Canon 1.4 or X2 Converter..advice please

[Mooseman]

Hi,

I'm new on here, but have been photographing aircraft and Military vehicles for about 30 years, so will start posting some pictures shortly. I use an EOS 70D with an L series 100-400 for most of my pics, but sometimes could do with that little bit extra.. so I'm thinking of investing in either a 1.4 or x2 Canon converter. I understand they would reduce the aperture but would the quality be affected..? Any thoughts or advice would be gratefully received.

Thanks
Dave

[Mark]

If its the Mark 1 your autofocus won't work.

[Mooseman]

Thanks Mark, I didn't realise that.
Mind you, if I can club together the pennies it might be time to upgrade anyway...

Thanks.
Dave

[trotsenstein]

I think it might be ok if you use a non Canon TC like Kenko. I'll try it on mine later. Works fine on my 400 f5.6 with the 70d.

[Supra]

That 'old chestnut' again?? To fit a tele-converter or not to? If you were to fit the latest 1.4 Mark III converter to the later EF100-400 Mark II Lens, I personally think you would be £2000 lighter with very acceptable performance & results. IMO the Canon 2X TC. (any Mark!!) should stay on their shelf, as the loss of 2 stops & painfully slow autofocus allied to IQ. reduction is not viable on the 100-400 set-up!
Please see the following for good opinion...
https://www.dpreview.com/forums/thread/3856026
https://www.dpreview.com/forums/thread/3772454
I'm not familiar with the 70D, but 20.2 Megapixel on an APS-C (1.6) Crop-factor is giving you an equivalent 640mm focal length at full extent of 100-400 lens & as such you should be able to able to do a sizeable crop & get great results? Put your money into the later lens (it's the optical difference between a milk-bottle & a Lens!) & add a 1.4 Mk3 TC. if you need it!
FWIW....Always use a Canon TC. I would take a Mark II Canon 1.4 TC. over an aftermarket type anytime! PS- I'm selling one of my three just now.

[trotsenstein]

Just had a try with the 100-400 Mki and 1.4tc, and it hunts a bit (light not great to be fair).

I used the 300mm f4 IS L last year with a Kenko 1.4tc on a 70d and happy with the results. No noticeable difference from the Canon brand one. The 300 prime you could pick up for about £650 second hand

[Mooseman]

Thanks again for all the advice, Supra I'm following your suggestion and have just purchased a Mk2 L 100-400, conveniently yesterday a woman at work advertised a Mk11 1.4 Canon converter for £70.
Now to start paying for it...No birthday presents for the kids and the dog has gone on a diet!
Thanks again all, very helpful.

Dave

[Supra]

I'm sure you won't regret it! Kids get spoilt already & a skinny dog is a happy dog.....sorry, I meant not regret the lens purchase!