What’s the difference between raw and S-Log ProRes – Re: FS5 raw output.

This is a question that comes up a lot.

Raw is the unprocessed (or minimally processed) data direct from the sensor. It is just the brightness value for each of the pixels, it is not a color image, but we know which color filter is above each pixel, so we are able to work out the color later. In the computer you take that raw data and convert it into a conventional color video signal defining the gamma curve and colorspace in the computer.  This gives you the freedom to choose the gamma and colorspace after the shoot and retains as much of the original sensor information as possible.Of course the captured dynamic and color range is determined by the capabilities of the sensor and we can’t magically get more than the sensor can “see”. The quality of the final image is also dependant on the quality of the debayer process in the computer, but as you have the raw data you can always go back and re-encode the footage with a better quality encoder at a later date. Raw can be compressed or uncompressed. Sony’s 12 bit FS-raw when recorded on an Odyssey or Atomos recorder is normally uncompressed so there are no additional artefacts from compression, but the files are large. The 16 bit raw from a Sony F5 or F55 when recorded on an R5 or R7 is made about 3x smaller through a proprietary algorithm.

ProRes is a conventional compressed color video format. So a ProRes file will already have a pre-determined gamma curve and color space, this is set in the camera through a picture profile, scene file or other similar settings at the time of shooting. The quality of the ProRes file is dependant on the quality of the encoder in the camera or recorder at the time of recording, so there is no way to go back and improve on this or change the gamma/colorspace later. In addition ProRes, like most commonly used codecs is a lossy compressed format, so some (minimal) picture information may be lost in the encoding process and artefacts (again minimal) are added to the image. These cannot easily be removed later, however they should not normally present any serious problems.

It’s important to understand that there are many different types of raw and many different types of ProRes and not all are equal. The FS-raw from the FS5/FS7 is 12 bit linear and 12 bit’s are not really enough for the best possible quality from a 14 stop camera (there are not enough code values so floating point math and/or data rounding has to take place and this effects the shadows and low key areas of the image). You really need 16 bit data for 14 stops of dynamic range with linear raw, so if you are really serious about raw you may want to consider a Sony F5 or F55. ProRes is a pretty decent codec, especially if you use ProResHQ and 10 bit log approaches the quality of 12 bit linear raw but without the huge file sizes.  Incidentally there is very little to be gained by going to ProRes 444 when recording the 12 bit raw from an FS5/FS7, you’ll just have bigger files and less record time.

Taking the 12 bit raw from an FS5 and converting it to ProRes in an external recorder has potential problems of it’s own. The quality of the final file will be dependant on the quality of the debayer and encoding process in the recorder, so there may be differences in the end result from different recorders. In addition you have to add a gamma curve at this point so you must be careful to choose the correct gamma curve to minimise concatenation where you add the imperfections of 12 bit linear to the imperfections of the 10 bit encoded file (S-Log2 appears to be the best fit to Sony’s 12 bit linear raw).

Despite the limitations of 12 bit linear, it is normally a noticeable improvement over the FS5’s 8 bit internal UHD recordings, but less of a step up from the 10 bit XAVC that an FS7 can record internally. What it won’t do is allow you to capture anything extra. It won’t improve the dynamic range, won’t give you more color and won’t enhance the low light performance (if anything there will be a slight increase in shadow noise and it may be slightly inferior in under exposed shots). You will have the same dynamic and color range, but recorded with more “bits” (code values to be precise). Linear raw excels at capturing highlight information and what you will find is that compared to log there will be more textures in highlights and brighter parts of your captured scenes. This will become more and more important as HDR screens are better able to show highlights correctly. Current standard dynamic range displays don’t show highlights well, so often the extra highlight data in raw is of little benefit over log. But that’s going to change in the next few years so linear recording with it’s extra highlight information will become more and more important.

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Warning – it’s Sunburn Season (Northern Hemisphere at least).

Just a reminder to anyone using a viewfinder fitted with an eyepiece, magnifier or loupe not to leave it pointing up at the sun. Every year I see dozens of examples of burnt  and damaged LCD screens and OLED displays caused by sunlight entering the viewfinder eyepiece and getting focussed onto the screen and burning or melting it.

It can only take a few seconds for the damage to occur and it’s normally irreversible. Even walking from shot to shot with the camera viewfinder pointed towards the sky can be enough to do damage if the sun is out.

So be careful, cover or cap the viewfinder when you are not using it. Tilt it down when carrying the camera between locations or shots. Don’t turn to chat to someone else on set and leave the VF pointing at the sun. If you are shooting outside on a bright sunny day consider using a comfort shade such as an umbrella or large flag above your shooting position to keep both you and the camera out of the sun.

Damage to the viewfinder can appear as a smudge or dark patch on the screen that does not wipe off. If the cameras was left for a long period it may appear as a dark line across the image. You can also sometimes melt the surround to the LCD or OLED screen.

