Category Archives: A7

Do the images from my Sony camera have to look the way they do?

— And why do Sony cameras look the way they do?

It all about the color science.

“Color Science” is one of those currently in fashion phrases that gets thrown around all over the place today. First of all – what the heck is color science anyway? Simply put it’s how the camera sees the colors in a scene, mixes them together, records them – and then how your editing or grading software interprets what is in the recording and finally how the TV or other display device turns the digital values it receives back into a color image. It’s a combination of optical filters such as the low pass filter, color filters, sensor properties, how the sensor is read out and how the signals are electronically processed both in the camera, by your edit/grading system and by the display device. It is no one single thing, and it’s important to understand that your edit process also contributes to the overall color science.

Color Science is something we have been doing since the very first color cameras, it’s not anything new. However us end users now have a much greater ability to modify that color science thanks to better post production tools and in camera adjustments such as picture profiles or scene files.

Recently, Sony cameras have sometimes been seen by some as having less advanced or poor color science compared to cameras from some other manufacturers. Is this really the case? For Sony part of the color science issue is that historically Sony have deliberately designed their newest cameras to match previous generations of cameras so that a large organisation with multiple cameras can use new cameras without having them look radically different to their old ones. It has always been like this and all the manufacturers do this, Panasonic cameras have a certain look as do Canon etc. New and old Panasonics tend to look the same as do old and new Canon’s, but the Canon’s look different to the Panasonics which look different to the Sony’s.

Sony have a very long heritage in broadcast TV and that’s how their cameras look out of the box, like Rec-709 TV cameras with colors that are similar to the tube cameras they were producing 20 years ago. Sony’s broadcast color science is really very accurate – point one at a test chart such as a Chroma DuMonde and you’ll see highly repeatable, consistent and accurate color reproduction with all the vectors on a vector scope falling exactly where they should, including the skin tone line.

On the one hand this is great if you are that big multi-camera business wanting to add new cameras to old ones without problems, where you want your latest ENG or self-shooters cameras to have the same colors as your perhaps older studio cameras so that any video inserts into a studio show cut in and out smoothly with a consistent look.

But on the other hand it’s not so good if you are a one man band shooter that wants something that looks different. Plus accurate is not always “pretty” and you can’t get away from the fact that the pictures look like Rec-709 television pictures in a new world of digital cinematography where TV is perhaps seen as bad and the holy grail is now a very different kind of look that is more stylised and much less true to life.

So Sony have been a bit stuck. The standard look you get when you apply any of the standard off-the shelf S-Log3 or S-Log2 LUT’s will by design be based on the Sony color science of old, so you get the Sony look. Most edit and grading applications are using transforms for S-Log2/3 based on Sony’s old standard Rec-709 look to maintain this consistency of look. This isn’t a mistake. It’s by design, it’s a Sony camera so it’s supposed to look like other Sony cameras, not different.

But for many this isn’t what they want. They want a camera that looks different, perhaps the “film look” – whatever that is?

Recently we have seen two new cameras from Sony that out of the box look very different from all the others. Sony’s high end Venice camera and the lower cost FS5 MKII. The FS5 MKII in particular proves that it’s possible to have a very different look with Sony’s existing colour filters and sensors. The FS5 MK II has exactly the same sensor with exactly the same electronics as the MK I. The only difference is in the way the RGB data from the sensor is being processed and mixed together (determined by the different firmware in the Mk1 and mk2) to create the final output.

The sensors Sony manufacture and use are very good at capturing color. Sony sensors are found in cameras from many different manufacturers. The recording systems in the Sony cameras do a fine job of recording those colors as data within the files the camera records as data with different code values representing what the sensor saw. Take that data into almost any half decent grading software and you can change the way it looks by modifying the data values. In post production I can turn almost any color I want into any other color. It’s really up to us as to how we translate the code values in the files into the colors we see on the screen, especially when recording using Log or raw. A 3D LUT can change tones and hues very easily by shifting and modifying the code values. So really there is no reason why you have to have the Sony 709 look.

