Category Archives: PXW-FS5

cameras, cinematography, PMW-F55, PXW-FS5, PXW-FS7

Auto Knee when shooting with Rec-709.

March 8, 2017 alisterchapman 7 Comments

Like many cameras the Sony PXW-FS7, PMW-F5 and F55 use an automatic knee circuit to help the camera handle strong highlights or overexposure when shooting using standard gamma curves such as Rec-709 (STD gamma 5). On some ENG cameras there is a very similar function called DCC (Dynamic Contrast Compensation) which is often selected via the Camera/Bars switch.

On the FS7, F5/F55 and many others the Auto Knee is on by default out of the factory. It can be turned on and off in the cameras paint settings. In most normal shooting situations, if you are correctly exposed the auto knee does a good job of bringing bright highlights down out of clipping. The auto knee threshold is at around 90% brightness. Expose with objects brighter than 90% in your scene and the auto knee starts to kick in.

The correct exposure for white, such as a 90% reflectivity white card or white piece of paper in Rec-709 is 90%. Skin tones, plants, walls, roads and in fact most objects will normally be below white or below 90%. However direct light sources, such as the sky or direct reflections such as shiny car body work will be brighter than white. So the knee should only ever effect objects brighter than white if you are exposed correctly. So for most situations it should not effect skin tones and the majority of the scene, just the bright highlights.

The auto knee detects highlight levels above 90% and tries to keep the highlight range below clipping by adding contrast compression to the highlights. The amount of compression depends on how strong the highlights are. As a result the auto knee effect will vary with exposure. If you have a scene with only a few highlights there will be some knee compression and it’s effect will only be seen above approx 90%. If you then open the aperture or have a lot of highlights the auto knee will increase the highlight compression to compensate. If the highlight range becomes very large then the knee will not only increase the amount of compression but also lower the knee point so more and more of the upper exposure range is effected by the knee. In extreme cases the knee point may get as low as 70-80% and this then starts to effect skin tones.

To prevent rapid fluctuations of the contrast in the highlight range the auto knee has a slight delay. This can result in a vicious circle where you open the iris a bit to help brighten the shot. The shot gets brighter. Then a couple of seconds later you look at the shot again and because the knee has now adjusted the highlights after it’s delay period it looks different to how it looked at the moment you made the initial adjustment. So you adjust again…. then the knee adjusts again and so on. Sometimes this lag can make it tricky to get your highlights to look exactly how you want.

Another common auto knee effect is to see the brighter parts of an entire image change as a result of a change in only a small part of the scene. A typical example would be an interview with a window in the background. As the highlight level in the bright window changes, perhaps as the sun comes and goes from behind passing clouds, the knee tries to compensate and all of the highlights in the scene go up and down in brightness whether they are over exposed or not. This looks very strange and can ruin an otherwise good looking shot.

If you are shooting in a studio against a white background the auto knee makes it impossible to get a brilliantly bright uniformly clipped white background. You increase your exposure to make the white background extra bright and because that white is now above 90% the auto knee treats it as a highlight and tries to control it’s brightness. The more you open the aperture the more the knee pulls down the white background, it never reaches clipping. Eventually you get to the point where the knee starts to effect the skin tones but your white backdrop still isn’t clipped. The image doesn’t look great.

In these cases the best thing to do is to turn off the Auto Knee. If you go into the paint settings you will find the knee settings. In most cases leave the knee on (except perhaps for the white studio example), but turn OFF the auto knee function. The fixed level knee will still give you a good highlight range but eliminate the pumping or other variable knee effects. Note that the knee options have no effect if using a Hypergamma or log. They only come into paly with standard gamma.

cameras, cinematography, PXW-FS5, Technology, Workflow

Raw and the PXW-FS5

February 23, 2017 alisterchapman 41 Comments

This isn’t a “how to” guide. There are many different recorders that can be used to record raw from the FS5 and each would need it’s own user guide. This is an overview of what raw is and how raw recording works to help those that are a bit confused, or not getting the best results.

First of all – you need to have the raw upgrade installed on the FS5 and it must be set to output raw. Then you need a suitable raw recorder. Just taking the regular SDI or HDMI output and recording it on an external recorder is not raw.

