Phantom Flex 4k overview - Steve Phillipps
Vision Research revolutionised the world of hi-speed slow motion shooting a few years ago with the introduction of the Phantom HD. I don't use the word "revolutionised" lightly - for work in the field, for example in wildlife filming, it really changed the whole experience. Unlike previous super-slow motion video cameras the Phantom HD was could be operated as a stand-alone unit, without the need to be connected to a computer - and therefore without all the encumbrance and awkwardness that comes with it. They did this with two simple additions; firstly on-board camera controls that allowed the user to change settings in-camera; and with the introduction of swappable solid-state storage magazine, so-called "Cinemags". These magazines had the added benefit of quick download times - with other cameras tethered to a laptop a shot might take 10 minutes to transfer, during which time the camera is out of action - with the Cinemag it only takes a matter of seconds.
It also didn't hurt that the image quality was excellent - arguably as good or better than the high-end cinema cameras which it was designed to operate alongside.
While the HD was fantastic and very useable in the field it was pretty obvious that it was still basically designed to be used with a computer - the design philosophy seemed to be "yes you can use it un-tethered if you really must, but only if you're desparate"! The camera only had 3 buttons (fiddly ones) and a limited amount of operations could be accessed, mostly shooting parameters. The Flex 4k has obviously been designed to make it 100% useable in the field - there is still more control to be had through a laptop, but basically you can do most things on-camera, and it's a joy to use.
The camera has a 4k CMOS sensor with a rolling shutter, allowing frame rates of upto 1000fps in 4k and 2000 in full HD. The lens is mount is user interchangeable, at the moment there is the choice of a PL, Nikon and a Canon EF mount. These are easy to change, very similar to the RED Epic, with 4 allen bolts to be undone, slide the mount off and attach the new one - very easy and literally a 2 minute job. The Nikon mount allows use of "G" lenses without aperture rings - though as with all these mechanisms it's a bit fiddly.
The base of the camera has several 3/8" mounting holes and will interface with Arri products. Also has a riser for correct height on 19mm bars. Overall the camera kind of looks a bit like a Sony F55, but feels like it's made from a solid block of iron - really nice.
Vision Research have had an OLED viewfinder designed for the camera and it's really nice. Loads of menu options like zebras, peaking etc. and bolts securely off the side of the camera. The camera has SDI out and power outs so other viewfinders or monitors will work fine too.
Power is via mains or onboard batteries - plates are available for 12v V-lock or Gold mount, or 24v V-lock batteries. The camera does use a fair bit of power - a 230w/h battery will last maybe 2 hours, I didn't test it precisely though. Boot-up time is pretty slow, takes about 30 seconds - I suppose it's performing all sorts of pre-flight checks, getting up to working temperature and checking the sensor etc. is working properly. It does make it tempting to want to leave it on between shots but you will need a few spare batteries if you're going to do that. On the topic of operating temperature, one of the issues with the original Phantom HD was fixed-pattern noise, partly due to temperature changes, that required a black balance more or less every shot to be safe! That issue was fixed with the update of the cameras to "HD Gold" and pretty much became a non-issue, with the advice just being to do a black balance (also known as a "current session reference" (CSR)) after massive temperature changes or a matter of course at the start of a shoot. The same situation exists with the Flex 4k - no need to black balance except in extreme circumstances. When performing a black balance there is an internal shutter so no need to cap the lens.
Onto the control panel - this kind of looks again like an F55 / Alexa panel, with a central screen and 6 buttons which correspond to settings on the screen - it's very easy and quick to operate. Eventually the assignment "User" settings will be enabled, but even now there are short-cuts for various command, so for example with frame rates you can jump to 25fps or 1000fps with a single button press rather than scrolling back and forth - it seems really well thought out. Most menu settings are operated with the large, easy to operate scroll wheel - press it in to choose the parameter, scroll to desired setting, press again to select. The button around the screen are mostly for shooting parameters (frame rate, white balance, shutter angle etc.) For camera system settings such as project frame rate, video system, partitioning the RAM etc. the scroll wheel is pushed in revealing a menu system - again easy to use and navigate. Compared to the Phantom HD it's a breeze! And by any standard it's a pleasure to use. The only downside is that it's only on the right side of the camera - so for a single operator on the viewfinder side it's a bit of a pain. There is a blank panel on the operator side and I gather there always were plans to duplicate the menu screen on this side but not sure if that's going to happen or not.