As well as the viewfinder don’t point your camera directly into the sun. Even an ND filter may not protect the sensor from damage as most regular ND filters allow the infra red wavelengths that do much of the damage straight through.  Shutter speed makes no difference to the amount of light hitting the sensor in a video camera, so even at a high shutter speed damage to the cameras sensor or internal ND’s can occur. So be careful when shooting into the sun. Use an IR ND filter and avoid shooting with the aperture wide open, especially with static shots such as time-lapse.

 

Will a bigger recording Gamut give me more picture information?

The short answer is it all depends on the camera you are using. With the F55 or F65 then S-Log2/S-Gamut and S-Log3/S-Gamut3 will give you a larger range of colours in your final image than S-Log3/S-Gamut3.cine. But if you have a PMW-F5, PXW-FS7 or PXW-FS5 this is not going to be the case.

What is Gamut?

The word Gamut means the complete range or scale of something. So when we talk about Gamut in a video camera we are talking about dynamic range and color range (colorspace) taken together. Then within the Gamut we can break that down into the dynamic range or brightness range which is determined by the gamma curve and the color range which is determined by the colorspace.

Looking at the current Sony digital cinema cameras you have a choice of 3 different gamuts when the camera is in log mode plus a number of conventional gamuts you get when shooting rec-709, rec-2020 or any other combination of rec-709 color with cinegammas or hypergammas.

Log gamma and gamuts.

But it’s in the log mode where there is much confusion. When shooting with log with the current cameras you have 3 recommended combinations.

S-Gamut (S-Gamut colorspace + S-log2 gamma).

S-Gamut3 (S-Gamut3 colorspace + S-Log3 gamma).

S-Gamut3.cine (S-Gamut3.cine colorpace + S-Log3 gamma).

The S-log2 and S-log3 gamma curves both capture the same dynamic range – 14 stops, there is no difference in the dynamic range captured.

In terms of the range of colors that can be recorded S-Gamut and S-Gamut3 are the same size and the largest recording colorspaces the cameras have. S-Gamut3.cine is a smaller colourspace but still larger than P3 (digital cinema projection) or rec-709.

Gamuts-only Will a bigger recording Gamut give me more picture information?

But those were all designed for the F55 and F65 cameras that have extremely high quality (expensive) colour filters on their sensors. The reality is that the F5/FS7/FS5 sensor cannot see the full range of any of the S-Gamut colorspaces so in reality you gain very little by using the larger versions. Don’t expect to see a noticeably greater range of colours than any of the other colour modes if you have the F5/FS7/FS5. But all the LUT’s designed for these cameras are based on the S-Gamuts and if you want to mix an FS5 with an F55 in one production it helps to use the same settings so that grading will be easier. It is worth noting at this point that most natural colors do fall within Rec-709, so while it is always nicer to have a bigger color range it isn’t the end of the world for most of what we shoot.

S-Log3 is a great example of what it means to have a bigger recording range than the camera can “see”. S-log3 is based on the Cineon film transfer log gamma curve developed back in the late 1980’s. Cineon was carefully tailored to match film response and designed around 10 bit data (as that was state of the art back then). It allows for around 16 stops of dynamic range. Much later, Arri and many others then adapted Cineon for use in video cameras – The “C” in Arri’s LogC stands for Cineon.

When Sony started doing wide dynamic range cameras they developed their own log gammas starting with S-Log, then S-Log2. These curves are matched very precisely to the way a video sensor captures a scene rather than film. In addition they are matched to the sensors actual capture range, S-Log can record 13 stops as that’s what the sensors in the cameras with S-Log can see. Then S-Log2 is 14 stops as the second generation cameras can all see 14 stops. As a result of being purpose designed for a video sensor, when using S-Log2 you maximise the entire recording range because the sensor is matched to the log which is matched to the record range.

But, these curves drew much criticism from early adopters and colorists because they were very different from the Cineon curve and all the other log curves based on this old school film curve. Colorists didn’t like it because none of their old Cineon LUT’s would work as expected and it was “different”.

S-log-levels Will a bigger recording Gamut give me more picture information?
Chart showing S-Log2 and S-Log3 plotted against f-stops and code values. Note how little data there is for each of the darker stops, the best data is above middle grey. Note that current sensors only go to +6 stops over middle grey so S-Log2 and S-Log3 record to different peak levels.

In response to this Sony then developed S-Log3 and surprise, surprise – S-log3 is based on Cineon. So S-log3 is based on a 16 stop film transfer curve, but the current cameras can only see 14 stops. What this means is that the top 14% of the gamma curve is never used (that’s where stops 15 and 16 would reside) and as a result s-Log3 tops out at 92% and never gets to the 107% that S-Log2 can reach. If Sony were to release a 16 stop camera then S-Log3 could still be used and then it would reach 107%.

