Category Archives: PXW-FS7

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.

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Revised and improved HLG camera LUT for FS7, F5 and F55.

I have created a new and improved HLG camera LUT for the PXW-FS7, PMW-F5 and PMW-F55 cameras. This 3D LUT can be used to shoot HLG directly by baking the LUT in to the recordings in camera. This allows you to create “instant HDR” footage that just like the HLG footage from an FS5 or Z90 does not need to be graded or modified to provide an HDR image on an equipped HDR TV. Skin tones should be exposed at around 55-60% and white at around 70-75%.

Click here to download the LUT AC-HLGSL3-V2.cube

ProRes Raw and Atomos Inferno and Sumo – BIG deal for the FS5 and FS7!!

proresraw-logo ProRes Raw and Atomos Inferno and Sumo - BIG deal for the FS5 and FS7!!Over the last few days there have been various rumours and posts coming from Apple about how they intend to get back to providing decent support for professional users of their computers. Apple have openly admitted that the Trash Can Mac Pro has thermal problems and as a result has become a dead end design, which is why there haven’t been any big updates to the flagship workstation from Apple. Apple have hinted that new workstations are on the way, although it would seem that we won’t see these until next year perhaps.
Another announcement came out today, a new version of FCP-X is to be released which includes support for a new ProRes codec called ProRes Raw. This is BIG!

PRORES RAW.

Raw recordings can be made from certain cameras that have bayer sensors such as the Sony FS5 and FS7. Recording the raw data from the sensor maximises your post production flexibility and normally offers the best possible image quality from the camera. Currently if you record 4K raw with these cameras using an Atomos Shogun or similar the bit rate will be close to 3Gb/s at 24p. These are huge files and the cDNG format used to record them is difficult and clunky to work with.  As a result most users take the raw output from the camera and transform it to S-Log2 or S-Log3 and record it as 10 bit ProRes on the external recorder. This is a bit of a shame as going from 12 bit linear raw to 10 bit S-log means you are not getting the full benefit of the raw output.

Enter ProRes Raw:  ProRes Raw will allow users to record the cameras raw output at a much reduced bit rate with no significant of quality. There are two versions, ProRes Raw and ProRes Raw HQ. The HQ bit rate is around 1Gb/s at 24fps. This is not significantly bigger than the ProRes HQ (880Mb/s) that most users are using now to record the raw, yet the full benefit of 12 bit linear will be retained. A 1TB SSD will hold around an hour of ProRes Raw, compare that to uncompressed raw where you only get around 20 mins and you can see that this is a big step forwards for users of the FS5 in particular.

ProRes Raw (the non HQ version) is even smaller! The files are smaller than typical ProRes HQ files. This is possible because recording raw is inherently more efficient than recording component video.

It is claimed by Apple that ProRes Raw will play back in real time on MacBook Pro’s and iMacs without any additional rendering or external graphics cards, so it obviously isn’t terribly processor intensive. This is excellent news! Within FCP-X the playback resolution can be decreased to bring improved playback performance in less powerful systems or mutistream playback.

It looks like you will be able to record from a 4K DCI  from an FS5 or FS7 at up to 60fps continuously. This breaks through the previous limits for the Shogun of 30fps. The FS7 will be able to record 2K raw at up to 240fps and the FS5 will be able to record 4K raw at 100 and 120fps for 4 seconds. Other raw cameras are also supported by the Atomos recorders at differing frame sizes and frame rates.

At the moment the only recorders listed as supporting ProRes Raw are the Atomos Shogun Inferno and the Sumo19 and it looks like it will be a free update. In addition the DJI Inspire 2 drone and Zenmuse X7 Super 35mm camera will also support ProRes Raw.

Whether you will be able to use ProRes Raw in other applications such as Resolve or Premiere is unclear at this time. I hope that you can (or at least will be able to in the near future).

SEE: Apple Press Release.

SEE: Apple ProRes Raw White Paper

SEE: ATOMOS ProRes Raw INFO PAGE.

 

 

Beware the LC709 LUT double exposure offset.

