4K video is becoming "The Next Big Thing", with screen resolution that is much greater than what you get from that measly 1920 x 1080 pixel display. Since there's not a lot of content available in the 4K format at this time, how do you impress your friends with the incredible resolution? Ultrakam (US$9.99) turns your iPhone 6 or iPhone 6 Plus into a 4K video camera, giving you the chance to capture your own cinema-quality video. You can also download Ultrakam as a bundle with the Ultrakam Remote app.
First, let's clear something up: this app isn't truly shooting 4K video. The best resolution possible is "4K mjpeg" at 3264 x 2448 resolution (7,990,272 pixels, 24 frames per second). Not only is that nowhere close to the 3840 x 2160 (8,294,400 pixels) UHDTV standard, but it's also a 4:3 aspect ratio - not the 16:9 we're all used to seeing our TV in.
Now, this is probably all nitpicking, since even at the lower resolution of Ultrakam you're getting about 3.85 times the number of pixels that you'd get by shooting standard 1080p (1920 x 1080) HD video.
The app interface is quite sparse, getting right down to the business of shooting video. Ultrakam's screen (always in landscape orientation) shows you what you're filming, with buttons on the left side to turn on the light, change the filming orientation vertically or horizontally, add a guide to show the "frame" of the video, a white balance button, and exposure and focus locks.
The right side of the display features five buttons as well - one to get into the gallery (where your videos are stored), one to go to a help file, a bright red "record" button, another to let you use another device as a remote, and a settings button.
The settings include the ability to set the camera up in a number of formats, set film speed, define the video codec used, choose the aspect ratio, define "quality" of the video, and scale the video if you wish. There are also tabs for setting up timelapse and slow-motion video at a higher resolution than usual for the iPhone 6 family.
The bottom of the Ultrakam screen always displays the current format, resolution, frames per second, and sound codec. A handy set of meters at the top shows how much storage is available on your device - shooting video can chew up a lot of storage very quickly - and your phone's battery level.
Once you've shot your video, moving to the gallery displays all of the video that you've taken. Each clip shows the date and time of creation, the resolution, codec, data rate (i.e., 5 MB/second), duration, frame rate, and the file size. In most cases, the app asks if you wish to create a "reference proxy" preview - that takes the RAW movie and optimizes it for smooth playback on your device.
There's also a button that sends you to the Cinekolor app - it's another product by Ultrakam developer Hassan Uriostegui that allows you to design custom filters for video or retouch, and even export those to Photoshop. The idea here is that you can apparently apply those filters to Ultrakam.
Also in the gallery is an edit button. Sadly that only allows you to edit a single shot, not put together a complete "movie" like you can with Vizzywig 8xHD. Once you've edited your shots, they can be exported to a YouTube account or to your Photo Library. Those videos - once in your Photo Library - can be exported to a Mac or PC for further editing.
When you export, the video is rendered rather quickly - of course, most shots are going to be of rather short duration. Likewise, those videos are uploaded quickly on a Wi-Fi network.
Since there's no way for me to create a full "4K" sampler within the app, nor do I have a way to edit video of this resolution on my current iMac, I decided to point you to three short sample videos that I shot using an iPhone 6 Plus that are currently out on YouTube. It should be noted that YouTube does have a video editor available, which might be useful with Ultrakam.
Compared to Vizzywig 4K/8xHD, the video is much smoother. There was a lot of jerkiness in the videos from that app, although it may have changed along with the name when Vizzywig 8xHD came out. My opinion after trying both of these apps? Well, if you want to be able to shoot "4K" video on your iPhone 6 or 6 Plus at decent frame rates, you'll want to get Ultrakam. If you want to be able to actually edit your clips, add titles and transitions, and then send the output to YouTube as a complete "movie", spend the extra $40 and get Vizzywig 8xHD.
And if you're very serious about doing real 4K UHDTV videography, pass on both of these apps and get yourself an actual 4K camera. Got $500? About the least expensive 4K camera out there is the GoPro Hero4 Black, which shoots true 4K (3840 x 2160) at 30 frames per second.