This is a part of a much larger project I have been working on recently for Philips. The Philips “Extreme Earth” project. The idea being to show of some of the latest technologies in their HDR Ambilight TV’s.
Last year we started the project up in Norway filming the Northern Lights. This year we travelled to Nevada and Arizona to shoot the second set of films under the “Canyon” headline, then we spent another couple of weeks travelling all over the Midwest shooting what will be the 3rd set of films under the headline “Storm”. We are now looking ahead to next year with several ideas being looked at from Volcanoes to Rain Forests.
For the Norway and Canyon shoots competitions were run ahead of the shoots in various consumer technology magazines . The winners getting to come on our adventures, stay in nice hotels and take part in various activities such has horse riding.
The main Canyon film was shot by myself on a Sony Venice using Sigma FF Primes as well as an Angenieux EZ zoom. The 1000fps Super Slow motion by Dustin Farrell on a Phantom Flex. I shot some additional 4K 120fps footage on an FS5 on a gimbal recording ProRes raw to a Shogun (horse riding and some tracking shots). The interviews and behind the scenes footage was shot by the projects director Leigh Emmerson of Persistence of Vision Productions (POV) using an A7sII, but there is a fair bit of FS5 (ProRes Raw) footage that I shot in there too.
The main film was produced at 60fps in HDR (I did the grade and encoding) and will be shown at the IFA trade show next month. The other films are all SDR.
Here is the HDR main video. To view this correctly ensure your HDR TV or HDR monitor is set to HDR10 (ST2084 gamma with Rec2020 colour).
Both webinars will feature a Q&A session where you will be able to ask questions online. You will find the full details about both webinars by following the links above, including how to register. The webinars are free but registration is required to obtain the login details for the events.
Just over a week ago I was in Cape Town with a few hours to spare before my flight home and access to a Sony Venice. So what could I do other than go out and shoot. Here is some of the footage with a quick grade applied – in HDR.
The workflow: I shoot X-OCN ST at 25p and 50p on the Venice camera. 25p was requested by Visual Impact South Africa, the owners of this camera as this is the most common frame rate used in productions they are involved with. The material was backed up to a small portable USB3 raid unit so I could bring it home. Then it was graded using DaVinci Resolve and it’s ACES colour managed workflow with the output set to Rec2100 ST2084. I used a Shogun Inferno and both an LCD HDR Sony Bravia TV and an OLED HDR Philips TV to get a feel for how the images would look on both LCD and OLED technologies.
The file was exported as a UHD ProRes file so that the file direct from Resolve could be uploaded to YouTube. Because I used a colour managed workflow Resolve adds the correct HDR flags to the clip when you render the timeline out. As a result YouTube knows the file is HDR and if you view with a computer or SDR TV YouTube applies it’s default HDR10 to Rec709 LUT and you see the video in SDR. Watch with a direct connection to YouTube with an HDR TV (for example using a browser or YouTube player built in to the TV) and you will get the HDR version. This is probably the simplest way to reliably get HDR clips to play properly on YouTube (which currently does not accept HEVC files).
So here’s the clip.
IMPORTANT: The clip is HDR10, designed to be watched directly on an HDR TV using the TV’s built in web browser or YouTube player application.
Those watching on a normal computer, SDR TV or any other non HDR device will see the HDR clip with YouTube’s SDR/Rec709 LUT applied, so it isn’t exactly optimum for SDR. The YouTube HDR to SDR LUT causes some slightly odd colours in some of the clips. If you can, watch the clip directly on YouTube with an HDR TV.
Hello all. So after numerous problems for some people trying to download the official Sony s709 LUT for Venice, I decided to create my own Venice Look LUT’s. These LUT’s have been created using image matching techniques plus some small tweaks and adjustments to make the LUT’s work well with the 14 stop cameras.
Venice is a 15 stop camera with a new sensor and as a result the official s709 LUT’s are not quite right for the current 14 stop cameras like the FS5, PMW-F55, FS7 and even the A7 series. So the LUT that I have created is slightly different to allow for this.
