Kenko Teleplus PRO 300 DGX 1.4x AF Teleconverter - possible solution to zoom needs?

Started 5 months ago | Discussions thread
EJLiu
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Re: Kenko Teleplus PRO 300 DGX 1.4x AF Teleconverter - possible solution to zoom needs?
In reply to TeeJay626, 5 months ago

TeeJay626 wrote:

EJLiu wrote:

1.4x TC + f/5.6 lens will not AF on Canon DSLR body.

1.4x TC increase by 1-stop and 2x TC increases by 2-step. Need a lot of light to use 2x TC.

If you decide to trick the connector to show f/5.6 (ignoring the TC), the AF will be very slow due to the equivalent f/8 after adding TC.

For ~$1k, best bet to go with Tamron 150-600 for reach or Canon 300L F/4 IS for best IQ.

If you really need a zoom, the last option is to find an used Sigma 100-300mm f/4 HSM. Reasonable price for a f/4 and then you can add your TC.

Your first statement is false. I have the Kenko Pro 300 DGX 1.4x TC and have been using with with my Sigma 70-300mm DG OS f4-5.6 lens, and AF works perfectly fine through the entire zoom range. The AF does hunt a little more with the TC, but I was able to get good results with this combo, some nice sharp images too. (better than I was expecting)

With that being said however, I am hoping to eventually get the Tamron 150-600 or the Sigma 150-500 or 50-500. All depends on how much money my wife lets me spend

Kenko 1.4x DGX does not report the correct aperture to Canon dslr.  Please read the 3rd statement above.  If a canon 1.4x is used, then there will no AF.

1.4x TC drop 1-stop and 2x TC drops 2-stops.  Almost all Canon dslr stops AF when reaches f/8.  So any f/5.6 + 1.4x will not AF if TC is reporting the correct aperture.  The reason is that Canon Dslr AF will hunt like crazy.

you can check this easily by using aperture priority on a constant lighted subject.  Chk calculated shutter w and wo 1.4 TC.  W/TC will require 2x longer shutter speed.

Latest Nikon d7100/d600/d800 now allow f/8 AF at a few specific cross AF sensor due to higher sensitives.  If I remember correctly, 5D3 and 1dx do the same.

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