Category Archives: Shooting Tips

Timecode doesn’t synchronise anything!!!

There seems to be a huge misunderstanding about what timecode is and what timecode can do. I lay most of the blame for this on manufactures that make claims such as “Our Timecode Gadget Will Keep Your Cameras in Sync” or “by connecting our wireless time code device to both your audio recorder and camera everything will remain in perfect sync”. These claims are almost never actually true.

What is “Sync”.

First we have to consider what we mean when we talk about “sync” or synchronisation.  A dictionary definition would be something like “the operation or activity of two or more things at the same time or rate.” For film and video applications if we are talking about 2 cameras they would be said to be in sync when both start recording each frame that they record at exactly the same moment in time and then over any period of time they record exactly the same number of frames, each frame starting and ending at precisely the same moment.

What is “Timecode”.

Next we have to consider what time code is. Timecode is a numerical value that is attached to each frame of a video or an audio recording in an audio device to give it a time value in hours, minutes, seconds, frames. It is used to identify individual frames and each frame must have a unique numerical value. Each individual successive frames timecode value MUST be “1” greater than the frame before (I’m ignoring drop frame for the sake of clarity here). A normal timecode stream does not feature any form of sync pulse or sync control, it is just a number value.

Controlling the “Frame Rate”.


And now we have to consider what controls the frame rate that a camera or recorder records at. The frame rate the camera records at is governed by the cameras internal sync or frame clock. This is normally a  circuit controlled by a crystal oscillator. It’s worth noting that these circuits can be affected by heat and at different temperatures there may be very slight variations in the frequency of the sync clock. Also this clock starts when you turn the camera on, so the exact starting moment of the sync clock depends on the exact moment the camera is switched on. If you were to randomly turn on a bunch of cameras their sync clocks would all be running out of sync. Even if you could press the record button on each camera at exactly the same moment, each would start recording the first frame at a very slightly different moment in time depending on where in the frame rate cycle the sync clock of each camera is. In higher end cameras there is often a way to externally control the sync clock via an input called “Genlock”.  Applying a synchronisation signal to the cameras Genlock input will pull the cameras sync clock into precise sync with the sync signal and then hold it in sync. 

And the issue is………..

Timecode doesn’t perform a sync function. To SYNCHRONISE two cameras or a camera and audio recorder you need a genlock sync signal and timecode isn’t a sync signal, timecode is just a frame count  number. So timecode cannot synchronise 2 devices. The camera’s sync/frame clock might be running at a very slightly different frame rate to the clock of the source of the time code. When feeding timecode to a camera the camera might already be part way through a frame when the timecode value for that frame arrives, making it too late to be added, so there will be an unavoidable offset. Across multiple cameras this offset will vary, so it is completely normal to have a +/- 2 frame (sometimes more) offset amongst several cameras at the start of each recording.

And once you start to record the problems can get even worse…

If the camera’s frame clock is running slightly faster than the clock of the TC source then perhaps the camera might record 500 frames but only receive 498 timecode values – So what happens for the 2 extra frames the camera records in this time? The answer is the camera will give each frame in the sequence a unique numerical value that increments by 1, so the extra frames will have the necessary 2 additional TC values. And as a result the TC in the camera at the end of the clip will be an additional 2 frames different to that of the TC source. The TC from the source and the TC from the camera won’t exactly match, they won’t be in sync or “two or more things at the same time or rate”, they will be different.

The longer the clip that you record, the greater these errors become as the camera and TC source drift further apart.

Before you press record on the camera, the cameras TC clock will follow the external TC input. But as soon as you press record, every recorded  frame MUST have a unique new numerical value 1 greater than the previous frame, regardless of what value is on the external TC input. So the cameras TC clock will count the frames recorded. And the number of frames recorded is governed by the camera sync/frame clock, NOT the external TC.  

So in reality the ONLY way to truly synchronise the timecode across multiple cameras or audio devices is to use a sync clock connected to the  GENLOCK input of each device.

