All posts by alisterchapman

New LUTs from Sony

Side-by-Side2_small-600x338 New LUTs from Sony

 

I was asked by Sony to produce a couple of new LUT’s for them. These LUT’s were inspired by many recent blockbuster movies and have been named “Space Adventure” and “Super Hero”.

Both LUT’s are available for free and there is a link on the page linked below that will allow you to obtain them.

Rather than explain the two different looks here go to this page on the Sony website https://pro.sony/en_GB/filmmaking/filmmaking-solutions/full-frame-cinematic-look

Scroll down to where it says “Stunning Cinematic Colour” and there you will find a video called “Orlaith” that shows both LUT’s applied to the same footage.

Orlaith is a gaelic name  and it is pronounced “orla”. It is the name of a mythical golden princess. The short film was shot on a teeny-tiny budget in a single evening with an FX3 and FX6 using S-Log3 and SGamut3.cine. Then the LUTs were applied directly to the footage with no further grading.




 

PXW-FX9 Version 3 Firmware Update Latest News

No, it hasn’t been released yet.  And it’s now not expected to arrive before the end of November. But it will be worth the wait.

We already knew about some of the new features but there is much more to this release than first announced. Let’s take a look:

Touch to focus, focus tracking: Yes, you heard it right. You will be able to use the touch sensitive LCD to touch on an object in the shot and then the camera will track that object as it moves around the shot. A box will appear around the touched object and you will be able to monitor what the AF is focussing on by looking at what the tracking box is over. This is a feature available on the A7S3 and FX3 that is VERY useful.

Anamorphic De-Squeeze. It will become much easier to shoot anamorphic with the FX9. When shooting Anamorphic the image produced by the lens is squeezed horizontally, and that’s what you record. But to monitor it correctly you then need to de-squeeze it by squashing it vertically by the correct amount. The V3 firmware update will allow the image to be squashed vertically (de-squeezed) for the LCD viewfinder so you can view with the included VF in the correct widescreen aspect ratio. Do note however that the SDI and HDMI outputs will NOT be de-squeezed, so to monitor externally you will need a monitor with de-squeeze, but most of them have this these days.

Super 16 Scan Modes: The camera will gain a 2K center scan mode that can be used to shoot at up to 180fps in full HD. Using the center scan mode for slow motion above 60fps will eliminate the aliasing issues currently seen when using the 2K FF or 2K S35 scan modes. Additionally you will be able to use Sony’s 2/3″ B4 lens adapter. When using the B4 adapter the camera will support ALAC  which corrects for chromatic aberrations in lenses that support this feature.

Switch Scan Modes via Assignable Button: This has been something on everyone’s wish lists for years. Now at last you will be able to set up an assignable button to switch scan modes. 

Add Camera ID and Reel Numbers to Clip Names: You will be able to use clip names that are prefixed by a camera ID number and a reel number similar to the clip naming system on the FS7.

Modify the Status Page List: This function allows you to remove pages from the status page menu. So you will be able to remove the pages you rarely use.

DC IN Alarm: Don’t get too excited just yet, but in V3 you will be able to set a low voltage alarm for the cameras DC input as well as the extension units DC input. This does NOT mean that there will be a low voltage warning with the current 3rd party V-Lock battery adapters as these convert the battery voltage to a fixed 19.5v supply that never changes. But it does mean that a clever manufacturer could now design a V-Lock adapter that could reduce it’s output voltage when the voltage of the V-Lock battery gets low allowing you to have an alarm in the camera before the battery cuts off.

Proxy Upload while recording: Currently you cannot upload proxies while recording. This will be improved in V3 and the camera will be able to upload proxies in the background while you are recording.

Zero Focus Distance function: When working with a lens that shows the focus distance on the LCD screen you will be able to focus on an object and then “zero” the focus distance. Then as you change the focus distance the the screen will display a +/- value that is how far from zero the focus is. You will be able to use this for a pull focus. Focus on the end object and set the focus distance to zero. Now focus on the start object. To pull focus turn the focus ring so you are back at zero again. Not actually sure how useful this will be, but hey – it isn’t costing us anything.