Raw is raw data direct from the cameras sensor with very little image processing. It isn’t even a color image, it won’t become color until some external processing, often called “De-Bayer” is done to convert the raw data to a color image.

For raw to work correctly the camera has to be set up just right. On the FS5 you should use Picture Profile 7. Don’t try and use any other profile, don’t try and shoot without a profile. You must use Picture Profile 7 at it’s factory default settings. In addition don’t add any gain or change the ISO from 3200 (2000 ISO from version 4.02 firmware). Even if the scene is a dark one, adding gain will not help and it may in fact degrade the recorded image.

White balance is set using the appropriate SGamut + color temperature preset chosen from within Picture Profile 7, there are only 3 to choose from for S-Gamut, but with a raw workflow you will normally fine tune the white balance in post. No other color matrix or white balance method should be used. Trying to white balance any other way may result in the sensor data being skewed or shifted in a way that makes it hard to deal with later on.

All of the above is done to get the best possible, full dynamic range data off the sensor and out of the camera.

If you are viewing the S-Log2 (ie don’t have viewfinder gamma assist enabled) then the exposure level that Sony recommend is to have a white card at 60%. So consider setting the zebras to 60%. Don’t worry that this may look a bit dark or appear to be a low level, but that’s the level you should start with… More about exposure later on.

This raw data is then passed down the SDI cable to the external recorder. The external recorder will then process it, turn it into a color signal (de-bayer) and add a gamma curve so that it can be viewed on the recorders screen. Exactly what it will look like on the monitor screen will depend on how the recorder is set up. IF the recorder is set to show S-Log2, then the recorders screen and the FS5’s LCD should look similar. However you might find that it looks very different to what you are seeing on the FS5’s LCD screen. This is not unexpected. If the recorder is setup to convert the raw to Rec-709 for display then the image on the recorder will be brighter and show more contrast, in fact it should look “normal”.

Under the surface however, the external raw recorder is going to be doing one of two things (normally at least). It’s either going to be recording the raw data coming from the camera as it is, in other words as raw. Or it will be converting the raw data to S-Log2 and recording it as a conventional ProRes or DNxHR video file. Either way when you bring this footage in to post production it will normally appear as a flat, low contrast S-Log2 image rather than a bright, contrasty rec-709 image. So understand that the footage will normally need to be graded or have some other changes made to it to look nice.

Recording the actual raw data will give you the best possible information that you can get from the FS5 to work with in post production. The downside is that the files will be huge and will take a fair amount of processing power to work with. Recording a ProRes or DNxHR video file with S-Log2 gamma is second best. You are throwing away a bit of image quality (going from 12 bit linear down to 10 bit log) but the files should still be superior to the 8 bit UHD internal recordings or even an external recording done via the HDMI which is also limited to 8 bit in UHD.

Most raw recorders have the ability to add a LUT – Look Up Table – to the image viewed on the screen. The purpose of the LUT is to convert the S-Log2/raw to a conventional gamma such as Rec-709 so that the picture looks normal. If you are using a LUT then the normal way to do things is to view the normal looking picture on the recorders screen while the recorder continues to record S-Log2 or raw. This is useful as the image on the screen looks normal so it is easier to judge exposure. With a 709 LUT you would expose the picture so that the image on the recorders screen looks as bright as normal, skin tones would be the usual 70% (ish) and white would be 90%.

There is a further option and that is to “bake in the LUT”. This means that instead of just using the LUT to help with monitoring and exposure you actually record the image that you see on the recorders screen. This might be useful if you don’t have any time for grading, but… and it’s a big BUT…. you are now no longer recording S-log2 or raw. You will no longer have the post production grading flexibility that raw or S-Log2 provide and for me at least this really does defeat the whole point of recording raw.

