The Olympus E-1 is the first removable lens digital SLR with a lens mount and imaging system specifically designed for digital. As such it is also the first removable lens digital SLR from Olympus and marks the beginning of a whole new camera system (bodies, lenses, flashes and accessories), the 'E System'. The E-1 has a five megapixel 4/3" type (18 x 13.5 mm) CCD sensor from Kodak, it carries the '4/3' logo on the camera body and lens indicating that it is part of this standard (sensor size and lens mount). The camera system and '4/3 System' has a public history (although in private it is likely to have started much earlier) stretching back to February 2001 when Kodak and Olympus announced they would be joining forces to 'develop digital camera technology'.

The 'E System' & '4/3 System' timeline

It's worth noting that Fujifilm has also expressed an interest in the 4/3 system. This standard defines the size* of sensor (4/3" type, 18 x 13.5 mm) and the lens mount / lens communication protocol. In theory you should be able to use a 4/3 lens from any manufacturer on a 4/3 body.

* There has been some confusion about the exact meaning of '4/3', at one stage it was published elsewhere that this referred to the aspect ratio of the image. I can confirm that although a coincidence the 4/3 name was never meant to refer to the image aspect ratio. For more information on sensor type sizes click here.

The Olympus E-1 Key Features

  • Magnesium-alloy body with environmental sealing (splash proof)
  • Five megapixel 4/3" Kodak Full Frame Transfer CCD (4/3 System compliant)
  • 4/3 System lens mount
  • Range of four ZUIKO DIGITAL lenses initially available (smaller and lighter than 35 mm)
  • TTL viewfinder with removable focusing screen
  • "Supersonic Wave Filter" cleans CCD at each camera start-up (dust is shaken from CCD)
  • Dual USB 2.0 (full 480 Mb/s speed) and IEEE 1394 (Firewire) connectivity
  • 3-point TTL phase difference AF
  • Focus-by-wire manual focus
  • Manual focus after AF lock available (switchable)
  • 3 bulb AF assist lamp
  • 3-zone multi-pattern metering
  • Program Shift in Program AE mode
  • Shutter speed range of 60 to 1/4000 sec (up to 8 minutes in Bulb mode)
  • Custom delay 'Anti-Shock' feature (similar to mirror lock-up on other SLR's)
  • Continuous shooting 3 frames per second up to 12 frames
  • Sensitivity range of ISO 100 - 800 plus 1600 and 3200 with 'ISO BOOST'
  • Exposure steps of 1/3, 1/2 or 1 stop (EV)
  • Exposure compensation -5.0 to +5.0 EV
  • Selectable color space; sRGB or Adobe RGB
  • Wide range of white balance options, four manual presets, fine tuning
  • Hybrid white balance sensor (on external surface of camera and using CCD)
  • Customizable image parameters (saturation, sharpness, contrast)
  • Noise reduction for ISO noise and long exposure noise (both can be disabled)
  • RAW format and RAW+JPEG support
  • In-camera RAW Data Edit
  • Compact Flash Type I & II storage including IBM Microdrive and FAT32
  • User upgradeable firmware
  • 1.8" 134,000 pixel LCD monitor with anti-reflective coating
  • Control Panel LCD display with backlight (panel also has anti-reflective coating)
  • Flash hot-shoe and PC Sync flash terminal
  • Shading compensation (removes potential vignetting)

4/3 system, size, lenses and implications

The 4/3" type sensor measures 18.0 x 13.5 mm, just slightly smaller than the size of the CMOS sensors Canon have used in their EOS-D30, EOS-D60 and EOS-10D digital SLR's. That may come as a surprise to some as it can be difficult to visualize the size of a sensor. The diagram below shows the relative sizes of various sensors compared to a normal 35 mm film negative. Indeed what's interesting is that the 4/3 sensor is exactly half the width of a 35 mm negative, vertically the measurement is different because of the different aspect ratio.

The use of a smaller sensor means that you don't need such a large imaging circle (as would be produced by a 35 mm lens), this means you can make the lenses smaller and lighter, it also means that you can build lenses tailor made for the purpose, lenses which should perform better at wide angles.

(Diagram shown to scale but much larger than in real life)

What's probably more startling is the relatively minute size of the 2/3" type sensor used in the two previous digital ZLR cameras, the E-10 and E-20. The other implication of a larger sensor is larger photodiode sizes (larger pixel pitch - a measurement of the distance from the top corner of one pixel to the next). Larger photodiode size makes for lower noise and higher sensitivity, and looking at the table below we can see that the E-1's sensor has a photodiode with four times the area of the E-20 and just smaller than the sensor used on the EOS-10D.

Camera Sensor Total pixels Pixel pitch Sensor size
Olympus C-4040 Zoom 1/1.8" CCD 4.1 million 3.1 x 3.1 µm 7.2 x 5.3 mm
Olympus C-5050 Zoom 1/1.8" CCD 5.2 million 2.8 x 2.8 µm 7.2 x 5.3 mm
Olympus E-20 2/3" CCD 5.2 million 3.4 x 3.4 µm 8.8 x 6.6 mm
Olympus E-1 4/3" CCD 5.6 million 6.8 x 6.8 µm 18.0 x 13.5 mm
Canon EOS-10D CMOS 6.5 million 7.4 x 7.4 µm 22.7 x 15.1 mm
Canon EOS-1Ds CMOS 11.4 million 8.8 x 8.8 µm 36 x 24 mm
Kodak DCS-14n CMOS 13.8 million 7.9 x 7.9 µm 36 x 24 mm

Interesting note for the future: if Kodak could produce a 4/3 type sensor with a 2.8 µm pixel pitch it would have 31 million pixels, so there is plenty of scope for expansion at this sensor size.

Lenses and the lens mount

The other thing that the four thirds standard defines is the lens mount, communication protocol and other details relating to lens, zoom and focus. This is perhaps even more important, it means that in theory a Kodak four thirds camera could use Olympus lenses and that we may see third party manufacturers such as Sigma and Tamron producing their own four thirds lenses. Acceptance and wide ranger use of this open lens mount standard is vital to the survival of the four thirds system.