October 18, 2010

Panasonic Unsuccessfully Clarifies Micro 4/3 Sensor Size

Ever since the announcement of the Panasonic AF100, I've been surprised by the number of commenters who seem to think the AF100's Micro 4/3 chip is "too small." In two short years, we've apparently gotten so accustomed to a full-frame DSLR that we've now unimpressed by a chip that's several times larger than anything in its price range (in an actual "pro" video camera body). In an attempt to clarify how large the Micro 4/3 sensor is (in which case perhaps they shouldn't have named it "Micro?"), Panasonic New Zealand has released a video comparing the 4/3 sensor with 35mm motion picture film. There's just one problem with the video: it's wrong.

There's no sound in the video, so feel free to add your own tunes:

However, their math -- both in terms of percentages, and more egregiously in terms of the on-screen illustration -- is off. I've gone through the process of illustrating sensor size and how it relates to depth-of-field (the free eBook of the DSLR Guide contains an even more in-depth explanation), so I can tell at a glance what looks correct and what doesn't. The above video did not look right, so I went in and checked their numbers. In the illustration, Panasonic illustrates the 4/3 sensor as being 76% the size of 35mm motion picture film. In fact (using their own numbers), the Micro 4/3 sensor is 64% the size of 35mm motion picture film. ((Math is not my strong suit, so by all means, let me know if my corrections to their numbers are also, in fact, wrong.)) In the below graphic, the red area is the true Micro 4/3 sensor size:

It's not a HUGE difference, but... just thought I should clarify, since their whole point in making this video was to tell the "truth" about the two different sensor sizes. And, of course, you can see how large the 5D Mark II's sensor is -- but there are many factors above and beyond sensor size that contribute to a good image.

There are a lot of positives to the camera, and if you have access to real Cine lenses and an external HD-SDI recorder, it'll be hard to beat the AF100 without stepping up to much higher-priced cameras. However, if you're thinking about investing in glass, Stu also makes some good points about the Micro 4/3 format and its limitations.

[via Cinema5d]

Your Comment


There's definitely some fuzzy math going on here ... It probably all comes out in the wash though. According to AbelCineTech's online calculator - http://www.abelcine.com/fov/ - you get this:

AF100 (16x9) = 18.8x10.6
35mm (16x9) = 24.9x14

According to this video, it's:

AF100 (16x9) = 19x10.7
35mm (16x9) = 22x12.3

In other words, according to Panasonic, 35mm motion picture film is smaller, and their sensor is larger.

On the other hand, who really cares about two milimeters one way or the other, as long as it looks good? Lighting, composition and color grading are going to make a lot more of a difference in any given shot than a fingernail's-width difference in sensor size.

October 18, 2010 at 10:53AM, Edited September 4, 7:54AM


I agree -- my point is that not only is their math wrong (in their favor), but they also represent that math wrong in the video (in their favor). If you're going to release a video expressly to show how large your sensor is (now it sounds like we're dealing in euphemisms), don't lie about it -- that's all.

Of course there are a million other more important factors than sensor size, but people were harping on the camera's Micro 4/3 sensor, Panasonic released a video to rebut those complaints, and now I'm just pointing out that their video (which has been picked up by a number of blogs) is erroneous.

Moving on...

October 18, 2010 at 11:58AM, Edited September 4, 7:54AM

Ryan Koo

> What really strikes me as strange is that a company that produces video equipment couldn't put a simple soundtrack, let alone narration, on an official video. If they can't even find a piece of royalty-free background music, no wonder they can't do accurate math.

Keep this in mind, though ... Maybe Panasonic is RIGHT, and whatever other source you used to get your dimensions from is wrong. Where DID you get your numbers?

October 19, 2010 at 5:36AM, Edited September 4, 7:54AM


I'm using their numbers -- I'm just pointing out that they misrepresent their own measurements in the video (and in their calculations).

October 19, 2010 at 9:37AM, Edited September 4, 7:54AM

Ryan Koo

OK, I'm just running these numbers through my head again because I'm still a little confused. First of all the AF100 chip is a native 4:3 chip, and the F3 is a native 16:9 chip, correct?

With that in mind, you can't really compare them directly. You need to decide on a aspect ratio first, like ALEX did.

So, using the self-published dimensions of their sensors, at 16:9, the usable sensor sizes are:

Sony F3: 23.6mm x 13.3mm (the whole sensor) = ~314mm2
Pansonic AF100: 17.3mm x 9.73mm (4:3 cropped to 16:9) = ~168mm2


Of course, Koo is right, there is a lot more than just sensor size that is important, but when it comes to low light performance, and achieved depth of field, it's pretty damn important.

Can someone just confirm that I'm not smoking crack with the above claim? And then I can "move on" too:)

January 29, 2011 at 10:24AM, Edited September 4, 7:54AM


My biggest issue with the AF100 is that it looks ugly. Like a CP16 (the old 16mm camera that I've heard was often used to film the vietnam war) minus the film magazine. Check it out: http://www.flickr.com/photos/39153031@N03/3607386905/

Look familiar? Definitely retro. :-)

October 18, 2010 at 4:28PM, Edited September 4, 7:54AM


I think the camera is great. It is a little to price for a student like me to just run out and buy when I have already invested in DSLRs. I think that the 4/3rds sensor was the best work around for a larger sensor that won't over heat easily and create a jellying effect when moving. Any thoughts on that?

October 18, 2010 at 7:16PM, Edited September 4, 7:54AM


Would all this math say that the 7D or the new Nikon D7000 be Cinema "full frame"? And going on that math, I think the Nikon's are actually closest. Which is good now that they're coming out with a competing camera for the HDSLR market...

October 18, 2010 at 8:30PM, Edited September 4, 7:54AM


The test footage so far - the model photo shoot and Phil's posted tonight are starting to make me really feel the burn of the EOS's line skipping. This and the sdi out are the real advantages to me. We've been working with the DSLRs long enough to find a decent work flow for sound, so the two xlr ins aren't a deal breaker. It's lovely stuff, but the price tag's pushing it - for me at least.

NIce one for pointing out the discrepancy, Koo

October 19, 2010 at 7:48PM, Edited September 4, 7:54AM


Any news on the native iso? And what are the different lens mounts available?

October 21, 2010 at 6:05PM, Edited September 4, 7:54AM


The argument they are making is for Academy 35mm cinema, which is a square format and hardly every used for films any more. Super 35mm loses the soundtrack and a set of sprocket holes for a much wider image, more like APS-C.

October 21, 2010 at 10:43PM, Edited September 4, 7:54AM


The math of Panasonic is not off fortunatly ! they take the 16/9 ratio's numbers... anyway canon 5D doesn't shot in 4/3 !

October 22, 2010 at 5:54AM, Edited September 4, 7:54AM


Keep in mind there are two types of FourThird sensors.
1. True FourThird sensor that has the aspect ratio of, well, FourThirds.
2. Variable ratio FourThird sensor that supports 16:9 ratio (GH1, 2 uses this type of sensor)

The comparison picture you have above clearly shows that your math is based on 4/3 ratio calculation.


December 15, 2010 at 5:04AM, Edited September 4, 7:54AM