Connecting an external TC source to a cameras TC input is likely to be more result in much closer TC values for the audio recorder and camera(s) than no connection at all. But don’t be surprised if you see small 1 or 2 frame errors at the start of clips and possibly much larger errors at the ends of clips, these errors are expected and normal. If you can’t genlock everything with a proper sync signal, a better way to do it is to use the camera as the TC source and feed the TC from the camera to the audio recorder. Audio recorders don’t record in frames, they just lay the TC values alongside the audio, as an audio recorder doesn’t need to count frames the TC values will always be in the right place in the audio file to match the cameras TC frame count. 

CineEI is not the same as conventional shooting.

I’ve covered this many, many times before, but so many people still struggle to get their head around using the CineEI mode in a Sony camera.

Shooting using CineEI is a very different process to conventional shooting. The first thing to understand about CineEI and Log is that the number one objective is to get the best possible image quality and this can only be achieved by recording at the cameras base sensitivity. If you add in camera gain you add noise and reduce the dynamic range that can be recorded, so you always need to record at the cameras base sensitivity for the best possible “negative” or captured image.

Sony call their system CineEI. On an Arri camera the only way to shoot is using Exposure Indexes and it’s the same with Red, Canon and almost every other digital cinema camera. You record at the cameras base sensitivity.

It is assumed that when using CineEI that you will control the light levels in your shots to levels suitable for the recording ISO of the camera, again it’s all about getting the best possible image quality.

Then changing the EI allows you to tailor where the middle of your exposure range is and the balance between more highlight/less shadow or less highlight/more shadow detail in the captured image. On a bright high contrast exterior you might want more highlight range, while on a dark moody night scene you might want more shadow range.

EI is NOT the same as ISO.

ISO= The cameras sensitivity to light.
EI = Exposure Index.

Most cine film stocks had both an ISO rating, where the ISO was the laboratory measured sensitivity and an Exposure Index which was the recommended value to use in a light meter to obtain the best results in a typical practical filming situation. More often than not the ISO and EI values were slightly different.

EI is an exposure rating, not a sensitivity rating. EI is the number you would put into a light meter for the best exposure for the type of scene you are shooting or it is the exposure value of the LUT that you are monitoring with. The EI that you use depends on the desired shadow/highlight range and it is more often than not unwise to raise the EI in a low light situation.


A higher EI than the base ISO will result in images with less shadow range, more highlight range and more noise. This is not what you normally want when shooting darker scenes, you normally want less noise, more shadow range. So with CineEI, you would normally try to shoot a darker, moody scene with an EI lower than the base ISO.

Screenshot-2022-02-11-at-10.15.43-600x270 CineEI is not the same as conventional shooting.
In this chart we can see how at 800 EI there is 6 stops of over exposure range and 9 stops of under. At 1600 EI there will be 7 stops of over range and 8 stops of under and the image will also be twice as noisy. At 400 EI there are 5 stops over and 10 stops under and the noise will be halved.



This goes completely against most peoples conventional exposure thinking. But the CineEI mode and log are not conventional and require a completely different approach if you really want to achieve the best possible results. If you find the images are too dark when the EI value matches the recording base ISO, then you need to add light or use a faster lens. Raising the EI to compensate is likely to create more problems than it will fix. It might brighten the image in the viewfinder, making you think all is OK, but you won’t see the extra noise and grain that will be in the final images once you have raised your levels in post production on a small viewfinder screen. Using a higher EI and not paying attention could result in you stopping down a touch to protect some blown out highlight or to tweak the exposure when this is probably the last thing you want to do.

I’ve lost count of the number of times I have seen people cranking up the EI to a high value thinking this is how you should shoot a darker scene only to discover they can’t then make it look good in post production. The CineEI mode on these cameras is deliberately kept separate from the conventional “custom” or “SDR” mode to help people understand that this is something different. And it really does need to be treated differently and you really do need to re-learn how you think about exposure.

The CineEI mode in some regards emulates how you would shoot with a film camera. You have a single film stock with a fixed sensitivity (the base ISO). Then you have the option to expose that stock brighter (using a lower EI) for less grain, more shadow detail, less highlight range or expose darker (using a higher EI) more grain, less shadow detail, more highlight range. Just as you would do with a film camera.

Handy Tips For Using The Sony Variable ND Filter Values.

