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The biggest Four Thirds sensor yet

The new, larger, Four Thirds sensor from Panasonic makes wider format shooting more efficient

It may look very similar to a DMC-G1, but Panasonic's new DMC-GH1 has new, larger, Four Thirds sensor.

It's widely assumed that the Four Thirds image sensor size is fixed at 18x13.5mm. But the truth is that it can be any aspect ratio as long as the sensor diagonal, which is the same as the Four Thirds image circle, remains 22.5mm. By coincidence, Four Thirds has standardised on a 4:3 frame aspect ratio. The system name 'Four Thirds' does not relate to this at all. Instead, Four Thirds is a reference to the chip carrier size and, in turn, distantly relates to video camera tube sizes, four thirds inches, in the early days of video cameras.

The fact that you could implement a sensor chip of any aspect ratio for Four Thirds was something confirmed to me by Olympus engineers right at the beginning, when the first Four Thirds camera, the Olympus E-1, was launched. Later, when Panasonic replaced Kodak as the primary supplier of sensors for Four Thirds cameras, I soon discovered that Panasonic was keen to explore the possibility of a Four Thirds sensor that would enable user-selection of a variety of frame aspect ratios. I was asked to keep this under my hat, which I have done until now, because the new Lumix DMC-GH1 is the first (Micro) Four Thirds camera to deliver on the variable frame aspect ratio promise - without simply cropping a 4:3 frame. Panasonic has already produced the DMC-LX1 compact camera, the first compact camera to be fitted with a 16:9 'wide screen' CCD sensor.

A wider sensor is better

The Panasonic Lumix DMC G1 and Olympus' E-30 and E-620 models all offer different aspect ratio frames for the user to choose from, but non can be wider or taller than the basic 4:3 aspect ratio frame, which is representative of the actual sensor physical limits. However, the Lumix DMC-GH1 breaks out beyond those limits thanks to a new over-size Four Thirds compliant sensor. Proof is in the pixel dimensions of the various optional frame choices:

  DMC-G1 Olympus E-30/E-620 DMC-GH1
Total pixels 13.1MP 13.1MP 14MP
1:1 N/A 3024x3024 9.1MP 2992x2992 9MP
4:3 4000x3000 12.0MP 4032x3024 12.2MP 4000x3000 12.0MP
3:2 4000x2672 10.7MP 4032x2688 10.8MP 4128x2752 11.4MP
16:9 4000x2248 9.1MP 4032x2272 9.2MP 4352x2448 10.7MP

In all but the 1:1 aspect (square frame) choices, the Lumix G1 and Olympus E-30 and E-620 are limited to the maximum width of the 4:3 sensor area. But the Lumix GH1's sensor goes wider than the width of its 4:3 aspect frame for 16:9 and 3:2 frame formats.

The diagram above shows the Four Thirds image circle and how the typical Four Thirds 4:3 frame fits within it. Please note that the effective dimensions of a 4:3 Four Thirds frame are slightly smaller than 18x13.5mm, at 17.3x13mm.

In this diagram (above) the blue area shows a 16:9 frame on a Lumix DMC-GH1. The wider sensor enables the 16:9 format to fill the maximum area under the Four Thirds image circle.

Finally, the red area shows the limited area of a 16:9 frame that Lumix DMC-G1 and Olympus E-30 and E-620 users have to make do with compared to the unrestricted blue area thanks to the larger sensor of the GH1.

Panasonic has chosen not to publish any dimensions for the sensor in the GH1, but we can logically estimate it to have the width of the 16:9 format and the height of the 4:3 format frame areas, making it 4352x3000 pixels, or about 10:6.9 (about 18.8mm x 13mm), a total of 13.1 million available pixels, instead of 17.3x13mm and 12.1million available pixels..

The future?

The benefit at 16:9 is around 1.5 million pixels, and just over half a million pixels for 3:2 (35mm film frame format). It shouldn't cost much more to manufacture such a chip, so it's not unreasonable to expect it to be rolled out beyond the GH1, in future Panasonic models.

It would seem logical that Olympus should follow the Panasonic lead in employing this new, larger, Four Thirds sensor, at some time in the future, perhaps with the expected successor to the Olympus flagship E-3 DSLR, and with the forthcoming Olympus Micro Four Thirds cameras.

