Kenko Pro 3x teleconverter review
Kenko 3x teleconverter review
Subject of this review
Let’s start with the basics: what are the teleconverters ?
In short: optical magnificators. Let’s say we have a 100mm focal length lens. If we attach the 3x converter the focal length will be 300mm. In the same time the brightness will be diminished 3 times: for example the f5.6 lens going to be f16, the f2.8 lens going to be f8 lens.
The coverters works best with longer lenses at least 100mm focal length, perhaps better at 200, or 300 mm-s. 50mm lenses makes terrible pictures even with the 2x converters.
Decent optical quality perhaps only can be achieved with a 3x converter attached with the sharpest prime lenses. For example Canon or Nikon 300 f2.8, perhaps Canon Nikon or Minolta 200 f2.8 lenses. In case of f4 brightness lenses the viewfinder going to be very dark, even with the f2.8 lens the viewfinder going to be quite dark. Autofocus not maintained: perhaps even with the I series Canon body, and f2.8 or brighter lenses if works, perhaps quite slow and unreliable. Perhaps autofocus can works with the Canon 200 f2 and I series Canon camera body for example Canon 1D Mk III.
I would say 1/1250s for a 400mm lens, 1/1600s for 600mm lens, if we want critical sharpness handheld. On a tripod perhaps the movement of the subject is the critical factor.
Let’s say straightly this converter ruins the picture of the sharpest most bright lens in a good bit. Especially mostly contrast, perhaps sharpness is also suffer. But this long focal length is a fun. If we can get this converter cheaply can be a real fun to play with the long focal length cheaply.
Logic tells to use this converter wide open at f8 to not use high iso-s. Most f2.8 lenses not the sharpest wide open except the most expensive ones.
With the Canon f2.8 attached the pictures are relatively good in short distances up to 15-20 metres, after the weakness is more apparent.
a 2x and a 1.4 converter is much more useful and flexible with significantly higher cost. Difference in picture quality compare to the 3x is very small, if any. The two converter combination is brighter and can have autofocus (not in the shade) if one of the converter is a latest types of Kenko converters (blue dot version).
Samples with Canon 200f2.8 with a Kenko 3x no post processing except resize:
Kenko 3x Canon 200f2.8 Canon 30d iso 1600 f8 1/400s.
I don’t recommend this converter if you not have the 1.4x and 2x converters or don’t have the really good f2.8 prime lens, because this converter is quite limiting and has the worst image quality. If you have the other two converters and can get this cheaply, it is not bad optically and can be fun in bright weather to play with it.