Sony rate the ND filters in most of there cameras using a fractional value such as 1/4, 1/16, 1/64 etc.

These values represent the amount of light that can pass through the filter, so a 1/4 ND lets 1/4 of the light through. 1/4 is the equivalent to 2 stops ( 1 stop = half,  2 stops = 1/4,  3 stops = 1/8,  4 stops = 1/16,  5 stops = 1/32, 6 stops = 1/64,  7 stops = 1/128).


These fractional values are actually quite easy to work with in conjunction  with the cameras ISO rating.

If you want to quickly figure out what ISO value to put into a light meter to discover the aperture/shutter needed when using the camera with the built in ND filters, simply take the cameras ISO rating and multiply it by the ND value. So 800 ISO with 1/4 ND becomes 800 x 1/4 = 200 (or you can do the maths as 800 ÷ 4). Put 200 in the light meter and it will tell what aperture to use for your chosen shutter speed.

If you want to figure out how much ND to use to get an equivalent overall ISO rating (camera ISO and  ND combined) you take the ISO of the camera and divide by the ISO you want and this gives you  a value “x” which is the fraction in 1/x. So if you want 3200 ISO then take the base of 12800 and divide by 3200 which gives 4, so you want 1/4 ND at 12800.

My Exposure Looks Different On My LCD Compared To My Monitor!

This is a common problem and something people often complain about. It may be that the LCD screen of their camera and the brightness of the  image on their monitor don’t ever seem to quite match. Or after the shoot and once in the grading suite the pictures look brighter or darker than they did at the time of shooting.

A little bit of background info: Most of the small LCD screens used on video cameras are SDR Rec-709 devices. If you were to calibrate the screen correctly the brightness of white on the screen would be 100 Nits. It’s also important to note that this level is the level that is also used for monitors that are designed to be viewed in dimly lit rooms such as edit or grading suites as well as TV’s at home.

The issue with uncovered LCD screens and monitors is your perception of brightness changes according to the ambient viewing light levels. Indoors in a dark room the image on it will appear to be quite bright. Outside on a Sunny day it will appear to be much darker. It’s why all high end viewfinders have enclosed eyepieces, not just to help you focus on a small screen but also because that way you are always viewing the screen under the very same always dark viewing conditions. It’s why a video village on a film set will be in a dark tent. This allows you to then calibrate the viewfinder with white at the correct 100 NIT level and then when viewed in a dark environment your images will look correct.


If you are trying to use an unshaded LCD screen on a bright sunny day you may find you end up over exposing as you compensate for the brighter viewing conditions. Or if you also have an extra monitor that is either brighter or darker you may become confused as to which is the right one to base your exposure assessments on. Pick the wrong one and your exposure may be off.  My recommendation is to get a loupe for the LCD, then your exposure assessment will be much more consistent as you will then always be viewing the screen under the same near ideal conditions.

It’s also been suggested that perhaps the camera and monitor manufacturers should make more small, properly calibrated monitors. But I think a lot of people would be very disappointed with a proper calibrated but uncovered display where white would be 100 NITs as it would be too dim for most outside shoots. Great indoors in a dim room such as an edit or grading suite but unusably dim outside on a sunny day. Most smaller camera monitors are uncalibrated and place white 3 or 4 times brighter at 300 NIT’s or so to make them more easily viewable outside. But because there is no standard for this there can be great variation between different monitors making it hard to understand which one to trust depending on the ambient light levels.

SDI Failures and what YOU can do to stop it happening to you.

Sadly this is not an uncommon problem. Suddenly and seemingly for no apparent reason the SDI output on your camera stops working. And this isn’t a new problem either, SDI ports have been failing ever since they were first introduced. This issue affect all types of SDI ports. But it is more likely with higher speed SDI ports such as 6G or 12G as they operate at higher frequencies and as a result the components used are more easily damaged as it is harder to protect them without degrading the high frequency performance.