The end result is a LUT that gets you really close to the way Venice looks. It won’t magically turn your FS5 into a Venice, there is something very, very nice about the way Venice handles the extremes of it’s dynamic range, plus Venice has Sony’s best colour filters (similar to the F55 and F65). So Venice will always be that one very nice step up. But these LUT’s should get you close to the default Venice 709 look. This LUT should NOT be used with Venice as it this LUT is restricted to 14 stops.
Of course do remember that the default look and indeed the official s709 LUT was designed as a first pass look. An instant viewing output for a DIT or for on set viewing. It is not really meant to be the final finished look. It would be normal to grade the Venice material, perhaps from scratch rather than using the s709 LUT for the final output. But, s709 is what comes out of the cameras SDI connectors if you use the default LUT/Look. This is what this LUT set mimics, with some tweaks for the lower cost cameras.
This is one of the largest and most comprehensive LUT sets I have ever created. There are versions designed specifically for grading in Resolve or other grading suites. The bulk of the LUT’s are designed to be used with S-Log3 and SGamut3.cine. There are monitoring versions with offsets for use in monitors such as the Atomos range. I have created a set with offsets for both the Zacuto and Small HD viewfinders and monitors and finally I have also created sets of LUT’s for use with S-Log2 so users of the original A7s or those that wish to shoot with S-Log2 on an 8 bit camera are not left out.
The LUT’s work best with the PMW-F55 as this has the closest native color to the Venice camera, but I think they work really well on the rest of the Sony range.
If you find the LUT’S useful, please consider buying me a beer or a coffee using the “Buy Now” button below. There are different drink options depending on what you feel is fair, it takes time to prepare these and there are costs associated with hosting the files. I’m not paid to run this website and every little bit helps and is greatly appreciated.
If you don’t wish to buy me a coffee, that’s cool. But please don’t host the files elsewhere. Feel free to link back here and share the link, but please don’t distribute these anywhere else.
Here’s the link to the zip file containing the my Venice Look LUT set:
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Sony’s new Rec-709 style LUT for the Venice camera is now available. This Lut was designed to work with the Venice camera to provide a new film like look with beautiful highlight roll-off. In it’s current form it only works with S-Log3/S-Gamut3.cine material, although you could use the excellent LUTCalc app to create different versions.
Although designed for Venice the LUT works really well with footage from the FS5, FS7, F5 and F55 etc.
I recently completed a week long shoot with a Sony Venice in the USA, so I thought I would tell you about my experience. The camera I used had a beta of the dual ISO firmware so it could shoot at both the native ISO of 500 and the second native ISO of 2500. This was particularly useful for the shoot as a lot of the filming was done in some very dark places.
I can’t show any of the footage to you yet. But I will be able to link to the finished films once they are released a little later in the year by my client. I have to say straight away that I think the footage looks pretty amazing.
The first location was Las Vegas. I shot a number of views of the Las Vegas strip from the balcony of my hotel room in the Cosmopolitan hotel. These were pretty straight forward thanks to the cameras dual ISO capabilities. One of the shots was a day to night sequence, shooting locked off shots during the day and then at night to be blended together to go from day to night. The day time shots were done at the base 500 ISO and then the night shots done at 2500 ISO.
Sigma FF Fast Primes.
For these shots I used one of the really nice 24mm Sigma full frame high speed PL primes and the camera was setup in the 6K x 4K full frame mode.
For most of the shoot we did however shoot using the s35mm 17:9 DCI mode shooting at 60fps, and we made quite a few changes to the frame rates and frame sizes in the course of the shoot. The Sigma FF Primes are really beautiful lenses. Very well built, solid lenses that produce very sharp images even when wide open. The ability to shoot at T1.5 or T2.0 turned out to be a huge benefit on this shoot as many shots were done either at night or in some very dark locations.
One thing to note here is that I was working on my own. Venice is set up as a camera for high end shoots where it is expected that there will be a camera assistant working with the cinematographer or camera operator. During the shoot I made many changes to the cameras frame rate and aspect ratio. These changes are most easily done using the LCD screen and hot keys on the side of the camera away from the camera operator. So there were many times when I had to walk around to the other side of the camera or spin the camera around on the tripod to make these changes. It’s not really a big deal, but it is something to be aware of if you are going to use Venice as a “one man band”.