My Venice emulation LUT’s will make S-Log3 from an FS5 or FS7 look quite different to the old Sony Broadcast look. I also have LUT’s for Sony cameras that emulate different Fuji and Kodak film stocks, apply one of these and it really looks nothing like a Sony broadcast camera. Another alternative is to use a color managed workflow such as ACES which will attempt to make just about every camera on the market look the same applying the ACES film style look and highlight roll-off.

We have seen it time and time again where Sony footage has been graded well and it then becomes all but impossible to identify what camera shot it. If you have Netflix take a look at “The Crown” shot on Sony’s F55 (which has the same default Sony look as the FS5 MK1, FS7 etc). Most people find it hard to believe the Crown was shot with a Sony because it has not even the slightest hint of the old Sony broadcast look.

If you use default settings, standard LUT’s etc it will look like a Sony, it’s supposed to! But you have the freedom to choose from a vast range of alternative looks or better still create your own looks and styles with your own grading choices.

But for many this can prove tricky as often they will start with a standard Sony LUT or standard Sony transform. So the image they start with has the old Sony look. When you start to grade or adjust this it can sometimes look wrong because you have perhaps become used to the original Sony image and then anything else just doesn’t seem right, because it’s not what you are used to. In addition if you add a LUT and then grade, elements of the LUT’s look may be hard to remove, things like the highlight roll off will be hard baked into the material, so you need to do need to think carefully about how you use LUT’s. So try to break away from standard LUT’s. Try ACES or try some other starting point for your grade.

Going forward I think it is likely that we will see the new Venice look become standard across all of the Cinema style cameras from Sony, but it will take time for this to trickle down into all the grading and editing software that currently uses transforms for s-Log2/3 that are based on the old Sony Rec-709 broadcast look. But if you grade your footage for yourself you can create just about any look you want.

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New Venice Look LUT’s Version 3. Includes minus green LUTs. For FS5, FS7, F55, A7S, A7R.

I released my first version of the Venice Look LUT’s a few weeks ago and they have been a big hit. Overall most people seem to like them and get some great results. I’ve seen quite a few good looking videos produced using them.

I have received some feedback though that some people feel that the LUT’s may be crushing the blacks a bit too much for them, personally I think the deep shadows gives quite a film like look. However in response to that feedback I created an additional LUT set that keeps the blacks slightly higher. This can make grading a little easier, especially in FCP-X. You will find these new version 3 LUT’s here in the packages below – but please read on…..

While I was at it I also created another set of LUTs with a minus green offset. The idea behind these was that they can be used for material shot under lights with a green tint such as many LED or fluorescent light fixtures. Playing with these “-G1” LUT’s I have decided that I really like the slightly warmer and even less “Sony” look that these versions of the LUT’s give when shooting under “normal” lighting. So do please give them a try for a warmer look for skin tones both with LED/Fluorescent lighting and also with full spectrum lighting such as tungsten and sunlight.

Taking that a step further I have also included an even stronger minus green offset in a further -G2 set of LUT’s. So between the 3 sets of LUT’s offered in this download you should be able to find a set for most types of lighting with a variety of skin tone renditions.

Included in the LUT sets are LUTs for grading (with exposure offsets), LUT’s for Small HD monitors and the Zacuto Gratical. The grading LUT’s can also be used in other monitors and devices such as the Atomos recorder/monitors.

As always (to date at least) I offer these as a free download available by clicking on the links below. However a lot of work goes into creating and hosting these. I feel that this LUT set is worth $25.00 and would really appreciate that being paid if you find the LUT’s useful. But I will let you pay what you feel is fair, all contributions are greatly appreciated and it really does help keep this website up and running. If you can’t afford to pay, then just download the LUT’s and enjoy using them. If in the future you should choose to use them on a paying project, please remember where you got them and come back and make a contribution. More contributions means more LUT offerings in the future. I’m currently working on a couple of different film stock emulations based combined with the Venice look highlight rendition.