For judging exposure there are zebras in the viewfinder, but the most reliable way to set it is with the Threshold command. Just as with the other Phantoms Threshold mode shows areas of the image that are clipping in the different colour channels - this is based on the RAW data and so is not affected by ISO setting, white balance etc. and so is a true indication of what you're getting. There is also a setting in the menus for viewing "PhantomLog" in the viewfinder - again this shows the flat, full-sensor log data, giving a very good idea of what's clipping and what's being crushed - in most normal (ie non-extreme lighting) situations is pretty feasible to get an accurate exposure simply by eye with PhantomLog setting in the viewfinder - what you see is what you get.
The Threshold command is one area where I have a criticism - like the other Phantoms it can only be accessed through one button (in this case the "Tools" button) but to get to it you must press once which takes you into "Zoom" mode (for focus checking) and again to go into super-zoom mode, and finally into Threshold on the third press. I'd MUCH prefer to be able to just use a single press - either with a different button or just disable the 2 zoom modes.
There is a glitch, and it's the same as it was on the Phantom HD, and it concerns a very useful feature - Multicine. Multicine is the partitioning of the RAM, so rather than having a single shot which fills the whole memory you csan split the memory into anything upto something like 64 partitions. This is so useful as it allows several bites at the cherry when trying to capture unpredictable action - say for example a bird diving into water. If the bird spends long periods doing nothing and all of sudden has a burst of activity where it does several dives in quick succession, rather than getting one shot, saving it while it does 6 more dives, and then finding that it's gone by the time you're ready again, you can use 3, 4, 5 partitions. You shoot the first dive and ready straight away for the next, and again and again, and only once all shots are used do you need to save them. This is great, and it does work really well...but...as with the HD, for some reason once you've done your first bunch of shots and gone into save mode, when you then return to shooting mode you can only use one of the partitions. You do your first shot and it goes straight into save mode. With the HD you were stuck as there was no way to redefine the partitions in camera. With the Flex 4k it's not so bad - you just need to go into the menu where define the partitions, press enter, it asks if you're sure, click ok, then change the number of partitions and change it back again (so if you have 4 you just need to scroll to 3 then back to 4) and you're ready to go again. This does take a few seconds and is a bit of a pain - not the end of the world, but surely fixable? At least they have solved the other Multicine problem that the HD had - in that it does now tell you which shot you are on (so 2/5 or 4/7 for example). With the HD you just had to remember how many you'd done - in the words of Dirty Harry "did I fire 6 shots or only 5, in all the excitement I can't remember myself"!
As with all Phantoms once you've done your shot or shots you can trim them in camera to save space on the Cinemags - this is well worth doing as you tend to only use about 1/10th of the shot and if you save the whole thing the mags will fill up pretty quick. This is where having the screen and buttons on the dumb side is a bit awkward - it's ok if you have a monitor but with just a viewfinder it involves a bit of contorting and fumbling. Marking ins and outs and saving is dead easy though.
Jesse with the Flex 4k. This is what the Phantoms allow - field use with no laptops or cables in sight!
Like other Phantoms as well as the standard "Loop" recording mode (where the camera buffers and you can choose the trigger point) there is also the "Run / Stop" mode which records directly into the magazine, operating then very much like a normal video camera. The Phantom HD could do up to about 400fps in Run / Stop, but due to the huge data rates involved the Flex 4k tops out at about 100fps in 4k mode.
The magazines are hot swappable, no need to power down, and are very compact and available in 1TB and 2TB version. This is one area where you do need a computer - offloading shots and erasing the mags cannot be done from the camera. Vision Research's "Phantom Camera Control" software does its job pretty well. Not sure how many NLEs will accept the native .cine files the Phantoms produce, I only have DaVinci Resolve here and that takes them in without any problem.
I haven't done any scientific tests on the images but they look great to me. Certainly can't see any problems with noise or artefacts, they just look smooth and filmic to my eye, and I've experienced no operating glitches as yet. All in all I think it's an awesome bit of kit. It's much easier to use than the older models - and in actual fact I think the Phantoms in general are much less alien to camera operators than they were a few years back. Back then the cameras we used day in, day out tended to be 2/3" chips, compressed codecs, tapes, zebras and video gammas. To suddenly be introduced to RAW, log, histograms and Super 35mm sensors was a bit of a culture shock - but now most of the regular cameras are much like that so it's less of a transition. It's also true that a lot of the "regular" cameras today will shoot up to 180 or 240fps (possibly "only" in HD mode) and for a great majority of situations this will probably be adequate and so the need for a specialist, and very expensive, camera for occasional super-slow motion shots is probably much lessened. But, in the right situation, there's still nothing with quite the impact of a 1000fps shot!
Any questions to stevephillipps@yahoo.co.uk
Thanks to Jesse Wilkinson for the use of the Sigma 300-800 (handy tip - don't use 15mm bars!)
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