Sony FX9: Complete Technical Guide to Exposure

In this guide we will see, in a structured and practical way:

• The two main working philosophies with Sony FX9 Camera.
• How to expose correctly in Custom and Cine EI modes with S-Log3.
• How to get the most out of the electronic ND.
• Recommended settings for interview, fiction/advertising and run & gun.
• Professional use of hybrid autofocus.
• A complete workflow from shooting to post-production.

This article is intended to function as an advanced manual for actual use of the FX9.

1. Two ways of working with Sony FX9

The Sony Cameras FX9 allows two clear approaches to image and flow:

1.1. Custom modes (S-Cinetone, Rec.709, HLG...)

Custom modes are designed to obtain a "practically finished" image from the camera:

• Profiles like S-Cinetone offer
  • Very good skin reproduction.
  • Pleasant contrast.
  • Colour-ready for fast broadcasting or light colour matching deliveries.

When to use Custom:

• TV, reportage, quick corporate.
• Interviews where agility is more important than deep colour grading.
• Projects with little post-production time.

1.2. Cine EI + S-Log3 / S-Gamut3.Cine

The Cine EI mode with S-Log3 is oriented towards a digital cinema stream:

• Maximum dynamic range.
• Maximum flexibility in colour correction.
• Ideal for
  • Fiction.
  • Commercials.
  • High-end documentary.

In this mode, it is assumed that there will be serious post-production work, with dedicated colour management and colour grading.

2. How to expose in Custom modes (S-Cinetone, Rec.709, HLG)

In Custom modes, the FX9 behaves much like a high-end broadcast camera, but with a much more cinematic look.

2.1. Base ISO and recommended usage

Although it depends on the exact profile, a common practice is:

• Work around ISO 800 as low base ISO for well-lit exteriors and interiors.
• Move up towards ISO 4000 as high base ISO when light conditions worsen.

The priority is:

1. Adjust exposure with ND and lighting.
2. Use ISO as a secondary resource, not as a first tool.

2.2. Where to place skin and highlights

With profiles like S-Cinetone:

• Skin tones:

  • Placing them at approximately 60-70 IRE produces a natural and pleasing look.
  • Key reference for interviews and close-ups.

• Important highlights:

  • Keep them around 90-95 IRE.
  • Allow only very specific speculars to be slightly cropped.

2.3. Use of zebras and waveforms in Custom

• Zebra 1 (skin):

  • Set it to 70 IRE approx.
  • When you see zebra 1 on the skin, you know you are at a reasonable exposure.

• Zebra 2 (highlights):

  • Set it to 90-95 IRE.
  • It warns you which areas are about to burn.

• Waveform (WFM):

  • Overall view of the painting
    • Skin: 60-70 IRE.
    • Backgrounds: 20-50 IRE, depending on the style.
    • Specular: 90-95 IRE.

2.4. Practical method of exposure in Custom modes

1. Choose aperture according to depth of field
   • Example: T2.8 for interviews with somewhat out-of-focus background.
2. Set shutter
   • 1/50 or 1/48 at 25 fps (or 180º angle) for natural movement.
3. Adjust the electronic ND
   • Use the ND as the primary tool to nail the exposure while keeping aperture and shutter constant.
4. ISO
   • Adjust only when ND + lighting are no longer sufficient.
   • Switch to high base ISO (p.ej. 4000) in low light.

3. How to exhibit in Cine EI with S-Log3

In Cine EI the FX9 shows its most cinematic side.

3.1. What is Cine EI

In Cine EI mode:

• You work with a fixed base ISO (EI).
• You record in S-Log3, which captures the widest possible dynamic range.
• What you see on the monitor is
  • Log signal + monitoring LUT.
  • The LUT does not affect the recorded file, only the preview.
• You can decide to "expose above or below" the theoretical value to optimise noise or margin in highlights.