Coming back to colorspace. If you understand that the sensor in the F5/FS7/FS5 cannot see the full colour range that S-Gamut or S-Gamut3 are capable of recording then you will appreciate that like S-log3 (that is larger than the camera can see and therefore part empty) many of the possible code values available in S-Gamut are left empty. This is a waste of data. So from a colourspace point of view the best match when shooting log for these cameras is the slightly smaller colorspace S-Gamut3.cine. But S-Gamut3.cine is meant to be matched with S-Log3 which as we have seen wastes data anyway. If the camera is shooting using a 10 bit codec such as XAVC-I or XAVC-L in HD there are plenty of code values to play with, so a small loss of data has little impact on the final image. But if you are recording with only 8 bit data, for example XAVC-L in UHD then this does become much more of a problem and this is when you will find that S-Gamut with S-Log2 is going to give a better result as S-Log2 was designed for use with a video sensor from day 1 and it maximises the use of what little data you have.

The Fujinon Cabrio XK6x120 alongside the MK 18-55.

Having done a fair bit of shooting with the new and very nice Fujinon MK 18-55mm E-Mount lens I decided to take a much closer look at the Fujinon Cabrio XK6x20 20 to 120mm T3.5 lens with the servo hand grip.

AJC05580-1024x681 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
The Fujinon XK6X20 20 to 120mm lens on my PMW-F5. The lens was loaned to me by Fujinon at my request as I wanted to test it for myself.

The price of this lens is very competitive and it can now be found as low as £11K/$16K. Lets not try to pretend that good quality PL mount zooms are cheap, but this is a great price for what is very high quality glass. The 20 to 120mm zoom range is nice and of course it’s truly parfocal there is a back focus adjuster along with macro function.

AJC05581-1024x681 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
The XK6X20 viewed from the top.

Like the other similar ENG style PL zooms this lens is quite heavy. The front element of the lens is huge and I’m sure a lot of the weight comes from this big lump of glass. One of the nice things about this lenses baby brother the MK 18-55, is that the 18-55 is really very light, which is great on the smaller cameras like the FS5 or FS7.

AJC05591-1024x681 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
The XK6X20 and it huge front element on the left and the smaller and lighter MK18-55 on the right.

The 20-120mm Cabrio exudes quality. The build quality of the lens is wonderful, the witness marks are crisp and well engraved, the servo zoom is silky smooth. The large servo module acts as a handgrip just like traditional ENG lenses and it really comfortable to hold and use this way. But if you don’t need it it can be easily removed leaving the bare bones lens body and saving a little bit of weight. There are the usual 0.8 mod pitch gears on each of the focus zoom and iris rings. Focus ring travel is huge at about 200 degrees and due to the physical size of the lens this is as much as I’d ever want. Even towards infinity there is still a nice range of travel so focussing accurately on distant objects is easy.

But what about the image quality, how does the lens perform in real world situations?

To find out I used it for a shoot in Norway. The shoot was for TV manufacturer Philips. We wanted to obtain some high quality 4K HDR footage to show off the capabilities of a new 4K OLED Ambilight TV. Unfortunately the weather conditions on the shoot were pretty grim most of the time and this made it all the more challenging. But I’m pleased to say that both lenses performed very well despite snow, ice and cold.

AJC05587-1024x681 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
You can see the size difference here – XK6X20 on the left and MK18-55 on the right.

One of the great things about having both the high end Cabrio 20-120mm and the budget friendly 18-55mm for the shoot was that the overall look of the images from the FS5 and F5 was the same. Often mixing lenses from different manufacturers results in different looking images giving the colourist more work to do in post. Fujinon now have a range of lenses to suit most budgets from the high end Cabrio 19-90mm T2.9 down through the Cabrio 20-120 T3.5 to the MK 18-55 T2.9.

So what do the images from these lenses look like? I’m afraid I can’t show any of the footage from the Philips shoot yet, I should be able to show it later in the year. Below are a couple of frame grabs to give you an idea of the kind of images you can get. We didn’t shoot the same shots with the F5/XK6x20 and FS5/MK18-55 at the same time, I was the only cinematographer. So I don’t have a side by side comparison from the shoot, but the different scenes shot with each lens/camera combo match really well.

sami1-1024x540 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
Sami woman feeding reindeer shot with the XK6X20 in Norway. Click on the image for a hi res version.
sami2-1024x540 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
Wide of Sami woman feeding reindeer shot with the XK6X20 in Norway. Click on the image for a hi res version.
trmso1-1024x540 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
Annika Summerson filmed in Tromso with the Fujinon XK6X20.
Tromso2-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
Boats in the harbour on a cold but bright morning (the only one we had).
social-1024x540 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
Icicles on the window. Shot with the Fujinon XK6X20 with my PMW-F5.

TESTING BOTH LENSES:

In order to better directly compare the two lenses I shot some test shots. The XK6x20 on my F5 and the MK18-55 on my FS7. Both cameras were set to the same settings and hypergamma 3 with the cinema matrix used. The images you will see below have not been touched, this is how they looked straight from the camera. If you click on the picture you should get a link to the full frame 4K image, but do remember this are Jpegs.

AJC05593-1024x681 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
Testing the Fujinon MK18-55 and XK6X20 with my PMW-F5 and PXW-FS7.

