Image sensor

he heart of a film camera is the film stock. The heart of a digital camera is the image sensor. Alpha and Axiom both use a CMV12000 from CMOSIS - a high end sensor and the first of its kind that is available on the free market. The image area is larger than Super35 and thus perfect for a digital cinema camera at 4K resolution. It's also the first sensor of this kind with a global shutter. Most DOPs have already learned to live with the rolling shutter (and the resulting distortions/artifacts) of todays digital cinema cameras but that does not have to be that way anymore.

The image sensor has pretty much the same dimensions as analog 35mm film.

Image Sensor Tech Specs

Size	Super 35 / APS-C
Image Area	22.8mm x 16.9mm (28.1mm diameter)
Resolution	12 Megapixels - 4K (4096 x 3072)
Color Filter Array	Bayer Pattern
Shutter	Global, Electronic
Technology	CMOS
Pixel Size	5.5 x 5.5µm
Framerate	Up to 175(8bit)/150(10bit)/75(12bit) FPS at Full Resolution (12 Megapixels)
Bitdepth	8Bit / 10Bit / 12Bit
Features	FPN correction, X and Y mirroring, Binning, Vertical Window of Interest, HDR Modes
Dynamic Range	up to 15 F-stops (pseudo logarithmic response curve) / 10 F-stops (linear response curve)

High Dynamic Range

The image sensor supports three different High Dynamic Range (HDR) modes.

• One mode alters the sensors photosite response curve from a linear default behavior to a shape that is closer to a logarithmic response. This happens before the ADC so no digital data is sacrificed for the additional dynamic range.
• The second mode uses different exposure times for even and odd pixel coloumns. So two exposure brackets can be captured at the same time for sacrificing horizontal resolution.
• The third mode is possible due to the high speed nature of the sensor allowing alternating exposure times with each recorded frame and doubling/tripling/etc. frame rate result in double/triple/etc. the amount of data to be captured.

The response curve processing happens before the ADC so no digital data is sacrificed for the additional dynamic range.

Smart Dynamic Range

Imagine your camera had a knob for dynamic range like the one it has for shutter speed. You can turn it up or down just as you need it. Sounds crazy doesn't it? That's exactly what this sensor can do. While in general the notion is "the higher the dynamic range the better" you need to be aware that you sacrifice details (digital bandwidth) in shadows/midtones for gains in latitude when you increase dynamic range. This could be undesired in situations like when dealing with fine skin tones or when the scene does not require a high dynamic range at all e.g. when shooting well lit indoor scenes. Smart Dynamic Range for us means that you can dynamically influence the response curve for your particular situation in a range from 10 - 15 stops of dynamic range.