four thirds: Please Explain

Todd Frederick · Jan 22, 2005

I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the exception of some compact units, used the "four thirds" concept, including the E-20n.

Reading some info on Steve's Digicams I realize that I am wrong on that and that I have no clue what "four thirds" means.

I have yet to read anything that explains 4/3, 3/2, 2/3, APS, 35mm with regard to digital photography clearly.

I think it has something to do with sensor size and with image aspect ratio.

Will someone explain this in a simple way.

Thank you, Todd
--
Todd Frederick

lingsb · Jan 22, 2005

Todd Frederick said:
Will someone explain this in a simple way.

This site http://www.four-thirds.org/en/index_01.htm is a good place to start. Try the 'about the four thirds standard' links on the left.

adrianox · Jan 22, 2005

"The Four Thirds system is a new open standard for digital SLR cameras with interchangeable lenses that utilise a 4/3 inch image sensor. In addition to facilitating the development of camera lens systems specifically designed to maximise digital image sensor performance - without being bound by the design conventions imposed by 35mm film camera SLR systems - the Four Thirds system establishes a common standard for lens mounts, ensuring compatibility between lenses and bodies even if they are produced by different manufacturers. Furthermore, the Four Thirds system interchangeable lenses are much smaller and lighter than 35mm and APS SLR lens systems."

Todd Frederick said:
I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the
exception of some compact units, used the "four thirds" concept,
including the E-20n.

Reading some info on Steve's Digicams I realize that I am wrong on
that and that I have no clue what "four thirds" means.

I have yet to read anything that explains 4/3, 3/2, 2/3, APS, 35mm
with regard to digital photography clearly.

I think it has something to do with sensor size and with image
aspect ratio.

Will someone explain this in a simple way.

Thank you, Todd
--
Todd Frederick

--
adrianox

my stuff: http://www.pbase.com/adrianox

Olympus E Series 4:3 FAQ's (early days - but useful)
http://www.fourthirdsfaq.com/

Gerry Siegel · Jan 22, 2005

Welcome,Todd,from San Fran!. Did you part with your Canon digital stuff,or are you decided to be shoot both.

Welcome to the enthusiastic fraternity and sorority of E users...Regards,.Your photofriend, Gerry ( I read the origin of the 4/3 thing, a holdover from an old videcon tube TV yardstick and promptly decided to forget it.Except that it is something new, and delivers..GS) The origin is not important, the diameter of the circle is what it is. Not the diagonal of the polygon.

Todd Frederick said:
I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the
exception of some compact units, used the "four thirds" concept,
including the E-20n.

Todd Frederick said:
I think it has something to do with sensor size and with image
aspect ratio.

Both ,in result as you read.. I thought Bob Atkins did the photo showing relative sizes vis a vis 24 by 36 film. Not as teeny as our C 5050s.

BJL · Jan 22, 2005

adrianox said:
"The Four Thirds system is a new open standard for digital SLR cameras with interchangeable lenses that utilise a 4/3 inch image sensor.

A historical note; in the strange way that most digital sensor formats are described, dating back to old television camera technology, a 4/3" sensor is one whose total sensitive region is 18mm by 13.5mm. This happens to have the aspect ratio of 4:3 (18/13.5 = 4/3), like all traditional television camera sensors and most digital cameras sensors, though the name actually comes from a distance of 4/3 of an inch, not the shape.

As you might guess, 4/3" format has twice th height and width of 2/3" format (6.6x8.8mm), the biggest format used in fixed lens "digicams". Thus the 4/3" sensor has an area at least four times larger than any compact digicam's sensor.

jscott · Jan 22, 2005

Todd Frederick said:
I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the
exception of some compact units, used the "four thirds" concept,
including the E-20n.

Reading some info on Steve's Digicams I realize that I am wrong on
that and that I have no clue what "four thirds" means.

I have yet to read anything that explains 4/3, 3/2, 2/3, APS, 35mm
with regard to digital photography clearly.

I think it has something to do with sensor size and with image
aspect ratio.

Will someone explain this in a simple way.

Four-thirds refers to the sensor size, based on an type designation of television camera vidicons dating from the 1950's:

http://www.dpreview.com/learn/?/Glossary/Camera_System/Sensor_Sizes_01.htm

It happens to also be 4:3 aspect ratio.

Regards,
Scott

--
As we celebrate mediocrity all the boys upstairs want to see
How much you'll pay for what you used to get for free

Tom Petty

Todd Frederick · Jan 22, 2005

Thank you and good to hear from you again Gerry. I did part company with my 10D. Fine camera but I sort of fell into a wonderful deal on the E-1 kit from a friend.

