Admittedly, I am not excited or surprised by this announcement by Acer, which has stolen the thunder from Samsung with a 4K resolution video camera on a mobile device. The new toy from the Taiwanese giant, codenamed the Liquid S2, comes with a 6-inch Full HD 1920 x 1080 IPS display, 13-megapixel camera, and will be one of the first devices to unlock the 4K video recording capabilities.
Samsung was suppose to out a similar video capable camera on the Galaxy Note 3 but heck, I don't shoot video much to warrant the need of such a device so here goes nothing.
What the heck is 4K?For the record, 4K refers to the pixel resolution from end to end of a horizontal screen. Remember the old 1020p resolution? That referred to 1020 pixel from end to end of a horizontal screen. For 1020p, all you needed was a 2 megapixel sensor in your camera. Whereas the new 4K standard requires 8 megapixels.
These days, cinemas that have gone digital tend to adopt the 4K projection standard. Beyond Hollywood and Cineplexes, no one really uses 4K at least not until the advent of UHD TV, which is being rolled out to consumers now. To understand the technical nature of 4K, you can refer to the chart below, which it taken from Wikipedia.
Resolutions of common formats
|Format||Resolution||Display aspect ratio||Pixels|
|4K Ultra high definition television||3840 × 2160||1.78:1 (16:9)||8,294,400|
|Digital Cinema Initiatives 4k (native resolution)||4096 × 2160||1.90:1 (256:135)||8,847,360|
|DCI 4K (CinemaScope cropped)||4096 × 1714||2.39:1||7,020,544|
|DCI 4K (flat cropped)||3996 × 2160||1.85:1||8,631,360|
|Academy 4K (storage format)||3656 × 2664||1.37:1||9,739,584|
|Full aperture 4K (storage format)||4096 × 3112||1.32:1||12,746,752|
Video Versus Still Photography
I have said this before and I will say it again, 4K video has enough resolution to put still photography to bed. If you don't mind the weird aspect ratio, the 8 megapixel still you can pull out from a video feed is essentially a 8 megapixel still image.
There are even newer video cameras that can capture 6K resolution(6144 x 3160 pixels).
That means a 6K still image is 19 megapixels! But these are awfully expensive and are found in the RED Dragon video camera. It has the dynamic range to put any high end DSLRs to shame! It has 20 stops of dynamic range.
Never Miss a Moment
This is the frightening reality of the future. That for whatever reason that you do not wish to miss one moment, you can shoot 82 frames a second on 6K video and still put out a decent still image from one frame. That is incredible if you asked me.
There is no reason to shoot stills if you can shoot video at that high a resolution and frame rate. Even now, with a 4K camera, you can avail yourself to a 8 megapixel still image from a video feed. Discounting the 16:9 aspect ratio, that raw video footage has every frame from a scene you can think of.
Any Weak Points of 4K cameras on mobile?
There is of course, low light handling will be subjected to much scrutiny and of storage concerns. Your puny mobile isn't going to have enough storage to hold all that video if you used it constantly. Burning through 16GB of storage will be real easy.
Dynamic range will also be suspect as a small sensor found in the likes of the Galaxy Note 3 and Acer S2 won't have the muscle to capture high contrast scenes. Noise will be a problem in low light but it should be decent if you shot anything in daylight.