Alister’s NAB Round Up.

Unfortunately I didn’t get to spend a lot of time walking the floor at NAB. If you haven’t been, the venue and the event are huge. It would take days to go around and see everything. I was at NAB shooting some video’s for Sony Europe and that kept me busy, so I only got to see a few things away from the Sony booth. I’ll come back to the Sony stuff later.

BlackMagic and AJA cameras.

Lots of talk about these. I didn’t get to see the BlackMagic cameras so I can’t really comment on these. I have read a lot of negative comments about the size and weight of the BM Ursa. I did get to see the AJA Cion. It certainly looks the part and the design and ergonomics look pretty sound. But when I was over on the AJA booth the camera was shooting a couple of actors dressed in 1920′s clothes. The female actress was pretending to smoke a cigarette. Every time she brought her hand up to her face the back of her hand completely over exposed turning into a blobby white highlight. Not nice. Now this is a prototype camera, so maybe this will be sorted before release. AJA, like BlackMagic claim 12 stops of dynamic range for their cameras. I wasn’t seeing this at NAB.

Going forwards dynamic range is going to be just as important as high resolution. For a start being able to capture a greater dynamic range gives you more to play with in post and helps give pleasing highlights, even with today’s restricted range 709 based TV’s and monitors. But Dolby has developed Dolby Vision which brings images with a 100 times greater dynamic range to TV screens. Technicolor has also developed a system of it’s own a they claim is even better. These new technologies when combined with 4K will produce a viewing experience the likes of which we haven’t seen before. So it’s not just resolution that’s important but also dynamic range and 12 stops, whilst good isn’t really in the same league as cameras like the Alexa, F65, F55 which can all manage 14 stops or more.

New Dynacore V-Mount battery with 5V, D-Tap and Charger built in.

New Dynacore V-Mount battery with 5V, D-Tap and Charger built in.

Most of the cameras that I use rely on V-Mount batteries. I have been using batteries from various manufacturers and to be honest they have all worked well and without issue. One brand that I use is Dynacore. Dynacore are a Chinese manufacturer that specialise in batteries and lighting for broadcast. They had some interesting new batteries at NAB. First off it the one pictured to the left. This is a V-Mount or AB Gold mount battery with an integrated charger. It also has a D-Tap output as well as a 5v USB output. The D-Tap is great for powering lights and other 12v accessories and the 5V USB out can be used to power or charge a phone or tablet. With so many cameras now including control over WiFi, having that 5V output is very handy.

Dynacore DS-U77B, 77Wh battery for EX and PMW series.

Dynacore DS-U77B, 77Wh battery for EX and PMW series.

Another interesting Dynacore Battery is this one, the DS-U77B. This is a replacement for the Sony BPU series batteries as used on everything from the EX1 to the new PMW-300. I asked if this will work on the PMW-300 and was told yes, no problem. The 77Wh battery includes a D-Tap output and a 5V USB output making it very versatile, plus the higher capacity than the Sony BP-U60 (56Wh) means it will run your camera for longer.

Dynacore Bi-Color 1x1 LED panel.

Dynacore Bi-Color 1×1 LED panel.

Dynacore also make lights and had some nice 1×1 LED panels with pretty good CRI’s on show along with a LED Fresnel. The panels I saw were bi-color and DMX controllable. A test with a digital CRI meter returned an average CRI of 96 which is pretty good and pictures I took of objects illuminated by the lights look reasonably well balanced.

 

Dynacore LED fresnel.

Dynacore LED fresnel.

Another Dynacore light that caught my eye was this large Fresnel LED. The CRI is not as good as the 1×1 panels, coming in around 90 – 91, but I didn’t observe any nasty hue’s or color casts. It would be interesting to try this light in anger and see how it really performs in practice.

 

 

New high brightness LED camera light from Alphatron.

New high brightness LED camera light from Alphatron.