Regarding the 4/3" (inch) concept, the use of the term "inch" and the imporper fraction of 4/3 (or is it more of a ratio?) tends to throw me. Some people rant and rave about the 4/3 concept and I'm not sure why.

All I know is that with my previous Canon 10D, it seems to fit a 4x6 proof print format perfectly but with the 4/3 I lose a bit of image on the long side with a 4x6, which is not a big deal, really.

I'm not a tech person, but just asked the question for clarification.

I was having serious flash problems with the Canon 10D. Very unpredictable. When I got the E-1 yesterday, I put a Vivitar 285 on it, set the E-1 for ISO 400, the flash for ISO 400, on red mode, with the camera set in M mode at 1/100 at f/8 and the exposure was dead-on correct. No adjustments needed. I was very pleased. I'm still doing a few weddings and portraits and need predictable flash.

Beautiful lenses as well. I still love my E-10!

Todd

Gerry Siegel said:
Todd Frederick said:

I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the
exception of some compact units, used the "four thirds" concept,
including the E-20n.

Click to expand...

Gerry Siegel said:

I think it has something to do with sensor size and with image
aspect ratio.

Click to expand...

Both ,in result as you read.. I thought Bob Atkins did the photo
showing relative sizes vis a vis 24 by 36 film. Not as teeny as our
C 5050s.

--
Todd Frederick

Todd Frederick · Jan 22, 2005

Also, thanks for the links. I will check them out.

In my E-10 manual, I believe it says the "image pickup size" is 2/3" and the E-1 is 4/5" and the 10D is APS (I think).

I'm not sure what is ment by "inch."

So, I gather that the 4/3" is a physically larger sensor than the 2/3" in the the E-10, and the APS is a similar aspect ratio to APS film?

My friend, from whom I bought the E-1, just purchased a Canon 1Ds which has a 35mm size sensor.

As a non-tech person, am I getting closer to understanding this?

Todd

JScott said:
Todd Frederick said:

I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the
exception of some compact units, used the "four thirds" concept,
including the E-20n.

Reading some info on Steve's Digicams I realize that I am wrong on
that and that I have no clue what "four thirds" means.

I have yet to read anything that explains 4/3, 3/2, 2/3, APS, 35mm
with regard to digital photography clearly.

I think it has something to do with sensor size and with image
aspect ratio.

Will someone explain this in a simple way.

Click to expand...

Four-thirds refers to the sensor size, based on an type designation
of television camera vidicons dating from the 1950's:

http://www.dpreview.com/learn/?/Glossary/Camera_System/Sensor_Sizes_01.htm

It happens to also be 4:3 aspect ratio.

Regards,
Scott

--
As we celebrate mediocrity all the boys upstairs want to see
How much you'll pay for what you used to get for free

Tom Petty

--
Todd Frederick

jscott · Jan 22, 2005

Todd Frederick said:
Also, thanks for the links. I will check them out.

In my E-10 manual, I believe it says the "image pickup size" is
2/3" and the E-1 is 4/5" and the 10D is APS (I think).

I'm not sure what is ment by "inch."

2/3" and 4/3" refer to the dimeter (in inches) of the vidicon tube that would be necessary for that sized sensor. Except you don't put the sensors in vidicon tubes....

Todd Frederick said:
So, I gather that the 4/3" is a physically larger sensor than the
2/3" in the the E-10, and the APS is a similar aspect ratio to APS
film?

The sensor in the E-1 is twice as large (diagonal) as the one int the E-10 & E-20. And APS sized sensor is approximately the same size and an APS film frame.

Todd Frederick said:
My friend, from whom I bought the E-1, just purchased a Canon 1Ds
which has a 35mm size sensor.

Yes.

Todd Frederick said:
As a non-tech person, am I getting closer to understanding this?

Yes.

Regards,
Scott

--
As we celebrate mediocrity all the boys upstairs want to see
How much you'll pay for what you used to get for free

Tom Petty

Doehns · Jan 22, 2005

In Phil's E-1 review you can see the sensors in scale :

BJL · Jan 23, 2005

Todd Frederick said:
All I know is that with my previous Canon 10D, it seems to fit a 4x6 proof print format perfectly but with the 4/3 I lose a bit of image on the long side with a 4x6

True, and conversely you lose more of the image on the wide sides from the 3:2 shape of the 10D than with a 4:3 shape format if you make 8x10, 11x14 or standard inkjet 8.5x11 prints.