I tried to get the same shots with both combinations but you will see some small variations. I apologise for that. To give as fair a comparison as possible I did most of the shots at 20mm and 55mm, but then in addition shot at 18mm on the MK18-55 and 120mm on the XK6X20 so you can see the additional range each lens offers.

First test was of a neighbours Cherry tree in blossom.

FS7-Blossom-55mm2-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
The FS7 with XF 18-55mm at 55mm. Click on the image for the full size 4K frame.
F5-20-120-55-blossom-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PMW-F5 with XK20X6 at approx 55mm (sorry about the different framing). Click on the image for the size 4K full frame.
FS7-18-55-20mm-blossom2-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
The FS7 with XF 18-55mm at approx 20mm. Click on the image for the full size 4K frame.
F5-20-120-20-blossom-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PMW-F5 with XK20X6 at 20mm. Click on the image for the size 4K full frame.
F5-20-120-120-blossom-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PMW-F5 with the Cabrio XK6X20 at 120mm showing the extra reach of the 20-120mm zoom.

The next test was a simple setup shot of a couple of beer bottles on a table with strong sunlight from above and behind to create deep contrast. I wanted to see if either lens showed signs of loosing shadow detail due to the very large, very bright table top introducing flare into the shadows.

FS7-18-55-20-Beer-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PXW-FS7 with XF18-55mm at approx 20mm, high contrast scene.
F5-20-120-20-beer-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PMW-F5 with XK20X6 at 20mm. High Contrast scene. Click on the image for the size 4K full frame.
FS7-18-55-55-beer-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PXW-FS7 with XF18-55mm at 55mm, high contrast scene.
F5-20-120-55-beer-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PMW-F5 with XK20X6 at approx 55mm. High contrast scene. Click on the image for the size 4K full frame.
FS7-18-55-18-beer-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
The FS7 with the XF18-55 at 18mm showing the extra “width” that 18mm gives over 20mm.

My conclusion with the above shots is that there is remarkably little difference between these two lenses. Both perform extremely well. I think the XK6X20 might be marginally sharper at the wide end than the 18-55mm, either that or the slightly better viewfinder of the F5 is allowing me to focus more precisely. In addition I think the bokeh of the more expensive Cabrio is marginally smoother than the 18-55, but again it’s a tiny difference (not as big as the difference in white balance of the two cameras).

Finally a shot of my ugly mug just so you can take a look at some skin tones.

FS7-18-55-me-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PXW-FS7 with Fujinon XF 18-55 at approx 30mm. Click on the image for full size 4K frame.
F5-20-120-me-1024x576 The Fujinon Cabrio XK6x120 alongside the MK 18-55.
PMW-F5 with Fujinon Cabrio XK6X20 at approx 30mm. Click on the image for the full size frame.

Again very little difference between these lenses which is a good thing. Both perform very well, both produce pleasing images. Sure the XK6X20 20-120mm is more than twice the price of the MK18-55 but then it does offer twice the zoom range and it’s very hard to make fast parfocal lenses with big zoom ranges for large sensors. There will be a companion MK50-135mm lens coming later in the year, so with both the MK lenses you will be able to get the full range of the XK6X20 and a bit more, provided you don’t mind swapping lenses. It’s a tough choice if you have an E-mount Sony camera, which to get? For E-Mount I think the pair of MK lenses will be the way to go. If you have a PL mount camera the XK6X20 has to be a very serious contender. It’s a great all-round cinema zoom lens and a realistic price. Whichever way you do go you won’t be disappointed, these are proper cinema lenses.

Anatomy of a shot. Night Scene in Arctic Norway – Fujinon lenses, Stella Lights.

I have just return from one of the most challenging shoots I have been involved in. The shoot took place over 5 days in and around Tromso in Norway. The aim was to gather footage to show off the capabilities of a new type of 4K TV from Phillips.

We shot the Northern Lights, we shot dog sledding , snow mobiles, shots of the city and sailing on the fjords. Each part of the shoot had many challenges and a lot of the shoot took place at night and at night the crew slept in cabins, tents and on the yachts. Shooting from the ice and snow covered deck of a yacht in temperatures well below zero is not something I enjoyed. And to top it all off the weather was pretty grim fro most of the shoot. Heavy snow showers, freezing temperatures and towards the end strong winds.

Because image quality is paramount for this project I choses to use the best lenses I could, but at the same time space and time constraints dictated that zoom lenses would be desirable. We were shooting 16 bit raw as well as XAVC class 480 on my PMW-F5 and some pick-up shots in UHD XAVC-L on a PXW-FS5. For the PMW-F5 the primary lens was the Fujinon Cabrio XK6x20, 20-120mm PL zoom and to ensure we had similar looking images from the FS5 I used the new Fujinon XF 18-55mm. I have to say that I’m quite in love with both of these lenses.

fujinon-xk6x20-20-120mm-t3-5-pl-mount-lens-cc1-e1490981959479 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
Fujinon Cabrio XK6x20 PL mount cinema zoom. A beautiful lens!

