FS5 advanced shooting tips
Part two of Alister Chapman’s expert camcorder advice on getting the best image quality from Sony’s PXW-FS5.
The PXW-FS5 has many advanced features to support impressive creative visual effects to make your projects really stand out.
Slow and Quick Motion (S&Q Motion) means you can shoot at frame rates from 1 frame per second to 60 frames per second. This allows you to speed up or slow down motion for time-lapse or slow motion effects.
Super Slow Motion allows you to slow down the action even further as you can shoot all the way up to 960 fps (frames per second).
The camera has a Center Scan mode that allows you to use just the centre ‘super 16mm’ part of the sensor as well as Clear Image Zoom, an intelligent form of electronic zoom that allows you to zoom in and out by up to 2x with any lens and with no appreciable loss of image quality.
The FS5 can also be upgraded to output a 12 bit RAW signal to an external recorder via an optional firmware key. The RAW option makes it possible to output DCI 4K (4096 x 2160) at up to 60fps as well as 4K slow motion at 100/120fps in 4 second bursts. In addition you can also output continuous 2K slow motion at 100/120fps and 200/240fps. To record this RAW output you will need a compatible external RAW recorder.
There is a wonderful Variable ND filter system that allow for very precise control of your exposure and depth of field and it’s this feature that I’m going to look at first.
Variable ND filter
Many cameras have internal ND filters. An ND filter acts like a pair of sunglasses to reduce the amount of light falling on the sensor. To engage the ND filter system on the FS5 you have to turn the ND filter wheel from the clear position to one of the 1, 2 or 3 positions. In the clear position, the entire ND filter system is removed from the optical path, so it has no effect. But when ND position 1, 2 or 3 is selected, the ND filter is moved into position in front of the sensor.
When the ND select switch is set to Preset, much like other cameras with built in ND, each of the filter positions gives a different light reduction with ND1 giving a ¼ reduction, ND2 giving a 1/64th reduction and ND3 a 1/128th reduction. However, unlike most cameras the ND level for each filter position can be changed in the camera menu, so you can have as little or as much ND as you need at each filter position.
Moving the switch to Variable allows you to use the variable dial wheel to manually control the darkness of the ND filter. When using the variable ND control the adjustment of the ND is fine enough that you won’t see any steps in the resulting exposure change. This is particularly useful when using the camera with lenses from manufacturers other than Sony where the iris/aperture operates in coarse steps as the ND filter can be used to alter the exposure during a shot smoothly.
The variable ND filter is also very useful for helping to manage the depth of field of a shot. By setting the cameras iris to a large aperture, perhaps f4 or f2.8 you can get a shallow, film-like depth of field. Then you can use the ND filter to obtain the correct exposure. This can even be done automatically by setting the ND filter to auto while the aperture setting is made manually.
Control of the ND filter can be assigned to the dial control on the handgrip if you wish, but do remember that for the ND filter to work you must first chose position 1 ,2 or 3 on the ND filter wheel.
[1] [2] Variable ND filter variable operation
Center Scan
The Center Scan mode allows you to use just the centre part of the sensor rather than the full sensor. So instead of using the full super 35mm sized frame you are now just using the middle super 16mm sized part. Center Scan only works when the camera is set to HD; it can’t be used for UHD (4K).
By using Center Scan you can use a very wide range of lenses on the camera including lenses designed for Super 16 film and some 2/3” B4 broadcast style zoom lenses.
Compared to the full frame mode, the camcorder’s field of view becomes narrower by a factor of 2. A 50mm lens becomes the equivalent of a 100mm lens. This can be useful for getting a close up shot when you only have a wide angle lens, although there is a better way to zoom in with the FS5 and that’s a function called Clear Image Zoom. It should be noted that Center Scan can not be combined with Super Slow Motion.
[1] Center Scan Super 16mm [2] Super 35mm
[3] Center Scan [4] Center Scan OFF [5] Center Scan ON
[6] The same lens in both cases
Clear Image Zoom
Clear Image Zoom is a type of electronic zoom that allows you to zoom in by up to two times with no appreciable loss of image quality. It works with any lens including prime lenses. So if you fit a fixed focal length prime lens to the FS5 and enable Clear Image Zoom in the camera menu you can use the cameras zoom rocker to zoom in and out by up to 2x in HD and up to 1.5x in UHD.
If you are using a Sony power zoom lens such as the 18-105mm f4 lens that is available as a package deal with the PXW-FS5, the zoom rocker will first zoom in the optical zoom and then virtually seamlessly introduce the Clear Image Zoom function. In effect this converts the 18-105 from a 7x optical zoom to a hybrid 14x zoom in HD.
Unlike other basic and low quality digital zooms, Clear Image Zoom uses sophisticated image processing that includes a library of textures to give almost no loss of image quality when it is used, so you should find it perfectly usable for the majority of shooting situations.