Guy Parsons · Jan 23, 2005

Those stupid Vidicon measurements still being used by the digital camera makers in this new century and make no sense at all.

Possibly they did it to....

1). Confuse people.
2). Hide the fact that the sensors are sooooo small in digicams.
3). Confuse people.

My old page at .....

http://homepages.ihug.com.au/~parsog/photo/sensors1.html has a picture of the old Vidicon tube and may help you understand what's going on.

It's weird that 4/3 and down quote the Vidicon inch standard, the Canon/Nikon/etc SLRs don't give the inch measure, or even say the fact that the sensor is just under APS size. They just vaguely mention the 1.6x (or whatever) crop factor and leave it to you to work out the sensor size.

In the end, the sensor size really doesn't matter much if the image coming out of the camera has the coverage and quality that pleases you.

Regards............... Guy

BJL · Jan 23, 2005

Guy Parsons said:
Those stupid Vidicon measurements still being used by the digital
camera makers in this new century and make no sense at all.

Possibly they did it to...

... out of sheer inertia, like engineers still using inches at all: "it has worked for describing 4:3 shaped sensors for decades, so why should we change, just because most of the people designing and making these things have never seen a vidicon tube, and do not know what an inch is?"

Guy Parsons said:
It's weird that 4/3 and down quote the Vidicon inch standard, the Canon/Nikon/etc SLRs don't give the inch measure

That is because the Vidicon standard is specifically for sensors with the standard 4:3 shape of the video industry (and most of the digital camera industry), not the 3:2 shape of Canon/Nikon/etc DSLRs.

Sony does follow this quirk with their one DSLR sensor, calling it "type 1.8", meaning 1.8", but they also do something far more sensible:

Describing sensors types by the actual diagonal measure of the sensitive region, in millimeters!

In this Sony-speak, their IQX413AC DSLR sensor is "Diagonal 28.4mm (type 1.8), 4/3 is "Diagonal 22.5mm (type 4/3)", and the biggest fixed lens digicam format is "Diagonal 11mm (type 2/3)".

Todd Frederick · Jan 23, 2005

I agree. My Masters Degree is in theology/philosophy. What do I know about antique Vidicon technology? Not a damn thing! Do I care? No way!

I truly think that for the 80%+ of us who are not Computer Science PhD's, a more simple way of communicating to us would be most appreciated.

Also, is the IRS listening!?

Blessings to you all. My E-1 is the finest camera I've ever used even if I don't understand what it's all about.

The image rules!

Todd

BJL said:
Guy Parsons said:

Those stupid Vidicon measurements still being used by the digital
camera makers in this new century and make no sense at all.

Possibly they did it to...

Click to expand...

... out of sheer inertia, like engineers still using inches at all:
"it has worked for describing 4:3 shaped sensors for decades, so
why should we change, just because most of the people designing and
making these things have never seen a vidicon tube, and do not know
what an inch is?"

BJL said:

It's weird that 4/3 and down quote the Vidicon inch standard, the Canon/Nikon/etc SLRs don't give the inch measure

Click to expand...

That is because the Vidicon standard is specifically for sensors
with the standard 4:3 shape of the video industry (and most of the
digital camera industry), not the 3:2 shape of Canon/Nikon/etc
DSLRs.

Sony does follow this quirk with their one DSLR sensor, calling it
"type 1.8", meaning 1.8", but they also do something far more
sensible:

Describing sensors types by the actual diagonal measure of the
sensitive region, in millimeters!

In this Sony-speak, their IQX413AC DSLR sensor is "Diagonal 28.4mm
(type 1.8), 4/3 is "Diagonal 22.5mm (type 4/3)", and the biggest
fixed lens digicam format is "Diagonal 11mm (type 2/3)".

--
Todd Frederick

David Hughes124436 · Jan 24, 2005

Todd Frederick said:
I agree. My Masters Degree is in theology/philosophy. What do I
know about antique Vidicon technology? Not a damn thing! Do I
care? No way!

How strange, a theologist/philosopher who cares nothing about reasons, history or ancient knowledge... ;-p

Regards, David

Guy Parsons · Jan 24, 2005

David Hughes said:
Todd Frederick said:

I agree. My Masters Degree is in theology/philosophy. What do I
know about antique Vidicon technology? Not a damn thing! Do I
care? No way!

Click to expand...

How strange, a theologist/philosopher who cares nothing about
reasons, history or ancient knowledge... ;-p

Regards, David

You don't have to be a rabbit to study rabbits. So am far as I'm concerned, all is OK.