Whilst on the subject of lights Alphatron had a nice new Ledpro ES96 camera Light. The example on show at NAB was a pre-production unit, production should start soon. What’s interesting about this light is that it uses the same LED’s as the very nice and very bright Cineroid LM400 LED light. Shining it around the hall at NAB showed the Alphatron/LedPro light to be extremely bright for it’s size and the color purity looked to be excellent for an LED. As always Alphatron like to try to offer good value and I was assured that this LED light will be extremely competitively priced. On the back there are brightness and color controls as well as a socket for external power. Also on the Alphatron booth was their new Matte Box, based on a Vocas design this is a really nice Matte Box. I have a sample for review and will be writing about this soon.

My F5 with Alphatron Matte Box and Vocas shoulder kit.

My F5 with Alphatron Matte Box and Vocas shoulder kit.

Talking about Vocas, they had some new bit’s and pieces including a new shoulder mount for the Sony F5 and F55 cameras. This new base plate is extremely light. A lot of thought has clearly gone into the design. It looks pretty simple, but the design allows it to be slid forward and back for balance and then the shoulder pad can be moved forward and back within the shoulder mount. I’ll be writing a more in depth review of this very soon.

 

So what about Sony?

New Sony A7S.

New Sony A7S.

Lots of fuss around the Sony A7S. This is a new version of the already popular and highly regarded Sony A7 stills camera. Some big difference though. The A7S has a sensor better suited to video.  It “only” has 12 megapixels compared to the 24 million or more found on most DSLR’s. The benefit being that as this is a full frame sensor the pixels are huge and you only need 8.8 Million pixels for 4K. Big pixels means great sensitivity and excellent dynamic range. The A7S has incredible low light performance with the ISO going almost all the way up to almost 1/2 a million (409,600 ISO to be precise). As well as low light sensitivity and high dynamic range the A7R can also output 4K video over micro HDSDI. So this means that with a 4K capable recorder like the new Atomos Shogun or perhaps the Convergent Design Odyssey (if they enable the HDMI as a 4K input) you can use this camera to shoot 4K. Internally the camera records very high quality HD using XAVC-S or Mpeg4. With no line or pixel skipping the video from this pocket sized camera are really very good. To take advantage of the large dynamic range the A7S even has Sony’s SLog2 gamma curve. It’s a full frame sensor that uses Sony’s E-Mount. You can still use your older non full frame E-Mount lenses from the NEX range or your FS100/FS700, the camera reverts to a crop frame mode when you do this. If you want to know more about the A7S then take a look at Den Lennie’s in depth review and videos. It’s all very impressive. http://www.fstopacademy.com/blog/sony-alpha-7s-first-hands-on-shooting-review/

As well as the A7S Sony were also showing a new E-Mount power zoom lens. The 28-135mm lens looks very nice, but the specs are a bit vague and subject to change. There will be a firmware update later in the year for FS700 owners so that these new lenses can be used on the FS700. In addition the firmware update will auto-correct for geometric distortions and shading present in may E-Mount lenses, so a nice little update coming soon.

Another new camera from Sony is the PXW-X180.

New Sony PXW-X180 1/3" camcorder.

New Sony PXW-X180 1/3″ camcorder.

The X180 is a 1/3″ camera that replaces not only the XDCAM PMW-150 but also the NXCAM NX5. The “X” in the X180 signifies that the camera also has Sony’s new XAVC codec. So, the X180 includes a multitude of codecs starting with standard definition DVCAM going up to HD with NXCAM AVCHD then on to XDCAM and finally XAVC. That’s an impressive list! In order to record all these different codecs there are also a number of different recording media options. The camera can use SD cards, SxS cards or XQD cards.

The rear end of the PXW-X180

The rear end of the PXW-X180

There are two SxS sized card slots and adapters are used for the other cards. An SD card adapter will be included in the box, so NXCAM owners moving up to this camera will be good to go from day 1. The two card slots can be independently controlled, so you can use the record button on the handgrip to trigger record on one slot and the record button on the handle for the other. Dual recording can be used for safety or to shoot say one long clip for a conference with shorter highlights clips for fast turn-around editing.

PXW-X180's 25x zoom lens.

PXW-X180′s 25x zoom lens.

