My Love – Hate Relationship with the Sony FS7

The FS7 is an amazing camera for the price, but sometimes I wish that I could pay a little more and get the camera I really want. Here’s what I discovered while using it on a recent shoot…

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One of my regular clients likes shooting with Canon C300s: they’re small, cheap and great for doc-style shooting, which is what we do for one particular corporate client. This time, though, the client asked for slow motion, and while the C300 will shoot 60fps it only does so at 720p. As this project is to be shown on a large screen at a huge company event our minimum shooting resolution was 1080p.

I’ve worked as a consultant for Sony, along with fellow writer/technologist Adam Wilt, and a month or two ago Sony sent us an early model FS7 for feedback and testing. It wasn’t completely ready at the time, but I felt confident that the production models would be good enough to get us through this job with flying colors. The increase in rental cost over the C300 was minimal compared to the benefits of slow motion (up to 180fps in XAVC HD), so we committed to using the FS7.

The shoot took place in Philadelphia. We brought one camera with us and rounded up the others on location. One shoot day required three cameras and we could only round up two FS7s, so we added a Sony F5 instead. The FS7 and F5 share the same sensor and color filter array, and the F5 matched our FS7s perfectly.

Sony has a habit of segmenting their markets: they want to make sure that there are clear delineations between camera models, and that you pay for exactly the camera you can afford. For example, the F55 records 4K XAVC while the F5 doesn’t. (The FS7 does, though.)

The FS7 is about 2/3s of an F5 for half the cost, in a doc-style form factor. While I love the camera overall, there are a couple of things that skew it toward the documentary and owner/operator markets over the commercial and high-end corporate markets.

THE GOOD NEWS

I love this camera for handheld work. It weighs a smidge more than an F5 but it takes small EX3-sized Sony batteries instead of bricks, which reduces weight considerably. This project required both handheld and Movi work and the FS7 was the lightest professional camera available that could capture high speed.

While we had third party handheld support for the camera, along with an EasyRig for use with the Movi, I found I never used more than the Sony-supplied shoulder pad and handgrip. This may have been due to the fact that I didn’t use an external monitor, relying instead on Sony’s stock LCD display. We used a round metal clip-on lens shade instead of a matte box with our Zeiss Ultraprime lenses. I also eschewed a follow focus, opting instead to simply grab the lens barrel. This made the camera extremely lightweight and easy to shoot with for long periods of time.

The FS7 is a little heavier on its right side, and I’d heard reports that it pulled to the right in handheld use, but I never found this to be the case.

The FS7 has the LC709 Type A “Alexa emulation” MLUT built in. I don’t like to shoot the F5/F55/FS7 cameras in “custom” mode, using standard Rec 709 color matrices and stock gamma curves, as I think they look too video-like. Shooting in “Cine-EI” mode, with the SGamut3.cine color space and SLog3 gamma in conjunction with the LC709 Type A MLUT, looks amazingly cinematic and is a significant improvement from the standard “Sony look” that I grew up with.

The F5 and F55 also contain this MLUT but yield slightly different looks, as the F55 shares the F65’s color filter array (CFA) while the F5 reportedly uses the same CFA as the F3. Still, the Cine-EI LC709 Type A look in either camera is a far cry from the saturated highlights, orange flesh tones and crushed and hue-distorted highlights seen in many traditional video cameras. It took a while for Sony to catch on that most professional cinematographers have grown beyond the traditional video aesthetic, but with these three cameras they’ve delivered a wonderfully filmic look at affordable prices.

There’s a convenient switch that toggles S&Q motion (“slow and quick motion”), which is great for jumping quickly into and out of a preset non-normal frame rate. I’d choose a frame rate depending on the action in the scene (usually either 40fps or 120fps) and I could quickly toggle between that and 23.98p as needed. Changing between 40fps and 120fps was a bit more time consuming as that required crossing the 60fps barrier. More on that below.

The viewfinder has buttons for toggling zebras and peaking on and off, and the image itself looks as color accurate as any other monitor I have on set that I’d trust. We had TV Logic VFM-058W 5” on-board monitors at our disposal but the Sony viewfinders looked considerably better so I ditched the 058W when shooting handheld.