3.2. Dual base ISO: 800 EI and 4000 EI

The FX9 has dual base ISO in Cine EI:

• 800 EI (low base)
  • General use in well-lit or controlled scenes.
• 4000 EI (high base)
  • Intended for low light conditions.

Typical use:

• Day and indoor in good light → 800 EI.
• Night or low light → 4000 EI.

3.3. Slightly overexpose S-Log3

With S-Log3 it is very common to overexpose slightly with respect to the "neutral" exposure to reduce noise in shadows:

• The mean grey in S-Log3 is around 41 IRE.
• Viewing the image with LUT Rec.709
  • Many operators place skin at 60-65 IRE, which is roughly equivalent to +1 or +1.5 steps of overexposure in Log.
• Advantages
  • Cleaner shadows.
  • Better signal to noise ratio.
  • Then you can lower the overall exposure in colour correction.

3.4. Cine EI exposure procedure step by step

1. Picture mode:

   • Select Cine EI + S-Log3 / S-Gamut3.Cine.
   • Activate a shooting LUT (Rec.709 standard or custom show LUT).

2. Choose Base ISO:

   • 800 EI in well-lit scenes.
   • 4000 EI in low light.

3. Set metering:

   • Enable Waveform on camera or monitor.
   • Use False Colour if your monitor offers it.

4. Set creative shutter and aperture:

   • Shutter 180º.
   • Aperture (T1.5-T4, depending on look).

5. Use electronic ND to adjust exposure:

   • Adjust ND until, when viewed with the LUT
     • Skin is around 60-65 IRE in interviews.
   • Check that important highlights are maintained with detail.

6. Note exposure intent:

   • Record on camera part (or mentally, minimum) if you are working at +0.5, +1, +1.5 steps from base.

4. FX9 electronic ND: key tool

The continuous electronic ND is one of the FX9's great advantages.

4.1. ND Modes

• Manual ND:

  • Continuous density adjustment.
  • Ideal for controlled shooting (film, advertising, interviews).

• Auto ND:

  • The camera adjusts the ND automatically to maintain a constant exposure.
  • Very useful in documentary, run & gun, outdoor with sudden changes of light.

4.2. Practical advantages of electronic ND

• Allows you to set aperture and shutter and compensate for all light variation with the ND alone.
• Changes are smooth, without abrupt jumps, perfect for long shots with natural light variations.
• Makes it easy to work on multi-camera productions
  • You equalise exposure between bodies by adjusting ND instead of compromising diaphragm or shutter.

4.3. Strategies for use

• In fiction / advertising:

  • "Creative" aperture (T1.5-T2.8).
  • Fixed shutter (180º).
  • Manual ND to compensate light.

• In documentary / run & gun:

  • Reasonable fixed aperture (T2.8-T4).
  • Fixed shutter.
  • Auto ND for indoor-outdoor, clouds, etc.

5. Recommended settings according to shooting type

5.1. Interviews and classic documentary

Objective: clean skin, nice look, agile workflow.

• Image mode:

  • Fast flows → S-Cinetone.
  • Careful colour flows → Cine EI + S-Log3.

• ISO:

  • 800 EI in bright interiors.
  • 4000 EI only if there is a real lack of light.

• Aperture:

  • T2.8-T4 for good subject-ground separation without compromising depth of focus too much.

• ND:

  • Adjust to maintain that aperture.

• AF:

  • AF-C with Face/Eye Priority.
  • AF speed medium, sensitivity medium.

• Audio:

  • CH1: boom / shotgun mic.
  • CH2: lavalier.
  • Peaks around -12 dBFS, nominal -18 dBFS.

5.2. Fiction and advertising

Objective: maximum quality and flexibility in colour grading.

• Image mode:

  • Cinema EI + S-Log3 / S-Gamut3.Cine.

• ISO:

  • 800 EI most of the time.
  • 4000 EI when aesthetics or light situation demand it.

• Exposure strategy:

  • Very usual to work at +1 or +1.5 steps above base.
  • Skin (with LUT) at 60-65 IRE.