Probably the most common cause of an SDI port failure is the use of the now near ubiquitous D-Tap cable to power accessories connected to the camera. The D-Tap connector is sadly shockingly crudely designed. Not only is it possible to plug in many of the cheaper ones the wrong way around but with a standard D-Tap plug there is no mechanism to ensure that the negative or “ground” connection of the D-Tap cable makes or breaks before the live connection. There is a however a special but much more expensive D-Tap connector available that includes electronic protection against this very issue – see: https://lentequip.com/products/safetap

Imagine for a moment you are using a monitor that’s connected to your cameras SDI port. You are powering the monitor via the D-Tap on the cameras battery as you always do and everything is working just fine. Then the battery has to be changed. To change the battery you have to unplug the D-Tap cable and as you pull the D-Tap out, the ground connection disconnects fractionally before the live connection. During that moment there is still positive power going to the monitor but because the ground on the D-Tap is now disconnected the only ground route back to the battery becomes via the SDI cable through the camera. For a fraction of a second the SDI cable becomes the power cable and that power surge blows the SDI driver chip.

After you have completed the battery swap, you turn everything back on and at first all appears good, but now you can’t get the SDI output to work. There’s no smoke, no burning smells, no obvious damage as it all happened in a tiny fraction of a second. The only symptom is a dead SDI.

And it’s not only D-Tap cables that can cause problems. A lot of the cheap DC barrel connectors have a center positive terminal that can connect before the outer barrel makes a good connection. There are many connectors where the positive can make before the negative.

It can also happen when powering the camera and monitor (or other SDI connected devices like a video transmitter) via separate mains adapters. The power outputs of most of the small, modern, generally plastic bodied switch mode type power adapters and chargers are not connected to ground. They have a positive and negative terminal that “floats” above ground at some unknown voltage. Each power supplies negative rail may be at a completely different voltage compared to ground.  So again an SDI cable connected between two devices, powered by different power supplies will act as the ground between them and power may briefly flow down the SDI cable as the SDI cables ground brings both power supply negative rails to the same common voltage. Failures this way are less common, but do still occur. 

For these reasons you should always connect all your power supplies, power cables and especially D-Tap or other DC power cables first. Then while everything remains switched off connect the SDI cables. Only when everything is connected should you turn anything on. If unplugging or re-plugging a monitor (or anything else for that matter) turn everything off first. Do not connect or disconnect anything while any of the equipment is on.  Although to be honest the greatest risk is at the time you connect or disconnect any power cables such as when swapping a battery where you are using the D-Tap to power any accessories. So if changing batteries, switch EVERYTHING off first, then disconnect your SDI cables before disconnecting the D-Tap or other power cables next.

(NOTE: It’s been brought to my attention that Red recommend that after connecting the power, but before connecting any SDI cables you should turn on any monitors etc. If the monitor comes on OK, this is evidence that the power is correctly connected. There is certainly some merit to this. However this only indicates that there is some power to the monitor, it does not ensure that the ground connection is 100% OK or that the ground voltages at the camera and monitor are the same. By all means power the monitor up to check it has power, then I still recommend that you turn it off again before connecting the SDI).
 
The reason Arri talk about shielded power cables is because most shielded power cables use connectors such as Lemo or Hirose where the body of the connector is grounded to the cable shield. This helps ensure that when plugging the power cable in it is the ground connection that is made first and the power connection after. Then when unplugging the power breaks first and ground after. When using properly constructed shielded power cables with Lemo or Hirose connectors it is much less likely that these issues will occur (but not impossible).

Is this an SD fault? No, not really. The fault lies in the choice of power cables that allow the power to make before the ground or the ground to break before the power breaks.  Or the fault is with power supplies that have poor or no ground connection. Additionally you can put it down to user error. I know I’m guilty of rushing to change a battery and pulling a D-Tap connector without first disconnecting the SDI on many occasions, but so far I’ve mostly gotten away with it (I have blown an SDI on one of my Convergent Design Odysseys).

If you are working with an assistant or as part of a larger crew do make sure that everyone on set knows not to plug or unplug power cables or SDI cables without checking that it’s OK to do so. How many of us have set up a camera, powered it up, got a picture in the viewfinder and then plugged an SDI cable between the camera and a monitor that doesn’t have a power connection yet or already on and plugged in to some other power supply? Don’t do it! Plug and unplug in the right order – ALL power cables and power supplies first, check power is going to the camera, check power is going to the monitor, then turn it all off first, finally plug in the SDI.