As well as all the neat recording features the X180 has an amazing 25x zoom lens! From very wide to very long this camera can do it all and with optical stabilisation. The cool features don’t stop there either. On the top of the handle there is a MI hot shoe. We have seen this shoe before on many consumer cameras, but the version on the X180 will allow you to connect many accessories including radio mics directly to the camera. If you have one of Sony’s new UWP-D radio mics the receiver will slide into a simple hot shoe which will power the mic as well as routing audio into the camera without wires or cables. Very neat. All in all the PXW-X180 is a very interesting camera, I hope to get one soon to review.

The PDW-850 was a bit of a surprise!

The new Sony PDW-850 XDCAM optical disc camcorder.

The new Sony PDW-850 XDCAM optical disc camcorder.

I wasn’t really expecting to see a new optical disc camcorder, but here it is the PDW-850. On the outside this doesn’t look a lot different to the older PDW-700 and F800 cameras, but under the skin there are some very useful updates. For a start power consumption has been reduced to 41W in record and 37w in standby giving a useful extension to operating times when battery powered. In addition the weight has been reduced to 4.2Kg. New 2/3″ CCD sensors are used so picture quality may be a little better. The small info LCD on the side of the camera has gone (to save weight and power) and the LCD screen has been upgraded with a higher resolution panel that is quite a big improvement over the one used on the  700 and F800.

And For Sony’s PMW-F5 and PMW-F55?

PMW-F5 and F55 shoulder mount kit.

PMW-F5 and F55 shoulder mount kit.

Just before NAB Sony announced a codec upgrade option for the PMW-F5 and F55. This new board will add both Apple ProRes and Avid DNxHD.  AT the show itself Sony revealed a very interesting shoulder kit for the cameras that converts them into fully fledged ENG camera.

 

The front end of the F5/F55 shoulder kit.

The front end of the F5/F55 shoulder kit.

This rig is a lot more than just a fancy shoulder mount. At the front it adds a number of extra assignable buttons as well as familiar switches for white balance camera/bars select and gain. Under the front of the camera it adds a shutter select switch and white balance switch along with a rotary gain control for audio.

 

SONY DSCAt the back on the side there are more audio controls including 4 knobs to set the audio levels across 4 tracks. On the very rear, just where they would be on a XDCAM shoulder camera are a pair of XLR audio inputs, a 5 pin XLR out and a headphone socket. On the right side of the mount at the front there is a 5 pin XLR input for the on-camera mic. At the top of the camera there is a new much longer handle that includes posts for a carry strap (hooray). It should be noted that the mount shown at the show was an early prototype so the finished product may be a little different/improved.

 

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New Canon ENG style cinema lens.

Canon CN7x17 KAS servo zoom for s35mm sensors.

Canon CN7x17 KAS servo zoom for s35mm sensors.

I want one! What more can I say. The Fujinon Cabrios are very nice but on paper at least this looks like it’s going to be great. Designed for 4K and super 35mm sensors this is a 7x zoom (compared to the 4.7x of the 19-90mm Cabrio) with a really useful range, 17-120mm, nice and wide, reasonably long. It has a servo hand grip for smooth power zooms and is not too big (although it is heavier than most 2/3″ B4 zooms).  At T2.95 it’s not too slow either, but the aperture does ramp at the long end of the lens down to T3.9. I guess this is a small price to pay for a compact lens with such a large zoom ratio. Must take a look at NAB. Now, I wonder how much this beauty is going to cost? UPDATE: Well it appears that the price will be approx $33K/£20K, which is very good value compared to a Cabrio. It’s still a bit steep for me to buy, but it’s certainly one to consider on a rental basis. That’s a pretty good price, if it was £14K then I’d be seriously tempted to lay down some cash.

Follow this link to go to Canon’s press release and more information.

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Understanding Sony’s SLog3. It isn’t really noisy.

It’s been brought to my attention that there is a lot of concern about the apparent noise levels when using Sony’s new Slog3 gamma curve. The problem being that when you view the ungraded Slog3 it appears to have more noise in the shadows than Slog2. Many are concerned that this “extra” noise will end up making the final pictures nosier. The reality is that this is not the case, you won’t get any extra noise using Slog3 over Slog2 and Slog3 is generally easier to grade and work with in post production.

