Olympus MC-14 teleconverter for Micro 4/3

Olympus MC-14, lens side (extra contact is visible at lower-left to center)
Olympus MC-14 mounted between Olympus 300 mm f/4 Pro and E-M1.

The Olympus MC-14 is so far the only native teleconverter for the Micro 4/3 lens system. The only other teleconverter that can be used on Micro 4/3 cameras without losing electronic communication to the lens is the Olympus EC-14 for 4/3 lenses, which in turn requires a 4/3 to Micro 4/3 adapter (available from Olympus, Panasonic and third parties), and in practice provides a usable AF only on the Olympus E-M1 camera (and the coming E-M1 Mark II).


The MC-14 is designed for use exclusively with the Olympus 70-150 and 300 mm Olympus Pro lenses (and perhaps future Olympus long-telephoto lenses and zooms not yet announced). Its front optics project a full 7 mm forward of the flange of the front (lens-side) mount. Don't attempt to use the MC-14 on other Micro 4/3 lenses, because you risk damaging them or the teleconverter.

Mechanical and optical build

The MC-14 is quite lightweight (102 g without caps) and physically very short for a teleconverter. It adds only 15 mm to the lens length, thanks to the projecting front elements, and its presence between lens and camera is hardly noticeable. It contains 6 elements in 3 groups, and is compatible only with the two lenses mentioned above. All external parts and attachment bayonets are metal, except the lens release button and its mount. The MC-14 is weather-proof, like the lenses it is compatible with.

The front cap of the MC-14 is a proprietary BC-3 cap. An ordinary Olympus body cap cannot be used on the MC-14, because of its projecting front optics, so take good care of this special cap and don't lose it. The rear cap is a standard LR-2 lens rear cap.

Electrical contacts

The MC-14 has one extra electrical contact on its front mount (and no extra contacts on its rear, other than the normal 11 contacts found on all lenses). The extra front contact touches one of the two extra contacts of the Olympus 40-150 mm Pro and 300 mm Pro. I discuss briefly these contacts in the context of the Olympus 300 mm f/4. My guess is that the extra contact of the MC-14 tells the two compatible lenses that a 1.4x teleconverter is present between camera and lens. In turn, the lens tells the camera the effective aperture being used (f/5.6 fully open in the case of the 300 mm f/4). Other than this, the teleconverter seems to simply forward the electrical signals and power between camera and lens, probably through simple copper traces joining its front and rear contacts. It contains no updateable firmware, and the Olympus Camera Updater software does not detect its presence.


Olympus recommends mounting the MC-14 on the camera first, then adding the lens on the MC-14. I have done this as well as the opposite, and could not tell a difference, except that the procedure recommended by Olympus may put a little less wear and stress on the lens mount of the camera and a little more on the front mount of the MC-14.

There is no significant difference in handling of the compatible lenses with the MC-14 mounted between lens and camera. Just take care not to accidentally press the lens release button of the MC-14 when reaching for the switches on the left side of the lens. This is a potential weakness of all teleconverters, which could be remedied with a simple flip-out switch cover, a more recessed release button, or a raised rim around the button, but no camera maker has regarded it as important enough to do something about it.

Performance and portability

My tests, as well as tests available on the web, tell that this teleconverter introduces a very slight, barely noticeable degradation of image quality with the 300 mm f/4 on 16 Mpixel cameras. This degradation is less of what you would obtain by enlarging and cropping an image shot without teleconverter.

Updated On a 20 Mpixel camera like the E-M1 II, image degradation with the 300 mm + MC-14 is slight, but undeniable. In fact, I cannot really decide whether it is worth at all to use the MC-14, because it does not seem to add any detail that is not already visible with the 300 mm alone. It would seem that the 300 mm has been designed for maximum performance with sensors of 20 Mpixel, or perhaps 24 Mpixel, but no higher.

The maximum aperture where image quality is not visibly affected by diffraction is, on a Micro 4/3 sensor with approximately 20 MPixel, around f/8. This means that the 300 mm, when used alone, should not be stopped down beyond f/8 (i.e., two stops from fully open) when maximum image resolution is desired. In some situations, however, the lens can be further stopped down to trade some resolution in return for a higher DOF. With the MC-14 added, the 300 mm should be stopped down by no more than one stop for maximum performance. With a 2x teleconverter, the 300 mm should be used fully open.

The MC-14 is said to perform somewhat worse on the 40-150 mm, where image quality without teleconverter is acceptable with the lens zoomed to 150 mm, but cannot be called excellent. Therefore, technically the MC-14 can be regarded as:

  • useful for the 300 mm on a 16 Mpixel camera,
  • not-so-useful for the 300 mm on a 20 Mpixel camera,
  • not really recommended for use with the 40-150 mm.

The difference in field of view between 150 and 300 mm is significant, but not enormous. In conditions where an FL around 200 mm would be ideal, my choices would be, from best to worst:

  1. Use the 300 mm unless it crops parts of the subject.
  2. Move away from the subject to avoid cropping it, and still use the 300 mm.
  3. Approach the subject if possible, use the 40-150 at 150 mm without MC-14, then slightly crop the picture if necessary.

With these two lenses and the MC-14, easily fitting in a carry-on backpack together with one or two E-M1 bodies, you have access to the equivalent of 80-840 mm FLs on full-frame, which covers all telephoto and super-telephoto lenses used by professional wildlife photographers, at a small fraction of the weight and cost of the full-frame equivalents. This is the area in which Micro 4/3 has finally reached its full potential to change wildlife photography forever. Still unattained is the goal of making AF and low-light performance of Micro 4/3 cameras as good as, or better than, full-frame DSLRs of 2008-2010, although we are getting incrementally closer.

Updated The E-M1 II does have a significantly better AF than the E-M1 with long telephoto lenses. The E-M1, in turn, has far better AF with native Micro 4/3 lenses than any of the "lower" models that lack on-sensor phase-detection AF. For practical purposes, the E-M1 II has a good enough AF (in contrast-detection mode) even with legacy lenses like the Olympus 50-200 mm for 3/4 cameras. Since I already have this lens, I never got the 40-150. The E-M1X and E-M1 III are both slightly better than the E-M1 II in AF performance, but the difference does not seem to amount to much in practical use.

Prices and availability

The MC-14 is expensive for a teleconverter, even compared to brand teleconverters like the Nikon models.

It is often available, on eBay, at significantly lower prices than elsewhere. The key factor is that by ordering these lower-priced items you get the teleconverter and its manual, but no box and no warranty certificate. These relatively cheap MC-14s were originally packaged as parts of a lens kit or special-offer set, then the sets were broken apart for selling the items separately. If you find a 40-150 mm or 300 mm kit that contains the MC-14, you might get a comparable discount.


The MC-14 is an optically and mechanically excellent 1.4x teleconverter for the Olympus 40-150 mm f/2.8 and 300 mm f/4. It is surprisingly expensive for a teleconverter. Results with the 300 mm are too good to pass up on a 16 Mpixel camera, but not so useful on a 20 Mpixel camera, and not really recommended with the 40-150 mm.