This is an annotated list of lenses and lens accessories available for the Olympus E-Series and, in general, Four Thirds cameras.

Introduction

Upon introduction of the E-1 back in 2003, Olympus faced an ambitious task of coming up with not just the first digital, interchangeable-lens SLR designed from ground up as such (and not adapted from a film model), but also with a variety of lenses, designed to work well (mechanically, electronically, and optically) with the new body, and addressed at various layers of the market.

Olympus is not new to lens design. The Zuiko line for their legendary OM SLR series of almost 30 years ago were top performers. The company delivered three lenses at the moment the E-1 was introduced, and more followed shortly thereafter, at a steady and consistent pace.

With the introduction of the further E-Series models, aimed at enthusiast amateur market, there arose a need for less expensive lenses to fit the Four Thirds mount. Olympus addressed that with a number of "economy" lenses, starting from the 14-45 and 40-150 mm zooms. No miracles, they cannot be as good or as versatile as the more expensive Digital Zuikos, but they may be more than good enough for the intended users, comparing favorably with the "kit" lenses offered by other manufacturers. Most importantly, the price difference is reflected mostly in more modest specifications, not in significant sacrifices in performance.

The original kit lenses have been later replaced with the "new", compact 14-42 mm and 40-150 mm ZD, amazingly leighweight and compact, and capable of surprisingly good results.

Sigma is continuously expanding their own line of lenses in the Four Thirds standard, having started in 2005. The earlier ones were priced aggressively, with attractive specs-to-price ratios. Some of the ones that followed have more ambitious specifications. Short supply is a notorious problem here.

The offer by Leica/Panasonic includes four lenses, even if not all of them are yet available as of this update (May, 2008: the 14-150 mm Vario-Elmar still seems like a waporvare).

Lenses

This table lists all Four Thirds lenses available now, or announced to be available soon, as well as those already discontinued. In addition to the specs, it contains links to respective manufacturers' product pages, and, if known, U.S. prices, with links to B&H or Adorama online catalogs.

Note: some of these links product pages may occasionally get broken: their Web designers move the contents around, and must have never heard of URL redirection via .htaccess files. While I'm occasionally fixing those, this is not my primary goal. Tough luck. (Links last verified February 1, 2008.)

Tab end

In case some of the acronyms I'm using in table headers are not quite clear:

• FL is the actual focal length in millimeters. The EFL (35-mm film equivalent) is twice this value.
• MaxAp stands for the maximum lens aperture (smallest F-number); MinAp — for the minimum aperture.
• When two numbers are shown with a hyphen, the first one refers to the zoom at the widest setting, and the second — at the longest one.
• MFD is the minimum focus distance in meters.
• EC shows the compatibility with the EC-14 teleconverter (see below): Y (yes, including autofocus), M (manual focus only), - (none). This is based mostly on Olympus data, with an asterisk denoting a correction based on users' feedback.
• El/Gr stands for the number of elements and element groups in the lens design.
• A/S shows the number of elements with aspherical surfaces and using special (low or extra low) dispersion glass. Both kinds are usually a sign of quality (especially for wide-angle lenses), and may raise the cost considerably.
• Wgt is the weight, as per manufacturer's published specs.
• D×L are lens dimensions (diameter and length), rounded to the nearest millimeter.
• Filter specifies the front filter thread (mm).
• Year refers to when the lens became (or is expected to become) available on the market.
• Price — as quoted by a selected merchant (usually B&H) at the time I last checked. Prices, obviously, vary with time and between merchants, so consider this column only as a rough guide.

Lens Designation

Usually the lens name, as quoted by the manufacturer, contains of the manufacturer's name, focal length and aperture numbers, and then anything the manufacturer wants; sometimes meaningful and sometimes not.

• In Panasonic/Leica the prefix Vario- denotes a zoom lens, a redundant information. The names Elmar, Elmarit and Summilux refer to some classic Leica lenses from the past (when such a name would be used only for one kind of design), but these are just empty sounds now.
• Sigma includes some acronyms which describe the lens features and, to some extent, design:
  • DG — the lens has not been designed for the APS-C or Four Thirds format; it has a full 24×36 mm frame coverage; a film-era design adapted for digital (more effective multicoating?).

    For comparable results, the actual lens resolution for the Four Thirds system has to be twice as high as that for a 35-mm film frame. This means that if a DG lens is more than sharp enough for a film camera, it may be sharp enough for the smaller 4/3 sensor, but it may be not, especially wide open.

  • DC — the lens has been designed specifically to cover the APS-C frame. As the Four Thirds frame height is only 12% smaller, only the extreme peripheries of the designed image circle are rejected; actually, the lens may perform better on a Four Thirds body than on an APS-C one.
  • HSM (Hypersonic Motor) refers to Sigma's improved AF driver technology, quieter and faster than in non-HSM Sigma lenses. Some makers (like Leica) do not put this information into the lens name.
  • APO — derived from apochromatic; here the word only reflects a claim of improved chromatic aberration correction (as compared to non-APO Sigma lenses, that is).
  • EX denotes better external finish than in non-EX Sigma lenses.
  With some Sigma lenses carrying up to five such specifiers, no wonder than everybody tends just to ignore them, including Sigma, who often skip one or two when referring to a specific lens.
• As of recently, Olympus lens designations contained only the letters ZD (Zuiko Digital), but looks like Olympus is adapting the common trend of ornamenting lens names with acronym sequences (which reminds me of Brezhnev giving himself a new order from time to time).
  • PRO denotes a premium lens line. Earlier premium lenses from Olympus did not carry this designation, so for a few years this will only add to confusion.
  • ED — low-dispersion glass used for some lens elements. Again, most Olympus lenses with such glass do not carry this designation, so it is not really meaningful; invented by some Einstein in the marketing.
  • SWD stands for Supersonic Wave Drive, yet another proprietary name for the ring technology of the in-lens AF driver, similar to that used by other manufacturers.

