Kenko Converters

clowesey

clowesey

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Name
Jackie
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Can someone please calrify my understanding on how the 1.4 & 2x Pro 300 converters will/won't work with my lenses?

I'm not in a position financially to buy any faster lenses at the moment but really could do with a bit more reach.

I know the 1.4x loses me one stop & the 2x two stops putting both lenses to 8 or 11 from 5.6.

I also know that at some stage I will lose AF on one/both of them. Can someone clarify at which point this is likely to happen. I would ideally like the 2x but think that the 1.4x is going to be more practical.

Mostly used for head on rugby shots so movement is not much of a problem as it would be side on, but also the reason for needing the reach.

Hubby promised to buy me one and the new season starts next weekend......
 
Think you could be in trouble with auto focus if the converter puts your lens beyond about f4.5 or thereabouts.
Also be sure to check the converter is actually compatible with your lens.
 
Your lens / camera combinations will be out-of-spec for autofocus with either the 1.4 or 2x converters.

Canon's consumer range of cameras only autofocus at up to f/5.6. The 1-Series cameras will autofocus at f/8.

HOWEVER...many of the third-party (i.e. not Canon) teleconverters do not pass on aperture information, so the camera "thinks" it still has an f/5.6 lens. Even if they do pass on this information, putting piece of tape over the relevant pin (Google "pin trick") will stop it. In practice this means that the camera will attempt to autofocus. In good light, and with a high-contrast target, you may have some luck - but you are operating beyond the realms of what Canon deems should work.

Also, teleconverters are really best on high-quality primes and zooms. There's a very real chance that they will be no better (or even worse) than cropping your photo.

See this review of a Tamron teleconverter on a EF75-300/4-5.6IS !
 
They should work with any EF or EF-compatible lens (ie, not an EF-S or DC lens) - I'd have thought they'd work with both of your long lenses but can't guess if you'd lose AF or not; from memory it sometimes happens after about f/8
 
Adding a Kenko Pro 300 tc to either of the long lenses listed in your sig will loose AF - The 400D will only AF if the lens (or lens and TC combo) has a max aperture of f5.6 or wider. By adding a 1.4x tc to either lens you'll be at f8 so will not have AF, you can trick the camera by taping some of the contact pins on the TC. If you do this the camera should attempt to AF but how well it works is very variable. I should add that I would not recommend doing this as I have a feeling that it can lead to problems.
 
As stated, the AF switches off at f/5.6 on Canon consumer bodies.

I have a 100-400L f/4.5-5.6 zoom and Kenko Pro 1.4x. When you tape the pins, it will try to AF but on my 40D it is hopeless. It hunts and shunts and still fails to lock. Very frustrating.

But I heard not all Canons are the same in this respect so I tried it with my old 350D, and that is actually quite a bit better! It may be worth trying if you're desperate, but it's no substitute for the real thing and is far from 100% reliable. No sir.
 
I bought the tamron 1.4x converter. I can confirm it fits, and works with the canon 70-300 IS and 100-400IS, both with IS and Autofocus (which the 100-400 says neither will work).
That is on the 400d. This converter does not change the aperture value, or focal length.
 
Thanks for the help all.

Opinion seems to be mixed, not just here.

Decided to take the plunge on the 1.4. No chance of having the cash for the glass yet for at least another twelve months so if it gets me through that I'll be fine. Will also then have the extra length on whatever I do decide to take the plunge on and may be able to save some cash by smaller faster lens (300 rather than 400).
 
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