Canon Kenko 1.4 x teleconverter

[aniket_sardana]

ok I know this isnt technically a canon product, but I bought the kenko DG pro 1.4 x teleconverter for my canon 30D

which I mostly use with a 100-400mm L lens. I read several reviews online which mostly implied that there was little

difference in quality between the kenko and canon own teleconverters. I am however finding that pictures I take with

the kenko just arent that sharp, compared with what I normally shoot with my 100-400 lens that gives me crisp razor

sharp images. Is this normal? Im even finding it when I taken pictures in ample light at shutter speeds of several

hundred that are perfectly addequate for the focal length. I am just wondering if there is something wrong with my

piece or this is just how they are.

 

Cheers

[bobatkins]

You will lose some sharpness, even with the Canon 1.4x (and more so with the 2x). My experience with Tamron and Kenco 1.4x TCs is that they are pretty good, and close to the quality of the Canon in the center of the frame. Some show more vignetting when used with long telephotos and full frame cameras, but center sharpness is generally good.

 

See http://www.bobatkins.com/photography/reviews/ef_100_400_l_is_review2.html for some test shots of the 100-400 lens with 1.4x and 2x Canon TCs.

 

With a 1.4x it really shouldn't be THAT much softer, especially if you stop down a stop.

 

If you want to run the lens though some real tests, take a look at http://www.bobatkins.com/photography/technical/testing_lenses.html.

 

It's always hard to say whether there is a real problem, or just a problem with the user's technique or expectations. Frequently (but not always) it turns out to be the latter

[james_alexander]

Could this be a focusing issue since the 30D isn't designed to autofocus with the 100-400 plus 1.4x TC? My understanding is the 30D will still attempt to autofocus with the Kenko TC even though autofocus is automatically disabled with the Canon TC.

[mrossi]

I had to tape the pins on my Kenko Pro 1.4x, it helped with AF. Google 'tape trick' for that, but regardless, definitely a loss of sharpness with any TC, and you need a lot of light to really get a great shot out of it IMO, at least with birds and in-motion stuff. I still use it all the time though, but not without a tradeoff - it actually makes me appreciate the performance of the 100-400L more when I take the TC off, but I do manage to use the TC as well, the extra reach with a tripod is ok.

[yakim_peled1]

"little difference in quality" can mean different things to different people.

 

Happy shooting,

Yakim.

[geoff_foale]

Are you handholding the camera? The 100-400 is difficult enough to handhold on its own and a converter will just magnify the problem. It can make autofocus a bit soft as well. Try it on a tripod with manual focus and see what happens. A sheet of newspaper stuck to a vertical wall is often recommended as a focus test. Close up the lens a bit for best results, say around F8 as the starting point.

 

As the others have said, some lack of sharpness is the trade off against extra magnification. I'm afraid the only real answer for a totally sharp longer lens means spending a considerable sum of money.