The use o f the LC709 Type A LUT in Sony’s Cinealta cameras such as the PXW-FS7 or PMW-F55 is very common. This LUT is popular because it was designed to mimic the Arri cameras when in their Rec-709 mode. But before rushing out to use this LUT and any of the other LC709 series of LUT’s there are some things to consider.

The Arri cameras are rarely used in Rec-709 mode for anything other than quick turn around TV. You certainly wouldn’t normally record this for any feature or drama productions. It isn’t the “Arri Look” The Arri look normally comes as a result of shooting using Arri’s LogC and then grading that to get the look you want. The reason it exists is to provide a viewable image on set. It has more contrast than LogC and uses Rec 709 color primaries so the colors look right, but it isn’t Rec-709. It squeezes almost all of the cameras capture range into a something that can be viewed on a 709 monitor so it looks quite flat.

Because a very large dynamic range is being squeezed into a range suitable to be viewed on a regular, standard dynamic range monitor the white level is much reduced compared to regular Rec-709. In fact, white (such as a white piece of paper) should be exposed at around 70%. Skin tones should be exposed at around 55-60%.

If you are shooting S-Log on a Sony camera and using this LUT to monitor, if you were to expose using conventional levels, white at 85-90% skin tones at 65-70%, then you will be offsetting your exposure by around +1.5 stops. On it’s own this isn’t typically going to be a problem. In fact I often come across people that tell me that they always shoot at the cameras native EI using this LUT and get great, low noise pictures. When I dig a little deeper I often find that they are exposing white at 85% via the LC709 LUT. So in reality they are actually shooting with an exposure the equivalent of +1 to +1.5 stops over the base level.

Where you can really run into problems is when you have already added an exposure offset. Perhaps you are shooting on an FS7 where the native ISO is 2000 ISO and using an EI of 800. This is a little over a +1 stop exposure offset. Then if you use one of the LC709 LUT’s and expose the LUT so white is at 90% and skin tones at 70% you are adding another +1.5 stops to the exposure, so your total exposure offset is approaching 3 stops. This large an offset is rarely necessary and can be tricky to deal with in post. It’s also going to impact your highlight range.

So just be aware that different LUT’s require different white and grey levels and make sure you are exposing the LUT at it’s correct level so that you are not adding an additional offset to your desired exposure.

Sony Cash-Back Offer Ends Soon (Europe).

Camcorder-Accessory-Promotion_home-medium-EN Sony Cash-Back Offer Ends Soon (Europe).Sony are offering up to £220/€250 cash back on accessories purchased with an FS5 and up to £400/€450 cash back on accessories purchased with  FS7 or FS7M2 if you purchase one before the end of March 2018. So there’s only 2 weeks left to take advantage of this offer!

So if your looking at investing in a nice camera kit with perhaps one of the excellent UWP-D radio mic kits that connect directly to the cameras MI shoe or some extra batteries this might be a great way to get some money back from Sony. There are various terms and conditions so please take a look at the promotion page for the full details. Here’s a link to the promotion page.

 

Use the cameras media check to help ensure you don’t get file problems.

Any of the Sony cameras that use SxS or XQD cards include a media check and media restore function that is designed to detect any problems with your recording media or the files stored on that media.
However the media check is only normally performed when you insert a card into the camera, it is not done when you eject a card as the camera never knows when you are about to do that.
So my advice is: When you want to remove the card to offload your footage ensure you have a green light next to the card, this means it should be safe to remove. Pop the card out as you would do normally but then re-insert the card and wait for the light to go from red, back to green. Check the LCD/VF for any messages, if there are no messages, take the card out and do your offload as normal.
 
