The Good, the Bad and the Possibilities of Contrast Detection

(Camera: Ricoh CX1)

It is generally thought that indecisive focusing is quintessential of contrast detection adpoted in smaller-sensor compacts.  This detection operation has an inherit constraint: it is limited by the level of contrast available for detection.  In a nutshell, in low-light situations, the photographers have to convince and wait for the focus to really lock on the subjects.  This observation still holds true.  But the perception of contrast detection as such is changing.

Until recently, contrast detection has lagged behind in focusing when compared with phase detection.  As the Panasonic's top-class model GF2 attests, the MFT sensor using contrast detection is really fast in good lighting situations.  Probably in those situations, it is marginally slower than phase detection.  If you've not checked it out, go here.

So, while contrast detection still sucks in low-light settings, it has caught up quite close focusing-speed-wise.

The common saying goes, "There is no rose without a throne": but this time use a bit of reverse thinking and look at the rosy side of the moral.  Fact is, contrast detection has a big advantage since it uses the whole plane of the sensor.  The photographer can theoretically (in effect the marginal areas are excluded) run through the frame to choose any points to focus and meter.  Take the shot of today for example.

The shot of today was taken with the tiny-sensor CX1. Unlike the big boys, the CX1 uses contrast detection which, in this case, allowed easy selection of the AF on the buildings and AE metering on the bright part of the scene. For a camera fitted with an APS-C or bigger-size sensor using phase detection, the photographer would have to spot-meter and recompose. That is not a lot more troublesome, but troublesome enough when decisiveness is important for a decisive moment which is usually short.

In another development, the Fujifilm F300EXR offers the capability to use contrast AF or phase AF on account of the lighting situations. There is a high chance that the two will become complimentary in the coming camera models.

Fujifilm is being creative too with its X100, which is heard to hit the stores in February, to combine the EVF and OVF.  Rumours have it that Sony's next translucent model will adopt the same trick.
 

So, it is not foolhardy to predict that new camera models which blend the two detection modes and both types of viewfinders will soon exist.  The dream camera could be one which adopts these technologies, coupled by Sony's lightening translucent-mirror focusing-speed and Sigma's Foveon sensor.

 

The codename?  Let's call it Big Daydream no. 1 for the moment.