Regards.............. Guy

David Hughes124436 · Jan 26, 2005

"the proper measure of mankind is man... "

Regards, David

Richard Pavek · Jan 26, 2005

Todd, I understand your confusion. Four Thirds means two things, one of them is Oly's use which includes aspect ratio (length of height to width) and other merchandising concepts (which I will not try to explain).

As to aspect ratio (also called film format when used with film), the E-1's aspect ratio or "format" is 4 X 3. This translates into a printed image that is 4" x 3" or 8" x 6" or 16" x 12"or 20" x 15" or 36" x 24"and so on. An older (and still current) way of stating the same ratio (format) is "645". Numerous cameras have been made and still are being made with that ratio. Pentax, Mamiya, Contax to mention a few. "645" refers to the film size of 6 cm x 4.5 cm. They still have the same format now that they have digital backs.

I used to be a 35mm buff but moved upscale when I added a Mamiya 645 to my cameras. Liked the format a lot. Still do even though I no longer shoot film. Hope this helps, Richard

Todd Frederick said:
I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the
exception of some compact units, used the "four thirds" concept,
including the E-20n.

Reading some info on Steve's Digicams I realize that I am wrong on
that and that I have no clue what "four thirds" means.

I have yet to read anything that explains 4/3, 3/2, 2/3, APS, 35mm
with regard to digital photography clearly.

I think it has something to do with sensor size and with image
aspect ratio.

Will someone explain this in a simple way.

Thank you, Todd
--
Todd Frederick

BJL · Jan 26, 2005

Richard Pavek said:
An older (and still current) way of stating the same ratio (format) is "645". Numerous cameras have been made and still are being made with that ratio. Pentax, Mamiya, Contax to mention a few. "645" refers to the film size of 6 cm x 4.5 cm. They still have the same format now that they have digital backs.

Indeed, and Hasselblad and Fuji now make 645 too. The digital sensors for those 645 bodies are still not up to the full 645 film frame size of 56x41.5mm, with the Dalsa 22MP sensor used by many backs being 48x36mm, and yet these top of the line medium format sensors use that 4:3 shape, instead of using a 3:2 shape of the same size, like 51x34mm.

The high end medium format camera sector seems to like that 4:3 shape!

KuroNeko · Jan 26, 2005

All the 4/3rds system hype, at least what I understand or think that they are trying to "endorse" us, is about being a standard that is to be followed by manufacturers, so you don't have to buy a whole line of equipment when you buy another DSLR in a future. That would be really nice, but I don't think that it'll ever happen. OK, there's Kodak Fuji and Panasonic, but I was not choosing between a Olympus/Kodak/Fuji/Panasonic when I thought of buying DSLR, I was choosing between Canon/Nikon/Olympus, so as long as every manufacturer follows the same standard I won't "buy" what they are trying to "sell" us.

I'm not very knowledgeable about sensors, so please correct me if I'm taking something the wrong way .I don't understand how they decided for such a "small" size for the sensor that is supposed to be carried on in future models. It's already small than those of their rivals (being lower resolution cameras), and it already showed a bad behavior in terms of ISO&noise, so I can´t expect the new professional body coming from Olympus this year to spot a 12Mp sensor without the same ISO&noise issue. Or maybe they'll switch to a 3ccd/4ccd approach in new models, but I believe that kind of sensors are not cheap to produce, and don't know if they are suitable for digital photography cameras. My point is that it would have been easier if they choose a bigger size for the sensor to ensure the long last of the standard they want to introduce, so when it become wide accepted, as it seems it's becoming now, it won't be out-aged because that kind of decisions.

Richard Pavek said:
Todd Frederick said:

I have a C-5050, E-10, and now an E-1.

I was under the impression that all Olympus digitals, with the
exception of some compact units, used the "four thirds" concept,
including the E-20n.

Reading some info on Steve's Digicams I realize that I am wrong on
that and that I have no clue what "four thirds" means.

I have yet to read anything that explains 4/3, 3/2, 2/3, APS, 35mm
with regard to digital photography clearly.

I think it has something to do with sensor size and with image
aspect ratio.

Will someone explain this in a simple way.

Thank you, Todd
--
Todd Frederick

Click to expand...

four thirds: Please Explain

Leading Member

Forum Enthusiast

Veteran Member

Senior Member

Veteran Member

Senior Member

Leading Member

Leading Member

Senior Member

Senior Member

Veteran Member

Forum Pro

Veteran Member

Leading Member

Veteran Member

Forum Pro

Veteran Member

Veteran Member

Veteran Member

Forum Enthusiast

Keyboard shortcuts