Why? Every time you put an XQD or SxS card into the camera the card and files stored on it are checked for any signs of any issues. If there is a problem the camera will give you a “Restore Media” warning. If you see this warning always select OK and allow the camera to repair whatever the problem is. If you don’t restore the media and you then make a copy from the card, any copy you make will also be corrupt and the files may be inaccessible.
Once the files have been copied from the card it is no longer possible to restore the media.  If there is a problem with the files on the card, the restore can only be done by the camera, before offload. So this simple check that takes just a few seconds can save a whole world of hurt. I wish there was a media check button you could press to force the check, but there isn’t. However this method works.
It’s also worth knowing that Catalyst Browse and the old Media Browser software performs a data integrity check if you directly attach an SxS card or XQD card to the computer and access the card from the software. If a problem is found you will get a message telling you to return the media to the camera and perform a media restore. But if this is some time after the shoot and you don’t have the camera to hand, this can be impossible. Which is why I like to check my media in the camera by re-inserting it back into the camera so that it gets checked for problems before the end of the shoot.

Scene files for the Sony PXW-FS7M2.

Here are some scene files for the PXW-FS7-II and original PXW-FS7. The first 5 scene files I published a couple of years ago but never got around to converting them over to the PXW-FS7-II. You can download the files in their correct folder structure to put on to an SD card so you can load them directly in to an FS7 or FS7-II. Or you can manually copy the settings from here. If copying the settings in manually I recommend you start by going to the “Files” section of the cameras menu and “Scene File” and import a “standard” default scene file from the cameras internal memory first to ensure you paint settings are at the original factory defaults prior to entering the settings by hand. The easiest way is to load the files linked at the bottom of the page onto an SD card and then go to the files section of the menu to load the scene files into the camera from the SD card.

If you find these useful, please consider buying me a coffee or other drink. It’s always appreciated!


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pixel Scene files for the Sony PXW-FS7M2.

The paint settings in for each of these setups are standard except for the items listed in each profile.

Scene File 1: AC-Neutral-HG4.

Designed as a pleasing general purpose look for medium to high contrast scenes. Provides a neutral look with slightly less yellow than the standard Sony settings. I recommend setting zebras to 60% for skin tones or exposing a white card at 75-80% for the best results.

Black: Master Black: -3.  Gamma: HG4 .  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Standard. User Matrix: ON. Level: 0. Phase: 0.

R-G: +10. R-B: +8. G-R: -12. G-B: -9. B-R: -5. B-G: -15.

Scene File 2: AC-Neutral-HG3

Similar to the above except better suited to lower contrast scenes or lower light levels. Provides a neutral look with slightly less yellow than the standard Sony settings. I recommend setting zebras to 60% for skin tones or exposing a white card at 75-80% for the best results.

Black: Master Black: -3.  Gamma: HG3 .  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Standard. User Matrix: ON. Level: 0. Phase: 0.

R-G: +10. R-B: +8. G-R: -12. G-B: -9. B-R: -5. B-G: -15.

Scene File 3: AC-FILMLIKE1

A high dynamic range look with film like color. Will produce a slightly flat looking image. Colours are tuned to be more film like with a very slight warm tint. I recommend settings zebras to 57% for skin tones and recording white at 70-75% for the most “filmic” look.

Black: Master Black: -3.  Gamma: HG7 .  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Cinema. User Matrix: ON. Level: -3. Phase: 0.

R-G: +11. R-B: +8. G-R: -12. G-B: -9. B-R: -3. B-G: -12.

Scene File 4: AC-FILMLIKE2

A high dynamic range look with film like color. Will produce a n image with more contrast than Filmlike1. Colours are tuned to be more film like with a very slight warm tint. I recommend settings zebras to 57% for skin tones and recording white at 70-75% for the most “filmic” look.

Black: Master Black: -3.  Gamma: HG8.  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Cinema. User Matrix: ON. Level: -3. Phase: 0.

R-G: +11. R-B: +8. G-R: -12. G-B: -9. B-R: -3. B-G: -12.

Scene File 5: AC-VIBRANT-HG3

These setting increase dynamic range over the standard settings but also increase the colour and vibrance. Designed to be used for when a good dynamic range and strong colours are needed direct from the camera. Suggested zebra level for skin tones is 63% and white at approx 75-80%.

Black: Master Black: -3.  Gamma: HG3.  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Standard. User Matrix: ON. Level: +23. Phase: -5.