So what’s going on?

Slog3 mimics the Cineon Log curve. As a result the shadow and low key parts of the scene are shown and recorded at a brighter level than Slog2. Because the shadows are brighter, the noise in the shadows appears to be worse. It isn’t. The noise level might be a bit higher but the important thing, the ratio between wanted picture information and un wanted noise is exactly the same whether in Slog2 or Slog3 (or in fact any other of the cameras gamma curves at the native ISO).

Let me explain:

The signal to noise ratio of a camera is determined almost entirely by the sensor. This is NOT changing between gamma curves.

The other thing that effects the signal to noise ratio is the exposure level, or to be more precise the aperture and how much light falls on the sensor. This should be same for Slog2 and Slog3. So again no change there.

As these two key factors do not change when you switch between Slog2 and slog3, there is no change in the signal to noise ratio between Slog2 and Slog3. It is the ratio between wanted picture information and noise that is important. Not the noise level, but the ratio. What people see when they look at ungraded SLog3 is a higher noise level (because the signal levels are also higher), but the ratio between the wanted signal and the noise is actually no different for both Slog2 and Slog3 and it’s that ratio that will determine how noisy your pictures will be after grading.

Gamma is just gain, nothing more, nothing less, just applied by variable amounts at different levels. In the case of log, the amount of gain decreases as you go further up the curve.

Increasing or decreasing gain does NOT significantly change the signal to noise ratio of a digital camera (or any other digital system). It might make noise more visible if you are amplifying the noise more, for example in an under exposure situation where you add gain to make a very dark object brighter. But the ratio between the dark object and the noise does not change, it’s just that as you have made the dark object brighter by adding gain, you have also made the noise brighter by the same amount, so the noise also becomes brighter and thus more obvious. The ratio between the wanted signal and the unwanted noise remains constant, no matter what the gain, it is a ratio and gain does not change ratios. With Slog3 in post production you will need less gain in the shadows than you would with Slog2 and this negates the extra gain that the camera adds to the shadows when shooting SLog3.

Lets take a look at some Math. I’ll keep it very simple, I promise!

Just for a moment to keep things simple, lets say some camera has a signal to noise ratio of 3:1 (SNR is normally measured in db, but I’m going to keep things really simple here).

So, from the sensor if my picture signal is 3 then my noise will be 1, or if my picture signal is 6 then my noise will be 2.

If I apply Gamma Curve “A” which has 2x gain then my picture becomes (6×2) 12 and my noise (2×2) 4. The SNR is 12:4 = 3:1

If I apply Gamma Curve “B” which has 3x gain then my picture becomes (6×3) 18 and my noise becomes (3×2) 6. The SNR is 18:6 = 3:1 so no change to the ratio, but the noise is 6 compared to the 4 of Gamma “A”, as a result Gamma “B” will appear to be noisier when viewed on a monitor.

Now we take those imaginary clips in to post production:

In post we want to grade the shots so that we end up with the same brightness of image, so lets say our target level after grading is 15.

For the gamma “A” signal we need to add 1.25x gain to take 12 to 15. As a result the noise now becomes (1.25 x 4) 5.

For the gamma “B” signal (our noisy looking one) we need to use 0.8333x gain to take 18  to 15. As a result the noise now becomes (0.83333 x 6) 5.

Notice anything? In both cases the noise in the final image is exactly the same.

OK, so that’s the theory, what about in practice?

Take a look at the images below. These are 400% crops from larger frames. Identical exposure, workflow and processing for each. You will see the original Slog2 and SLog3 plus the Slog 2 and Slog 3 after applying the LC-709 LUT to each in Sony’s raw viewer. Nothing else has been done to the clips. You can “see” more noise in the raised shadows in the untouched SLog3, but after applying the LUTs the noise levels are the same. This is because the Signal to Noise ratio of both curves is the same and after adding the LUT’s the total gain applied (camera gain + LUT gain) to get the same output levels is the same.

Slog2-400
Slog3-400Slog2-to-709-400Slog3-to-709-400

It’s interesting to note in these frame grabs that you can actually see the improvement in shadow detail that SLog3 brings. The bobbles and the edge of the picture frame look better in the Slog3 in my opinion. A little bit more shadow data has given a more pleasing result with fewer artefacts.

