EF 2x III at EOS 5D III: three times three makes good
Super Telephoto: Most come with me this Extender to my old EF 500mm f / 4.5 L USM for use. Although he has since the disadvantage that it also despite a new firmware 1.2.1 for initial Aperture f = 9 still no phase autofocus in the viewfinder allows (contrast AF in Live View is on, albeit slowly with considerable pumps). But when a shy bird sits well and I have time to focus manually, the results are surprisingly decent. Although the sharpness goes against the lens without extender significantly (the lens is old but visually top class). But the images are still very usable, if the air is clear. For this effectively you get a 1000 mm lens. In the post-processing can be subtly sharpen. Surprisingly good are contrasts and colors. The vignetting is clearly in the corners, but remarkably better than my Kenko 1.4x extender. The focus of the new 2x Canon is almost better than the KENKO Tele Plus MC PRO 300 DGX, 1.4x (1.4fach) TELE CONVERTER for Canon EOS 5D, 10D, 20D, 30D, 40D, 50D, 60D, 300D, 350D, 400D 450D, 500D, 550D, 1000D, 1D, 1Ds, 1Ds Mark II, 1D Mark II N, 1Ds Mark III, 1Ds Mark III, 1D Mark IV, 5D Mark ....
"Small Teles" Amazingly fast focused the combination 2x III with the Canon EF 300mm 1: (! Firmware 1.2.1) 4.0 L IS USM Lens (77mm filter thread) on the 5D III, ditto with my Canon EF 70- 200mm 1: 2.8 L IS II USM lens (77mm filter thread). Again, the optical quality of such an extreme Extender is quite acceptable. The stabilization works well with the Extender reliable.
EF 2x III at EOS 7D: breaking into the focus
At one in the center much higher resolution camera like the 7D my strong loss falls on all lens combos described here but then on the image sharpness. For the visible during full-frame eliminates vignetting. Here I would rather consider whether a good 1.4 times extender would be a better choice.
AF lock trick:
Below the 1-Series (since depending on the model) so turn all EOS cameras from a certain initial aperture autofocus off. The EOS 5D3 now like the EOS 1D X "drilled" with the new firmware updates to f = 8. Other cameras like the EOS 7D strike already above initial aperture f = 5.6. That also applies in general only to the rapid phase AF, which is active when looking through the optical viewfinder. The contrast AF in Live View goes even with much smaller top Hide yet, but he will be even slower and pumping vigorously.
Generally, you can trick the barrier but the cameras by covering the three pins in the Extender with a Tesa. When viewed from the lens side, it is the left three pins, so if you turn the Extender that the sheet with the pins on top. The camera then not get with that the Extender is interposed. However, one must then correct (by a factor of 1.4 or the 1.4-fold EXENDER) the aperture value manually by a factor of 2.
In my already mentioned 1.4x extender of the Kenko goes halfway. The AF is quite slow especially on the 7D, but he holds at some point on. But too reliable he is no longer even. When 2x III Extender I advise completely against it. Both with the 7D and the 5DIII pumping the AF then only back and forth without finding its target. Canon has already good reasons to disable the AF in such small initial aperture. Then, the sensor for the phase AF is illuminated in a too small area to still work reliably.
CONCLUSION:
Plus points:
++ Mechanical processing Topp
+ Optical performance overall tidy at full frame - for as an extreme Extender
+ Vignetting on full frame available, but acceptable to crop sensors even practically not there
+ Stabilization in the lens remains fully functional.
+ Quite handy and easy, so just good for the lighter luggage
+ On cameras from the EOS 5D3 (firmware 1.2.1) upwards central autofocus point even in estates with early Aperture f = 8
Neutral / satisfactory:
o also a good lens is optical zoom with this never good 2x extender on a comparable focal length without Extender rich (if it is a good lens).
o of high-resolution cameras, such as the Crop 7D breaks the sharpness with good L prime lenses but a clear (not surprising, therefore not recognized under negative points)
Negatives:
- Actually only the comparatively high price.