R-G: +12. R-B: +8. G-R: -11. G-B: -6. B-R: -6. B-G: -17.

Scene File 6: AC-VIBRANT-HG4

These setting increase dynamic range over the standard settings but also increase the colour and vibrance. HG4 has greater dynamic range than HG3 but is less bright, so this variation is best for brighter high dynamic range scenes. Designed to be used for when a good dynamic range and strong colours are needed direct from the camera. Suggested zebra level for skin tones is 60% and white at approx 72-78%.Black: Master Black: -3.  Gamma: HG3.  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Standard. User Matrix: ON. Level: +23. Phase: -5.

R-G: +12. R-B: +8. G-R: -11. G-B: -6. B-R: -6. B-G: -17.

Scene File 7: AC-KODAKISH3200K (Include “Scene White Data – ON” when loading from the SD card).

This is a highly experimental scene file that uses a heavily tweaked matrix along with extensive colour adjustments via the multi-matrix. The aim being to reproduce a look reminiscent of Kodak film stock. The white balance is deliberately skewed very slightly bue/teal and then skin tones and orange shades boosted. When loading this scene file from an SD card you must also set “White Data” to ON to import the offset color preset. You can then either use the preset white balance or white balance using memory A/B and a white card. Do NOT use ATW.  This version is intended for use under TUNGSTEN lighting where the white balance would normally be 3200K. Please test that this profile produces a result you like before you start shooting with it as the look is quite strong and may be difficult to change later if you don’t like it. I recommend settings zebras to 57% for skin tones and recording white at 70-75% for the most “filmic” look.

White: Preset White 2800K

Offset White A: ON.  Warm Cool A: -25. Warm Cool Balance A: +10

Offset White B: ON.  Warm Cool B: -25. Warm Cool Balance A: +10

Black: Master Black: -3.  Gamma: HG4 .  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Cinema. User Matrix: ON. Level: -10. Phase: 0.

R-G: +61. R-B: +29. G-R: -6. G-B: -35. B-R: +21. B-G: -5.

MultiMatrix: ON

B: Hue -18, Saturation 0.

B+: Hue +5, Saturation 0.

MG-: Hue +5, Saturation 0.

MG: Hue +5 Saturation -7.

MG+: Hue 0, Saturation -3.

R: Hue -21, Saturation +65.

R+: Hue +0, Saturation +99.

YL-: Hue +39, Saturation +44

YL: Hue 0, Saturation 0.

YL+ Hue +20, Saturation -10.

G-: Hue -71, Saturation 0.

G: Hue -61, Saturation +10.

G+: Hue -23, Saturation +11

CY: Hue -40, Saturation +9.

CY+:Hue -22, Saturation +54.

B-:Hue +20, Saturation -5.

Scene File 8: AC-KODAKISH5600K (Include “Scene White Data – ON” when loading from the SD card).

This is a highly experimental scene file that uses a heavily tweaked matrix along with extensive colour adjustments via the multi-matrix. The aim being to reproduce a look reminiscent of Kodak film stock. The white balance is deliberately skewed very slightly bue/teal and then skin tones and orange shades boosted. When loading this scene file from an SD card you must also set “White Data” to ON to import the offset color preset. You can then either use the preset white balance or white balance using memory A/B and a white card. Do NOT use ATW.  This version is intended for use under daylight lighting where the white balance would normally be 5600K/6000K. Please test that this profile produces a result you like before you start shooting with it as the look is quite strong and may be difficult to change later if you don’t like it. I recommend settings zebras to 57% for skin tones and recording white at 70-75% for the most “filmic” look.

White: Preset White 4900K

Offset White A: ON.  Warm Cool A: -25. Warm Cool Balance A: +10

Offset White B: ON.  Warm Cool B: -25. Warm Cool Balance A: +10

Black: Master Black: -3.  Gamma: HG4 .  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: Cinema. User Matrix: ON. Level: -10. Phase: 0.

R-G: +61. R-B: +29. G-R: -6. G-B: -35. B-R: +21. B-G: -5.