The only way you can alter the SNR of the system (other than through electronic noise reduction) is by changing the exposure, which is why EI is so important and so effective.

Noise is always most problematic in shadows and low key. As we are putting more data into the shadows with SLog3 we are in effect recording the noise in the shadows more precisely, you won’t enhance it or increase it. All that will happen is that it is more accurately reproduced with fewer artefacts, which is a good thing.

In addition Slog3 has a near straight line curve. This means that in post production it’s easier to grade as adjustments to one part of the image will have a similar effect to other parts of the image. It’s also very, very close to Cineon and to Arri Log C and in many cases LUT and grades designed for these gammas will also work pretty well with SLog3.

The down side to Slog3?

Very few really. Fewer data points are recorded for each stop in the brighter parts of the picture and highlights compared to Slog2. As a result Slog3 is slightly less forgiving of overexposure than Slog2. You probably don’t want to push your EI gain quite as hard with Slog3. 1.5 stops over should be OK (so using an EI 1.5 stops down from native) but 2 or more will hurt your pictures.

Want to pick my brain for 10 days, fancy an adventure and a chance to see and shoot some very cool sights? Why not join me for a storm chasing adventure. 

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New Extended Version Supercell Video.

Storm chasing season is on the way and I will be off to the USA to shoot landscapes, storms and maybe tornadoes in May. If you fancy a bit of an adventure and want to shoot stuff like this why not join me? See this link for more info. In the mean time why not take a look at this extended and re-graded version of the Supercell storm video I shot last May. It’s on YouTube in 4K if you select “2160″ as the image size. Just wish YouTube wouldn’t compress stuff so much.

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Are You Screwing Up Your Footage In Resolve?

First of all let me say that DaVinci Resolve is a great piece of software. Very capable, very powerful and great quality. BUT there is a hidden “Gotcha” that not many are aware of and even more are totally confused by (including me for a time).

This has taken me days of research, fiddling, googling and messing around to finally be sure of exactly what is going on inside Resolve. I am NOT a Resolve expert, so if anyone thinks I have this wrong do please let me know, but here goes……

These are the important things to understand about Resolve.

Internally Resolve Always Works With Data Levels (bit 0 to bit 1023 or CV0-CV1023 – CV stands for Code Value).

Resolve’s Scopes Always Measure The Internal Data Levels – These are NOT necessarily the Output Levels.

There Are 3 Data Ranges Used For Video – Data CV0 to CV1023, Legal Video 0-100IRE = CV64 to CV940 and Extended Range Video 0-109IRE CV64 to CV1023 (1019 over HDSDI).

Most Modern Video Cameras Record Using Extended Range Video, 0-109IRE or CV64 to CV1019.

Resolve Only Has Input Options For Data Levels or Legal Range Video. There is no option for Extended Range video.

If Transcoding Footage You May Require Extended Range Video Export. For example converting SLog video or footage from the majority of modern cameras which record up to 109IRE.

Resolve Only Has Output Options For Data Levels or Legal Range Video. There is no simple option to output, monitor or export using just the 64 to 1019 range as a 64 to 1019 range.

So, clearly anyone wanting to work with Extended Range Video has a problem. Not so much for grading perhaps, but a big issue if you want to transcode anything. Do remember that almost every modern video camera makes use of the full extended video range. It’s actually quite rare to find a modern camera that does not go above 100IRE.

So why not just use data levels for everything? Well that is an option. You can set your clips attributes (in the media pane) to Data Levels, set you monitor output to Data Levels and when you render choose Data Levels. In fact this is what YOU MUST DO if you want to convert files from one format to another without any scaling or level shifts. But be warned, never, ever, grade like this unless you add a Soft Clip LUT (more on that in a bit) as you will end up with illegal super blacks, blacks that are blacker than black and will not display correctly on most devices.

There are probably an awful lot of people out there using Resolve to convert XAVC or other formats to ProRes and in the process unwittingly making a mess of their footage, especially SLog2 and  hypergammas.