Exposure: Raw will not help you in low light. Raw needs to be exposed brightly (there are some data limitations in the shadows with 12 bit linear raw compared to 16 bit raw and possibly even 10 bit log). If viewing S-Log2 then Sony’s recommendation is to have a white card or white piece of paper at 60%. I consider that to be the absolute minimum level you can get away with. The best results will normally be achieved if you can expose that white card or piece of paper at around 70% to 75% (when looking at an S-Log2 image). Skin tones would be around 55%. If you expose like this you may need to use a different LUT on the recorder to ensure the picture doesn’t look over exposed on the recorders monitor screen. Most of the recorders include LUT’s that have offsets for brighter exposures to allow for this. Then in post production you will also want a LUT with an exposure offset to apply to the S-Log2 recordings. You can use the search function (top right) to find my free LUT sets and download them. Exposing that bit brighter helps get around the shadow data limitations of 12 bit linear raw and pushes the image up into the highlights where there is more data.

cameras, cinematography, PXW-FS5

PXW-FS5 Native ISO’s

February 13, 2017 alisterchapman 12 Comments

THIS DOCUMENT IS OUT OF DATE NEW FIRMWARE HAS CHANGED THE CAMERAS ISO”S.

This is as much for my benefit as yours as I can never remember what the native ISO (0dB) is for each of the gamma curves in the FS5.

Standard 1000 ISO
Still 800 ISO
Cinegamma 1 800 ISO
Cinegamma 2 640 ISO
Cinegamma 3 1000 ISO
Cinegamma 4 1000 ISO
ITU709 1000 ISO
ITU709(800) 3200 ISO
S-Log2 3200 ISO
S-Log3 3200 ISO

Using dB and setting it to 0dB really is so much easier with this camera!

cinematography, lenses, PXW-FS5, PXW-FS7, Review

The new Sony FS7 zoom lens, the Sony SELP18110G.

February 13, 2017 alisterchapman 19 Comments

When Sony launched the FS7 II they also launched a new lens to go along with it. The previous zoom lens that was bundled with the FS7 was the SELP28135G, a 28-135mm f4 zoom lens that would work with Super 35mm, APS-C and full frame cameras. While generally well received this lens is not without it’s problems. For a start it’s not really wide enough for use as a general purpose lens on an APS-C or Super 35mm sensor. The other problem is that the zoom is very slow. Even when set to manual zooming in and out takes a long time. You turn the zoom ring and then have to wait for the lens to catch up.

The new lens is a wider 18mm to 110mm f4 lens. This is a really useful zoom range for a Super 35mm camera. But the new lens can only be used on S35mm and APS-C cameras. It can’t be used with full frame cameras like the A7s in full frame mode.

The front element of the Sony SELP18110G.

But what about the zoom speed? Well this has been addressed too. On the 28-135mm lens the zoom function is electronic. There is no mechanical connection between the zoom ring and the optics of the lens. The 18-110 has a proper mechanical connection between the zoom ring and the internal lenses, so now you can crash zoom in and out as fast as you want. In addition the zoom servo motor is much faster and motorised zooms take place much more rapidly. One downside to this is that it’s a bit harder to control the zoom speed. You can do slow creeping zooms if you are very careful with the cameras zoom rocker, but it’s hard to do. The difference in pressure on the zoom rocker between creeping zoom and medium speed is tiny. The lens tended to change zoom speed quite quickly. While it is indeed very nice to have a variable speed motorised zoom, don’t expect the fine degree of control that you get from admittedly more expensive traditional ENG lenses. Lets face it this lens is only around £3K/$5K which is remarkable cheap for a parfocal s35mm zoom. Take a look at the video below for an idea of the zoom speeds etc.

Is it really parfocal? Well yes, it does seem to be parfocal. I only had the lens for a morning to play with, but in all my tests the focus remained constant throughout the zoom range.

So, what about focus? Like the 28-135mm lens there is a nice big focus ring that slides fore and aft.

Focus, zoom and iris rings on the SELP18110G.

In the rear position the focus is manual and there are calibrated focus markings and end stops. You get about 180 degrees of focus travel from 0.95m (3.1ft) to infinity (in autofocus you can focus slightly closer when the lens is at the wide end). The focus ring has 0.8mm pitch teeth for use with most standard follow focus units, although this gear ring is very close to the end of the lens, so it may be tricky to use if you have a matte box in place. Breathing is very well controlled and barely noticeable unless going through very large focus throws. Out of focus Bokeh isn’t bad either, I didn’t observe any nasty surprises in the limited time I had to play with the lens.