The menus are almost the same as the F5 and F55. There are a couple of differences, the most significant being the addition of a new flavor of XAVC. XAVC-I is the same intraframe format found in the F5 and F55–where each frame is self contained–while XAVC-L is a long-GOP implementation where image information is spread out across a group of pictures (“GOP”). Long-GOP generally results in better compression at lower bitrates until too many things in the frame move, at which point the codec throws fine detail to the wind to keep up. I chose to shoot in XAVC-I as I know it well and trust it.

THE BAD NEWS

I can’t complain too much. After all, this is a US$8,000 camera. If I did complain a lot, though, I would complain about the following:

The software isn’t completely bug-free at the moment. Zebras and waveforms are accurate but aren’t available in all modes. Sony changed the structure of how the zebras work in the F5 and F55 line of cameras: zebra 2 works the way zebras have always worked, where the operator sets a point beyond which they come on and any image value above that point shows zebras. Zebra 1, however, works by asking the operator to set a value around which it will create a “window.” For example, if one sets zebra 1 to 60% and then sets the related “aperture” value to +/- 5%, zebras will come on at 55% and go off at 65%. I suppose this is handy for those who use zebras to judge flesh tones, but I only use them to judge clipping so I have to be careful to use zebra 2 instead of zebra 1 when I’m running-and-gunning.

The problem is that the FS7 I used, which was out-of-the-box new from an east coast rental facility, showed zebra 2 acting exactly the same as zebra 1, making it useless for evaluating highlight clipping. Our other FS7, which we brought with us from a rental house on the west coast that is quite aggressive about keeping firmware updated, did not show this problem.

For this reason, and for others, I strongly encourage FS7 owners to keep their firmware updated. If a new version comes out, just load it up and don’t ask questions. I’ve only ever seen software updates from Sony as improvements.

The lack of the F5/F55 screen-and-soft-button interface on the smart side of the camera makes certain functions hard to get to. Changing S&Q framerates and shutter speeds/angles requires a trip into the menus, whereas this is not the case on the F5/F55. I often change between shutter speed and shutter angle, and it was a pain to have to resort to the internal menus to make these adjustments. (If I’m shooting under discharge sources I’ll select shutter speed and set it to 1/60 in order to put myself directly in the middle of the 60hz flicker-free window, but if I’m shooting high speed outdoors I’ll select shutter angle and choose 180 so the shutter compensates automatically with speed changes.)

As with the F5/F55 any frame rate above 60fps requires a shift into “full frame” mode, which bins photosites in order to reduce the amount of data being shuffled off the sensor at high speeds. (The camera can’t get 4K data off the sensor fast enough, so “binning” or combining photosites reduces the amount of data moving through the camera while preserving the full Super 35mm frame size. There is some loss of resolution and increase in moire, but under normal conditions this isn’t noticeable.) The good news is that it’s possible to select any frame rate from 61fps through 180fps in 1fps steps, whereas the F5/F55 offered 120fps and 180fps as the only options above 60fps.

Playback is a hassle. It’s not completely obvious how to get into playback mode as there’s no playback mode button or switch. One has to know to push the “thumbnail” button, which automatically switches the camera into playback mode and presents thumbnails for all the clips currently on the internally-mounted cards. The thumbnails take a long time to populate, so it could be several seconds from pushing the thumbnail button to seeing the thumbnail of the clip that you want to play. As with the F5/F55 the processor that drives the user interface seems underpowered, so it may take multiple button presses to play a clip. And the play button is also the menu selection scroll wheel. (I never figured out how to fast forward or rewind. I’m sure it’s in the manual; I should read that someday.) Pressing “thumbnail” again causes the camera to revert to shooting mode.

Playback is not a quick process, which is a problem when shooting slow motion as I, as DP, and the director and/or client want to see what effect we’re getting before we commit to a frame rate when shooting a scene.

