How many chips?

[Ed Roo]

In the past, it seems that the video cameras that were touted to produce the "best" images were those that used three chips. In the past few years, new cameras with a single chip (not to include DSLRs) are becoming the the latest and greatest in the mid-level prosumer market.

So what is the story here? Are single chip video cameras not equal to or better than the previous generation three chip video cameras?

What are the determining factors when one is researching a new camera to purchase?

[Brian Drysdale]

It's the larger sensor that is the driving force behind single chip cameras. This gives a shallower depth of field, the larger sensor allows for larger pixels (so more sensitive) and some fulfil the desire for 4k resolution. Better depends on your requirements, many new generation cameras are 3 chip, but these are 2/3", 1/2" and 1/3", with a few of the latter meeting broadcast standards.

Each has its advantages and disadvantages, the determining factor is what you want to use the camera for.

[Roger Gunkel]

My understanding is that a 3 chip camera will give better colour rendition and separation as each of the RGB colour channels is using it's own chip. A single chip camera is using a filter to divide the light through the sensor into the 3 channels, but will usually have larger pixels as Brian said, therefore greater sensitivity and better low light performance.

It would also be fair to say that that is assuming that the single sensor is bigger than the sensors in the 3 chip. A camera with 3x 2/3" sensors will of course give better all round performance than a 1x 2/3" sensor, so in any comparison, it will be important to know the sensor sizes.

Roger

[Seth Bloombaum]

To my eye, large-sensor single chip cams have their own look, quite apart from the available shallow depth-of-focus. Meaning, even if I stop down so everything is in focus, the image still looks very different than from a small-sensor three chip cam.

There's a certain linearity and even-ness out to the edges. I suspect this is due both to the sensor and the glass in front of it; primes and close ratio zooms are common on dSLRs and the camcorders they've inspired.

For example, Canon makes a lovely wide-angle zoom for full-frame, the 16-35mm L lens. The zoom ratio is only a little over 2x. Their 70-200mm telephoto zooms about 3x. I've used a lot of under-$10k USD 3-chip camcorders, zoom ratios of 16x to 22x are common.

Lenses that cover a large sensor would be monstrous in size and weight at 16x! But at 3x quite managable, and we've quickly gotten used to quality glass that projects the image onto a big sensor quite nicely.

Not to mention the trend towards exposing flatter to preserve maximum dynamic range, which these large-sensor cams have really enabled for the masses.

I've come to really like the aesthetic of the large-sensor images... recognizing that the glass, shallow DoF, exposure techniques, and post color correction are all contributing to what we're seeing out of them.

[Petter Flink]

Not to forget is the bayer patterned sensors often showing aliases on diagonal frequencies.
Three sensor cameras are far less susceptible by this.

[Heiko Saele]

I just got a Sony PMW 350K 2/3" and it actually has a 3-CMOS system, so the 3-chip technology still seems to have its advantages. However Red or Arri seem to be doing fine with one chip, I guess both systems have their positive and negative sides (Bayer patterns being one of the negative sides of a single-chip)

It is probably like asking what motor is better, a normal one or a diesel? You can't really say what is "better", you need to look at the whole product and see what it can do for you.

[Chris Medico]

Maybe one day someone will make a 3-chip s35 sized camera and we can better compare apples to apples.

[Kevin Spahr]

I never liked the idea of a imaging chip that only has full resolution for the green channel and then calculates the red and blue from half as much data. No matter how good the algorithm is, they are still guessing. But the Bayer chips are quite popular with a lot of camera makers...