Please feel free to share a link to this page if you wish to share these LUT’s with anyone else or anywhere else.

To make a contribution please use the drop down menu here, there are several contribution levels to choose from.


Your choice:



pixel New Venice Look LUT's Version 3. Includes minus green LUTs. For FS5, FS7, F55, A7S, A7R.

There are two different LUT sets. One set is for S-Log3 and S-Gamut3.cine. The other set is for S-Log2 and SGamut. Please only download what you need to save my bandwidth!

Typically if you are shooting with 8 bit, for example with an FS5 in UHD or an A7S, A7R etc, then I recommend you use S-Log2 with SGamut. For most other cameras that have 10 bit recording then I recommend S-Log3 and SGamut3.cine.

Here are the links to my Venice Look Version 3 LUT’s. Including the minus green offset LUTs. Make sure you choose the right version and once you have downloaded them please read the README file included within the package.

Alister V-Look V3 LUT’s S-Log2/SGamut

Alister V-Look V3 LUT’s S-Log3/SGamut3.cine

I got a request for a set of Rec-709 Venice Look LUT’s – So here they are. I’m not expecting miracles from these, you will be starting with a much reduced dynamic range by shooting with Rec-709, but try them if you wish. I make no promises as to how well they will or will not work!

Alister Venice Look for Rec709

 

 

Mac Driver For Sony Alpha and PXW-FS5 firmware updates. USB Firmware driver for High Sierra.

If like me you use a Mac computer and are using the High Sierra OS then if you want to upgrade your camera you will need this supplemental driver from Sony:

https://support.d-imaging.sony.co.jp/mac/driver/1013/en/index.html

This is for any Sony camera that is upgraded via a direct USB connection between the computer and the camera, so that includes cameras like the A7s, A7r, A6300 and the rest of the Sony Alpha series. It is also for many of the PXW video cameras including the PXW-FS5. You don’t need it for cameras like the PMW-F55 or PXW-FS7 where the update is done by placing the upgrade file on an SD card.

Without this driver the upgrade software will install and all appears to be working OK. Except you can’t get a good USB connection between the camera and the mac computer and the upgrade will fail.

Venice Look LUT’s For 14 stop cameras A7, FS5, FS7, F5, F55 etc.

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:

Click Here to download Alister’s Venice Look LUTs V2

If you are new to XDCAM-USER.COM please take a look around at the various tutorials, guides, tips and tricks that are hosted here. Click on the green search button at the top right to open a search window or follow the links in the drop down menus at the top of the page. Thanks for visiting!

Why is the white balance limited to 3 presets when using S-Log2, S-Log3 or raw?

This seems to be a source of frustration for many people shooting  raw or using S-Log2 or S-Log3 on a Sony camera. When shooting log and raw you should also be using a matching S-Gamut colour gamut if you want to get the best from the camera and this ties you into one of 3 preset white balances.

With a PXW-FS7, PMW-F5 or F55 it is possible to use custom mode to select a different colour space to mix with S-Log2 or S-Log3 and then have a variable white balance. With the Alpha cameras, PXW cameras such as the FS5 you can choose any Gamut you want in the picture profiles, but I don’t recommend this. For a start, if you don’t use one of the S-Gamuts you will be limited to Rec-709 Gamut, so you won’t be recording  the cameras full colour range. Also in custom mode there are some other things like noise reduction that you really don’t want when shooting S-log2/3 (it can cause banding).

So why is the S-Gamut white balance fixed to the 3 presets for daylight, fluorescent and tungsten? The main reason is to ensure you get the cameras full dynamic range in each colour. White balance is a gain function, it adjusts the gain of the red, green and blue channels so that white objects appear white under differing light sources. So if the light source lacks blue light – making the pictures look excessively warm – you add extra gain to the blue channel to compensate.