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.

What Benefits Do I Gain By Using CineEI?

This is a question that comes up a lot. Especially from those migrating to a camera with a CineEI mode from a camera without one. It perhaps isn’t obvious why you would want to use a shooting mode that has no way of adding gain to the recordings.

If using the CineEI mode shooting S-log3 at the base ISO, with no offsets or anything else then there is very little difference between what you record in Custom mode at the base ISO and CineEI at the base EI.

But we have to think about what the CineEI mode is all about. It’s all about image quality. You would normally chose  to shoot S-Log3 when you want to get the highest possible quality image and CineEI is all about quality.

The CineEI mode allows you to view via your footage via a LUT so that you can get an appreciation of how the footage will look after grading. Also when monitoring and exposing via the LUT because the dynamic range of the LUT is narrower, your exposure will be more accurate  and consistent because bad exposure looks more obviously bad. This makes grading easier. One of the keys to easy grading is consistent footage, footage where the exposure is shifting or the colours changing (don’t use ATW with Log!!) can be very hard to grade.

Then once you are comfortable exposing via a LUT you can start to think about using EI offsets to make the LUT brighter or darker. When the LUT is darker you open the aperture or reduce the ND to return the LUT to a normal looking image and vice versa with a brighter LUT.  This then changes the brightness of the S-log3 recordings and you use this offsetting process  to shift the highlight/shadow range as well as noise levels to suit the types of scenes you are shooting. Using a low EI (which makes the LUT darker) plus correct LUT exposure  (the darker LUT will make you open the aperture to compensate) will result in a brighter recording which will improve the shadow details and textures that are recorded and thus can be seen in the shadow areas. At the same time however that brighter exposure will reduce the highlight range by a similar amount to the increase in the shadow range. And no matter what the offset, you always record at the cameras full dynamic range.

I think what people misunderstand about CineEI is that it’s there to allow you to get the best possible, highly controlled images from the camera. Getting the best out of any camera requires appropriate and sufficient light levels. CineEI is not designed or intended to be a replacement for adding gain or shooting at high recording ISOs where the images will be already compromised by noise and lowered dynamic range.
 
CineEI exists so that when you have enough light to really make the camera perform well you can make those decisions over noise v highlights v shadows to get the absolute best “negative” with consistent and accurate exposure to take into post production. It is also the only possible way you can shoot when using raw as raw recordings are straight from the sensor and never have extra gain added in camera.
 
Getting that noise/shadow/highlight balance exactly right, along with good exposure is far more important than the use of external recorders or fatter codecs. You will only ever really benefit fully from higher quality codecs if what you are recording is as good as it can be to start with. The limits as to what you can do in post production are tied to image noise no matter what codec or recording format you use. So get that bit right and everything else gets much easier and the end result much better. And that’s what CineEI gives you great control over.
 
When using CineEI or S-Log3 in general you need to stop thinking “video camera – slap in a load if gain if its dark” and think “film camera – if its too dark I need more light”. The whole point of using log is to get the best possible image quality, not shooting with insufficient light and a load of gain and noise. It requires a different approach and completely different way of thinking, much more in line with the way someone shooting on film would work.

What surprises me is the eagerness to adopt shutter angles and ISO ratings for electronic video cameras because they sound cool but less desire to adopt a film style approach to exposure based on getting the very best from the sensor.  In reality a video sensor is the equivalent of a single sensitivity film stock. When a camera has dual ISO then it is like having a camera that takes two different film stocks.  Adding gain or raising the ISO away from the base sensitivity in custom mode is a big compromise that can never be undone. It adds noise and decreases the dynamic range. Sometimes it is necessary, but don’t confuse that necessity with getting the very best that you can from the camera.

For more information on CineEI see:

Using CineEI with the FX6  
 
 

Rigging the FX6 – Shoulder mounts, Rod, Brackets, etc.

In this video I take a look at all sorts of rigging options for the Sony FX6.

Some of the key areas discussed:

0:01:30 Camrade Travel Mate 360 carry-on camera wheelie bag.