The Cabrio 20-120 is a beautiful lens and it’s really nice to have a servo zoom that is truly parfocal. The 20-120 produces really nice images even in the most challenging of conditions and at T3.5 it’s reasonably fast throughout the entire zoom range. This was the lens that I used for the majority of the shoot, in particular for the many night scenes we shot. The E-Mount 18-55 on the FS5 produces images that matched really well with the bigger lens and camera. This is a combination I would love to use on more shoots where the budget will allow.

One particular scene that we had to shoot was particularly challenging. It was a set up shot of a night time arrival of a couple of snowmobiles at a Sami camp site. The Sami people are the indigenous people of Northern Norway and they have a particular style of tent know as a Laavu which is similar to a teepee or wigwam. The idea behind the shot was to have the snow scooters arriving with headlights blazing and for the drivers to then enter the tent lit only by the light of a campfire inside the tent. At the time of the shoot it was snowing heavily and was totally dark. Turn off the lights of the snowmobiles and you could not see a thing.

A007C001_170317I9snwscter-wide-1.-e1490980652498 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
Wide shot of the snowmobiles arriving at the camp in the dark.

While modern cameras like the F5 are very sensitive, the light of a campfire inside a tent will not adequately light a scene like this on it’s own. I didn’t want a totally dark background, so I decided that I would subtly light the trees of the forest that we were in to add some drama and give some depth to the background and a sense of being in a forest.

In-tent-wide-e1490980747645 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
A slightly closer shot of the tent with backlit trees behind it.

As we were travelling continuously on this shoot there was no space for a large or complex lighting kit and the remote location meant we needed battery powered lights. In addition I knew before we left that there was a chance of bad weather so I needed lights that would work whatever mother nature decided to throw at us.

snw-scter-start-e1490980892561 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
A snow scooter comes into the shot. You can see just how heavily it was snowing in this shot.

I decided to take a set of 3 Light & Motion Stella battery powered LED lights. It’s just as well I had the Stella lamps as on top of all the other difficulties of the shoot the weather decided it was not going to play ball. We had to shoot the scene (and much of the shoot) in the middle of a snow storm. Fortunately the Stella lights are completely waterproof, so I didn’t need to worry about rain or snow protection. Just set them up turn them on and use the built in dimmer to set the light output.

To light the scene I set up a Stella Pro 5000 in the woods behind the Sami tent, aimed through the trees and pointed directly towards the camera. I chose to backlight the trees to provide a sense of there being trees rather than lighting them. I felt this would look less lit than throwing a ton of light into the forest from the front and I’m pleased with the result.

20170317_201335-e1490980965481 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
A Light & Motion Stella Pro 5000 was used to back light the trees and tent. The heavy snow was no problem as the light is totally waterproof.

The Stella Pro 5000 is very bright for a compact battery operated light, it’s 5000 lumen 120 degree output that is pretty close to what you would get from a 200W HMI, it’s very bright. It has a very high CRI and gives out great quality daylight balanced light.  It was positioned so that the light itself was behind the tent on a small bank, about 20m back in the woods. You couldn’t see it in the shot, but the light coming through the trees created shafts of light in the snow and the trees appeared as silhouettes. It added depth and interest to what would have otherwise been a near totally black background.

20170317_203855-e1490981224538 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
Light & Motion Stella 2000 used to light the forground, again the lamp is waterproof so bad weather is no problem.

Then to provide a small amount of light so that we could see the riders of the snow scooters as they walked to the tent I used a Stella 2000. I didn’t really want the light from this lamp to be too obvious as this would really make the scene look “lit”. I didn’t need the full 2000 lumen output so I used the built in dimmer to reduce the output to around 70%.

The third light was a small Stella 1000 and this was placed inside the tent with a scrunched up orange gel. The Stella 1000 would typically be used as a camera top light, but it’s full dimmable and produces a very high light quality, making it suitable for many applications. The creases and folds in the orange gel helped break up the light a little creating a less lit look sympathetic to the fire inside the tent.

in-tent-mid-e1490981340247 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
A Stella 1000 with orange gel was used inside the tent to give the light from the fire a small boost.

It allowed me to increase the illumination in the tent, adding to the light from the fire without it being obvious that the tent interior was lit. For some of the shots I had an assistant sit in the tent, out of shot and slowly move the gel in front of the light to add a little movement to the light to mimic the firelight even better.

sihuette-e1490981444887 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
One particular shot on the storyboard was the silhouette of the drivers entering the tent. The Stella 1000 really helped punch trough the canvas sides of the tent.

At the moment I can’t show you the footage. That will have to wait until after the launch of the TV. But I’m really pleased with the way this scene came out. It’s challenging trying to shoot in the dark, in a blizzard, in temperatures well below freezing. Every aspect of getting this scene was hard. Opening a flight case to get out some kit meant getting snow on everything inside it. Just positioning the light up the woods was tough, the snow was up above my knees as I waded through it. Operating the camera is so much harder when it has a rain cover on it. The viewfinder was constantly misting up as snow fell on it non stop. Seeing the witness marks on the lens is difficult (although thankfully the marks on the Fujinon 20-120 are huge and easy to see).