Change Network Settings via Mobile Phone App: You will be able to use a mobile phone to change the cameras network settings making it easier to enter addresses and passwords of FTP servers etc.

USB Phone tethering: you will be able to connect a couple of mobile phones to the camera via USB to use it them as modems for internet streaming (I believe this is via the USB ports on the top of the XDCA-FX9).

LCD Gamma Adjustments for SR Live: SR live is a type of HDR workflow developed for live productions that will be broadcast in both standard dynamic range and high dynamic range. This setting allows you to change the gamma of the LCD screen between SDR and HDR range when shooting using HLG in the HDR mode. This allows you to preview either what a viewer will see watching in SDR or a good approximation of what a viewer viewing in HDR will see.

S700 Remote Control: The camera will be able to be controlled remotely using s700 protocols (via ethernet).

KitPlus Show Twickenham 14/9/21

Screenshot-2021-09-10-at-10.17.51-600x316 KitPlus  Show Twickenham 14/9/21Just a quick note to tell you that I will be co-presenting a session at the Kit Plus show in Twickenham on Tuesday the 14th of September 2021. Philip Bloom on the subject of “Buying the right camera IS important – don’t get sucked into the marketing hype”.  We will be discussing how people make their purchasing decisions, what different manufacturers have to offer and debating – what does “cinematic” mean – if anything at all.

Come and join us it should be fun and it’s face to face!!

https://www.kitplus.com/events/KPS_London/97.html

Chroma Key and Greenscreen – Should I use S-Log3 or might Rec-709 be Better?

I’ve covered this before, but as this came up again in an online discussion I thought I would write about it again. For decades when I was doing a lot of corporate video work we shot greenscreen and chroma key with analoge or 8 bit, limited dynamic range, standard definition cameras and generally got great results (it was very common to use a bluescreen as blue spill doesn’t look as bad on skin tones as green). So now when we have cameras with much greater dynamic ranges and 10 bit recording is it better to shoot for greenscreen using S-Log3 (or any other log curve for that matter) or perhaps Rec-709?

Before going further I will say that there is no yes-no, right-wrong, answer to this question. I will also add that Rec-709 gets a bad rap because people don’t really understand how gamma curves/transfer functions actually work and how modern grading software is able to re-map the aquisition transfer function to almost any other transfer function. If you use a colour managed workflow in DaVinci Resolve it is very easy to take a Rec-709 recording and map it to S-Log3 so that you can apply the same grades to the 709 as you would to material originated using S-Log3. Of course the 709 recording may not have as much dynamic range as an S-Log3 recording, but it will “look” more or less the same.

Comming back to shooting greenscreen and chromakey:

S-Log3:
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Shoot using 10 bit S-log3 and you have 791 code values available (95-886) to record 14/15 stops of dynamic range. so on average across the entire curve each stop has around 55 code values. Between Middle Grey and +2 stops there are approx  155 code values – this region is important as this is where the majority of skin tones and the key background are likely to fall.