0:04:30 Vocas Sliding Plate Basic.

0:06:30 Chrosziel Base Plate and Quick Lock Plate.

0:09:00 Vocas Sliding VCT Base Plate.

0:10:00 Making sure the rod height is correct.

0:12:00 Vocas Matte Boxes.

0:17:00 Using a V-Mount battery to balance the camera.

0:22:30 Paglink V-Mount Batteries and flying with large batteries.

0:30:00 Vocas Flexible Camera Rig.

0:38:30 Arms for the hand grip (Vocas and Chrosziel).

0:40:30 Viewfinder considerations and options.

0:42:00 Gratical Viewfinders with Vocas Nato Rail.

0:44:00 FX6 Screen with FX9 Loupe.

0:46:00 Adding Extra hand grips, other hand grip mounting options.

0:51:00 Using the FX6 with the FX9 viewfinder.

0:52:30 TopTeks and CVP FX6 viewfinder modification.

0:54:30 Notes on the potential for LCD screen sun damage.

0:57:00 Vocas PL Mount adapter – importance of shims.

1:00:00 Why I avoid magic arms, especially for viewfinders.

1:03:00 Atomos Ninja V discussion.

1:07:00 H&Y Variable ND filter.
1:12:00 Summary and wrap up.

There Is No Such Thing As A “12G” SDI Cable.

The way the coax cables used for SDI works is very different to the way an HDMI cable works. HDMI cables are indeed constructed quite differently between early HDMI 1.0 – 1.4 classes and the more recent 2.0+ classes. So with HDMI you will find that an old, early version HDMI cable won’t work with the latest standards.

SDI cables are nothing fancy.

SDI uses nothing more sophisticated than a single core coax cable that is no different in it’s basic design, construction and mode of operation to an ordinary TV aerial down lead. It is a very simple type of cable and really nothing fancy.

Frequency matters.

The SDI signal is very high frequency; in effect it is a radio signal. From a cabling point of view the ONLY difference between the original SDI standard and the latest standards is the frequency. The way the cable works is no different between the original SDI standard and the latest and a camera or monitor has no way of telling or knowing what type of cable you are using.

Frequency is important because the higher the frequency, the more lossy ANY coax cable will become (leaky kind of describes what’s going on). Low quality cable – more signal leaks out, high quality cable less leaks out so the signal will go further.

But even the very earliest SDI cables were normally made using good quality very low loss coax. These original SDI cables are perfectly capable of carrying the higher frequencies used by 12G SDI. BUT over very long lengths there will be more loss at 12G than at 1.5G.  

It’s not the “G” that counts, it’s the quality.

So really when looking for SDI cables, the question isn’t – “is it 12G” the question should be “what are the cable losses” or more simply “is it a good quality cable”. There are plenty of original SDI cables that can be used at 50m at 12G without issue. At the same time I have also seen cables marketed as “12G” that are nowhere near as well screened, with much higher losses, that barely work at 10m.

Just as important as the cable losses is the construction. Have the connectors been fitted correctly? Are the connectors correctly sized for the cable that’s being used, has the crimping or soldering been done well? Most coax cable failures are due to poor connector assembly or the use of low-quality connectors.

Impedance Matter.

One other thing to watch for is the cable impedance. SDI cables should be made using 75 ohm impedance cable and connectors. Radio cables for radio communications normally use 50 ohm cables and connectors and the two are not really compatible. But often cheaper cables sold for SDI and video applications may be made using 50 ohm parts as often these are cheaper. These cables will fit and more often than not they appear to work. BUT the pins in the BNC plugs are a different size and this can result in intermittent connections and over time can even damage the connectors on cameras and monitors etc. So do make sure your cables really are 75 ohm.

In the real world:

For most shorter cables, up to 5m cable losses are rarely an issue unless the cable is of particularly low quality or badly made. For between 5m and 10m you should avoid the very thin coax cables as the losses become more significant. Above 10m use only low loss cables with good quality screening. A cable sold as a “12G” cable should indicate good quality low loss cable, but it is not a guarantee. And the vast majority of well-constructed normal SDI cables will work just as well unless you want extremely long runs in which case you need ultra-low loss cable.