Like the F5 and F55, you can see an MLUT-corrected image in Cine-EI mode as long as you aren’t playing back. MLUTs are not applied to playback, and I’m told that this is physical issue that can’t be corrected in firmware. Your client will see LC709 Type A while you’re setting up the shot and while you’re shooting it, but on playback they’ll see a flat, desaturated SLog3 image. And, if you’re like me and you hate noise enough to rate the camera at ISO 1000 instead of 2000, playback will also be a stop brighter. I knew we’d be looking at a lot of high speed playback on this project so I opted to bake in the LC709 Type A look to avoid awkward technical explanations in the field.

Like the F5/F55, the FS7 only has three white balance options in Cine-EI mode: 3200K, 4300K and 5500K. I’m not sure why 4300K is an option, as 4100K is the exact mid-point between 3200K and 5500K (calculated using the MIRED system). Still, it works well enough. When I asked why we couldn’t white balance in Cine-EI mode I was told that the SGamut color spaces were so massive that white balancing was a non-trivial math problem that was much easier to solve in advance for known values. Both Adam Wilt and I emphasized the need for white balancing in Cine-EI mode, and last I heard Sony is working on a manual system that will allow us to dial in white balance corrections using a combination of Kelvin temps and plus/minus green offsets. Look for that in a future firmware release.

The biggest hassle, though, is Sony’s E-mount lens system. I learned this one the hard way. For a three-camera interview setup we put a Canon 30-300 zoom on one of the FS7s, and focus didn’t hold between the long and short focal lengths. This is the classic sign of improper flange focal distance, or loss of back focus, and the assistant who prepped it swore he didn’t see this at the prep. After a little research we figured out what happened:

“PL” in PL-mount stands for “positive lock.” The PL lens mount consists of four flanges on the lens that are actively engaged by a friction locking ring on the camera side: tightening the ring pulls these flanges tight against the mount, locking the lens into exactly the right distance from the film/sensor and not allowing for any movement (short of breaking the mount free of the camera). Sony’s E-mount is a still lens system designed for light-weight glass, and it does not contain a friction ring: there is a ring that rotates to hold the lens in the mount, but it doesn’t hold the lens firmly at the proper flange focal distance: it has some play in it. While PL-mount to E-mount adapters exist, the weak spot is where the adapter mounts to the camera, at the E-mount. The adapter can shift and bend in the E-mount, throwing out back focus.

That’s what happened to us: because the lens wasn’t perfectly supported–the rod support was probably not adjusted as high as it should have been, or it might have been set too high–the E-mount adapter was pushed one way or the other, resulting in bad back focus and a zoom lens whose front focus wouldn’t track across all focal lengths.

There are two ways this might have been resolved. The first solution employs an old trick that I was taught in film school but almost never see used in the field: rather than mounting a heavy lens on a level camera, put the camera in your lap facing straight up and lower the lens onto it. Set the rod support while the camera is in the face-up position. This takes gravity out of the equation when squaring the lens off to the camera and attaching the support, helping to ensure that the lens doesn’t sag in the mount. (This also makes it easy for dust particles to fall into the open lens port and settle on the sensor’s cover glass, so this is probably more easily used with film cameras than digital cameras.)

The second solution is to use a Fujinon Cabrio zoom lens. I’m not sure why more zoom manufacturers haven’t given us adjustable back focus, but the Cabrios have B4-style back focus adjustments built into each lens. These are a great way to get yourself into trouble if you don’t know how to use them, but any decent cinematographer or assistant should know how they work and they’re great for solving back focus-related problems that pop up in the field. (Cabrios also incorporate a B4-style macro adjustment which is great for avoiding image breathing during huge focus shifts: set focus at the far distance and use the macro lever to pull focus forward. The image size doesn’t change at all!)

The biggest bummer of all is that there’s no overall back focus setting, and no FS7 seems to have come from the factory with the back focus perfectly set. If you’re using cine lenses and want the distance marks to accurately represent where the focus plane lies in front of the lens, you are completely out of luck. It’s demonstrably impossible for a camera assistant to pull focus using just the marks on the lens. My hope is that someone released an adjustable PL-to-E-mount adapter that allows for fine back focus adjustment, although considering the flimsiness of the E-mount adapter I’m not sure the adjustment will hold over time.