20170317_205922-e1490981701785 Anatomy of a shot. Night Scene in Arctic Norway - Fujinon lenses, Stella Lights.
The Fujinon Cabrio XK6X20 lens all iced up at the end of the day. After shooting out in sub zero temperatures don’t take the camera inside until you are sure you have wrapped for the day!

But sometimes it’s challenges like these that make the job interesting. I know I was cursing and swearing at times trying to make these shots work, but seeing the scene come to life in the grade is all the more rewarding.

I’ll be writing more about the Fujinon 20-120 very soon, so why not subscribe to my blog using the subscribe bottom on the left.

PW-FS5 and PXW-Z150 to get Hybrid Log Gamma for direct HDR production.

For the full details please see the official Sony announcement: https://www.sony.co.uk/pro/press/pr-sony-expands-hdr-production-capabilities

The PXW-FS5 and PXW-Z150 will both get a free firmware update some time around June that will add the ability to shoot using a special gamma curve called “Hybrid Log Gamma” or HLG.

In the case of the FS5 this will be added through an additional picture profile, PP10. As well as HLG the camera will also have the ability to record using Rec2020 color. As a result the camera will become compatible with the new Rec2100 standard for HDR television.

In addition the FS5 will get the ability to change the base ISO for S-Log2 and S-Log3 from 3200 ISO to 2000 ISO. This will help produce cleaner images that are easier to grade. On top of that via a paid firmware update you will be able to shoot continuously at up to 120fps in full HD, no need to use the Super Slow Motion memory cache function.

These are all great upgrades for this little highly versatile camera.

By selecting Picture Profile 10  the camera will shooting using Hybrid Log Gamma. If you were to plug the camera into an HDR TV that supports HLG then what you would see on the TV would be a HDR image with an extended dynamic range. This should give brighter more realistic highlights and a quite noticeable increase in overall contrast compared to SDR (Standard Dynamic Range). There will be no need to grade the footage to get a perfectly watchable vibrant HDR image. The real beauty of HLG (developed by the BBC and NHK) is that it is backwards compatible with normal SDR (Standard Dynamic Range) TV’s. So feed the very same signal into a conventional SDR TV and it will look just fine. Skin tones will be a touch darker than with Rec709 and  it won’t be HDR, but it will be perfectly watchable picture and most people won’t realise it’s anything different to normal SDR TV.

So HLG provides a simple very fast, direct HDR workflow that is backwards compatible with SDR TV’s. As a result you don’t need any special monitors to shoot with it, you can just monitor with existing SDR monitors, although it would be beneficial to have an HDR monitor to check the HDR aspect of the signal. HLG isn’t designed to be graded, although a little bit of post production tweaking can be applied, just as with Rec709.  Bottom line is it’s quick and easy, no special monitors or skills needed – simples.

If you want the very best possible HDR then you should shoot with S-Log2/S-Log3 or raw and then grade the material in post using an HDR capable monitor.  But that takes time and large HDR monitors are not cheap (for a small monitor you could use an Atomos Flame or Inferno).  The FS5 will give you the ability to work either way. HLG for simple and quick, S-Log for the best possible image quality.

Hopefully we will see HLG rolled out to other cameras in the near future.

ISO Confusion Once Again!

I’m going to keep bringing this up until people start to take note and understand that with an electronic camera ISO is NOT sensitivity.

With an electronic camera ISO is a guide to the required shutter speed and aperture needed to get the correct exposure. This is different to sensitivity. The ISO rating of a video camera and it’s sensitivity are closely related, but they are not quite the same thing. Because different gamma curves require different exposures the ISO rating for each gamma curve will be different even though the gain and actual sensitivity of the camera may be exactly the same.

Lets take the  Sony PXW-FS5 as an example.

If you shoot using the standard camera settings you should expose white at 90%, middle grey will be around 42% and skin tones typically around 70%. At 0dB gain the camera the camera will display an ISO equivalent rating of 1000 ISO. So let’s say you are using a light meter. You set it to 1000 ISO and it tells you you need an aperture of f5.6 to get the right exposure.

Now you change to S-Log2. If you do nothing else your white card will now be at around 75% and middle grey will be around 40%. At 0dB gain the camera will show an equivalent ISO of 3200 ISO.

But hang on – The camera is still at 0dB gain, so there is no change in sensitivity. .But the camera is over exposed, S-Log2 is supposed to be exposed with white at 59% and middle grey at 32%.

So we go to our light meter and change the ISO on the light meter from 1000 ISO to 3200 ISO. Because the light meter now “thinks” the camera is more sensitive by almost 2 stops it will tell us to close the aperture by nearly 2 stops. So we go to the camera and stop down to f10 and bingo, the image is exposed correctly.

But here’s the important thing – The camera hasn’t become any more sensitive. We haven’t replaced the sensor with a different, more sensitive one (as you would do with a film camera where you actually change the film stock). We are still at 0dB gain (even though the camera tells us this is the equivalent to a higher ISO).