Frame Grab. Near and far out of focus bokeh is reasonable on the Sony SELP18110G. Click on the image to view a full size copy.

Sharpness and flare. The lens appears to be nice and sharp at the wide end but just a touch soft at the long end. It’s not bad overall but when shooting at 4K I could just about detect the lens becoming marginally softer as I zoomed in. The sample I had was a well used pre-production prototype, but I’m going to guess that the production lenses won’t be hugely different. Shooting the roof of a house against a bright sky revealed only a small amount of flare, certainly nothing out of the unusual for a zoom lens.

Frame grab from the Sony SELP18110G at 110mm. Click on the image to view a full size copy.

Frame grab shot with Sony SELP18110G at 18mm. Click on the image to view the full size image.

Overall I really like this lens. It even has a support point at the front of the lens body for additional stability. While f4 isn’t the largest of apertures it is quite usable and even wide open the lens performs well. For the money it is a lot of lens. I think we need to be realistic with our expectations for zoom lenses and large sensors. Bigger zoom ratios require bigger lens elements if we want to maintain a constant aperture. Bigger lens elements cost more to produce.

Underside of the Sony SELP18110G showing the extra lens support points. A lens foot that attaches to the rear mounting is included with the lens.

One advantage Sony have over the competition is that it’s easier to make zoom lenses for the very short flange back distance of the E-Mount cameras compared to the deeper flange back of PL or Canon mounts. The closest competition to this lens is the Canon 18-80mm T4.4 (f4 ish) which is a fair bit more expensive (£4K/$6K). If you want a similar zoom range then you’re looking at the beautiful Fujinon 20-120 T3.4 at around £14K/$19K.

cameras, cinematography, PXW-FS5, Technology

Not all raw is created equal. Log may be better

February 11, 2017 alisterchapman 12 Comments

This keeps cropping up time and time again.

Unfortunately every now and again a new term or buzzword comes along that gets taken as a holy grail term. Two that come to mind right now are log and raw. Neither log, nor raw, are magic bullet solutions that guarantee the best performance. Used incorrectly or inappropriately both can result in inferior results. In addition there are many flavours of log and raw each with very different performance ranges.

A particular point in case is the 12 bit raw available from several of Sony’s mid range large sensor cameras, the FS700, FS7 and FS5.

Raw can be either log or linear. This particular flavour of raw is encoded using linear data. If it is linear then each successively brighter stop of exposure should be recorded with twice as many code values or shades as the previous stop. This accurately replicates the change in the light in the scene you are shooting. If you make the scene twice as bright, you need to record it with twice as much data. Every time you go up a stop in exposure you are doubling the light in the scene. 12 bit linear raw is actually very rare, especially from a camera with a high dynamic range. To my knowledge, Sony are the only company that offer 14 stops of dynamic range using 12 bit linear data.

There’s actually a very good reason for this: Strictly speaking, it’s impossible! Here’s why: For each stop we go up in exposure we need twice as many code values. With 12 bit data there are a maximum of 4096 code values, this is not enough to record 14 stops.

If stop 1 uses 1 code value, stop 2 will use 2, stop 3 will use 4, stop 4 will use 8 and so on.

STOP: CODE VALUES: TOTAL CODE VALUES REQUIRED.

+1 1 1
+2 2 3
+3 4 8
+4 8 16
+5 16 32
+6 32 64
+7 64 128
+8 128 256 Middle Grey
+9 256 512
+10 512 1,024
+11 1,024 2,048
+12 2,048 4,096
+13 4,096 8,192
+14 8,192 16,384

As you can see from the above if we only have 12 bit data and as a result 4096 code values to play with, we can only record an absolute maximum of 12 stops of dynamic range using linear data. To get even 12 stops we must record the first couple of stops with an extremely small amount of tonal information. This is why most 14 stop raw cameras use 16 bit data for linear or use log encoded raw data for 12 bit, where each stop above middle grey (around stop +8) is recorded with the same amount of data.