Rec-709:
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Shoot using vanilla Rec-709 and you are using 929 code values (90-1019) to record 6/7 stops so each stop has on average across the entire curve has around 125 code values. Between Middle Grey and +2 stops there are going to be around 340 code values.
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That is not an insignificant difference, it’s not far off the  difference between shooting with 10 bit or 12 bit.
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If you were to ask someone whether it is better to shoot using 10 bit or 12 bit I am quite sure the automatic answer would be 12 bit because the general concensus is – more bits is always better.
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A further consideration is that the Sony cameras operate at a lower ISO when shooting with standard gammas and as a result you will have an improved signal to noise ratio using 709 than when using S-log3 and this can also make it easier to achieve a good, clean, key.
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However you do also need to think about what it is you are shooting and how it will be used. If you are shooting greenscreen in a studio then you should have full control over your lighting and in most cases 6 or 7 stops is all you need, so Rec-709 should be able to capture everything comfortably well. If you are shooting outside with less control over the light perhaps Rec-709 won’t have sufficient range.
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If the background plates have been shot using S-Log3 then some people don’t like keying 709 into S-Log3. However a colour managed workflow can deal with this very easily. We should consider that 709 and S-Log3 in a workflow where grading is a big part should not be though of as “looks” but simply as transfer functions or maps of what brightness/saturation seen by the camera is recorded at what code value. Handle these transfer functions correctly via a colour managed workflow and both will “look” the same and both will grade the same within their respective capture limits.
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For an easy workflow you might chose to shoot the greenscreen elements using log with the same settings as the plates. There is nothing wrong with this, it works, it is a very commonly used workflow but it isn’t necessarily always going to be optimum. A lot of people will put a lot of emphasis on using raw or greater bit depths to maximise the quality of their keying, but overlook gamma choice altogether, simply because “Rec-709” is almost a dirty word these days.
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If you have more control, and want absolutely the best possible key, you might be better off using Rec-709. As you will have more data per stop which makes it easier for the keying software to identify edges and less noise. If using Rec-709 you want to chose a version of Rec-709 where you can turn off the camera’s knee as this will prevent the 709 curve from crushing the highlights which can make them difficult to grade. In a studio situation you shouldn’t need to use a heavy knee.

I suggest you experiment and test for yourself and not every situation will be the same, sometimes S-Log3 will be the right choice, other times Rec-709.
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Chroma Key and S-Cinetone

A question poped up today asking about how to expose S-Cinetone when shooting green screen. 
The answer is really quite simple – no differently to how you would expose S-Cinetone anywhere else. But, having said that it is important to understand that S-Cinetone is a bit different to normal Rec-709 and this needs to be considered when shooting for chroma key or green screen.

S-Cinetone’s highlight roll off and shoulder starts much lower than most “normal” rec-709 curves. From around 73% the gamma curve changes and starts to compress the levels and reduce contrast. In the shdows there is a variable toe that increases contrast at lower brightness levels. The nominal “normal” brightness levels are also lower, all part of the contemporary film like look S-Cinetone is designed to give. A 90% reflectivity reference white card would be exposed at approx 83% instead of the more normal 90% (if you were using a light meter you should end up with a 90% white card at 83IRE). A white piece of paper will be a bit brighter than this as printer and copier paper etc is designed to look as bright as possible, typically printer paper comes out around 3 to 5% brighter than a proper white card.

The lower start to the highlight roll-off means that if you place skintones around 70% the brighter parts of a face will be affected by the rolloff and this will make them flatter. Expose skin tones at 60% and the face will be more contrasty and in my opinion look better. Although darker this would still be well with the “normal” exposure range for S-Cinetone so you will not have excessive noise and it will still key well.

exposing-cinetone-600x316 Chroma Key and S-Cinetone

S-Cinetone would be considered correctly exposed when a 90% white card is exposed between 78% and 88%. This is quite a wide window and is due to the way S-Cinetone is designed to give differening contrast levels simply by exposing a touch brighter or darker. The variable toe and shoulder mean that exposing brighter will make the image flatter and exposing darker more contrasty. Exposing as you would with normal Rec-709 levels with a white card at 90% will place skintones rather higher than “normal” and they will appear very flat. So either expose so a white card falls in the 78-88% window or use a calibrated monitor to observe how the skin tone look and be careful not to overexpose them.

Your greenscreen should be between 40IRE and 60IRE for a good clean key, I normally aim for 50IRE with S-Cinetone, but provided you don’t go below 40IRE or above 60IRE you should be good.

Nanlite Forza 300 LED Spotlight

 The Nanlite Forza 300 is a LED COB spotlight normally used with a reflector to provide a 55 degree light cone.

Forza-2_2.3.1-600x338 Nanlite Forza 300 LED Spotlight
Nanlite Forza 300 spotlight with included reflector.

 

The lamp is 300 watts and can be powered from the mains with the included power adapter or vai a pair of V-lock batteries. It is daylight balanced at 5500K and has a CRI of 95 (measured by myself). It has always resulted in very pleasing skin tone whenever I have used it.

