provided it is of reasonable quality it should be calibrated adequately well for judging exposure.

I find that on an EX or F3 the LCD panel ends up with the contrast at zero, colour at zero and brightness at about +28 on most cameras.

TVLogic VFM-056WP 5.6″ Monitor/Viewfinder Review.

DSC03701-300x199 TVLogic VFM-056WP 5.6" Monitor/Viewfinder Review.
TVLogic VFM-056WP 5.6" monitor.

At NAB I was offered a TVLogic 5.6″ monitor kit for review and assessment. The VFM-056WP sits somewhere between being a monitor and a viewfinder. It’s not as big as most monitors and it’s not really a viewfinder, like the soon to be released Alphatron/TVlogic EVF. So I was somewhat sceptical as to how useful it would be as my normal cameras all have built in LCD panels.

The kit included the monitor, a deep detachable hood, battery adapter for the ever so common Sony NP-F batteries, mounting ball joint, power supply and a few other small accessories, all inside a good quality flight case.

DSC03703-300x199 TVLogic VFM-056WP 5.6" Monitor/Viewfinder Review.
The rear of the VFM-056W

One of my few criticisms of this kit is the size of the flight case. The monitor itself is very compact and lightweight, but the flight case really is quite big. For my fly-away jobs I probably wouldn’t use this flight case, it’s just to big for such a small monitor. Anyway back to the monitor. Externally it feels nice and solid and to be made of good quality materials. On the bottom there are a pair of BNC’s for the HDSDi input and output. The HDSDi input works in both conventional 1.5G and 3G modes (WP version only) making it suitable for use with cameras that have a 3G 4:4:4 output, so it works great with the S-Log output of my PMW-F3. As well as the HDSDi there is also an HDMI input plus 3 phono connectors for the composite and component input. So all in all there is just about every type of input you could possibly want. In addition the WP version will convert any connected HDMI signal to HDSDi

DSC03702-e1335529922308-199x300 TVLogic VFM-056WP 5.6" Monitor/Viewfinder Review.
VFM-056W with deep hood on top of my PMW-F3

On plugging in the HDSDi feed from my F3 I was presented with a very good looking, sharp and clear display. Checking the colour response using a DSC Chroma Du Monde chart showed very accurate colour reproduction, brightness and contrast. Although the LCD panel is quite small the resolution at 1280×720 makes the image look nice and crisp. Next I tried using it to focus. On the whole I found I could achieve reasonably accurate focus without resorting to peaking, but turning on the monitors coloured peaking function does make it much easier to find optimum focus. The other tool that helps focussing is a 1:1 pixel image zoom that is accessed using the menu switch on the rear.

The VFM-065WP has all the usual tools in the menu’s. The menu system is easy to use with a Function button on the rear of the monitor and a rotary dial on the side used to select and change settings. One thing that would be nice perhaps is a couple of assignable buttons to which you can assign your favourite functions.

DSC03707-300x199 TVLogic VFM-056WP 5.6" Monitor/Viewfinder Review.
The clear display of the VFM-056WP (click to enlarge)

As well as the common stuff like markers, false colour and zebras, it has some nice extra functions like a DSLR zoom feature that will expand the less than full screen output of Canon and Nikon DSLR’s so that it fills the screen. There is also a Range Error feature that allows the user to set maximum and minimum levels for luma and chroma. If these levels are exceeded, the areas in excess of these values blink on and off. The WP model includes waveform and vectorscopes that can be superimposed over the pictures in 3 different sizes, small, large and full screen.

So with it’s full set of features and tools, excellent build and image quality, the diminutive  TVLogic VFM-056WP is a great little monitor that can be camera mounted without adding a lot of extra weight to your kit. I have been quite impressed by this neat little monitor and I’m sure it will end up in my kit for most shoots. It’s small size and low weight makes it particularly suitable for overseas shoots where I need to keep the total weight of my kit to a minimum to avoid excessive airline baggage charges.

Sony PVM-740 OLED Monitor. Like looking through a window!

pvm-740 Sony PVM-740 OLED Monitor. Like looking through a window!
Sony PVM-740

Sony PVM-740 OLED monitor

One of the things that really caught my eye at NAB was Sony’s new PVM-740 field monitor. This is one of the first professional monitors to use OLED technology (Organic Light Emitting Diode). Traditional LCD screens work by using a backlight that has a liquid crystal panel in front of it. When a charge is applied to the liquid crystals they change the polarisation of the light passing through them, this light then passes through a second polariser and between them they vary the amount of light passing through the panel to the viewer (If you have ever seen a VariND filter or tried twisting one polarising filter relative to another you can see how this works). While on the whole this works reasonably well there are some issues with this technology. The first is that the liquid crystals never fully block the passage of all the light, so black is never truly black, some light always seeps through. In addition brightness is limited to that of the backlight and the light is attenuated as it has to pass through the crystals and polariser. In addition if the backlight is too bright then the blacks get brighter too which limits the overall contrast range. Another issue is that LCD’s take time to change state from on to off and off to on. This leads to lag and smear with fast motion or high refresh rates. While a lot of money has been spent over the years developing LCD technology and there are some excellent LCD monitors available, these issues still exist and LCD performance still lags behind that of CRT’s.

Enter OLED. Organic Light Emitting Diode displays use a grid of light emitting devices, each pixel is a separate emitter, so when it’s off, it’s truly off. This means that blacks are completely black. When the emitter is on the light it emits is not passing through a polariser or crystal so it’s brightness is not diminished, this means that whites are really bright. In addition you can switch an LED on and off pretty much instantly so there is no lag or smearing. When you see the new Sony PVM-740 OLED monitor side by side with a similar LCD monitor the difference is striking! It’s like looking through a window, the image is clear and crisp, blacks are… well.. black and whites are bright and sparkle. The pictures from the PVM-740 are much more like the images you would expect to get from a top spec CRT monitor, yet the 740 is light weight, compact and uses less power. It should also be more robust and will not be affected by magnetic fields like a CRT monitor.

You really need to see this monitor in the flesh to appreciate the images it produces.