What is four thirds?

teaorcoffee

teaorcoffee

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Brian
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Sorry to ask such a basic question...

Is it bigger than full frame?
 
It's a smaller format, I can't remember the crop factor (I think it's a crop factor of 2 :thinking:), but it's the format used by the Olympus dSLR's.
 
Thanks for all the useful answers (but Lasagne needn't have bothered; it's not even funny).

So it's actually half frame (in terms of area). I can be forgiven for thinking it was 1.33 x Full Frame!!

:-)

B
 
teaorcoffee said:
Thanks for all the useful answers (but Lasagne needn't have bothered; it's not even funny).

So it's actually half frame (in terms of area). I can be forgiven for thinking it was 1.33 x Full Frame!!

:-)

B
Click to expand...

I thought that considering your question had been answered, Lasagne's was quite funny :)

I'm not sure how it works though, surely a smaller sensor = less detail :thinking:
 
I think four thirds comes from the aspect ratio of the sensor... I seem to recall reading somewhere that it's a 4:3 aspect ratio.
 
The aspect ration is indeed 4:3. The format was developped by Olympus and Kodak, and is soon to be replaced by the new Micro four thirds system.

This Wikipedia article has further info, and also a handy diagram showing the relative sensor sizes, and as you'll see four thirds is very small...hence why I've just moved to Nikon!
 
its smaller than the basic dslr sensor aps-c, the sensor ratio is 4:3 (four thirds) because its smaller image quality is sacrificed and there are high noise levels. some manufactuers adapted this sensor because it was cheaper and made the bodies smaller.
 
ChrisMClark said:
The aspect ration is indeed 4:3. The format was developped by Olympus and Kodak, and is soon to be replaced by the new Micro four thirds system.

This Wikipedia article has further info, and also a handy diagram showing the relative sensor sizes, and as you'll see four thirds is very small...hence why I've just moved to Nikon!
Click to expand...

I dont think Micro replaces it. I think they will run in tandem. :)
 
foodpoison said:
I thought that considering your question had been answered, Lasagne's was quite funny :)

I'm not sure how it works though, surely a smaller sensor = less detail :thinking:
Click to expand...
I too thought that was funny foodpoison! :)

However, I am no expert on these matters (I am sure DD will pop along when he sees this and add some expert advice :) ) but smaller sensor doesn't equate to less detail. What it does equate to is an increase in noise because the individual light sensitive photosites are physically closer together on the sensor. Early Oly DSLR's were prone to awful noise at ISO 400 and above (as indeed are earlier Nikons such as the D40 AND D2!! so no picking on Oly here OK :) ) However, recent Olympus cameras such as the E-3 and E-20 have significantly reduced the noise and while nowhere near the awesome capabilities of the FF brigade such as the D3/D700 and 5DII - can easily be used at much higher ISO levels. I regularly use mine at ISO1600 (and have at ISO3200 too) and don't get too much noise.

4/3 is actually a reference to the ratio of the size sensor i.e. 4 long / 3 wide so an image size you would regularly see online such as 800 * 600 would, if taken with a camera using a 4/3 sensor, need no cropping, however if taken on any other format it would need cropping or adjusting to get it to that size.

There is a crop fctor of x2 meaning this format is better used for longer range telephoto imagery, and is not so good for wide angle (only because you dont get as much in the frame with say the Oly 11-22mm lens as you would with a Canon or Nikon 11-22 equivalent. If I used my 70-300, I'd get half as much in the frame (i.e. effectively closer to the subject) as I would if I used a 70-300mm lens on a full frame camera.

Horses for courses really... though the high ISO capabilities of the recent FF kit are stupendously brilliant.

There's nothing really wrong with the 4/3 format, it's just another format as are Canon and Nikons 1.6 crop formats et al.

I don't think the 4/3 format, as Chris suggests, is going to be replaced per sé with the Micro 4/3 format, as this new format is predominantly aimed at the compact market and will allow users of those cameras to have and use interchangeable lenses etc.

I am a happy 4/3 format user, and I manage to take some very 'detailed' shots at high(ish) ISO's ;) though I'd love the high ISO capability of a D700 :)
 
afaik 4/3 & micro 4/3 are the same sensor format but different sized mounts.
 
heidfirst said:
afaik 4/3 & micro 4/3 are the same sensor format but different sized mounts.
Click to expand...

The sensors are the same and the mount is a different size but the main difference is the mount to sensor distance. On m4/3 this is much smaller because the camera uses an evf and hence doesn't have a mirror between the mount and sensor like an SLR does.
 
A bit of clarification on the term 4/3rds....

THE FOUR THIRDS SYSTEM

A new standard design paradigm for digital cameras is called the “Four
Thirds System”. This name (always spelled out) cleverly has two
meanings:

• It refers to the “Vidicon system” sensor size description of the
standard sensor for the system, 4/3”. The sensor is
17.3 mm x 13.0 mm in size, approximately twice the size of that
of the 2/3” Vidicon tube.

• It refers to the frame aspect ratio (ratio of horizontal to vertical
dimension), 4:3 (which ratio can be written “4/3”).
The sensor size description for these cameras is stated as 4/3” (not
1/1.33”).
Click to expand...
 
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