So how are Sony doing it on the FS5, FS7 etc? I suspect (I’m pretty damn certain in fact) that Sony use something called floating point math. In essence what they do is take the linear data coming off the sensor and round the values recorded to the nearest 4 or 8. So, stop +14 is now only recorded with 2,048 values, stop +13 with 512 values etc. This is fine for the brighter stops where there are hundreds or even thousands of values, it has no significant impact on the brighter parts of the final image. But in the darker parts of the image it does have an impact as for example stop +5 which starts off with 16 values ends up only being recorded with 4 values and each stop below this only has 1 or two discreet levels. This results in blocky and often noisy looking shadow areas – a common complaint with 12 bit linear raw. I don’t know for a fact that this is what they are doing. But if you look at what they need to do, the options available and you look at the end results for 12 bit raw, this certainly appears to be the case.

Meanwhile a camera like the FS7 which can record 10 bit log will retain the full data range in the shadows because if you use log encoding, the brighter stops are each recorded with the same amount of data. With S-Log2 and 10 bit XAVC-I the FS7 uses approx 650 code values to record the 6 brightest stops in it’s capture range reserving approx 250 code values for the 8 darkest stops. Compare this to the linear example above and in fact what you will see is that 10 bit S-Log2 has as much data as you would expect to find in a straight 16 bit linear recording below middle grey (S-Log 3 actually reserves slightly more data for the shadows). BUT that’s for 16 bit. Sony’s 12 bit raw is squeezing 14 stops into what should be an impossibly small number of code values, so in practice what I have found is that 10 bit S-log has noticeably more data in the shadows than 12 bit raw.

In the highlights 12 bit linear raw will have more data than 10 bit S-log2 and S-Log3 and this is borne out in practice where a brightly exposed raw image will give amazing results with beautiful highlights and mid range. But if your 12 bit raw is dark or underexposed it is not going to perform as well as you might expect. For dark and low key scenes 10 bit S-Log is most likely going to give a noticeably better image. (Note: 8 bit S-log2/3 as you would have from an FS5 in UHD only has a quarter of the data that 10 bit has. The FS5 records the first 8 stops in 8 bit S-log 2 with approx 64 code values, S-Log3 is only marginally better at approx 80 code values. 12 bit linear outperforms 8 bit log across the entire range).

Sony’s F5 and F55 cameras record to the R5 and R7 recorders using 16 bit linear data. 16 bit data is enough for 14 stops. But I believe that Sony still use floating point math for 16 bit recording. This time instead of using the floating point math to make room for an otherwise impossible dynamic range they use it to take a little bit of data from the brightest stop to give extra code values in the shadows. When you have 16,384 code values to play with you can afford to do that. This then adds a lot of extra tonal values and shades to the shadows compared to 10 bit log and as a result 16 bit linear raw will outperform 10 bit log across the entire exposure range by a fairly large margin.

So there you have it. I know it’s hugely confusing sometimes. Not all types of raw are created equal. It’s really important to understand this stuff if you’re buying a camera. Just because it has raw it doesn’t necessarily mean an automatic improvement in image quality in every shooting situation. Log can be just as good or possibly even better in some situations, raw better in others. There are reasons why cameras like the F5/R5 cost more than a FS5/Shogun/Odyssey.

A7, cameras, cinematography, PMW-F55, PXW, PXW-FS5, PXW-FS7, Shooting Tips, Technology

The great S-Log2 or S-Log3 debate.

December 21, 2016 alisterchapman 21 Comments

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

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

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

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

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

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

S-Log3 has noisy shadows.

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

Chart showing S-Log2 and S-Log3 plotted against f-stops and code values. Note how little data there is for each of the darker stops, the best data is above middle grey. Note that current sensors only go to +6 stops over middle grey so S-Log2 and S-Log record to different peak levels.

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

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

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

BUT THERE ARE SOME OTHER FACTORS WE NEED TO CONSIDER.

S-Log2 and S-Gamut:

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

S-Log3 and S-Gamut3.

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

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

Getting the data from camera to post.

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

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

8 Bit Recording.

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

The end result should be the same.

