Using Face Detection

November 8, 2013
X-Pert Corner
85 Comments

Using Face Detection

Talk to Rico (open forum for questions & feedback) – Rico’s Flickr sets – Expanded XQ1 Sample Images Set – Expanded X-E2 Sample Images Set – X-E2 AF tracking samples – Mastering the Fujifilm X-Pro1 reading samples (65 free pages) – Order my NEW book (print or DRM-free eBook/PDF): Mastering the Fujifilm X-E1 and X-Pro1 (use code FUJISAVES30 to save 30%!)

Fujifilm kindly delivered the LMO and PDAF upgrades for most of the X-Mount lenses a day earlier than expected, and they have also fixed the manual focus glitch in firmware 2.00 for the classic X100. I am looking forward to read about your first impressions with the X-E2 (and XQ1) using the new hybrid tracking autofocus.

If you need assistance upgrading your camera or lens firmware, you might find this article helpful. Sadly, there’s still no word if or when Zeiss will issue similar firmware updates for their X-Mount Touit lenses.

In Your Face!

Face Detection has always been available in most of Fujifilm’s “consumer” cameras. Among others, you can find this feature in the X10, X-S1, X20, XF1 and XQ1, and now also in the X-A1, X-M1 and X-E2. Face Detection is also available in combination with the tracking autofocus feature of the XQ1 and X-E2. This means that you can use Face Detection along with AF-C (in either single shot or low-speed burst mode) to keep the face of a person in focus while this person is moving left or right, or towards or away the camera.

While the hybrid PDAF/CDAF (combining on-sensor Phase Detection Auto Focus with on-sensor Contrast Detection Auto Focus) allows the camera to focus faster on a subject, Face Detection has to rely mostly (if not entirely) on the camera’s CDAF, because in many real-life situations, the face the camera is locking on will not be fully located inside of the nine central AF frames (the area that is equipped with PDAF pixels).

PDAF helps the camera establish and lock focus faster, but it’s not mandatory to enable autofocus tracking. Just think of the Olympus OM-D EM-5, which doesn’t have PDAF, but still offers fast AF and subject tracking capabilities. Your X-E2 and XQ1 can do this, too: Both cameras can track subjects with any of their 49 AF frames, not just the nine central ones (aka those with PDAF pixels).

In addition to selecting one of the camera’s 49 AF frames, you can also set the X-E2 and XQ1 to track subjects using Face Detection. Click here to access a private Flickr set that illustrates both standard AF tracking (pre-production 23mm lens) and Face Detection AF tracking (pre-production 50-230mm lens) with a pre-production X-E2.

Wait, There’s More!

While most users will immediately understand how Face Detection and the camera’s autofocus work hand-in-hand, some may not realize that Face Detection also influences the exposure metering of the camera. To illustrate this, let’s have a look at an example.

Here’s a straight-out-of-camera (SOOC) JPEG taken with Face Detection. I used Auto White Balance and the Pro Neg. Hi film simulation, which delivers natural skin tones. I took the shot with a pre-production sample of the new XC50-230mmF4.5-6.7 OIS telephoto zoom lens.

I didn’t have to apply any exposure correction, as the X-E2 automatically adjusted the exposure to the detected face. This is also why only multi metering (not spot or average metering) is available when the Face Detection feature is turned on.

So what happens when the Face Detection feature loses track of a face, or when the feature is manually turned off? In this case, the same shooting situation will play out like this:

Again, no exposure compensation was applied, and as you can clearly see, the camera is now overexposing the scene because its multi metering isn’t concentrating on the face and skin tones, but on the entire scene.

Luckily, nothing was lost in this particular case. I could salvage the image by reprocessing it with the X-E2’s built-in RAW converter, pulling the exposure down by 1 EV:

The reason why this worked so well is that the X-E2 (which was set to DR-Auto) selected DR200% for this shot, so it was “underexposing” the RAW by 1 EV and applied digital gain during JPEG processing. I simply took away that gain with the RAW converter’s push/pull function. Click here to learn more about options to expand a shot’s dynamic range.

Of course, there’s a lesson to be learned by these examples: Keep in mind that Face Detection will influence the camera’s exposure metering! This is a nice feature as long as the camera detects a face, but it can become tricky when it fails to do so. When Face Detection is losing track of a face, the exposure metering will revert to standard multi metering.

Relax! In many situations, the difference will be less pronounced. I obviously chose a rather drastic scene that illustrates the effect very clearly.

It’s worth knowing that Face Detection works in video mode, too, where it also influences focusing and exposure metering based on whether a face is detected or not. Of course, these observations not only apply to the X-E2, but also to the X-M1, X-A1, XQ1 and other Fuji cameras with built-in Face Detection.

Improving Face Detection

While automatic exposure adjustment based on Face Detection may be beneficial to most if not all “consumers”, I can imagine that photographers who belong to the “enthusiast” or “professional” crowd would prefer to have an option that allows them to choose whether Face Detection should influence both focusing and exposure metering, or only focusing without exposure metering.

With the “focusing only” option enabled, the camera could allow the use of either multi, spot or average metering in concert with Face Detection. I have already asked Fuji to add such an option in a future firmware upgrade. I image you’ll agree, but feel free to express your thoughts about this matter in the comment section of this article.

Another Face Detection quirk: The camera always reverts to the central AF frame when no face has been detected, or when the camera has lost track of a face. Instead, I would much prefer the camera to revert to a user-selected AF frame.

A related quirk is this X-E2’s inability to toggle Face Detection with any of its four Fn buttons or the Quick Menu. You have to navigate to the second entry of the fourth tab of the shooting menu to switch Face Detection on and off. I have asked Fujifilm to add Face Detection to the list of Fn button function choices.

For your convenience, here’s a TOC with links to my previous X-PERT CORNER articles:

Rico Pfirstinger studied communications and has been working as journalist, publicist, and photographer since the mid-80s. He has written a number of books on topics as diverse as Adobe PageMaker and sled dogs, and produced a beautiful book of photographs titled Huskies in Action (German version). He has spent time working as the head of a department with the German Burda-Publishing Company and served as chief editor for a winter sports website. After eight years as a freelance film critic and entertainment writer in Los Angeles, Rico now lives in Germany and devotes his time to digital photography and compact camera systems. His book “Mastering the FUJIFILM X-Pro1” (Kindle Edition) (Apple iBook Store) (German version) is available on Amazon and offers a plethora of tips, secrets and background information on successfully using Fuji’s X-Pro1 and X-E1 system cameras, lenses and key accessories.