TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

Started Aug 20, 2011 | Discussions
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MagicRandy Regular Member • Posts: 109
TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

I have the Canon EF 70-300mm f/4-5.6 IS USM (non-L) and would like to extend the reach with a Teleconverter. I'm considering the Kenko 1.4X PRO 300 Teleconverter DGX and was wondering if anyone has experience with this combination.

Specifically:
1) Does this combination work
2) Does the auto focus still work
3) Does the IS still work

4) Do other auto functions still work (e.g. auto aperture or auto shutter speed..)

Or are there other suggestions?

My camera body is the EOS 7D.

canuck dave
canuck dave Senior Member • Posts: 2,903
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

With this combination, AF will not work unless three of the eleven pins are taped over to 'fool' the camera. Everything else should work ok.

I had the 70-300 lens you have and I found it unsatisfactory in the 250-300 range, which is usually what you bought it for! With the Kenko (or Canon) 1.4TC you will only compound this, what I consider an 'issue'.

I sold my 70-300 and got a 400L prime, and it is superb! I got the Kenko 1.4TC a few weeks ago and with the 'tape-trick' it is a very good combo.

I hope this helps with at least some of your concerns. Not all of us can afford (or justify) the best stuff. To fill the gap I am seriously considering the Canon 70-200 f4 non-IS.

MagicRandy OP Regular Member • Posts: 109
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

Thanks for the feedback. I was hoping the AF would work as the Kenko website says the PRO 300 1.4x DGX full AF operation is possible with camera lenses having a maximum aperture of F4 or brighter.

canuck dave
canuck dave Senior Member • Posts: 2,903
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

The thing is that the 70-300 quickly goes to f5.6 when zooming.
The tape 'trick' works well enough; here is a link to some info on that:

http://atinyblip.com/articles/photography/kenko-2x-teleplus-pro-300-teleconverter/

tymevest Senior Member • Posts: 1,495
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

I don't have the Canon lens but do have a Tamron 70-300 VC and Kenko 1.4X (non pro) and use on a T3i. It has no trouble focusing normally in good light in either contrast detect or phase detect modes. I haven't tried lower light, cloudy conditions yet. The lens is f/5.6 @ 300mm and the teleconverter bumps it to at least f/8. It is not sharp there but is at f/13. Handheld, the ISO should be increased (or use auto mode) up to at 400. If not, the shutter speed will be slow and it's possible to blur the pictures.

Here are a couple moon shots with this combination taken last week. I used a tripod, remote release, and mirror lock-up. These were in raw and are at full resolution.

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Tymevest

MagicRandy OP Regular Member • Posts: 109
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

The tape trick looks pretty straight forward. Thanks for the link.

I'm pretty sure this is not the best solution to increase my reach, but it looks like I can do pretty well without spending much money. The best of course would be to buy better glass, but that can get very expensive. Maybe later I can do that.

For now, I'm thinking that if I only push my 70-300mm to about 250mm, this is effectively 400mm on a full frame camera. If I add a 1.4 TC to that I can get reasonable reach and may not impact the quality too much.

MagicRandy OP Regular Member • Posts: 109
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

Looks encouraging. The Canon and Tamron are both f4-5.6, so hopefully I can achieve similar results. But it looks like I can use the tape trick if needed.

MagicRandy OP Regular Member • Posts: 109
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

Dave, can you confirm one more thing?

Will the IS on my lens still work?

canuck dave
canuck dave Senior Member • Posts: 2,903
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

"Will the IS on my lens still work? "..................

It should, but I haven't got the 70-300 anymore to try it! Hopefully someone else can confirm this.

wallybarthman Regular Member • Posts: 360
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

Yes - IS works no matter what.

Why do you need to tape the TC? My understanding was that the 70-300 IS USM was a non-reporting lens so the camera would attempt to autofocus even with the TC in place. You only need the tape trick when you're dealing with a reporting lens and TC (like the 70-200 f4L USM).

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MagicRandy OP Regular Member • Posts: 109
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

Thanks...

MagicRandy OP Regular Member • Posts: 109
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

Thanks for the confirmation.

canuck dave
canuck dave Senior Member • Posts: 2,903
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

"Why do you need to tape the TC? My understanding was that the 70-300 IS USM was a non-reporting lens so the camera would attempt to autofocus even with the TC in place. You only need the tape trick when you're dealing with a reporting lens and TC (like the 70-200 f4L USM). "................

I still believe it's in the fact that it will 'attempt' to AF. My understanding is that the combo will likely hunt a fair amount, whereas with the 'tape' trick' it is less of an issue, except in lower light.
My 400L and Kenko 1.4TC combo (taped) is very accurate and fast in good light.

tymevest Senior Member • Posts: 1,495
Re: TC for Canon EF 70-300mm f/4-5.6 IS USM (non-L)

The lens may hunt less and focus quicker if you manually focus first to get it in the ballpark and then autofocus. Sometimes, if the focus is too far off one way or the other, the AF will overshoot and miss the focus.
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Tymevest

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