On input you can choose clip attributes for Data 0-1023 or Video 64-940 as well as Auto (in most cases if Resolve detects luma levels under 64 the footage is treated as Data, otherwise video levels). Anything set to video levels or detected as video levels gets scaled from the sources  CV64-940 range to Resolve’s internal CV0-1023 range.

As Resolves waveform/vector scopes etc always measure the internal scaled range there is no way to tell just by looking at the scopes what range your original material was in or whether it’s been scaled. If you do want to check the range of the source clip, try reducing the video level in the colour panel. If your clip is extended range then you should be able to se the previously hidden high range by pulling the levels down. A legal range clip on the other hand will have nothing above Resolves 1023 so the peak level will just drop.

On output you can choose Data 0-1023 or Legal Video 64-960 for your output or monitoring range (Resolve uses 960 which is the CbCr max value, Y is 940). For Resolve to handle the majority of modern cameras and many modern workflows where outputting 64-1023  may be required, there is no option!!!!!! So if you are working with video levels, anything you want to work with using extended range ends up either scaled on input or clipped/range restricted, blacks crushed, on output.

For example:

Import Hypergamma or SLog which is 64-1023, don’t touch or grade the footage, then export using video levels and the range is clipped and will no longer have the highlights recorded above 100IRE in the original. The original input files will be CV64-1023 but the video range output files will be CV64-940, the range is clipped off at 940 (100IRE).  If you set the clip attributes to “video 64-940″ then on input CV940 is mapped to CV1023 in Resolve, so anything you shot between 100 and 109IRE (940-1019) goes out of range and is not seen on the output (It’s still there inside Resolve, but you can’t get to it unless you grade the footage). There just isn’t a correct option to pass through Full Range video 1:1, unless you use data in, data out, but then you run the risk of having illegal super blacks. If you leave the clip attributes as video and the export using Data Levels then your original CV64 black gets pulled down to CV0 so your blacks are crushed, however you do then retain the stuff above 100IRE.

If you’re using Resolve to convert XAVC SLog2 or SLog3 to something else, ProRes perhaps, this means that any Look Up Tables used in the downstream application will not behave as expected because your output clip will have the wrong levels. So for file conversions you MUST use data levels on the input clip attributes and data levels on output to pass the video through as per the original, even though you are working with footage that complies with perfectly correct, Extended Range video standards. But you must never edit or grade like this as you will get super blacks on your output….. Unless you generate a soft clip LUT.

 If you import a full range video clip that goes from CV64 to CV1019(1023) (0 to 109IRE) and do nothing to it then it will come out of Resolve as either data levels CV0 to CV1023 (-7IRE to 109IRE) or legal video CV64 to CV940 (0 – 100IRE), neither of which is ideal when transcoding footage. 

 So what can you do if you really need an Extended Range workflow? Well you can generate a Soft Clip LUT in Resolve to manage your output range. For this to work correctly you need to work entirely with data levels. Clip attributes must be set to Data levels, Monitor out to Data Levels and Exports should be at Data Levels. This is NOT necessary for direct 1:1 transcoding as the assumption is that you want a direct 1:1 copy of the original data, just in a different format.

You use Resolves Soft Clip LUT generator (on the Look Up Tables settings page) to create a 1D LUT with a Black Clip of 64 and a White Clip of 1019. This LUT is then applied as a 1D Output LUT. If you are using an existing output LUT (1D or 3D) then you can use the Soft Clip LUT generator to make a modified version of that existing LUT, adding the 64 and 1019 clip levels.

 So what is it doing?

As you are working at Data Levels your clips and footage will come in to Resolve 1:1. So a clip with a range of CV0-1023 will come in as CV0-1023, a CV64-940 clip will come in with CV64-940 and a CV64-1019 clip as CV64-1019. Most video clips from a modern camera will use CV64-1019.  A clip using CV64-1019 will be imported and handled as CV64-1019 within the full 0-1023 range, but the levels are not shifted or altered so if it’s CV220 in the original it will be CV220 inside Resolve. One immediate benefit is that Resolves scopes are now showing the actual original levels of the source clip, as shot. Phew – that’s a lot of CV’s in that paragraph, hope your following along OK.