But the problem with this is that gain affects dynamic range. When shooting log (or raw) the camera needs to operate the sensor at the optimum gain level to squeeze the highest possible dynamic range from the it. Changing the gain in just one colour channel to shift the white balance could result in a reduction of dynamic range in the channel. This could manifest itself as colours in one channel that clip sooner than the others. This can be really hard to deal with in post production and can show up as things like bright clouds with a colour cast that isn’t in the rest of the picture.

Another potential issue is that because of the way silicon sensors work the blue channel is almost always noisier than the red and green. So you want to keep the gain in the blue channel as low as possible to prevent the pictures getting too noisy. This is particularly important when shooting log as you won’t see your end result until after the images have been graded. So manually shifting the gain of the blue channel in camera to correct the white balance could lead to footage that ends up noisier than you would expect.

So – Sony chose to fix the white balance to 3 carefully tuned presets designed to avoid this situation and maximise the dynamic range. After all, when shooting log or raw it is expected that the footage will be graded anyway, so the white balance will normally be adjusted as part of the post production process.

There are some people that advocate adjusting the FS5’s white balance via the picture profile settings, personally I don’t recommend this or feel that it’s necessary. But yes, you can do this, but just keep a very close eye on your highlights and if you can use monitor with RGB parade to make sure you have equal recording levels for your whites without one colour channel clipping ahead of the others. Also apply a LUT in the monitor that is close to your desired output so that you can keep an eye on the noise levels.

In summary – the white balance is preset to ensure you don’t encounter problems later on. You should be able to fully adjust and fine tune your white balance in post production to a far greater degree than is possible in camera anyway, so don’t worry if the WB is a touch off when shooting.

The only exception to this is the new Sony Venice. Venice has enough dynamic range and enough internal processing power to allow you to make a wide range of white balance adjustments in camera. Hopefully we will see some of this flexibility trickle down to the next generations of lower cost Sony digital cinema cameras.

Sony RX0 – Is this the ultimate mini-cam (for now at least).

RX0 Sony RX0 - Is this the ultimate mini-cam (for now at least).Sony have just released a rather exciting looking new type of mini-cam, the RX0.

I have not played with one yet, so I can only base my comments on the specs, but the specs are both impressive and exciting.

Most gopro type cameras use tiny sensors packed with pixels. This presents a problem as they tend not to be very light sensitive. However those small sensors when combined with an ultra wide angle lens eliminates the need to focus as the depth of field is vast. But for many applications that’s not what you always want. Sometimes you don’t want an ultra wide fisheye view of the world, sometimes you want to get in a bit closer. Sometimes you want a bit of selective focus. In addition it’s hard to be creative when you have no focus or depth of field control. Talking of control most mini-cams have very, very little in the way of manual control as they don’t have adjustable apertures and as a result rely entirely on variable gain and shutter speeds to control the exposure.

Enter the RX0. The RX0 shares a lot of features with the well regarded RX series of compact stills cameras. It has a 1.0″ type sensor, huge compared to most other minicams. It has 24mm f4 lens so it’s less wide and has a shallower DoF. It can shoot in 4K, it can even record using S-Log2 to capture a greater dynamic range so it may turn out to be a great mini-cam for HDR productions (although how big that dynamic range is is not clear at this time). I wish I had some of these for the HDR shoots I did at the beginning of the year.

It’s a camera you can control manually and it even has a special high speed shutter mode for all but eliminating rolling shutter artefacts.

Want to shoot slow-mo? No problem, the maximum frame rate is 960fps (although I suspect that the image quality drops at the higher frame rates).

It’s still very small and very compact, it’s also waterproof and has a high degree of shock proofing.

I can see myself using this as a time lapse camera or in a VR rig. So many applications for a camera like this. Can’t wait to get my hands on one.

Here’s the Sony product page: https://www.sony.co.uk/electronics/cyber-shot-compact-cameras/dsc-rx0#product_details_default

The great S-Log2 or S-Log3 debate.

