1x4 or x2 extender

john starkey

john starkey

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Hi, i have a canon 100-400mm L is lens,if i bought a 1x4 or x2 extender,i know i lose AF on both with my 450D,but what do i lose,and achieve with either one,
Also i am going to be getting a 7D in the summer so what affect will i get with this body,
Thanks for your help :thumbs:,
regards,john.
 
Would suggest the 1.4, as you'll lose af with the 2x, will have to check if you'll lose it with the 1.4 as well with the 7D
 
People do say IQ is lost with either, more IQ loss on the 2x.

I use a 1.4x on a 70-200mm, dont really notice a hugeamount of IQ loss on it though :)
But I havn't got a 2x so cannot comment i'm affraid
 
George said:
Would suggest the 1.4, as you'll lose af with the 2x, will have to check if you'll lose it with the 1.4 as well with the 7D
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The 100-400 is already f/5.6 so no AF except for 1srs bodies.

Bob
 
1.4x at the most (you will lose AF, except if you mask the pins but it should be sharp enough and AF with masked pins in good light).

With the 2x you lose AF in all conditions + the IQ will be much worse (PC enlargement will give you better results).

Been there, done that :) :) :)
 
Sorry John, it's a lens that I passed over but CT seems to use one occasionally (and to good effect).

Bob
 
john starkey said:
Hi, i have a canon 100-400mm L is lens,if i bought a 1x4 or x2 extender,i know i lose AF on both with my 450D,but what do i lose,and achieve with either one,
Also i am going to be getting a 7D in the summer so what affect will i get with this body,
Thanks for your help :thumbs:,
regards,john.
Click to expand...

Remember true f-stops are f2.8 / 4 / 5.6 / 8 / 11 / 16

1 f-stop of light, manual focus (unless on 1D series body). 100-400mm f4.5-5.6 so lens will become a 140-560mm f8, which will give you sharper results than the 300mm f4 + 2x TC, but you need very good light and maybe stop it down an f-stop or 2 to improve things slightly.

2 f-stops of light, manual focus, so lens will become a 200-800mm f11, but you will definitely need very good light and stop down to f16 to improve the images.

http://www.bobatkins.com/photography/reviews/ef_100_400_l_is_review.html
 
pete.rush said:
......but you will definitely need very good light and stop down to f16 to improve the images.
Click to expand...

I would think that any benefit gained on the aberrations is likely to be lost to diffraction at the level required.

Bob
 
Hi John i have both the 1.4 and the 2x converters which i use on my 70-200 2.8 the main problem that i could tell you about is that when i use the 2x the af speed is slow and also " hunts " sometimes and that you end up bining a lot of shots due to them been soft, I dont have any issuses with my lens when it is coupled upto the 1.4 :thumbs:
 
I used to get pretty good sharpness from the 1.4 and 100-400 :)

some in here
 
Ditto what Pete says, had the 100-400mm but not very good in low light, exchanged it for the ef 70-200 f2.8 L IS + £, much better in low light and use with 2x converter. Much better lens.
 
I tried the 100-400 and Kenko 1.4x TC. Sharp results on my 5D, slightly less contrast and it retained AF with the pins taped. Go for it! Can recommend the Kenko Pro 300 DG, 95% as good as the Canon one but half the price. Things go downhill with the 2x though, you'd need to stop it down and would need a lot of light, even then it's pretty soft, and no AF even with taped pins. Hope this helps.
 
I find using the 1.4 on my Sigma 150-500 doesn't impinge too much on the IQ. This was shot with my 350D with the extender

Img_6217x.jpg
 
I have the 100-400 and a 1.4x and 2x tc. If ever I need really long reach then I've no issue using the TC with the lens and manually focussing.
 
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