Sony FX9 Sensor Scan Modes Explained

How To

by Florian MilzDecember 23^rd, 2020

Compared to the Sony FS7, the FX9 not only has a new larger sensor built in, it can also record at several different Sensor Scan Modes. This offers a lot of flexibility when you know when and how to use them.

At release (see our article, review and lab test), the FX9 was limited in resolutions and recording modes. Sony announced soon after release that there will be firmware updates that would bring missing features. With the introduction of Firmware version 2.0, the FX9 got even more versatile and offers more ways for you to use the camera in various production environments.

Sensor Scan Modes overview

The Sony FX9 features a 35mm Full Frame Sensor with the dimensions 35.7mm x 18.8mm. Although the camera has a 6K sensor, the maximum output and recording resolution is 4K DCI. This might make it confusing when you see the available Sensor Scan Modes:

• FF 6K
• FFcrop 5K
• S35 4K
• FF 2K
• S35 2K

The resolution that is spelled out in the sensor scan modes always refers to the used sensor resolution, not the recording resolution.

FF 6K

When choosing the FF 6K scan mode, the FX9 takes the total 6K image and downsamples it to 4K. The maximum recording area is achieved by recording 4K DCI (4096 x 2160) because the FX9 sensor is natively 17:9 aspect ratio. When recording 4K UHD (3840 x 2160) you simply get less horizontal resolution. Because this method takes up processing power, the maximum frame rate you can record in FF 6K scan mode is 30p.

FFcrop 5K

If you would like to record more than 30p in 4K, you can switch the sensor scan mode to FFcrop 5K, which was introduced in Firmware 2.0. Using this sensor scan mode, you lose some recorded image area, but you will be able to record up to 60 frames per second.

This smaller image area means a reduced field of view (around 1.25x smaller) from your full frame lens but it might be enough cropping that you will start seeing full coverage from many (older) cinema lenses that were advertised to only cover Super 35mm but had larger image circles than S35.

Angenieux has many lenses that show vignetting on Full Frame sensors but when you reduce the resolution (just like with RED cameras), you get flawless coverage, just like with the Fujinon MK zoom lenses. But again, even though the sensor scan mode is called FFcrop 5K, the maximum resolution is 4K.

S35 4K

Compared to the FF 6K sensor scan mode, the S35 4K mode will give you a similar field of view as when using the FS7 in 4K mode (1.5x crop if you will).

This is the desired recording mode when matching the FX9 recording to FS7 and other S35 cameras. As the name implies, this sensor scan mode will result in a 1:1 sensor readout for 4K recording (4K DCI and UHD).

FF 2K & S35 2K

Following the naming scheme, FF 2K takes the entire sensor width and downsamples the image to 2K (2K and HD). S35 2K does the same, but with the S35mm sensor crop. Sony mentions that the image quality will suffer, compared to the 6K/5K/4K modes. If you are planning to shoot in S-Log 3, Sony advises you to expose your image between 1 and 2 stops brighter than base in 2K scan modes.

There hasn’t been any mention of S16 recording modes unfortunately, so you could use broadcast zoom lenses which offer large zoom ratios in very compact form factors. This would be another welcome option, especially since the FS7 had this popular sensor scan mode.

Summing up, here is a handy frame rate overview:

If you are interested in an even more exploded view of the possible recording modes, frame rates and available record times, you can check out this knowledge base, where you can also find out about lens coverage on a wide variety of lenses: https://brains.florianmilz.com/ucdb/sony/fx9.

The latest Sony FX9 firmware and manual can be downloaded here:
https://pro.sony/ue_US/support-resources/pxw-fx9/software

Link: sonycine.com

Have you used the FX9 or even own one? What are your preferred scan modes? Still have questions? Ask us all your questions about the FX9 in the comment section below.