I’ve written about this many times before, but still it comes up again and again. Which is better? Which should I use? I hear all kinds of crazy comments and a lot of incorrect information, so first of all lets dispel a few myths:

S-Log2 captures more dynamic range than S-Log3, it goes to a higher level on the waveform, S-Log3 clips the highlights sooner.

On most of Sony’s current cameras S-Log2 and S-Log3 both currently record exactly the same dynamic range as this is limited by the sensors that Sony are using. The S-log3 curve could be used in a future camera to capture up to 16 stops and in fact the new Venice camera records over 15 stops.  But as all of Sony’s other cameras sensors can only see 14 stops and the S-Log3 curve is designed to go beyond 14 stops, stop No. 14 is not recorded all the way at the top of the recording range.  S-Log2 is a 14 stop maximum curve, so the peak level is recorded right at the top of the recording range. There is no space held in reserve for anything beyond 14 stops.

In Sonys current camera range (other than Venice) the limit is 14 stops whether it’s S-Log2 or S-Log3. The chart that Sony provide showing both S-Log2 and S-Log3 is a little confusing as it shows the entire gamma curve rather than what the camera can actually “see”. In their current implementations both curves stop at +6 stops over middle grey, both capture the same dynamic range, there is no difference.

S-Log2 is brighter than S-Log3 so it must be capturing highlights better.

No, not really, see above. Playback and on screen brightness comes from the levels chosen to record something at and is dependant on the shape and range of the gamma curve. But the actual captured range is dependant on what the sensor can cope with. As we are not changing the sensor, the captured dynamic range, brightness range and shadow range does not change between S-Log2 and S-log3, both of which take the entire sensor range (they just store that same range using slightly different levels or code values). After applying a LUT or other conversion to your normal viewing gamma both S-Log2 and S-log3 will have the same brightness, same highlight and same shadow range.

S-Log3 has noisy shadows.

No, not really. Shadows appear noisy with S-Log3 as the shadow part of the curve is stored using higher code values compared to S-Log2. So when you view S-Log3 uncorrected the shadows are raised and stretched on your conventional monitor and this gives the impression of a noisy picture. In reality once you restore the levels to normal there is no additional noise. See this article for a full explanation.

S-log-levels The great S-Log2 or S-Log3 debate.
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-Log record to different peak levels.

S-Log3 is newer than S-Log2 so it must be better.

Newer, perhaps not. Better, no not really. S-Log3 is based on the industry standard Cineon log gamma curve. This curve was developed in the 1980’s to allow the digitising of film using 10 bit data. So S-Log3 matches a curve designed to work with negative film and is capable of storing more than the 14 stops that most of the current cameras sensors can see. In effect it is an old log gamma curve. As it is a curve designed for more than 14 stops, when used in a 14 stop camera some of the available recording data is empty and wasted.

S-Log2 was specifically designed by Sony to work with an electronic sensor with 14 stops of dynamic range and is optimised to match the performance characteristics of video sensors. By using a 14 stop curve with a 14 stop camera almost every bit of available data is utilised, there is no wastage. So S-Log2 makes better use of the data you have available to you,

BUT THERE ARE SOME OTHER FACTORS WE NEED TO CONSIDER.

S-Log2 and S-Gamut:

As well as the gamma curve we also have different Gamuts or color ranges. S-Log2 was originally designed for the F65 camera. The F65 sensor can capture a huge color range beyond the range that most conventional video sensors can see. So as well as S-Log2 Sony introduced S-Gamut which was matched to the very wide color range of the F65 sensor. S-Log2 is designed to be used with S-Gamut. But many of the cameras we use, like the FS7, F5, FS5 cannot see this color range (Sony’s F55 and Venice can). In addition this very large color range can be a little tricky to deal with in post production. Add to this the fact that S-Log2 is quite different to the quite common Cineon gamma curve and behaves differently to other curves in post. The end result was that in the early days of S-Log2 there were a number of complaints and comments that Sony’s S-log2 material was difficult to grade.