MultiMatrix: ON

B: Hue -18, Saturation 0.

B+: Hue +5, Saturation 0.

MG-: Hue +5, Saturation 0.

MG: Hue +5 Saturation -7.

MG+: Hue 0, Saturation -3.

R: Hue -21, Saturation +65.

R+: Hue +0, Saturation +99.

YL-: Hue +39, Saturation +44

YL: Hue 0, Saturation 0.

YL+ Hue +20, Saturation -10.

G-: Hue -71, Saturation 0.

G: Hue -61, Saturation +10.

G+: Hue -23, Saturation +11

CY: Hue -40, Saturation +9.

CY+:Hue -22, Saturation +54.

B-:Hue +20, Saturation -5.

Scene File 9: AC-Minus-G1

A hand scene file to have for shooting under mixed lights or low quality lights where there is too much green. By using a combination of the FL-Light colour matrix and a custom preset matrix this profile reduces the some problematic green colour cast that can be present. It uses Hypergamma 3 to give a more pleasing highlight roll off and increased dynamic range without reducing the low light performance. Great for office interviews! I recommend setting zebras to 62% for skin tones and recording white (white card) at between 75 and 80% for the best results.

Black: Master Black: -3.  Gamma: HG3 .  White Clip: OFF.  Aperture : OFF

Matrix: ON. Adaptive Matrix: Off. Preset Matrix: ON. Preset Select: FL Light. User Matrix: ON. Level: 0. Phase: 0.

R-G: +10. R-B: +8. G-R: -12. G-B: -9. B-R: -5. B-G: -15.

 

Here are the files ready to load into you own FS7 or FS7II. Click on the link below to get to the download page where you can download a zip file with all of the scene files already in the correct folder structure to place on an SD card. Simply unzip the download and copy the “private” folder to the root of an empty SD card. These scene files have taken a lot of time and effort to develop. I offer them without charge for your own use. If you find them useful please consider buying me a coffee or other drink.


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pixel Scene files for the Sony PXW-FS7M2.

If you already have scen files on your own SD card then you can copy my files from either:

PRIVATE/SONY/PRO/CAMERA/PXW-FS7/

or

PRIVATE/SONY/PRO/CAMERA/PXW-FS7M2

To the same folder your own SD card. You can re-number the if you need to. Once the files are on an SD card insert the SD card in to the camera. Go to the “File” menu and “Scene File” and choose “Load from SD Card”.

FS7 – FS7M2 Scene Files

Want to know more – why not come to a workshop:

How does the Panasonic EVA1 stack up against the Sony FS7 and FS5?

This is a question a lot of people are asking. As I’ve mentioned in other recent posts, sensors have reached a point where it’s very difficult to bring out a camera where the image quality will be significantly different from any other on the market for any given price point. Most differences will be in things like codec choices or trading off a bit of extra resolution for sensitivity etc. Other differences will be in the ergonomics, lens mounts and battery systems.

So it’s interesting to see what Keith Mullin over at  Z-Systems thought of the EVA1. Keith knows his stuff and Z-Systems are not tied to any one particular brand.

Overall as expected there isn’t a huge difference in image quality between any of the 3 cameras. The EVA1 seems weaker in low light which is something I would have predicted given the higher pixel count. The dual ISO mode seems not to be anywhere near the same as the really very good dual ISO mode in the Varicam LT.

Why not take a look at the full article and video for yourself. http://zsyst.com/2017/12/panasonic-eva1-first-look/

 

Using LUT’s for exposure – choosing the right LUT.

If using a LUT to judge the exposure of a camera shooting log or raw it’s really important that you fully understand how that LUT works.

When a LUT is created it will expect a specific input range and convert that input range to a very specific output range. If you change the input range then the output will range will be different and it may not be correct. As an example a LUT designed and created for use with S-Log2 should not be used with S-Log3 material as the the higher middle grey level used by S-Log3 would mean that the mid range of the LUT’s output would be much brighter than it should be.