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

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

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

cameras, cinematography, PXW-FS5, Scene Files and Luts

Video Tutorials for the FS5. Picture Profiles and Raw Recording.

December 19, 2016 alisterchapman 12 Comments

I was recently asked by Sony to produce some videos to help users get the most from the PXW-FS5. The videos and articles can now be found on Sony’s website by following the links below. Part 1 covers the camera setup including using Picture Profiles to change the way the images look. Part 2 covers the special effects modes including S&Q, super-slow-motion, clear image zoom and the variable ND filter. Part 3 looks at the raw option for the FS5.

PXW-FS5 Shooting Tips Part 1. Camera Setup and Picture Settings.

PXW-FS5 Shooting Tips Part 2. Slow and Quick Motion, Variable ND, Clear Image Zoom.

PXW-FS5 Recording Raw and using the Raw output option (Atomos Shogun Flame and Convergent Design Odyssey 7Q used as examples).

cameras, PMW-F55, PXW-FS5, PXW-FS7, Scene Files and Luts

Looking For LUT’s for the Sony S-Log2 and S-Log3 Cameras?

November 30, 2016 alisterchapman 1 Comment

This website has a great feature. If you look up in the top left corner of every page you will see a small magnifying glass symbol. If you click on that it will allow you to search the entire site for information… and there’s lots and lots of hint, tips and guides going back many years.

One thing though that a lot of people keep asking about is LUT’s or Look Up Tables. I have lots and they are all (for the moment at least) provided for free. There will be some paid LUT sets coming soon. If you follow the link below you will get a single page that lists all the current LUT articles on the web site. Links to my free LUT sets will be included in these articles.

Remember that LUT’s for S-Log2 and S-Log3 can be used in any camera with S-Log2 or S-Log3. So a LUT for the FS7 can also be used in the FS5 for example.

Here’s the link: https://www.xdcam-user.com/?s=LUT%27s

cameras, PXW-FS5

PXW-FS5 Gets MPEG2 HD Option.

September 9, 2016 alisterchapman 4 Comments

A little bit of news from IBC in Amsterdam is that Sony are going to allow owners of the PXW-FS5 to buy an upgrade that adds the MPEG2 HD codec to the camera. This is the same 8 bit 50Mb/s 4:2:2 codec as used for many years for broadcast HD television production (XDCAM HD422) as well as the 35Mb/s 4:2:0 found in many lower cost Sony camcorders such as the PMW-300 or EX1.

The MPEG2 HD422 codec is one of the most commonly used codecs world wide for TV and video production. It’s supported by just about every edit system and is very easy to handle. So if you need compatibility with legacy edit software such as FCP7 this could be the option you’ve been looking for. When you buy the upgrade you will receive a special activation code that allows you to go online and enter the cameras serial number to generate an unlock key for the codec option. There’s no need to send the camera in and it takes just a few minutes to activate the option.

The upgrade option is called the CBKZ-SLMP and the list price is 500 Euro’s. It’s actually the same upgrade option/key as used to add MPEG2 HD to the PXW-X70, but now as well as the X70 you can use it to upgrade an FS5.

cameras, PXW-FS5, Scene Files and Luts

Picture Profiles for the PXW-FS5.

August 24, 2016 alisterchapman 29 Comments

PXW-FS5 Picture Profiles

The Sony PXW-FS5 is a great little camera. It’s a camera I really enjoy shooting with as I can just grab it and go, picking up some great pictures with the minimum of effort. The built in Picture Profiles offer a wide range of different looks that can be quickly selected by pressing the P Profile button and choosing a profile. But one of the best parts is that you can tweak and adjust each profile to suit different shooting applications.

I tend to leave Picture Profile 7 alone. This is the S-Log2/S-Gamut profile that you must use when shooting raw and S-Log2 is my preferred log curve for shooting 8 bit UHD. But that leaves profiles 1 to 6 to play with and adjust, plus profiles 8 and 9 if you don’t use S-Log3. If you want to go back to the factory settings each profile can be reset individually (using “reset” within the profile settings).