The only reason that ISO number changes is so that if we were using an external light meter we would get the recommended exposure levels for the gamma curve we are using. In this example closing the aperture increase the highlight range that the camera would be able to cope with and this helps us get that full 14 stop range from the camera, although closing the aperture means less light on the sensor so the pictures end up a little noisier as a result – That is unless you choose to rate the camera at a different ISO by over exposing the log a bit.

ISO is useful, but you need to understand that it isn’t really sensitivity. After all we can’t change the sensors on our video cameras and that would be the only way to truly change the sensitivity. Any “sensitivity” change is really nothing more than a gain or amplification change. Useful but not the same as changing the actual sensitivity. Gain will make a dark picture brighter but it won’t allow you to see something that the sensor can’t detect.

It is much easier to understand dB gain with an electronic camera as it actually tells you exactly what the camera is doing and it is actually my recommendation that people use gain rather than ISO for all of the above reasons.  The use of ISO on electronic cameras is very badly understood, in part because it’s a largely meaningless term because it doesn’t tell us how sensitive the sensor is, how much gain we are using or how much noise we are adding. Give any experienced camera operator a camera and ask them how noisy will it be a 18dB gain and they will have a pretty good idea of what the pictures will look like. Give them the same camera and ask them how noisy will it be at 8000 ISO and they won’t have a clue.

The problem is ISO is trendy and fashionable as that’s what “cinematographers” use. But lets be honest with ourselves – we are using electronic video cameras, whether that’s a Red, Alexa or FS5 so really we should be using the correct terminology for an electronic camera which is gain. It would eliminate an aweful lot of confusion and tell us how much noise and grain our pictures will have. It’s noise and grain will levels will determine how good a clip looks and how much we can grade it, so we need to clearly understand how much gain is being added in camera and dB gian tells us this. ISO does not.

Side Note: Modern film stocks will often have 2 ratings, the ISO or actual measured sensitivity of the film stock plus the EI or Exposure Index which is the recommended setting for the light meter to get the best exposure. In some respects the ISO rating of a video camera is closer to the EI rating of a film stock. Perhaps we should stop calling it ISO and use the term EI instead, this would be me appropriate and signify that it is a reference for best exposure rather than true sensitivity.

UPDATE: A comment on facebook was why not display both ISO and Gain side by side. This is an obvious solution really. Why do camera manufacturers force us to choose either ISO or gain? Why can’t we use a hybrid of the 2? I see no technical reason why cameras can’t show both the gain and ISO at the same time – Problem solved.

Sony naming system

Here’s a little insight into what some of the Sony product prefixes might mean. These may not be 100% correct but this is what I understand them to mean. There are also many exceptions to the standard naming convention, so use this as a guide only.

First letter: P = Professional, B = Broadcast, U = Utility,  D = Digital, H = Studio/OB,  L = LCD, O = Optical

Second letter: V = Video (means video tape if camera), M = SxS Memory, D = Optical Disc, X = XQD/SD/SxS(solid state media or digital workflow), S = System, D = Multi format, P = Projector or Printer, R = Remote Control, W = wireless

Third letter: (or 3 + 4th): W = Writer( deck or camera that can also record/camcorder), M = Monitor, C = Camera(no recording capability) CU = Camera Control Unit, CP = Compact camera(no recording), X = HD, Z = 4K, D = Digital (HDSDI?),  A = Archive

Then after the 3/4 letter prefix: F = Film (digital cinema, 16 bit raw when raw included), FS = Film Style (large sensor, 12 bit raw when raw included), X = HD from factory (often but not always upgradable to 4K) , Z is 4K from factory.  NX = AVCHD

The number of digits after the letters used to be significant. 2 digits was a product without an imager (PMW-50, PMW-EX30) 3 digits was a camera (PMW-200, PMW-500) and 4 digits was a deck (PMW-HD1500, F1600). However recently cameras have any number of digits.

 

For example PXW-X200:

P = Professional   X = Solid state media   W = Writer –  X = HD camcorder.

Example BVW-400 (Betacam SP camcorder – remember those!)

B = Broadcast  V = Video Tape  W = Writer

Example PXW-FS7

P = Professional X = Solid State Media  W = Writer – FS = Film Style.

Example PMW-F55 (Slight odd-ball this one as it was the very first XAVC camera, perhaps should really have been a PXW-F55 although as it’s SxS and has the XDCAM codec PMW works too).

P = Professional  M = SxS Memory  W = Writer – F = Film (Digital Cinema).

Example PDW-700 (Optical disc camcorder)

P = Professional  D = Disk  W = Writer.

Example PMW-300

P = Professional  M = SxS Memory W = Writer.

Some oddballs:

F65 = F65 Ultimate digital cinema camera, no prefix and a 35mm sensor, not 65mm as the name suggests. Other “F” only cameras used the sensor size for the name. The F35 had a super 35mm sensor and F23 which had a 2/3″ sensor.

CBKZ = Software upgrade option.

CBK = Camera build kit

HDW = HDCAM Writer.

SRW = HDCAM SR Writer.

DSR = Digital DVCAM camera/camcorder/deck.