Another consideration comes when you start offsetting your exposure levels, perhaps to achieve a brighter log exposure so that after grading the footage will have less noise.

Lets look at a version of Sony’s 709(800) LUT designed to be used with S-Log3 for a moment. This LUT expects middle grey to come in at 41% and it will output middle grey at 43%. It will expect a white card to be at 61% and it will output that same shade of white at a little over 85%. Anything on the S-Log3 side brighter than 61% (white) is considered a highlight and the LUT will compress the highlight range (almost 4 stops) into the output range between 85% and 109% resulting in flat looking highlights. This is all perfectly fine if you expose at the levels suggested by Sony. But what happens if you do expose brighter and try to use the same LUT either in camera or in post production?

Well if you expose 1.5 stops brighter on the log side middle grey becomes around 54% and white becomes around 74%. Skin tones which sit half way between middle grey and white will be around 64% on the LUT’s input. That’s going to cause a problem! The LUT considers anything brighter than 61% on it’s input to be a highlight and it will compresses anything brighter than 61%. As a result on the output of your LUT your skin tones will not only be bright, but they will be compressed and flat looking. This makes them hard to grade. This is why if you are shooting a bit brighter it is much, much easier to grade your footage if your LUT’s have offsets to allow for this over exposure.

If the camera has an EI mode (like the FS7, F5, F55 etc) the EI mode offsets the LUT’s input so you don’t see this problem in camera but there are other problems you can encounter if you are not careful like unintentional over exposure when using the Sony LC709 series of LUTs.

Sony’s  709(800) LUT closely matches the gamma of most normal monitors and viewfinders, so 709(800) will deliver the correct contrast ie. contrast that matches the scene you are shooting plus it will give conventional TV brightness levels when viewed on standard monitors or viewfinders.

If you use any of the LC709 LUT’s you will have a miss-match between the LUT’s gamma and the monitors gamma so the images will show lower contrast and the levels will be lower than conventional TV levels when exposed correctly. LC709 stands for low contrast gamma with 709 color primaries, it is not 709 gamma!

Sony’s LC709 Type A LUT is very popular as it mimics the way an Arri Alexa might look. That’s fine but you also need to be aware that the correct exposure levels for this non-standard LC gamma are middle grey at around 41% and white at 70%.

An easy trap to fall into is to set the camera to a low EI to gain a brighter log exposure and then to use one of the LC709 LUT’s and try to eyeball the exposure. Because the LC709 LUT’s are darker and flatter it’s harder to eyeball the exposure and often people will expose them as you would regular 709. This then results in a double over exposure. Bright because of the intentional use of the lower EI but even brighter because the LUT has been exposed at or close to conventional 709 brightness. If you were to mistakenly expose the LC709TypeA LUT with skin tones at 70%, white at 90% etc then that will add almost 2 stops to the log exposure on top of any EI offset.

Above middle grey with 709(800) a 1 stop exposure change results in an a 20% change in brightness, with LC709TypeA the same exposure change only gives a just over 10% change, as a result over or under exposure is much less obvious and harder to measure or judge by eye with LC709. The cameras default zebra settings for example have a 10% window. So with LC709 you could easily be a whole stop out, while with 709(800) only half a stop.

Personally when shooting I don’t really care too much about how the image looks in terms of brightness and contrast. I’m more interested in using the built in LUT’s to ensure my exposure is where I want it to be. So for exposure assessment I prefer to use the LUT that is going to show the biggest change when my exposure is not where it should be. For the “look” I will feed a separate monitor and apply any stylised looks there. To understand how my highlights and shadows, above and below the LUT’s range are being captured I use the Hi/Low Key function.

If you are someone that creates your own LUT’s an important consideration is to ensure that if you are shooting test shots, then grading these test shots to produce a LUT it’s really, really important that the test shots are very accurately exposed.

You have 2 choices here. You can either expose at the levels recommended by Sony and then use EI to add any offsets or you can offset the exposure in camera and not use EI but instead rely on the offset that will end up in the LUT. What is never a good idea is to add an EI offset to a LUT that was also offset.