Forza-skin_1.12.1-600x338 Nanlite Forza 300 LED Spotlight
Skin tones look good when using the Forza 300 from Nanlite.

 

The 300 watt LED COB emitter produces a similar amount of light to a 3000 watt tungsten lamp. This  makes the Forza 300 suitable for illuminating very large areas or as a source light for a large soft box or for use with large silk diffusers. Nanlite make a very nice parabolic reflectors/soft boxes for the Forza lamps that are very quick to erect due to the use of clever quick locking support arms.

Parabolic-reflector_5.1.1-600x338 Nanlite Forza 300 LED Spotlight
Parabolic reflector/soft box for the Nanlite Forza 300

 

The lamphead has a standard Bowens mount so there are many light modifiers that can be used, but one that I particularly like is the Nanlite zoomable Fresnel adapter. This large fresnel lens can be adjusted to provide a very tightly controlled light beam from just 5 degrees wide to 45 degrees wide. It comes with barn doors and turns the Forza 300 into something comparable to the old Arri 2K fresnel, just without the heat and power draw.

Fresnelbarn-doors_3.1.1-600x338 Nanlite Forza 300 LED Spotlight
Nanlite zoomable fresnel lens with barn doors for the Forza 300 and Forza 500.

 

I’m a big fan of fresnels as they give you good control of where your light is going. Make it dimmable as well and you have a very versatile lamp.

The light can be controlled via DMX as well as a couple of very cheap wireless remote control units (around £20/$30) and an app is due to be released soon. 

Like many modern lights it also has a number of effects modes including strobe, storm, TV and bad bulb and these can be quickly and easily selected from the lamps control unit and power supply. The build quality is very good. The lamp head is mostly metal while the control unit is a mix of good quality plastics and metal.  The whole thing weighs 4.8kg so you don’t need a particularly large light stand to support it.

with a street price of around £650/$850 this is a very affordable yet also very capable lamp. I would suggest that anyone trying to build their own versatile light kit should include at least one spot light and not just rely on LED panel lights. Having a good, bright spot light allows you to a lot more creative lighting as a spot light, especially if you add the Fresnel lens can be used with gobo’s or objects in the foreground to create interesting shadow effects.

Grab3_3.16.1-600x338 Nanlite Forza 300 LED Spotlight

For a recent short film shoot I used the Forza 300 to throw light through a forest of trees. The trees creating interesting shadows adding a lot of extra contrast to the shots.  For another scene I used the Forza 300 as a backlight through some smoke for an interesting mystic effect. A flat panel light cannot reproduce these effects in the same way.

grab1_3.3.1-600x338 Nanlite Forza 300 LED Spotlight

For this shoot I needed to power the lamp off batteries. It is worth noting that if running the lamp at is maximum output of 300 watts you will be drawing over 10 amps from each of the 2 V-Lock batteries need to run it. This is right at the limit of what many V-Locks can deliver.  As a result you may find your batteries cutting off before they are fully discharged. To run a high power LED lamp like this you should consider Lithium Manganese batteries or other batteries capable of at least a 12 amp output. My own preference is to use Pag Paglink batteries as by linking two batteries together you can double the amount of power they can deliver. Using 4 Paglink batteries (2 pairs of 2) I was able to run the lamp for 90  minutes at full power.

4xpags_3.13.1-600x338 Nanlite Forza 300 LED Spotlight
4 Paglink batteries will power the Forza 300 for around 90 minutes.



The lamp I used for the review was supplied by Prolight Direct UK. They are very knowledgable with many years of experience with all kinds of film and television lighting, so do contact them with your lighting needs.

I highly recommend the Forza 300. It is, in my opinion, one of the best of this type of lamp on the market today and very competitively priced. Please see the video above for more information.

Nanlite.com

Hollyland Lark 150 Dual Channel wireless Mic System

In this video – live streamed on June 24th 2021 I take a look at the new Hollyland Lark 150 dual channel wireless microphone system.