Slow and Quick Motion
S&Q Motion is one of the most useful features on the PXW-FS5 as it allows you to slow down or speed up the action that you are shooting.
It allows you to shoot between 1 and 60 frames per second. If you shoot at a low frame rate like 1fps then the action will be greatly sped up and this is good for shooting time-lapse. For example if I set the cameras base frame rate to 24fps I can then engage S&Q motion by pressing the S&Q button. If I press and hold the S&Q button I can then set the recording frame rate (using the control dial beneath the menu button). If I set this to 1fps when my recorded clip is played back at 24fps the motion will be sped up by 24 times. This is great for shooting time-lapse (remember you can always speed the clip up still further in post production if you need to).
If you are shooting at low frame rates such as 1 fps then you might also want to consider using a very slow shutter speed. If you set the shutter speed to ‘1’ the shutter will be open for 1 second and this is a way to introduce flowing motion blur into your time-lapse and is particularly effective when filming traffic at night.
In HD, S&Q motion can go up to 60fps. If the camcorder’s base frame rate is set to 24fps and I shoot using S&Q at 60fps, then the motion will be slowed down by a factor of 2.5 when the clip is played back.
In UHD, S&Q motion is limited to 1 to 30fps. Also note that no audio is recorded when shooting S&Q motion or Super Slow Motion.
[1] S&Q Motion 1fps, shutter 1 second
Super Slow Motion
If you really want to slow down the action with the FS5, then you should use the Super Slow Motion mode. To engage Super Slow Motion first ensure the camera is in HD, then press the S&Q button two times. Like S&Q motion, the frame rate can be set by pressing and holding the S&Q motion button and then using the control dial under the menu button or the joystick on the handgrip.
In order to be able to record at very high frame rates, the camcorder uses an internal memory to store the Super Slow Motion footage before writing it to the SDXC cards. It just not possible to write high quality full HD at 240fps to an SDXC card directly. As a result, there is a limit to how long you can record for in any one go. The table below gives the record times that are available depending on the quality level that you are shooting at.
Up to 240fps Super Slow Motion is full HD. At 400/480fps the camera records an HD sized frame but there is a decrease in the vertical resolution. It depends on what you are shooting as to how obvious this drop in resolution will be. For many shots you may not notice the difference, but for others it may be obvious. My recommendation is to shoot a test shot and play it back to asses the quality. Above 480fps the resolution is much reduced, again I recommend that you test to see if it is going to be acceptable for your production.
When shooting in Super Slow Motion because the camera uses an internal buffer memory you have three different record trigger options.
Start Trigger is very simple to understand. You press record and the camera starts to fill the internal memory with slow motion footage. During this stage of the recording process you will see ‘Buffering’ displayed at the top of the screen. Once the memory is full, the camcorder will automatically start to transfer the footage from the internal memory to the SD card. At this point the ‘Buffering’ message will change to ‘Recording’. While this is happening you can’t shoot any new footage, you have to wait until the cycle has finished. There is the option to ‘Cancel’ the transfer if you wish. When you select cancel, the footage prior to the point of cancellation is stored on the SD card, but anything after that point is discarded.
End Trigger is the one I find the most useful for Super Slow. Once you select the End Trigger, the camcorder’s internal memory starts to fill with slow motion footage. You will see a ‘Preparing’ message at the top of the viewfinder display. The camcorder’s internal memory is constantly being updated with new footage. Once the ‘Preparing’ message changes to ‘STBY’ you can use the Record Button to transfer the time period prior to the point where you press record from the camcorder’s internal memory to the SD Card. This is particularly useful for capturing unexpected or unpredictable events as you can wait for the action to happen, then press record. After pressing record, the footage from BEFORE you pressed record immediately starts to be transferred out of the cameras internal memory to the SDXC card.
Half End Trigger is just the same as the regular end trigger except the internal memory cache period is half of the normal time period, so you only get half of the maximum record time.
Note: When shooting at high frame rates under artificial lighting the shutter of the camera may be operating faster than the flicker rate of the artificial lighting. This can result in footage that contains flicker or a dark band that rolls up or down the image. When using Super Slow Motion, the footage is typically transferred from the camcorder’s internal memory to the SDXC card at twice the base playback rate. As a result, you may only see every other frame during this transfer process and this can hide flicker that will be obvious when the clip is played back. So I recommend that whenever you are shooting using Super Slow Motion under artificial lighting that you play back your first clip to check for flicker before proceeding. If you do have a flicker problem in most cases the only cure is to lower the shooting frame rate. Faster frame rates will be more prone to flicker than slower ones.
Additional information
Alister Chapman is a veteran broadcast cameraman with 20 years of experience and runs his own company, Ingenious, which is a one-stop shop for video production, TV production and multimedia. The opinions expressed in this article represent those of the individual author who is independent of the Sony Group of Companies. Accordingly the contents of this article do not necessarily represent the opinions or policies of Sony Corporation or its subsidiary companies.