On the operators side of the camera there is a small LCD panel where you can change the shutter speed, ND filter, EI and white balance. But for anything else you need to either use the LCD panel on the other side of the camera or go into the main menu. Talking of the menu system – it’s very well laid out and quite logical.
Venice is a much simpler camera to use than the F55. In part because at the moment the feature set is still a little limited – there are no high speed modes, time-lapse, picture cache or other stunt modes. But the main reason it’s simpler is the design and layout of the main LCD and hot keys has been simplified and is better organised.
The “Home” screen has they key functions that you are likely to change while shooting – shutter speed, EI, ND and white balance. There is also a control for the frame rate, although the options for this are currently quite limited with it currently normally being locked to a single fixed speed set in the project settings. The Home screen also tells you how much space is left on your media, the aspect ratio and frame size, clip name, recording format(s), the battery status. Plus there are audio level displays for channels 1 and 2.
If you need to make any other changes to the cameras setting then you press the large menu button to bring up the main menu. This is divided into 5 sections each with it’s own hot key – Project – TC/Media – Monitoring – Audio – Info. The 6th hot key takes you into further settings for some of the menu pages.
Something else a first time Venice shooter should be aware of is that the cameras audio input is via a single 5 pin XLR connector. This can be set up as either a 2 channel analog line/mic input (with switchable phantom power) or an AES/EBU digital input. There are no 3 pin XLR’s on Venice so make sure you have the right cables or adapters.
While Venice isn’t a big camera, it is very dense. That is to say – a lot of electronics has been packed into quite a small body. It is…. shall we say… reassuringly heavy! I guess I have been a bit spoilt by the light weight of the F55. Venice is quite a lot heavier even though it isn’t really all that much bigger. I was shooting using the R7 recorder, recording to 16 bit X-OCN files as my primary material. With the R7 and a couple of Pag Paglink batteries on the back the camera was nicely balanced with the Sigma primes.
I was pleasantly surprised by the power consumption. A single 95Wh Paglink battery would run the camera for over an hour and a PL150 for around 2 hours which is a pretty respectable run time for a digital cinema camera. Certainly a lot more that I would get from an F65 or Arri.
The new DVF-EL200 viewfinder is a big step up from the DVF-EL100 often used on the F55 and F5 cameras. The image is brighter, higher resolution and the dipoter adjustment much better. Venice puts the information displays outside the picture area so the image isn’t obstructed by any text information. The large rotary encoder on the front of the viewfinder controls peaking, brightness and contrast.
Rating the camera – I had already done a few camera tests with Venice so I knew that the base ISO’s of 500 and 2500 matched well with my light meter. I also knew that there is very little noise at 500 ISO and only a little bit more at 2500. For most daylight shots I shot at 500 ISO/500 EI. I don’t feel that there is the same need to rate the camera 1 to 2 stops lower as I do with the F55, FS7 or FS5. It just isn’t necessary for normal light levels. For some scenes that had low average brightness levels I did choose to shoot at 500 ISO/320 EI as it seemed a waste to shoot at 500 EI when the scene highlights were no where near clipping. The slightly lower Ei helped to put just a little more information into the already highly detailed shadow areas of my images. For the darker locations and night scenes I switched the camera to the higher base ISO of 2500 to gain a pretty decent sensitivity boost. When using the 2500 ISO mode I found I ended up shooting at 1600 EI to keep the noise levels very similar to the noise levels at 500 ISO/500 EI.
The noise that you do get when shooting at the 2500 ISO base is really pleasing. I’m not normally a fan of any noise, my personal preference is normally for clean images as these tend to give the greatest post production flexibility. But there is something that just looks nice about the little bit of extra noise that there is at 2500. It’s very, very fine grain that is different in every frame. Dare I say it looks very film like? I need to experiment with this further, but I suspect that many people may choose to use 2500 ISO even when they have plenty of light as the noise adds some character and a pleasing texture to the shots. I’m not going to get into too much of a debate here about the merits of shooting with a bit of grain verses adding it in post. Personally I would probably normally opt to shoot clean and add any noise later, but Venice certainly brings some interesting options to the table and I would not rule out deliberately choosing 2500 ISO, even when there is plenty of light, to take advantage of the really nice looking noise.