The Lark 150 is a compact digital wireless microphone system that is available as a single channel or dual channel kit. If you buy the single channel kit you can add an extra transmitter pack later if you wish and pairing the units is really simple.

Each kit is supplied in a storage box that acts as a drop-in charger. To pair the transmitters to the receiver simply place them all in the storage box together and they are paired automatically, it’s as simple as that.

The transmitter units have a built in microphone and come with a clip on fluffy wind gag. But in addition a plug in lavalier microphone of pretty good quality is also included in the kit, one for each transmitter pack. There is also a mute button on each transmitter unit.

The receiver outputs a mono output or stereo output via a 3.5mm TRS socket depending on you personal preferences (connecting cables for cameras or phones are included in the kit). There is also a handy “safety mode” that outputs at full level on channel 1 and at a reduced level on channel 2. This is great for filming in environments where the audio levels can suddenly change as the lower level recording helps avoid clipping or distortion if the levels suddenly increase. There are two large control knobs on the receiver that control the levels of the two channels and allow you to switch between the different operating modes. The LCD screen clearly shows how the microphone is configured along with the audio levels. There is an additional headphone output on the receiver for headphone monitoring in case your camera doesn’t have a headphone jack.

Battery life is excellent, I got around 8 hours of use from a single charge. To charge the transmitter and receiver units just put them in the carry case and the battery built into the case will charge them back up again. The case has a USB socket to charge it.

The sound quality is very good for a low cost system. As it is entirely digital there is virtually no hiss or noise. The only downside is that the range is more limited than most much more expensive professional radio mics. This system uses the licence free 2.4Ghz band so there are no licensing issues in most countries and the digital transmissions are very secure, so you don’t need to worry about people illicitly  listening in. 

While you can get up to 100m/300ft range from them in perfect conditions. I found that I reliably and consistently get a range of about 100ft (30m). Operate them in this distance range and they are generally rock solid. However if the presenters body or some other substantial objects gets between the transmitter and receiver there is a small decrease in range, perhaps dropping to a reliable  50ft (15m). This is still plenty for most applications.

I really like these microphones. They won’t replace my much more expensive Sony UWP-D professional microphones, but they are great when you need something compact, ultra light and really simple to use. They are perfect for a lot of blogging applications as well as for interviews etc. At a cost of around £210/$275 for the dual channel kit these are excellent value for the money.

Fixing Hot or Bright Pixels On the Sony FX3

The FX3’s larger brothers, the FX6 and FX9 have a function called “APR” that is used to periodically inspect every pixel on the sensor and normalise or map out any out of spec pixels. With modern 4K cameras having at least 8.8 million pixels the chances of a few going out of spec or being damaged by cosmic rays from time to time is quite high. So on the FX6 and FX9 you will get a reminder to perform the APR process around once a week.

From what I understand, the Alpha series cameras and FX3 also periodically perform a similar process automatically. Because these camera have a mechanical shutter to shut out any external light there is no need for any user intervention to perform this process so you will not be aware that it’s happening. On the FX6 and FX9 the user has to place a cap over the lens or sensor, hence why the camera asks you before it can happen.

But what if you find you have some bright or hot pixels with the FX3? Perhaps you have just travelled on a plane where the high altitude reduces the atmospheres damping effect of the high energy particles from space that can damage pixels. Well you can go into the camera’s menu system and force it to run its pixel mapping process which does the same thing as APR on the other cameras.

You need to go to:

MENU:  (Setup) ? [Setup Option] ? select [Pixel Mapping] and then select OK.  It doesn’t take long and I would recommend that you do this after flying on a plane or prior to any shoot where you will use large amounts of gain as this is when hot pixels are most likely to show up.

Understanding Sony’s Viewfinder Display Gamma assist.

Most of sony’s cameras that support S-Log3 or Hybrid Log Gamma also have a function called Viewfinder Display Gamma Assist.

Viewfinder Display Gamma Assist allows you to monitor with the cameras built in LCD screen or viewfinder with the correct brightness and contrast range when using gamma curves that are not directly compatible with these Rec-709 screens.