• LUT:

  • Ideally a project specific LUT show, loaded on camera and monitors.

• ND:

  • Manual setting to respect aperture decided by the director of photography.

• Focus:

  • Normally MF with focus puller.
  • AF can be used as spot assist or for pre-focusing.

• Video outputs:

  • 12G-SDI with LUT for director's monitor/DIT.
  • Additional clean outputs for external recorders or video village.

5.3. Run & gun, events and dynamic reportage

Aim: speed, reliability and usable material almost straight from the camera.

• Picture mode:

  • S-Cinetone for a nice direct Rec.709.
  • HLG if fast HDR delivery is planned.

• ISO:

  • Auto with limits (800-4000).
  • Or manual changes between 800 and 4000 depending on the situation.

• ND:

  • Auto ND almost essential with fast light changes.

• AF:

  • AF-C with higher sensitivity and fast speed to track unpredictable subjects.

• Stabilisation:

  • Optics with OSS.
  • Enable gyro metadata for advanced stabilisation in post with Catalyst or other streams.

6. FX9 hybrid autofocus in professional use

The AF system of the FX9 Sony cameras is advanced enough for serious use in professional contexts, provided it is set up properly.

6.1. AF modes and zones

• Wide
  • Ideal for unpredictable situations, events, run & gun.
• Flexible Spot
  • Perfect for interviews or shots where you know exactly what needs to be in focus.
• Face/Eye AF
  • Especially useful for interviews, documentaries, weddings, street interviews, etc.

6.2. AF speed and sensitivity

• Transition speed:

  • Slow in fiction/advertising for "cinematic" transitions.
  • Fast in sport, news, reportage.

• Subject change sensitivity:

  • Locked-on to prevent AF jumping to passing objects.
  • Responsive when you want it to prioritise the subject coming into the foreground.

6.3. Mixed AF + MF strategy

A very useful approach:

• Use AF to acquire fast focus.
• Assign a button to "AF Hold" or MF/AF switching.
• Lock focus when the shot requires it.
• Switch to MF for micro adjustments, especially on critical shots.

7. Complete workflow with FX9 in S-Log3

7.1. Pre-production

• Define:

  • Whether to work in Rec.709, ACES, HDR...
  • Which LUT will be used (Rec.709 or show LUT).
  • Exposure strategy: neutral, +0.5, +1, +1.5 steps.

• Perform tests:

  • Skin test, high contrast, low light.
  • See how far overexposure can be pushed without losing critical highlights.

7.2. Shooting

• Shoot in Cine EI + S-Log3.
• Always monitor with LUT.
• Use electronic ND as main exposure tool.
• Document
  • EI used.
  • Exposure offset (+1 step, etc.).
  • Comments on special scenes (extreme backlighting, etc.).

7.3. Post-production

• Ingesting and organising:

  • Sorting material by scenes, taking shooting notes into account.

• Normalisation / colour management:

  • In ACES: apply IDT for S-Log3/S-Gamut3.Cine.
  • In Rec.709: Apply S-Log3 → S-Log3 transform Rec.709.

• Global exposure adjustment:

  • Correct towards "shooting intention" exposure (if shot at +1 step, etc.).
  • Recover highlights and shadows within the camera's wide dynamic range.

• Creative colour grading:

  • Work on contrast, colour, skin, and specific looks (advertising, film, documentary).

8. Conclusion

The Sony FX9 is an extremely capable camera that, when properly configured, can cover everything from fast-paced TV shoots to high-end fiction and advertising projects. The key to getting the most out of it lies in:

• Understanding its two working philosophies (Custom vs Cine EI).
• Mastering exposure in S-Log3 and knowing when and how much to overexpose.
• Using the electronic ND as a central light control tool.
• Correctly set up the hybrid autofocus according to the type of shooting.
• Integrate the camera into a complete workflow including pre-production, shooting and post-production.