I don’t know what the HXR prefix stands for, this line of normally AVCHD solid state camcorders used to come from a different group within Sony to the broadcast group. These two groups now work together so the product numbering is now more consistent, but there are still many product names that don’t follow the convention.

It’s interesting to note that there are very few “Broadcast” B** products these days except for BVM (Broadcast Video Monitor) monitors. Most camcorders are now P** even if they are most definitely broadcast cameras, for example the PXW-X500.

If anyone would like to add to this list or correct any errors please let me know by adding a comment. Any input/additions are most welcome!

Auto Knee when shooting with Rec-709.

Like many cameras the Sony PXW-FS7, PMW-F5 and F55 use an automatic knee circuit to help the camera handle strong highlights or overexposure when shooting using standard gamma curves such as Rec-709 (STD gamma 5). On some ENG cameras there is a very similar function  called DCC (Dynamic Contrast Compensation) which is often selected via the Camera/Bars switch.

On the FS7, F5/F55 and many others the Auto Knee is on by default out of the factory. It can be turned on and off in the cameras paint settings. In most normal shooting situations, if you are correctly exposed the auto knee does a good job of bringing bright highlights down out of clipping.  The auto knee threshold is at around 90% brightness. Expose with objects brighter than 90% in your scene and the auto knee starts to kick in.

The correct exposure for white, such as a 90% reflectivity white card or white piece of paper in Rec-709 is 90%. Skin tones, plants, walls, roads and in fact most objects will normally be below white or below 90%. However direct light sources, such as the sky or direct reflections such as shiny car body work will be brighter than white. So the knee should only ever effect objects brighter than white if you are exposed correctly.  So for most situations it should not effect skin tones and the majority of the scene, just the bright highlights.

The auto knee detects highlight levels above 90% and tries to keep the highlight range below clipping by adding contrast compression to the highlights. The amount of compression depends on how strong the highlights are. As a result the auto knee effect will vary with exposure. If you have a scene with only a few highlights there will be some knee compression and it’s effect will only be seen above approx 90%. If you then open the aperture or have a lot of highlights the auto knee will increase the highlight compression to compensate. If the highlight range becomes very large then the knee will not only increase the amount of compression but also lower the knee point so more and more of the upper exposure range is effected by the knee. In extreme cases the knee point may get as low as 70-80% and this then starts to effect skin tones.

To prevent rapid fluctuations of the contrast in the highlight range the auto knee has a slight delay. This can result in a vicious circle where you open the iris a bit to help brighten the shot. The shot gets brighter. Then a couple of seconds later you look at the shot again and because the knee has now adjusted the highlights after it’s delay period it looks different to how it looked at the moment you made the initial adjustment. So you adjust again…. then the knee adjusts again and so on. Sometimes this lag can make it tricky to get your highlights to look exactly how you want.

Another common auto knee effect is to see the brighter parts of an entire image change as a result of a change in only a small part of the scene. A typical example would be an interview with a window in the background. As the highlight level in the bright window changes, perhaps as the sun comes and goes from behind passing clouds, the knee tries to compensate and all of the highlights in the scene go up and down in brightness whether they are over exposed or not. This looks very strange and can ruin an otherwise good looking shot.

If you are shooting in a studio against a white background the auto knee makes it impossible to get a brilliantly bright uniformly clipped white background. You increase your exposure to make the white background extra bright and because that white is now above 90% the auto knee treats it as a highlight and tries to control it’s brightness. The more you open the aperture the more the knee pulls down the white background, it never reaches clipping. Eventually you get to the point where the knee starts to effect the skin tones but your white backdrop still isn’t clipped. The image doesn’t look great.

In these cases the best thing to do is to turn off the Auto Knee. If you go into the paint settings you will find the knee settings. In most cases leave the knee on (except perhaps for the white studio example), but turn OFF the auto knee function. The fixed level knee will still give you a good highlight range but eliminate the pumping or other variable knee effects. Note that the knee options have no effect if using a Hypergamma or log. They only come into paly with standard gamma.

Upcoming workshops.

A busy couple of weeks coming up with several FS7 and FS7 II workshops in the USA. I’ll be covering all the essential stuff including gamma curves, log, CineEI, Rec2020 and HDR.

Austin Texas, Omega Broadcast, Tuesday 28th Feb. http://www.omegabroadcast.com/product-p/event-sonyfs7iimasterclass.htm

Dallas Texas – VideoTex systems, Wednesday 1st March. https://www.eventbrite.com/e/sony-fs7-m2-master-class-with-alister-chapman-tickets-31938387577

Minneapolis – Z-Systems. Thursday 2nd March. http://zsyst.com/2017/02/event-alister-chapman-3-2-17/

San Francisco/Bay Area private full day workshop Saturday 4th March. Use the contact form for full details.

Boston – Rule Camera. Tuesday 7th March. http://www.rule.com/

At the end of March I’ll be in Dublin for the Camerakit event.

Camera setup, reviews, tutorials and information for pro camcorder users from Alister Chapman.