S-Log3 and S-Gamut3.

Because some people were struggling a bit with S-Gamut and S-Log2 in post production (Resolve and many of the other tools we have today were not as well developed 4 years ago), Sony introduced S-Gamut3 and S-log3 as well as a further Gamut called S–Gamut3.cine. S-Log3 was based on Cineon as that’s what people were familiar with. Arri’s Log-C is also based on Cineon as are many other log curves. This makes it a more “familiar” grading experience for many colorists. In addition Sony created a modified version of the super large S-Gamut to make it easier to grade.  S-Gamut3 is just as big as S-Gamut but some tweaks inside make it easier to grade (fewer color shifts). At the same time Sony realised that most users were producing content for TV, the web or digital cinema that had little use for the huge color range of S-Gamut/S-Gamut3.  So S-Gamut3.cine was developed as a smaller, more manageable version of S-Gamut3 and it incorporated a few tweaks to the color science to provide colors closer to those used by other manufacturers. S-Gamut3.cine is also a better match for cameras with sensors that cannot see the full S-Gamut range (like the FS5, FS7, F5, A7).

The end result is that in general most people prefer or find it easier to grade S-Log3/S-Gamut3.cine material than S-Log2/S-Gamut. Plus you can often use LUT’s designed for Log-C or Cineon with S-log3 material (this isn’t optimum, but it can work).

Gamuts-1024x632 The great S-Log2 or S-Log3 debate.
SGamuts Compared.

Getting the data from camera to post.

In terms of getting the data from your cameras sensor in to post production S-Log2 is the better choice (unless you have a Sony Venice which only has S-Log3). S-Log2 is optimised for the way an electronic sensor works. S-log3 is essentially a curve designed for negative film applications, not video and no matter how you look at it, these are electronic video cameras. However, if you are recording 10 bit or greater you have a lot of data whichever curve you use, so in practice it will be rare to see any difference in the final result.

So use the curve you find easiest to work with. It is true that S-Log 3 allocates a little more data to the shadows and less to the highlights than S-Log2, but don’t confuse data and code values with more range. S-Log3 has a few extra code values in it’s darkest stops, S-log2 has a few extra in the bright stops, but the dynamic range, highlight and shadow handling is governed by the sensor not the gamma curve. Overall S-Log3 has fewer code values than S-Log2, S-Log2  makes better use of the data available, but with 10 bit this really isn’t going to make a huge difference.

8 Bit Recording.

But if you are only recording with an 8 bit codec you are already at a disadvantage. When recording 8 bit you really need to maximise the way what little data you have is used. For that reason I will always recommend that S-Log2 is used when recording 8 bit on a camera like the FS5 in UHD or A7s or similar (FS5 is 10 bit in HD). By using S-Log2 you are using as many of the limited code values available as you can. This doesn’t mean you can’t use S-log3, it just wouldn’t be my choice.

The end result should be the same.

At the end of the day, if you were to use matching LUTs, S-log2 and S-log3 material should look more or less exactly the same after grading or application of the LUT, no matter what the scene you are shooting. If they do look significantly different then you are doing something wrong. So your choice of curve, other than for 8 bit recordings will most likely come down to ease of use rather than anything else.

If your camera doesn’t have LUT’s then S-Log2 can be easier to work with as it is more contrasty. This makes it a bit easier to focus and also makes it easier to gauge exposure. If your camera has LUT’s and you use them, then you may decide to use S-Log3 simply because you should find it a little easier to work with in post. Either way both curves capture the same range of picture information and both should give more or less the same end result.

There may be some very, very subtle differences due to the small differences in data distribution, but often these will be hard to really see in the final image.

Using S-Log2 and S-Log3 with the Sony A6300 (with LUT’s to download).