You grade your footage as normal. The Soft Clip LUT will clip anything below CV64 (0 IRE, video black) but allow the full extended video range up to CV1019(1023) to be used. It won’t shift the level, just not allow anything to go below CV64. If grading for output do ensure that you really do want extended range (If you want to stay broadcast safe use video range).

The output to your HDSDI monitor will be unscaled data CV0-1019, but because of the LUT clipping at 64, there will be nothing below 64, no super blacks, this is how it should be, this is correct and what you want for an extended range workflow, perhaps for passing your footage on to another video editing application for finishing or where it will be mixed with other full range footage. The majority of grading workflows however will probably be conventional Legal Video Range.

When you render a file using data levels, the file will go from CV0-1019 but again because of the Soft Clip LUT there will be nothing below 64 (black) but you can use the Full Range above CV940 so super whites etc will be passed through correctly to the rendered file. This way you can make use of the complete extended video range.

 In Summary:

If you want to use Resolve to convert files from one codec to another, without changing your levels you must ensure the Clip Attributes are set to Data, your monitor out must be set to Data Levels and you must Render using Data Levels. If you don’t there is a very high likelihood that your levels will be incorrect or altered, almost certainly different to what you shot.

If you wish to grade and output anything above 100IRE (perhaps when mixing graded footage with full range camera footage) then again you must use data levels throughout the workflow but you should add a Soft Clip LUT with CV1019 as the upper clip and CV64 as the lower clip to prevent illegal black levels but retain full video range to 109IRE.

It would be so much simpler if Resolve had an extended range video out option.

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What causes CA or Purple and Blue fringes in my videos?

Blue and purple fringes around edges in photos and videos are nothing new. Its a problem we have always had. telescopes and binoculars can also suffer. It’s normally called chromatic aberration or CA. When we were all shooting in standard definition it wasn’t something that created too many issues, but with HD cameras and 4K cameras it’s a much bigger issue because as you increase the resolution of the system (camera + lens) generally speaking, CA becomes much worse.

As light passes through a glass lens the different wavelengths that result in the different colours we see are diffracted and bet by different amounts. So the point behind the lens where the light comes into sharp focus will be different for red light to blue light.

A simple glass lens will bend red, green and blue wavelengths by different amounts, so the focus point will be slightly different for each.

A simple glass lens will bend red, green and blue wavelengths by different amounts, so the focus point will be slightly different for each.

The larger the pixels on your sensor the less of an issue this will be. Lets say for example that on an SD sensor with big pixels, when the blue light is brought to best focus the red light is out of focus by 1/2 a pixel width. All you will see is the very slightest red tint to edges as a small bit of out of focus red spills on to the adjacent pixel. Now consider what happens if you increase the resolution of the sensor. If you go from SD to HD the pixels need to made much smaller to fit them all on to the same size sensor. HD pixels are around half the size of SD pixels (for the same size sensor). So now that out of focus red light that was only half the width of an SD pixel will completely fill the adjacent pixels so the CA becomes more noticeable.

In addition as you increase the resolution of the lens you need to make the focus of the light “tighter” and less blurred to increase the lenses resolving power. This has the effect of making the difference between the focus points of the red and blue light more distinct, there is less blurring of each colour, so less bleed of one colour into the other and as a result more CA as the focus point for each wavelength becomes more distinct. When each focus point is more distinct the difference between the in focus and out of focus light becomes more obvious, so the colour fringing becomes more obvious.

This is why SD lenses very often show less CA than HD lenses, a softer more blurry SD lens will have less distinct CA. Lens manufacturers will use exotic types of glass to try to combat CA. Some types of glass have a negative index so blue may focus closer than red and then other types of glass may have a positive index so red may focus closer than blue. By mixing positive and negative glass elements within the lens you can cancel out some of the colour shift. But this is very difficult to get right across all focal lengths in zoom lenses so some CA almost always remains. The exotic glass used in some of the lens elements can be incredibly expensive to produce and is one of the reasons why good lenses don’t come cheap.

