Canon 70-300L IS + Kenko 1.4x Teleconverter

[bklein61]

I am wondering if any one has any experience with the Canon 70-300L IS combined with the Kenko 1.4x Teleconverter.   I know that you will be losing one full stop which will make it a f8 at the 300mm end,  but it seems that you still will retain the auto fucus on the 50D.  It is suppose to be slow but still workable. I am just wondering how much it degrades the IQ.

The other other option that I was thinking of, to get more reach, is to invest in the Canon 400mm 5.6.  Would IQ of the 400mm 5.6 be greatly improved from the teleconverter and 70-300L Combination.  Also if any one know if the 400mm 5.6 compares to the 70-300L in IQ

Thanks for any advice

[bklein61]

Has nobody tried 70-300L IS with the Kenko 1.4 teleconverter

[K-amps]

There's one guy who has both... I forget who... but one of the major contributers on CR. Not knowing the quality of the Kenko, I cannot say, however I have owned both the 70-300L and the 100-400L, and the 70-300L smokes the 100-400L in almost everything but the 300-400 range  .

If it accepted Canon TC's, it would still be in my kit... amazing lens, albeit f5.6

[chas1113]

I have used the EF 70-300mm IS L with a Kenko DGX 300 Pro 1.4......it was not a happy experience. AF is erratic at best with wild oscillations from close to distant focusing with occasional inability to find focus at all. I have heard of this by others, and was unhappily surprised when I experienced exactly the same effect. The same Kenko TC works great with my EF 70-200 f/4 and EF 300mm f/4 IS. I have read where others had a good experience. Wish I could concur. I got frustrated and just took it off and haven't re-tried it. Sorry to dash any hopes you might have had.

-chas

[Immaculens]

my same experience - focus hunting focus hunting past the 220mm focal range.

I've requested a return and I have heard better things with the 70-300L + Canon EF 1.4 III CT - albeit it only works at 300mm, but that's why I want it anyways...

[Marsu42]

I am wondering if any one has any experience with the Canon 70-300L IS combined with the Kenko 1.4x Teleconverter.

The most important thing is: The combination is visibly better than cropping, so it's a good purchase since the Kenko is rather inexpensive and you can use it with *all* lenses (well, except the 100L on the 5d3 where where seems to be a bug).

As for iq, I'd say the 70-300L is not "stellar", but "very good", and with the tc it's still "good". It is prone to hunting with low contrast / bad lighting with *single* point af and the af is less precise than native, but does much better with multi-point. So forget tracking or critical shots, but still very useful for some type of shots esp. of non-moving objects.

[wickidwombat]

based on using the 28-300 L with kenko 1.4 TC if you stop down to f11 the IQ is pretty close to the bare lens wide open

[chasn]

I have the 70-300 and the kenko.  Sure the AF hunts a lot in poor light but in good light I have found it OK.  And of course there is MF.....  IQ I think is OK too given the price of the lens and the TC and an effective focal length on a crop of 580mm..I think you would have to spend much more to do better.  For me its a better combination than the 100-400 but then I don't like the push pull zoom or the overall size and most of the time I don't need the extra reach.   I have a 5DIII as well as a 7D so will be interesting to see if the firmware update helps the AF at all.

[Kmccarthy]

I have the 70-300L and a 5DIII. I purchased a Kenko PRO 300 AF DGX 1.4X on ebay and tried it for a few weeks. Overall, IQ was pretty good. It was definitely better than cropping. However, as others have mentioned, AF hunts quite a bit, particularly in low light.

I should mention that my unit was an older version. Apparently, the newer versions have a green or blue dot on them and have newer firmware that fixes some of the AF issues with certain lenses.

I ended up returning the Kenko and purchasing a used T2i body, which gives me 1.6x reach and better AF with the 70-300 (when compared to the Kenko+5DIII).

[Marsu42]

I should mention that my unit was an older version. Apparently, the newer versions have a green or blue dot on them and have newer firmware that fixes some of the AF issues with certain lenses.

Afaik the versions with only a red dot are really old, newer ones have a green dot (on the box next to the bar code and on the tc) and the most recent versions a blue dot - like mine, purchased in 4/2012. And I suspect they even do silent updates without changing anything. Thanks for transparent product specs and good communication, Kenko

[FlowerPhotog]

I posted some images showing the quality achieved using this combination several months ago on a previous thread.

http://www.canonrumors.com/forum/index.php?topic=4977.msg110430#msg110430

My pictures are on the middle of page 3 of the thread