Perhaps the two most challenging situations to shoot in are scenes that are high contrast and bright or low light scenes. Often you may encounter both types of scene on the same shoot, so it would be good if the pictures were at least similar. So we don’t want to use totally different color settings. But you can use different gamma settings to help better deal with the differing lighting levels and contrast ranges.

For brighter scenes I am a big fan of Sony’s “Cinegammas”. The Cinegammas differ from the standard gammas in the way they handle highlights. Basic television gamma has a very limited dynamic range, around 6 stops. Then to extend the dynamic range something called a “knee” is added to the top of the gamma curve. The point where the curve transitions from normal gamma to the knee is called the “knee point”. Everything above the knee is is compressed or squeezed. So in effect below the Knee 1 stop is record with 1 stops worth of data, but above the knee 3 or 4 stops may be recorded in the same space.

In practice this means anything brighter than the knee point will have very little contrast, when you have low contrast it is also hard to see any detail. So the highlights in the image look flat, lack texture and detail. If you have bright skin tones up in the knee they just look like blobs of color. Cotton wool clouds come out as white blobs in the sky and it is the knee that is largely responsible for the “video look”.

Sony’s Cinegammas are different. They do not have a knee. Instead of a hard knee point where you switch instantly from not compressed to compressed they have a slow and gradual transition from not compressed to very compressed. This is not unlike the way film behaves and is typically called a “highlight roll-off”. In practice because this transition is gradual it is less obvious. Because it is less obvious you can start the transition lower down the gamma curve which means you have more recording range for the highlights and can therefore increase the captured dynamic range. But to get the best looking recordings you want to keep faces and skin tones below the more aggressive parts of the roll off, so often you need to expose marginally darker than you would with conventional gamma.

For standard gammas it is typical to set the cameras zebras to 70% and have zebras just starting to appear on skin tones. With the Cinegammas I recommend reducing the zebras to 60%. See this article for more info on the correct exposure https://www.xdcam-user.com/2013/07/correct-exposure-levels-with-sony-hypergammas-and-cinegammas/

If you want to use the Cinegammas and are doing anything for broadcast TV that will not be graded and the video levels corrected to the 100% maximum required for broadcast then you should only ever use Cinegamma 2. All the other Cinegammas allow recording up to 109%.

All the Cinegammas record a similar extended dynamic range, Cinegamma 2 will almost always appear a little darker as it’s recording range is shrunk to ensure it does not exceed 100%., but even though it may appear a little darker, the captured dynamic range is the same.

For brighter scenes Cinegamma 1 is my go-to gamma curve on the FS5. It captures a large dynamic range. For darker scenes I will often use Cinegamma 4 as this raises shadows and the mid range. Cinegamma 4 is also useful for shooting back lit scenes.

Cinegamma 3 is a little more contrasty than Cinegamma 1 so if you want a picture with higher contrast this is the curve you should consider.

What about color?

The standard color mode is OK, but I find it a little gaudy. If you want a more film like look then the Cinema mode works quite well to give a more de-saturated look. But my favourite color mode is the Pro color mode. It’s not as vibrant or highly saturated as the standard or ITU709 color modes but it does produce very accurate colors. It’s a bit less green that the standard color mode. If you want a more vibrant image you can increase the saturation, I find Pro Color at +14 saturation gives great color straight out of the camera.

The Color Depth control is a bit of an odd control. It works by targeting a particular color, but instead of increasing/decreasing the saturation of the color it makes the luminance level of objects that are that color brighter or darker. If you make a red car darker in brightness it makes the color appear stronger relative to the brightness. A positive setting makes the luminance darker, so the color appears stronger, a negative setting makes the luminance brighter so the color appears slightly more washed out.

First the standard look (notice the blobby, flat, no texture look to the clouds from the knee):

PXW-FS5 Standard Settings

So, here are some suggested settings for different shooting conditions. Remember, you can mix and match the color and gamma settings, so if you like the colors from one profile you can take the color settings and use them with the contrast settings (gamma, black gamma) of another.

1: AC-GPMC – General purpose, medium contrast (good all-round profile).

Gamma: Cine3, Black Gamma Middle -7, Color Mode Pro, Saturation +16 (substitute Cine3 with Cine2 for direct to air broadcast).