Why don't they make all DSLRs with an electronic shutter?

Question

Why don't they make all DSLRs with an electronic shutter? Is it technically possible?

Surely this would allow easier syncing with flashes (rather than the usual 1/200s or 1/250s max).

I could even imagine a special RAW format that basically recorded all data from the CCD for, say, a second and then in software you could retrospectively shorten that time window. eg. only use data recorded in the first 1/100h of a second...

Or am I being stupid?

Answer 1

Sounds nice but apparently there are currently some technical limitations:

An electronic shutter requires the sensor to be equipped with what is commonly called "snap shutter" circuitry. Basically, this is a second set of diodes, as big as the light gathering photodiodes, but shielded under a dark cover, and some additional switches. To shoot, the photodiodes are cleared of charge, exposure starts, and at the end of exposure, the charge in the diodes is transferred over to the shielded storage part of the cell. The cell is already full of stuff, so the only way to make space for this extra circuitry is to cut the size of the photodiode in half. Which cuts dynamic range and low light, high ISO performance.

Source: Joseph Wisniewski

Answer 2

Some good readin' here.

Some key notes...

Cameras, typically smaller point-and-shoot cameras, that use no mechanical shutters typically use an interline transfer sensor. An interline transfer sensor dedicates a portion of each pixel to store the charge for that pixel. The added electronics necessary to be able to store the charge for each pixel reduces the fill factor of the pixel, in turn reducing it's ability to capture light since a portion of each pixel is not light sensitive.

Interline transfer sensor's typically have higher noise levels and lower sensitivity than the full frame sensor's used in high end digital SLR's.

So, basically, the electronics required for an electronic shutter result in compromised image quality.