We shot a lot of the film in the bottom of a deep Slot Canyon. For those that don’t know what this is – it is a very narrow, very deep, steep sided twisting gully carved out over millions of years by flood water. The Slot Canyon we shot in was often only 2 or 3ft wide (1m) and around 60ft (20m) deep. In most parts sunlight never reaches directly to the bottom, so it’s often very dark. But in a few spots very narrow shafts of light just about make it to the bottom when the sun is directly overhead. This creates some areas of incredibly high contrast as beams of full desert sun penetrate into near total darkness.
Venice was the perfect camera for this situation. The high base ISO mode and the 2500 ISO exposure rating allowed me to capture the dark textures of the sandstone walls of the canyon, while the 15 stop latitude meant that I could also capture the almost laser like light beams as they created intense pools of light. In addition towards the upper parts of the Canyon you get incredibly vivid reds and oranges as the sunlight reflects of the red rocks. To the naked eye it looks like the canyon walls are on fire and Venice did an amazing job of capturing these intense colours.
My hotel room in the city of Page, Arizona was decorated with photographs taken in Slot Canyons. In many of the photos the shafts of light were completely over exposed with no detail or texture. I’m pleased to say that the footage from Venice almost always retained some detail and texture, even in the the most extreme cases. This for me has been one of the most impressive things about the way Venice behaves. There is something very nice about the way that Venice reaches the extreme ends of it’s exposure range, something the F55 doesn’t quite do and I really like it. Venice seems to hang n to those exposure extremes just that bit better. In addition Venice also retains an amazing amount of color information in the deepest darkest shadow areas.
Another location we shot at was the Grand Canyon’s Horseshoe bend. This a well know spot and frankly, if you have good light, it’s tough to make a bad picture. This is one of those locations where everything is on a grand scale. So it deserved a big image. Time to use the 6K x 4K full frame mode and those beautiful Sigma FF primes again. In the grading suite whenever I show people the shots from Venice at Horseshoe Bend there is almost always a “wow” moment. The texture and detail in the shots is amazing and starting with a 6K image for a 4K production gives you quite a bit of room to crop in to the image if you wish.
What about skin tones? Well we did shoot some Navajo dancers doing traditional native American dances and hoop dances. Even in the very harsh Arizona light the skin tones looked great.
With so many different locations to shoot at in one week, some of them very remote, being highly mobile was really important to us. While Venice is heavier than the F55 that I normally shoot with, it is still an easy camera to transport. We had to lug the kit by hand across the desert to get to the Slot Canyon. I used a Miller CX18 fluid head with a 100mm bowl on a set of Miller carbon fibre legs. This is a pretty light tripod setup, similar to that used by ENG news crews. I didn’t need to go to a 150mm bowl or heavier tripod than this for this shoot because Venice is a very manageable weight and it worked very well.
One scene was a nigh time campfire scene. For the Venice camera shooting at 2500 ISO and paired with the Sigma T1.5 primes this wasn’t really too much of a challenge. The fire was a large wood fire and it was producing enough light to illuminate the faces of the subjects in the scene. Although perhaps this could have been shot without any additional lighting it was decided to add a little bit of extra light to fill in a few shadows and add a small amount of detail into the background of the wide shots.
For this I used a Light and Motion Stella Pro 5000 Led lamp. For a one man band these waterproof LED lights are really excellent. They produce lots of good quality light and can be fitted with all kinds of modifiers. For this application I used a Fresnel lens to narrow down the light cone. In addition they can be remotely controlled using a simple hand held Elinchrom remote control. This makes getting the light level just right really easy as you can look in the cameras viewfinder while dimming the lamps with the remote. It’s possible to control several lamps with one remote.
