see also:

• teleconverters explained
• a catalogue of Micro Four Thirds lenses

• these are small adapters which mount BETWEEN the camera and a lens
• also called tele-extenders
• they usually are 1.4x or 2x
• a 1.4x teleconverter effectively gives a field of view of a lens with focal length 1.4x that of the actual focal length at a cost of 1 stop of aperture (a 2x teleconverter comes at a cost of 2 stops aperture)
• if you are using Four Thirds lenses or a telescope, or legacy lens via a FT-MFT adapter, you can use teleconverters designed for the Four Thirds lenses

• announced in Sept 2014; 1.4x teleconverter;
• designed for, and only compatible with the Olympus mZD 40-150mm f/2.8 pro lens, Olympus 150-400mm f4.5 pro zoom with built-in 1.25x TC and Olympus mZD 300mm f/4 PRO lens
• the Olympus TC14 and TC20 when used with the Olympus mZD 300mm f/4 PRO lens loses 1EV of IS
• $US349 (but much cheaper if bundled with the Olympus mZD 40-150mm f/2.8 pro lens)

• released June 2019; 2x teleconverter;
• designed for, and only compatible with the Olympus mZD 40-150mm f/2.8 pro lens, Olympus 150-400mm f4.5 pro zoom with built-in 1.25x TC and Olympus mZD 300mm f/4 PRO lens
• 9 elements in 4 groups; ZERO coating
• 25.9mm long;
• 150g
• https://www.olympus-global.com/news/2019/contents/nr01268/nr01268_00001.pdf
• $US429
• the Olympus TC14 and TC20 when used with the Olympus mZD 300mm f/4 PRO lens loses 1EV of IS
• appears to give comparable image quality when used on the Olympus mZD 40-150mm f/2.8 pro lens at 286mm f/7.1 as a Panasonic 100-300mm f/4-5.6II shot at 284mm f/7.1 but slower to focus - if you need a zoom in that range and budget, the Panasonic may be more useful than the 40-150mm with MC-20 and the Panasonic lens only costs a fraction more than the MC-20 and you get f/4 at the short end not f/5.6 as with the Olympus lens with MC-20 ¹⁾
• where the MC-20 is likely to shine is when it is mated with the Olympus mZD 300mm f/4 PRO lens:
  • this then gives 35mm full frame reach equivalence of a 1200mm lens with cropped aperture of f/8 which is not possible to achieve by any other mechanism at this image quality, low weight and low size (of course it cannot compete with a full frame 600mm f/4 lens with 2x TC in terms of image quality, shallow depth of field (DOF) and high ISO performance, but then such a full frame lens is far heavier, larger and far more expensive and you wont get it into cabin luggage on your flight)
  • in addition, it gets you to almost 1:1 macro in 35mm full frame terms with a nice working distance of 1.4m close focus so you don't scare your insects
  • see https://www.imaging-resource.com/lenses/olympus/2x-mc-20/gallery-images/

• Panasonic DMW-TC14 1.4x TC
  • designed for and bundled with the Panasonic 200mm f/2.8 making if 280mm f/4 with close focus of 1.1m

• Panasonic DMW-TC20GC 2x TC
  • compatible with Panasonic 200mm f/2.8 making if 400mm f/5.6 with close focus of 1.1m and this gives 800mm 0.8x macro in 35mm full frame terms
• $AU979

• these are lenses that mount on the front of another lens via a bayonet mount to either make it wide field of view, more telephoto, fisheye, or more macro.
• Olympus MCON-P01 Macro Converter - designed for M. Zuiko 14-42mm MkII/R, 14-150mm, and 40-150mm lenses
• Olympus WCON-P01 Wide Angle Converter - converts M.Zuiko 14-42mm MkII kit lens into an 11mm ultrawide-angle lens
• Olympus FCON-P01 Fisheye Converter - converts M.Zuiko 14-42mm MkII kit lens into a fisheye lens.
• Olympus converter lens compatibility chart (pdf)
• Panasonic DMW-GWC1 Wide Conversion Lens - converts 14mm to 11mm for use on 14mm f/2.5 and the LUMIX G X VARIO PZ 14-42mm
• Panasonic DMW-GTC1 Tele Conversion Lens - 2x zoom - converts 42mm to 84mm for use on the LUMIX G X VARIO PZ 14-42mm
• Panasonic DMW-GMC1 Macro Conversion Lens - for use on 14mm f/2.5 and the LUMIX G X VARIO PZ 14-42mm
• Panasonic DMW-GFC1 Fisheye Conversion Lens - for use on 14mm f/2.5 and the LUMIX G X VARIO PZ 14-42mm