Whenever you try to view a gamma curve that is not normal Rec-709 on a Rec-709 screen the brightness and contrast that you will see will be incorrect. The most common scenario is perhaps viewing S-Log3 without any form of LUT. In this case the images will look less bright and have less contrast than they should and this makes judging exposure difficult and as well as making it less easy to see focus errors.

With a camera like the FX6 or FX9 most people will use the cameras CineEI mode and add a LUT to the viewfinder image to convert the S-Log3 to something that looks more contrasty and on the FX6 and FX9 the default LUT is “s709”.  However s709 is not the same thing as Rec-709.

I think a lot of people think that the default s709 LUT is the same as Rec-709, it’s not, it is very different. They look very different and result in quite different brightness levels when exposed correctly. s709 when exposed correctly will put skin tones somewhere around 50-60% and white at 78%. If you expose s709 using normal Rec-709 brightness levels (70% skintones, 90% white) this is actually over exposed by just over 1 stop. As a result if you expose the s709 LUT, using Rec-709 levels, and then turn off the LUT and instead use Viewfinder Gamma Assist, the gamma assist will look wrong, it will be too bright and may look washed out and this is simply because the exposure IS wrong.

Almost always, if the viewfinder display gamma assist looks wrong, the exposure is wrong. When it looks right, the likelihood is the exposure is right.

A few things to understand:
  • The viewfinder is a Rec-709 range display device only capable of showing Rec-709 range and colour.
  • Feed true Rec-709 to a Rec-709 device and you will have a correct looking image with “normal” brightness, contrast and colour.
  • Feed S-Log3 to a Rec-709 device and you will have an incorrect dull, flat looking image due to the gamma miss-match between the capture gamma and display gamma.
  • Feed S-Log3 to a device with S-Log3 gamma and you will once again have the correct brightness and contrast as there is no longer a gamma miss-match (S-Log3 only appears to be flat due to the gamma missmatch between S-Log3 and Rec-709, use the right gamma and you will see that it is not actually flat).

Viewfinder Display Gamma Assist works by changing the gamma curve used in the Viewfinder to a gamma curve similar to S-Log3. When you view S-Log3 with S-Log3 gamma you will have the correct contrast and brightness, so correct exposure will look correct.

But because the cameras LCD display screen can only show 6 to 7 stops you don’t get the full S-Log3 viewing range, just the central mid range part that is the direct equivalent of Rec-709. This very closely matches what you see if you use the Sony 709(800) LUT to convert the S-log3 to 709. The 709(800) LUT converts S-Log2 or S-Log3 to vanilla Rec-709 (70% skintones/90% white) with a knee that provides a slightly extended highlight range. It is broadly comparable to how most conventional Rec-709 cameras will look. So as a result viewfinder display gamma assist and Sony’s 709(800) LUT’s will look almost identical, while the s709 LUT will (and should by design) look different.


Viewfinder Display Gamma Assist is extremely useful for scenarios where you do not have a LUT option. It can help you make good exposure assessments. It can make it easier to see when you are in focus. But it isn’t a LUT, so can’t be applied to the cameras outputs, only the built in viewfinder. Additionally if you use zebras, the waveform or histogram, gamma assist has no effect on these so you must remember that you are still measuring the levels f the actual recording gamma, not Rec-709 levels.

Viewfinder Gamma Assist is useful not only for shooting with S-Log but also when shooting using HLG (Hybrid Log Gamma). HLG is an HDR gamma curve and because the LCD viewfinder isn’t HDR you can’t correctly monitor HLG directly. Viewfinder Gamma Assist allows you to monitor with the correct brightness and contrast when shooting HLG making it easier to confidently get the correct exposure levels, as much like S-log3 the levels required for the correct exposure of HLG are quite different to Rec-709.

One last thing: NEVER use Viewfinder Gamma Assist with a LUT at the same time, this will result in a completely incorrect looking image and could result in very bad exposure as a result.