Sony_A6300 Using S-Log2 and S-Log3 with the Sony A6300 (with LUT's to download).The new Sony A6300 is making quite a stir. This compact interchangeable lens camera has an amazing feature set that is very similar to the features found on it’s bigger brothers the A7sII and A7RII.

As a video camera it’s also capable recording using the XAVC-S codec in  both HD and UHD(4K). It can even shoot at 120fps in HD.  It also has picture profiles so you can tailor the look of the pictures or to suit different shooting conditions. The Cinegammas are very useful for challenging lighting conditions as they offer an improved highlight roll-off. As well as the Cinegammas the camera also has the S-Log2 and S-Log3 log gamma curves as well as S-Gamut, S-Gamut3 and S-Gamut3.cine.

Log gamma curves are very different to conventional gamma curves. Conventional gamma curves (like rec-709 or Cinegamma) are designed to produce a pleasing on screen image without any post production work (although the cinegammas do typically benefit with some tweaking in post). To do this conventional gammas keep the mid-range contrast compatible with conventional TV’s and monitors, so the picture has natural contrast when viewed on a TV. Then to help deal with bright highlights conventional gammas use some kind of highlight roll off or knee to increase the brightness range the camera can capture without effecting the mid range.  Unfortunately this means that the highlights are somewhat compromised, looking very flat, lacking contrast and this is often what gives video the “video look”. In addition it also means that if you are over exposed when you shoot, the picture will look bad and no amount of post production correction will ever make it look good. Most TV camera operators will be very familiar with the phrase “protect your highlights”, meaning don’t over expose, if anything under expose a tiny bit to keep the highlights looking good.

Log gamma curves such as S-Log2 and S-Log3 are very different.  They extended the dynamic range that the camera can capture. To do this they no longer try to be directly compatible with conventional TV’s and monitors and just focus on capturing the biggest possible range. The pictures will be made compatible with the TV or monitor via adjustments made during editing or in post production. So working with S-log2 and S-Log3 is a two step process – shooting and grading (grading is the term used for adjusting the look of an image in post production).

Because log gamma no longer needs to have a contrast range that matches the display range, more dynamic range can be squeezed into a conventional recording codec. It also means that there is no longer a need to use any highlight roll off or knee, so there is a lot more picture information in the highlights and brighter parts of the image. As a result exposing log gamma extra brightly is not normally a problem and in many cases brings lot of advantages. Log gamma curves do have a shadow roll off that mimics the real world shadow roll off. As a result log gammas really don’t like being under exposed, instead they prefer to be over exposed. So unlike conventional gamma where we “protect the highlights” with log gamma you need to “protect the shadows”. Under exposed log looks bad. It will lack color and it will be noisy and grainy.

For most camera operators it’s quite disconcerting to start shooting very slightly over exposed as it goes against everything you’ve learnt about shooting with a conventional video camera. But trust me, shooting 1 to 2 stops brighter than the recommended levels given by Sony on the A6300 (and any other Sony Log camera) will normally bring the best results.

I wrote a guide on how to do this with the Sony A7s here: http://www.xdcam-user.com/2014/08/exposing-and-using-slog2-on-the-sony-a7s-part-one-gamma-and-exposure/

The very same techniques can be used with the A6300, A7SII and A7RII. The A6300 etc also have S-Log3, but as these are 8 bit cameras (even when using an external recorder) I would still recommend that you use S-Log2. Besides, viewing and monitoring S-Log3 is tough as the pictures look even flatter than S-Log3.

If you follow the link below you will find a set of LUT’s (Look Up Tables) that can be applied to A6300 footage in post production to give different looks. There are some film-look LUT’s and 709 (normal TV look) LUT’s and in each case there are LUT’s for normal exposure as well as footage exposed 1 stop and 2 stops brighter. If a LUT name includes “1OVER” this means that the LUT is designed to work with footage that has been exposed 1 stop brighter than the levels given by Sony. My recommendation is to shoot at between 1 and 2 stops bright. For both S-Log2 and S-Log3 this would mean setting zebras to 70% and exposing a piece of white paper so that zebras are just starting to appear on the white paper.

