Kenko Teleplus Pro300DG v Canon 1.4TC's

[billhercus]

My first post so treat me gently!

I have read here how using the Kenko Pro 300 DG 1.4 degrades AF in lower light conditions with Canon's lovely 100-400L IS and I have just observed that with a simple test in my back garden. Soon as I removed the Kenko 300, AF was vastly improved in the same low light.

Q. Would there be the same degradation with the Canon TC. I assume there will always be some degradation because you reduce light to the sensor, but has anyone done a test to compare these?

[postcardcv]

Hi Billhercus and welcome to BirdForum.

Adding a 1.4x tc to this lens will definitely effect the AF, with anything but a 1 series body you'll need to tape the pins to retain AF. I would say that you would not notice any significant difference in this effect with a Canon tc, it will be just as bad.

[billhercus]

Possibly just saved me nearly 200 quid then!

Thanks!

[Roy C]

I have both tc's and reckon the Kenko is every bit as good as the Canon as far as IQ goes. The Canon is a bit better built and has weather sealing but that is about it. Whichever one you use you will lose one stop of light which means taping the pins to acheive AF on non 1 series bodies as 'Postcardcv' has already mentioned. Shooting at f8 in low light is bound to effect the AF no matter what tc you use.

[mike from ebbw]

I know I am using different gear but give this a go.I didnt get any AF when using my Kenko with my 350d and Sigma 500mm 7.2 unsurprisingly but when I tried using another AF point (centre far right) it will AF every time in good light.

[Roy C]

I know I am using different gear but give this a go.I didnt get any AF when using my Kenko with my 350d and Sigma 500mm 7.2 unsurprisingly but when I tried using another AF point (centre far right) it will AF every time in good light.
You got AF Mike because either the lens or tc did not have the pins to report the tc's presents. The 100-400 and Kenko pro 1.4 have both got the reporting pins so therefore on a non 1 series camera unless you tape the pins AF is absolutely impossible as the Cameras is seeing f8 and AF is shut-off.