I shot using Sony’s X-OCN codec recording on to AXS cards in the R7 recorder. These 16 bit linear files are surprisingly easy to work with. The compact file size was a huge help. I didn’t get through more than 2 x 512GB cards in a day, even though we were shooting 4K 60P or 6K 24p. This really helped with data management in the evenings. There’s big difference between backing up 1TB of X-OCN compared to what would have been around 5TB if it had been uncompressed raw. Yet there are no signs of any artefacts in the material. The X-OCN files are also very easy to handle in post production, I can even preview them in real time on my laptop at half resolution. In post production the 16 bit linear files handle beautifully, revealing amazing amounts of picture information.
At the end of this shoot I am left with a big problem though. Now I’ve shot a real production with Venice – I don’t want to shoot with anything else. I have been telling myself that I will stick with my F5/R5 for a bit longer, maybe upgrade the F5 to an F55 and then hire in a Venice as needed. But now I want to shoot with Venice whenever possible. Every time I pick up a Venice and go and shoot with it I come back with images that surprise me. They just seem to look great with very little effort. So now I think I might just have to figure out a way to buy one.
I’m writing this from a hotel room in Page, Arizona. Half way through a shoot covering everything from the city lights of Las Vegas to the Slot Canyons of Arizona. I’m using a Sony Venice to shoot most of the material, but I also have an FS5 recording to ProRes Raw on a gimbal for some shots.
It’s been an interesting shoot with many challenges. Some of the locations have been a long way from our vehicles, so we have had to lug the kit cross country by hand.
Almost everything is being shot at 60fps with some 120fps from the FS5. We also had a Phantom Flex for a couple of days for some 1000fps footage. For some of the really big panoramic scenes we have used the 4:3 6K mode on the Venice (at 24fps).
Our main lenses are a set of full frame T1.5 Sigma primes. These are absolutely amazing lenses and when paired with the Venice camera, it’s hard to produce a poor image. Our Venice has a beta of the dual ISO firmware which has been an absolute godsend as the bottoms of the deep slot canyons are very dark, even in the middle of the day. So being able to shoot at 2500 ISO has been a huge help.
I will write up this project in more detail once the shoot is over. I can’t share any footage yet, but once my client releases the film I will be able to let everyone see it. However I have been allowed to post some frame grabs which you will find below.
I have been working with Sony’s colour science guru Pablo at the Digital Motion Picture Center at Pinewood, looking at the outer limits of what Sony’s Venice camera can do. A large part of the reason for this is that Pablo is developing some really nice LUT’s for use on dailies or even as a grade starting point (Pablo tells me the LUT’s are finished but he is waiting for approvals and feedback from Japan).
As part of this process we have shot test footage with the Venice camera for ourselves and also looked long and hard at test shots done by other cinematographers. Last week we were able to preview a beta version of the cameras dual ISO modes. This beta firmware allowed us to shoot tests at both 500 ISO and 2500 ISO and the results of both are equally impressive.
I can’t share any of the test footage shot at 2500 ISO at this stage. The firmware is still in it’s early stages and the final version may well perform a little differently (probably better). But I can share some of the footage shot at 500 ISO.
Please remember what we were exploring was the extreme ends of the exposure range. So our little test set was set up with some challenges for the camera rather than trying to make a pretty picture.
We have deep, deep shadows on the right behind the couch and we also have strong highlights coming off the guitar, the film can on the shelves and from the practical lamp in the background. The reds of the cushion on the couch look very different with most Rec-709 cameras as the colors are outside the Rec-709 gamut.
Another aspect of the test was to check the exposure rating. For this I used my Sekonic lightmeter to measure both the incident light and the light reflected by the Kodak grey card. My light meter gave me T4 at 1/48th for 500 ISO and this turned out to be pretty much spot on with what the scopes told us. So straight away we were able to establish that the 500 ISO exposure rating appears to be correct. We also found that when we stopped down by 2.3 stops we got the correct exposure at 2500 ISO, so that too appears to be correctly rated.