  (Canon uses their USM moniker for two very different AF solutions: a ring driver around the lens, and a regular micromotor driving the lens gears very much like a similar motor placed in the camera body. This gives the masses who buy cheap Canon lenses an impression of having the same technology as one used in the Canon upscale glass.)

• Both Sigma and Leica sometimes put Aspherical or just ASPH into their lens names to denote the use of aspherical elements. Most often, however, they skip this designation when referring to such a lens, so I'm not bothering with it either. Number of aspherical elements, if any, is shown in the [A/S] column of the table.

Remarks

As marked within square brackets in the table:

1. In addition to the internal filter slot the 300/2.8 ZD lens does have a front filter thread, contrary to the Olympus official information (thanks to Richard Pavek for pointing this out). Filters of this diameter (112 mm), however, are not easy to find and they are also very expensive.
2. The 8 mm ZD is a full-frame fisheye lens. Minimum focus distance measured from the lens front is 2 cm.
3. Sold only as a part of an E-500 kit on some markets (including most of Europe, but also some U.S. retail chains).
4. Lens weight quoted without the tripod collar.
5. Some Panasonic/Leica lenses have an external aperture ring, but they remain compatible with Olympus cameras, in which the aperture is set electronically from the body.
6. The 14-42 mm ZD lens also contains one element made of high-refraction glass.
7. The 300-800 mm Sigma has a rear slot accepting 46 mm filters — at least a polarizer, probably also others are available.
8. The 24/1.8 Macro Sigma has a maximum magnification of 1:2.7; with the Four Thirds image size this is equivalent to 1:1.35 for a 35-mm film camera.
9. The lens provides internal image stabilization using the Panasonic Mega O.I.S. System.
10. The Vario-Elmar uses an XSM focusing motor (see HSM and SWD above).
11. The 14-35/2.0 ZD lens is so far the only one for which Olympus has missed the originally announced release date; it is finally expected to be in stock in March, 2008.
12. For the 50/2.0 Macro ZD lens the use of EC-14 is recommended only at apertures of F/4.0 and up.
13. This is the second version of the Sigma 18-50/2.8 M lens; an earlier one, accepting 67 mm filters and focusing down to 28 cm used to be made for other mounts, but not for Four Thirds.
14. According to Olympus, the 12-60 mm has one Super ED element, 2 ED ones, one aspherical ED, and two aspherical ones. Assuming that these numbers do not overlap, the count of special-dispersion glass elements would be four, and of asphericals — three (six "special" elements altogether, as one counts in both groups).
15. Focuses down to 95 cm in MF mode. Probably re-branded Sigma lens.

Lens accessories

By this I do not mean filters, hoods, or lens caps, only those affecting the lens optics and/or geometry.

• EC-14 Teleconverter provides a focal length increase by 1.4× at the expense of one F-stop in effective aperture. Consists of six elements in five groups; 140 g, 22 mm long.

  The converter is compatible (including AF) with most of Four Thirds lenses, Olympus or not; notable exceptions include two "economy" standard zooms (14-45 and 14-42 mm) and the "new economy" tele zoom (40-150/4.0-5.6); with these only manual focus is possible. For individual lenses (as per manufacturers' specifications, periodically updated) see the EC column of the table.

  (The compatibility data is quoted after Olympus. Some users reported using the EC-14 successfully with "economy" zoom lenses in AF mode without problems, but I haven't verified these claims.)

• The EC-20 Teleconverter doubles the lens' focal length at the expense of two F-stops in aperture, therefore it will be really useful only with brightest lenses because of viewing and focusing problems. It consists of seven elements in five groups and weighs 226 g. I have not tried it yet.
• EX-25 Macro Extension Tube adds an extra 25 mm lens extension (equivalent to 50 mm on a 35-mm film camera), allowing for closer focusing (greater magnification); 170g. Increase in magnification depends on focal length.

  According to Olympus, the tube is fully compatible (including autofocusing) only with the 50 mm F/2.0 ZD lens; with others it may work only in the manual focus mode, and that excludes (in some lenses, at least) shorter focal lengths.

  Note: In an apparent contradiction to the official Olympus data, a Reader from the U.K. reported that the EX-25 works just fine with his 300/2.8 and 50-200/2.8-3.5 ZD in the AF mode. I have not used it myself with these lenses, so this is really all I can say.

Web resources

Links for individual product pages at manufacturers' sites have been provided in the first column of the table above.

The Four Thirds Consortium maintains a section on lenses from Olympus, Sigma, and Leica/Panasonic. In particular, you can download from there a lens catalog brochure (PDF), although it does not seem to keep up with the actual product line. There is also a Lens Roadmap available, listing the current and planned releases.