 

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The biggest Four Thirds sensor yet

Four Thirds User editorial team The biggest Four Thirds sensor yet
It's not widely hailed, but Four Thirds has a new, bigger, image sensor from Panasonic and it made i... (more)

hschnee Re: The biggest Four Thirds sensor yet
This is a neat idea, and so simple you wonder why no one (as far as I know) has done it before. Of c... (more)

Ian Re: The biggest Four Thirds sensor yet
Panasonic say that the GH1 sensor's low light sensitivity has been improved slightly over the G1 ... (more)

John Perriment Re: The biggest Four Thirds sensor yet
The slight increase in pixels for the wider formats is interesting but nothing to really get excited... (more)

RogerMac Re: The biggest Four Thirds sensor yet
Ian, It seems that at some time in the future we are likely to get an Oly camera with selectable ... (more)

Ian Re: The biggest Four Thirds sensor yet
The E-30 and E-620 already offer a wide range of user-selctable frame aspect ratios: 4:3, 3:2, 16... (more)

RogerMac Re: The biggest Four Thirds sensor yet
Thanks for the response. Yes 7:5 is a good match for A4, I had not realised that this was like... (more)

Ian Re: The biggest Four Thirds sensor yet
On the E-30/E-620, the frame selections are only recorded in JPEG form. If you record RAW simulta... (more)

RogerMac Re: The biggest Four Thirds sensor yet
I could live with that:):)... (more)

fluffy Re: The biggest Four Thirds sensor yet
Of course, an amazing amount of printing goes on the non-metric paper areas, even if it's few countr... (more)

fluffy Re: The biggest Four Thirds sensor yet
Of course, an amazing amount of printing goes on the non-metric paper areas, even if it's few countr... (more)

RogerMac Re: The biggest Four Thirds sensor yet
Yes, I have spent a lot of time cutting down A4 prints to mount them in 8 by 10 frames - just ... (more)

Dummy00001 Re: The biggest Four Thirds sensor yet
But isn't that still a crop? Why does it matter so much what's original sensor size (4:3 vs. 1... (more)

viztyger Re: The biggest Four Thirds sensor yet
Panasonic's oversized, 14 megapixel sensor only allows for aspect ratios larger than 1.33 (4:3) t... (more)

RogerMac Re: The biggest Four Thirds sensor yet
Don't kock it - it may be a stepping stone to a circular sensor which is one ot the things I have... (more)

MikkoH Re: The biggest Four Thirds sensor yet
But the oversized sensor would need a bigger mirror if used in a dslr, otherwise the different aspec... (more)

Dummy00001 Re: The biggest Four Thirds sensor yet
Thanks for the diagram! It (unintentionally) answered my previous question to Ian.... (more)

RogerMac Re: The biggest Four Thirds sensor yet
Yes this sensor would require a wider mirror if used with an OVF but not a higher one. If we get ... (more)

thestickman Re: The biggest Four Thirds sensor yet
But I don't think a slightly bigger mirror/prism would be a big problem. Especially if coupled with ... (more)

Rick D Re: The biggest Four Thirds sensor yet
Neat! That's the same scheme Panny uses in the LX3--it's not simply an x-axis crop, which in my book... (more)

@zeta@ Re: The biggest Four Thirds sensor yet
is the crop ratio still X2 ?... (more)

Ian Re: The biggest Four Thirds sensor yet
Absolutely. No Four Thirds standard rules are being broken here. Ian... (more)

AdrianF Re: The biggest Four Thirds sensor yet
I'm looking forward to see how the wide angle eg 7-14 will look when shooting video. The fact that i... (more)

thestickman Re: The biggest Four Thirds sensor yet
Now that's an exciting idea :)... (more)

davidthornburg Re: The biggest Four Thirds sensor yet
Trade-offs, Trade-offs. Given a circle 22.5mm diameter, the greatest area (and so the greatest coun... (more)

Ian Re: The biggest Four Thirds sensor yet
1:1 is, in my mind, the least efficient format as unless you are shooting for square prints you w... (more)

davidthornburg Re: The biggest Four Thirds sensor yet
Alas, this is true more often than not, and illustrates the trade-off I mentioned. Square format ... (more)

dbutch Re: The biggest Four Thirds sensor yet
Would a larger sensor also benifit Olympus sensor shift image stabilization? persumably the more spa... (more)

Ledgem Re: The biggest Four Thirds sensor yet
I don't imagine that digital image stabilization would work. For those who don't know, this is a te... (more)

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