Once the base exposure was established we shot at 2 stops over and 2 stops under, so from T2 down to T8 using a Sony 35mm PL prime. We used the XOCN-ST codec as we felt this will be the most widely used codec. When looking at the files do remember that the 16 bit XOCN-ST files are smaller than 10 bit ProResHQ. So these are files that are very easy to manage. There is the option to go up in quality to Sony’s linear raw codec or down to X-OCN LT. XOCN-ST sits in the middle and offers a nice balance between file size and image quality, it being very hard to find any visual difference between this and the larger raw files.
The files I’m providing here are single X-OCN frames. They have not been adjusted in any way, they are just as shot (including being perhaps a touch out of focus). You can view them using the latest version of Sony’s raw viewer software or the latest version of DaVinci Resolve. For the best quality preview, at this time I recommend using Sony’s Raw Viewer to view the clips.
Sony’s X-OCN (X–Original Camera Negative) is a new type of codec from Sony. Currently it is only available via the R7 recorder which can be attached to a Sony PMW-F5, F55 or the new Venice cinema camera.
It is a truly remarkable codec that brings the kind of flexibility normally only available with 16 bit linear raw files but with a files size that is smaller than many conventional high end video formats.
Currently there are two variations of X-OCN.
X-OCN ST is the standard version and then X-OCN LT is the “light” version. Both are 16 bit and both contain 16 bit data based directly on what comes off the cameras sensor. The LT version is barely distinguishable for a 16 bit linear raw recording and the ST version “visually lossless”. Having that sensor data in post production allows you to manipulate the footage over a far greater range than is possible with tradition video files. Traditional video files will already have some form of gamma curve as well as a colour space and white balance baked in. This limits the scope of how far the material can be adjusted and reduces the amount of picture information you have (relative to what comes directly off the sensor) .
Furthermore most traditional video files are 10 bit with a maximum of 1024 code values or levels within the recording. There are some 12 bit codecs but these are still quite rare in video cameras. X-OCN is 16 bit which means that you can have up to 65,536 code values or levels within the recording. That’s a colossal increase in tonal values over traditional recording codecs.
But the thing is that X-OCN LT files are a similar size to Sony’s own XAVC-I (class 480) codec, which is already highly efficient. X-OCN LT is around half the size of the popular 10 bit Apple ProRes HQ codec but offers comparable quality. Even the high quality ST version of X-OCN is smaller than ProRes HQ. So you can have image quality and data levels comparable to Sony’s 16 bit linear raw but in a lightweight, easy to handle 16 bit file that’s smaller than the most commonly used 10 bit version of ProRes.
But how is this even possible? Surely such an amazing 16 bit file should be bigger!
The key to all of this is that the data contained within an X-OCN file is based on the sensors output rather than traditional video. The cameras that produce the X-OCN material all use bayer sensors. In a traditional video workflow the data from a bayer sensor is first converted from the luminance values that the sensor produces into a YCbCr or RGB signal.
So if the camera has a 4096×2160 bayer sensor in a traditional workflow this pixel level data gets converted to 4096×2160 of Green plus 4096×2160 of Red, plus 4096×2160 of Green (or the same of Y, Cb and Cr). In total you end up with 26 million data points which then need to be compressed using a video codec.
However if we bypass the conversion to a video signal and just store the data that comes directly from the sensor we only need to record a single set of 4096×2160 data points – 8.8 million. This means we only need to store 1/3rd as much data as in a traditional video workflow and it is this huge data saving that is the main reason why it is possible for X-OCN to be smaller than traditional video files while retaining amazing image quality. It’s simply a far more efficient way of recording the data from a bayer camera.
Of course this does mean that the edit or playback computer has to do some extra work because as well as decoding the X-OCN file it has to be converted to a video file, but Sony developed X-OCN to be easy to work with – which it is. Even a modest modern workstation will have no problem working with X-OCN. But the fact that you have that sensor data in the grading suite means you have an amazing degree of flexibility. You can even adjust the way the file is decoded to tailor whether you want more highlight or shadow information in the video file that will created after the X-OCN is decoded.