The F5/F55 do have internal back focus adjustability… but they cost a bit more to buy.

The Canon C300 didn’t originally allow for user adjustment of back focus; supposedly one had to send it in to the factory to have this tweaked. I know of one rental house that called Canon to complain:

Rental house: “I can’t adjust the flange focus depth in my C300, and it’s out! None of my lenses work on it!”

Canon support: “Oh, that’s easy: just shim your lenses to match the camera.”

Rental house: “I have dozens of cameras going out daily, and any lens can end up on any one of them. I can’t shim a lens to match a single camera!”

Canon support: “Ummmmm…”

Apparently Canon had initially thought of the C300 as an owner/operator camera, where it made sense to shim a set of lenses to work with one camera. This makes sense to some extent, as that’s the model around which they build DSLRs. I don’t think that’s why Sony left this adjustment out; for them it was a way to segment the market and protect the F5/F55 while reducing the cost of the FS7.

For the kind of work I was doing on this shoot–run-and-gun doc style–accurate focus marks didn’t matter. As long as the lens hit infinity I was in good shape. Camera weight and slow motion capability trumped everything, and in these areas the FS7 really came through. I have to question whether it is suitable for true film-style shooting, due to the weakness inherent in the E-mount, and it may not be. Still, that market segment is adequately served by the F5/F55, whereas the doc-style market segment has suffered for quite some time. I used a full set of Ultraprimes on an FS7 (16, 24, 32, 50, 85, 135mm) handheld for three days and never had a problem, focusing by eye all the while, so for that style of production the FS7 is perfect.

VERDICT

I like the FS7. It opens up a lot of possibilities. It’s cheap, it’s light, and it shoots high speed affordably. It’s not a perfect camera, but no camera is. The trick is choosing the right camera for the project, and for this project the FS7 was perfect.

Unfortunately those that hire me don’t always ask me what camera I want to use for a project, and often the camera gear is booked before I am. About fifty percent of the time they choose a camera that won’t work for a specific project and force me to explain why, but producers and directors don’t like to hear long technical explanations as to why something works on one project but not on another. Once they become comfortable with a new piece of technology they like to repeat it on every job: it’s one less thing to worry about, and as production is already controlled chaos they hate moving outside their comfort zone when they’ve had a good experience with a product. It’s already hard enough to tell clients that like to use the Canon C300 on every job that it’s fatal to use it for green screen, or that the F5 may not be the best camera to use on a car-to-car project due to rolling shutter artifacts, but now I have to tell them about the fragility of lens mounts, how that interacts with back focus, and how that forces us to work with specific lenses or in certain creative styles.

Sometimes I think I should quit being a DP and instead sell myself door to door as a walking encyclopedia. Honestly, I’d rather just shoot pretty pictures than know all this stuff, but this is the world we live in.

I get that Sony is trying to protect their existing product lines, but… as much as they make my life easier by introducing an inexpensive but powerful camera like the FS7 they make it more complicated by compartmentalizing it so carefully. All they have to worry about is selling the camera, but I have to worry about human nature and how it interacts with the creative chaos of the film industry.

Still, I’d rather have the FS7 than not, and I’m sure I’ll be pitching it for future projects. I just hope that someone comes out with an adjustable or shimmable lens mount adapter for it… and quick.

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About The Author

Art Adams

Director of photography Art Adams knew he wanted to look through cameras for a living at the age of 12. After ten years in Hollywood working on feature films, TV series, commercials, music videos, visual effects and docs he returned to his native San Francisco Bay Area, where he currently shoots commercials and high-end corporate marketing and branding projects.   When Art isn’t shooting he consults on product design and marketing for a number of motion picture equipment manufacturers. His clients have included Sony, Arri, Canon, Tiffen, Schneider Optics, PRG, Cineo Lighting, Element Labs, Sound Devices and DSC Labs.   His writing has appeared in HD Video Pro, American Cinematographer, Australian Cinematographer, Camera Operator Magazine and ProVideo Coalition. He is a current member of the International Cinematographers Guild, and a past active member of the SOC and SMPTE.

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