If you find these LUT’s useful please consider buying me a coffee or a beer. I’m not paid to write these articles. For the LUT set I would appreciate a Cocktail, but am happy with whatever you feel is appropriate or affordable.


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pixel Using S-Log2 and S-Log3 with the Sony A6300 (with LUT's to download).

To download the LUT set please click the link: Alisters A6300 Mega LUT Kit

 

Why It’s Helpful To Over Expose S-Log, Especially If You Only Have 8 Bit Recording.

This is something that keeps coming up in my workshops. It’s very important if shooting with S-Log2 or S-Log3 not to under expose and in most cases it can be highly beneficial to over expose a bit. Especially if you are using a camera like the A7s or FS5 in 4K when you only have 8 bit data.

S-log-levels Why It's Helpful To Over Expose S-Log, Especially If You Only Have 8 Bit Recording.

Take a look at this chart. It plots the S-Log2 and S-Log3 gamma curves on a log scale of f-stops against the amount of 10 bit or code values used to record each stop. The center line of the chart is middle grey. Both S-log2 and S-log3 provide 8 stops below middle grey and 6 stops above. Take a look at the darkest stop, the one that is -7 to -8 and look at how much data is allocated to that stop. With 10 bit recording you have according to this chart about 10 code values for S-Log2 and about 20 for S-Log3. That’s if you have 10 bit, and it’s not a lot of data. Admittedly there isn’t going to be a great deal of scene information in that darkest stop, deep in the shadows and the noise. But there’s part of the issue, the noise. If you have under exposed and you take this in to post and have to stretch out the shadows, the noise in these darkest shadows is going to look pretty coarse because it hasn’t been recorded with many shades/steps so stretching it out will make even “rougher” for want of a better term. If you are recording with 8 bit the problems is even worse. With 8 bit, S-Log2 will only have around 2 or 3 code values for that bottom stop, in effect the noise will have two values – black or +1 stop. Imagine how nasty that will look if you need to raise or stretch you blacks because you are under exposed, it will become very blocky and grainy.

The solution is to over expose a bit. By over exposing your footage by a stop when you go in to post production you will in most cases be bringing your levels down. So instead of stretching the noise out and making it worse you will be shrinking it down and reducing the negative impact it has on it’s image. Because cameras like the FS5, A7s etc have 14 stops of dynamic range this small bit of over exposure is going to make very little difference to your highlights in the vast majority of situations. Any slight over exposure you may have will likely look quite natural anyway, after all our own eyesight does also over expose, we don’t have unlimited dynamic range. On top of that the display technology does not exist to show a 14 stop range shot in it’s entirety and with natural contrast.

S-Log2 to Canon LUT’s for the FS7/F5/F55/A7s

More LUT’s for you to play with!

These LUT’s are primarily designed for the PMW-F5 and PXW-FS7 but they should also work with the PMW-F55 and A7s. You need to shoot in SGamut/S-Log2.

There are two types of LUT. The AC-Canon-Log versions will output Canon C-Log with Canon wide range colorspace while the AC-Canon-Look versions output using Canons wide dynamic range gamma. The C-Log versions should be a close match to a C300 shooting C-Log but the footage will need some grading as it is still log. The Canon Look versions will have better contrast and need less grading but have less dynamic range.

I don’t have a C300 to hand to test these, so I am not sure how close they are and it will vary a little depending on whether you use an FS7, A7s or F5/F55.

Click on the links below to download the LUT sets. PLEASE DO NOT HOST THESE ELSEWHERE OR DISTRIBUTE THESE ELSEWHERE OR VIA ANY MEANS OTHER THAN A LINK TO THIS PAGE.

Alisters S-log2 to Canon Luts

If you find the LUT’S useful, please consider buying me a beer or a coffee.


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pixel S-Log2 to Canon LUT's for the FS7/F5/F55/A7s