Why isn’t 16 bit much bigger than 10 bit? Normally a 16 bit file will be bigger than a 10 bit file. But with a video image there are often areas of information that are very similar. Video compression algorithms take advantage of this and instead of recording a value for every pixel will record a single value that represents all of the similar pixels. When you go from 10 bit to 16 bit, while yes, you do have more bits of data to record a greater percentage of the code values will be the same or similar and as a result the codec becomes more efficient. So the files size does increase a bit, but not as much as you might expect.
So, X-OCN, out of the gate, only needs to store 1/3rd of the data points of a similar traditional RGB or YCbCr codec. Increasing the bit depth from the typical 10 bit bit depth of a regular codec to the 16 bits of X-OCN does then increase the amount of data needed to record it. But the use of a clever algorithm to minimise the data needed for those 16 bits means that the end result is a 16 bit file only a bit bigger than XAVC-I but still smaller than ProRes HQ even at it’s highest quality level.
With the first of the production Venice cameras now starting to find their way to some very lucky owners it’s time to take a look at some features that are not always well understood, or that perhaps no one has told you about yet.
Dual Native ISO’s: What does this mean?
An electronic camera uses a piece of silicon to convert photons of light into electrons of electricity. The efficiency at doing this is determined by the material used. Then the amount of light that can be captured and thus the sensitivity is determined by the size of the pixels. So, unless you physically change the sensor for one with different sized pixels (which will in the future be possible with Venice) you can’t change the true sensitivity of the camera. All you can do is adjust the electronic parameters.
With most video cameras the ISO is changed by increasing the amount of amplification applied to the signal coming off the sensor. Adding more gain or increasing the amplification will result in a brighter picture. But if you add more amplification/gain then the noise from the sensor is also amplified by the same amount. Make the picture twice as bright and normally the noise doubles.
In addition there is normally an optimum amount of gain where the full range of the signal coming from the sensor will be matched perfectly with the full recording range of the chosen gamma curve. This optimum gain level is what we normally call the “Native ISO”. If you add too much gain the brightest signal from the sensor would be amplified too much and exceed the recording range of the gamma curve. Apply too little gain and your recordings will never reach the optimum level and darker parts of the image may be too dark to be seen.
As a result the Native ISO is where you have the best match of sensor output to gain. Not too much, not too little and hopefully low noise. This is typically also referred to as 0dB gain in an electronic camera and normally there is only 1 gain level where this perfect harmony between sensor, gain and recording range is achieved, this becoming the native ISO.
Side Note: On an electronic camera ISO is an exposure rating, not a sensitivity measurement. Enter the cameras ISO rating into a light meter and you will get the correct exposure. But it doesn’t really tell you how sensitive the camera is as ISO has no allowance for increasing noise levels which will limit the darkest thing a camera can see.
Tweaking the sensor.
However, there are some things we can tweak on the sensor that effect how big the signal coming from the sensor is. The sensors pixels are analog devices. A photon of electricity hits the silicone photo receptor (pixel) and it gets converted into an electron of electricity which is then stored within the structure of the pixel as an analog signal until the pixel is read out by a circuit that converts the analog signal to a digital one, at the same time adding a degree of noise reduction. It’s possible to shift the range that the A to D converter operates over and the amount of noise reduction applied to obtain a different readout range from the sensor. By doing this (and/or other similar techniques, Venice may use some other method) it’s possible to produce a single sensor with more than one native ISO.
A camera with dual ISO’s will have two different operating ranges. One tuned for higher light levels and one tuned for lower light levels. Venice will have two exposure ratings: 500 ISO for brighter scenes and 2500 ISO for shooting when you have less light. With a conventional camera, to go from 500 ISO to 2500 ISO you would need to add just over 12dB of gain and this would increase the noise by a factor of more than 4. However with Venice and it’s dual ISO’s, as we are not adding gain but instead altering the way the sensor is operating the noise difference between 500 ISO and 2500 ISO will be very small.
You will have the same dynamic range at both ISO’s. But you can choose whether to shoot at 500 ISO for super clean images at a sensitivity not that dissimilar to traditional film stocks. This low ISO makes it easy to run lenses at wide apertures for the greatest control over the depth of field. Or you can choose to shoot at the equivalent of 2500 ISO without incurring a big noise penalty.