Rather than trying to eliminate every last bit of CA optically the other approach is to electronically reduce the CA by either shifting the R G B channels in the camera electronically or reducing the saturation around high contrast edges. This is what ALAC or CAC does. It’s easier to get a better result from these systems when the lens is precisely matched to the camera and I think this is why the CA correction on the Sony kit lenses tends to be more effective than that of the 3rd party lenses.

Sony recently released firmware updates for the PMW200 and PMW300 cameras that improves the performance of the electronic CA reduction of these cameras when using the supplied kit lenses.
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Sony PMW-F5 and F55 to get ProRes and DNxHD codecs.

In a very welcome announcement today, Sony have stated as part of their on-going commitment to making the F5 and F55 cameras as versatile and flexible as possible and following customer feedback there will be a hardware upgrade option for both cameras that will allow you to add the popular ProRes and DNxHD codecs to the internal recording options.

This is great news, although I have to say I really like the XAVC codec for acquisition, as it will really help those still using FCP7 and provide the cameras with a codec for just about every possible scenario.

No details of when, or how much, but great news. You can find a few more details here: http://community.sony.com/t5/F5-F55/Announcing-ProRes-and-DNxHD-support-for-both-F5-and-F55/m-p/293988#U293988

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Premiere Pro CC now supports Sony Raw – WITHOUT the Sony Plug-In.

I was having “Media Pending” issues with Sony raw footage in Premiere on my mac. I did some digging and it appears that in the last update to Premiere Pro CC (version 7.2) Adobe included native support for Sony raw at 4K, 2K and HFR. If you are running Premiere CC and you still have the Sony Raw Plug-In installed it makes Premiere unresponsive and will result in a lot of “Media Pending” messages when you try to work with Raw footage. After removing the Sony raw importer plug-in all my media pending issues went away and I can now use 2K HFR footage in Premiere CC.

To uninstall the plugin on a Mac (called “ImporterSonyRawBundle”)  go to “Applications” then “Adobe Premiere Pro CC” and then right click on the “Adobe Premiere Pro CC” app file and select “Show Package Contents” then open “Content” and then “Plug-ins” you should find the file you need to trash.

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Storm Chasing Tour and Workshop, 2014.

Me shooting a tornado with the PMW-F5 and AXS-R5 on my Miller Solo tripod.

Me shooting a tornado with the PMW-F5 and AXS-R5 on my Miller Solo tripod.

So just there’s just a little over 3 months to go until my annual storm chasing expedition to the USA. Last years trip was an amazing success with some incredible storms and tornadoes captured on video and stills. This years trip is 11 days long to maximise the chances of seeing jaw dropping weather.

Please understand that I am not going to be trying to get as close as possible to a tornado or put my life or anyone else’s life in danger. This trip is about capturing dramatic and beautiful images of the Great Plains of the USA along with the severe storms that are common in spring. If you have seen any of my storm videos you will know that the structure of some of the storms that I expect to witness are incredible. The lightning shows breath taking and the scenery impressive. If you are a scenic or landscape photographer or videographer then this is a trip for you.

Dramatic Supercell Thunderstorm

Dramatic Supercell Thunderstorm

During the trip I will be on hand to share my knowledge and help you improve your photo and video skills. We will have a motion control rig for time-lapse, 4K cameras and all kinds of other cool gadgets to play with.

More details of the trip can be found here: http://www.xdcam-user.com/tornado-chasing/  . Please not that spaces are extremely limited, so it’s first come, first served.

If you really want to make the most of your trip then why not join me a few days early in Austin, Texas where I will be running a music video production workshop at Omega Broadcast on the 22/23 of May, more details of this to follow soon. After the storm chasing tour it’s Cinegear in LA on the 6/7th of June.

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The Cape Peninsular shot on an F55 with two lenses.

Here is a short selection of a few clips that I shot around the Cape Peninsular while waiting for my flight home after some workshops. Shot on an F55 with a 20mm and 85mm Sony PL lens. Most of it is 2k raw at 240fps, but there are some normal speed shots in there too as well as some S&Q motion time-lapse. Big thank you to Charles Maxwell for taking the time out to drive me around the Peninsular.

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