One of Venice’s key features is that it’s designed to work with Anamorphic lenses. Often Anamorphic lenses are typically not as fast as their spherical counterparts. Furthermore some Anamorphic lenses (particularly vintage lenses) need to be stopped down a little to prevent excessive softness at the edges. So having a second higher ISO rating will make it easier to work with slower lenses or in lower light ranges.
COMBINING DUAL ISO WITH 1 STOP ND’s.
Next it’s worth thinking about how you might want to use the cameras ND filters. Film cameras don’t have built in ND filters. An Arri Alexa does not have built in ND’s. So most cinematographers will work on the basis of a cinema camera having a single recording sensitivity.
The ND filters in Venice provide uniform, full spectrum light attenuation. Sony are incredibly fussy over the materials they use for their ND filters and you can be sure that the filters in Venice do not degrade the image. I was present for the pre-shoot tests for the European demo film and a lot of time was spent testing them. We couldn’t find any issues. If you introduce 1 stop of ND, the camera becomes 1 stop less sensitive to light. In practice this is no different to having a camera with a sensor 1 stop less sensitive. So the built in ND filters, can if you choose, be used to modify the base sensitivity of the camera in 1 stop increments, up to 8 stops lower.
So with the dual ISO’s and the ND’s combined you have a camera that you can setup to operate at the equivalent of 2 ISO all the way up to 2500 ISO in 1 stop steps (by using 2500 ISO and 500 together you can have approximately half stops steps between 10 ISO and 650 ISO). That’s an impressive range and at no stage are you adding extra gain. There is no other camera on the market that can do this.
On top of all this we do of course still have the ability to alter the Exposure Index of the cameras LUT’s to offset the exposure to move the exposure mid point up and down within the dynamic range. Talking of LUT’s I hope to have some very interesting news about the LUT’s for Venice. I’ve seen a glimpse of the future and I have to say it looks really good!
The raw and X-OCN material from a Venice camera (and from a PMW-F55 or F5 with the R7 recorder) contains a lot of dynamic metadata. This metadata tells the decoder in your grading software exactly how to handle the linear sensor data stored in the files. It tells your software where in the recorded data range the shadows start and finish, where the mid range sits and where the highlights start and finish. It also informs the software how to decode the colors you have recorded.
I recently spent some time with Sony Europe’s color grading guru Pablo Garcia at the Digital Motion Picture Center in Pinewood. He showed me how you can manipulate this metadata to alter the way the X-OCN is decoded to change the look of the images you bring into the grading suite. Using a beta version of Black Magic’s DaVinci Resolve software, Pablo was able to go into the clips metadata in real time and simply by scrubbing over the metadata settings adjust the shadows, mids and highlights BEFORE the X-OCN was decoded. It was really incredible to see the amount of data that Venice captures in the highlights and shadows. By adjusting the metadata you are tailoring the the way the file is being decoded to suit your own needs and getting the very best video information for the grade. Need more highlight data – you got it. Want to boost the shadows, you can, at the file data level before it’s converted to a traditional video signal.
It’s impressive stuff as you are manipulating the way the 16 bit linear sensor data is decoded rather than a traditional workflow which is to decode the footage to a generic intermediate file and then adjust that. This is just one of the many features that X-OCN from the Sony Venice offers. It’s even more incredible when you consider that a 16 bit linear X-OCN LT file is similar in size to 10 bit XAVC-I(class 480) and around half the size of Apples 10 bit ProRes HQ. X-OCN LT looks fantastic and in my opinion grades better than XAVC S-Log. Of course for a high end production you will probably use the regular X-OCN ST codec rather than the LT version, but ST is still smaller than ProRes HQ. What’s more X-OCN is not particularly processor intensive, it’s certainly much easier to work with X-OCN than cDNG. It’s a truly remarkable technology from Sony.
Next week I will be shooting some more test with a Venice camera as we explore the limits of what it can do. I’ll try and get some files for you to play with.
Camera setup, reviews, tutorials and information for pro camcorder users from Alister Chapman.