• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Autofocus for 40D & EF 400mm f4 DO with x2 converter (1 Viewer)

stephenB

stephenB

Well-known member
I currently have a 40D & the EF400mf4 DO f4 lens. With the Canon x1.4 teleconverter, autofocus is fine. However, does anyone know how this camera & lens work with a x2 converter attached?

I'm assuming that as the aperture will then be f8, autofocus will only be possible by pin taping, but on my older EF400F5.6 & EOS350D, there was then a lot of 'hunting' with the x1.4 TC. I suspect the same may be true of the EF400f4 DO, with the x2TC, but maybe worse?

Any info much appreciated - I'm not sure of the merits of the x2 converter, but an effective 800mm f8 lens might be useful on occasion.
 
You could try stacking two 1.4 tc's as only one will report to the camera so it will only pick up f5.6.
 
Save your money unless you have to have an image of, say, a rarity at any cost. You will not be happy with either the autofocus performance or image quality. Stick to the 1.4x.
Having used 1.4, 1.7 and 2x converters over the last 30 years, even stacked, only the 1.4x gets taken with me unless I'm chasing a rarity pic and must get a result.
 
Roy C said:
You could try stacking two 1.4 tc's as only one will report to the camera so it will only pick up f5.6.
Click to expand...

That's an interesting idea, but is it much different from taping the pins on a x2 converter? Both will 'fool' the camera into trying to autofocus... Then won't there be the 'hunting' type problem with both options, as the lens doesnt match with the autofocus expectations on focal length?
 
I occasionally use a 2x Teleplus converter (now called Kenko I think) and the AF works fine with a 20D & 400 DO combination but have no experience with the Canon 2x. Image quality is another matter though and so it's only used for record shots. It works pretty well with the sharper optics of the 500 - my mate's always borrowing it to use with his. I would try the top of the range 2x Kenko with your set up first before buying anything.
 
stephenB said:
That's an interesting idea, but is it much different from taping the pins on a x2 converter? Both will 'fool' the camera into trying to autofocus... Then won't there be the 'hunting' type problem with both options, as the lens doesnt match with the autofocus expectations on focal length?
Click to expand...
I only mention it because I have found that stacked 1.4's AF better than a taped 2x on my 70-200 f4. Also IMO stacked 1.4's give a better IQ than a 2x (I have seen many post by other people that come to the same conclusions). With the stacked 1.4's you do not need to tape either of the tc's on a f4 lens.

Taping converters and the AF expectations of a Camera is a strange thing. For instance a taped 1.4 on my 400mm f5.6 lens works far better on the 30D than the 40D (centre focus point).
I have also tried a cheap non reporting 1.4 tc on my 400 f5.6 and AF is superb compared with taping a tc and yet they are both effectively f8 - you would have thought they would have reacted the same.
 
Last edited:
Thanks Roy for the explanation. I might well investigate that option.

I note from above that loss of quality with TC's is a recurring theme. With my 400f4 DO, I have already tried a x1.4TC and am slightly disappointed with the results, whereas other reports I have seen speak well of the 400f4 DO & x1.4 TC combination. I am wondering whether it is just my lack of experience, or possibly due to a slightly below par x1.4 TC which I dropped once. Yet the same x1.4 TC seems to work OK with my original 400f5.6 - with less obvious less of quality. Maybe its just that the DO on its own is so good, a slight drop in quality is more obvious?

Does anyone else have any first had experience of the 400f4 DO with a x1.4 Canon TC?
 
Always use mine with the Canon 1.4x and whilst there inevitably has to be a slight loss in quality I consider it very acceptable. As for AF I've never really noticed any sluggishness or acquisition problems but then I suppose I wouldn't would I! www.bluebirder.wordpress.com
 
I too have a DO and tho acceptable I would agree the 1.4 does lead to some IQ loss. The canon does seem to have the edge over the Kenko with this lens. I would not have thought the x2 would be good for anything other than record shots. I do use stacked 1.4's at times( taped pins/ outer focus point) but the lens needs to be stopped down to f10 for reasonable results and that level of light never seems to be available when needed. I still prefer to digiscope if I want a distant record shot.
Most of the time I find cropping gives better results than resorting to the tc, but when the birds are very close (feeding stations) the addition of the TC reduces the minimum focus distance by a few feet and allows focus. I would however prefer to move back to 3.5 m but this is not always possible.
Regards
Mike
 
I have tried many different TCs with my 2 lenses. I agree with Roy. I only use the Canon 1.4 on my 400m f5.6.

I also own the Kenko AF1.5x DG and the Kenko 2xpro 300DG, although I have used the 2x Kenko on both lenses the quality is poor, unless the conditions are perfect.

My set ups with the 2 lenses I have after a lot of swapping and trial and error is,

30D body 400mm f/5.6 canon 1.4x TC, sometimes I will use it without the converter.

30D body 70-300mm f/4.5-5.6 DO IS USM 1.5 Kenko TC, also use this without the converter when I can get close enough.

I very rarely use the Kenko 2xPro 300DG unless I have to.

Regards. Neil.
 
I have the 400 DO and am very happy with the Canon 1.4 with this lens. I have tried stacking with that converter and a Kenko Pro 1.4 converter but was very disappointed and have not repeated the experiment.
 
michha62 said:
I would however prefer to move back to 3.5 m but this is not always possible.
Regards
Mike
Click to expand...

Mike

Have you considered using extension tubes to get closer than 3.5m? These are relatively cheap, and contain no glass and hence result in no loss of image quality. I use them regularly for dragonfly & damselfly pics when I want to get much more magnification than is possible at 3.5m. See my website for for details & some examples.
 
Cheers Steve. I have been promising to get some ext tubes for use on butterflies and also for the rare occasions I'm too close to birds. I generally use the closer focusing 100-400mm for the b'flies at the mo. I understand there is no loss of IQ but do you lose much light through them? Also would you recommend of full set of cheepies or a specific canon model?

regards
Mike

Ps Just had a look at your website - very informative. Should have looked before, it has answered my questions.
 
Last edited:
Thanks to all those who have provided input to this thread. I think I'll go with the consensus, and save my money for other things, by not going for a x2 converter, or even a second x1.4!
 
Warning! This thread is more than 16 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Similar threads

G
7D Autofocusing Questions
Replies
8
Views
2K
Granville Leong
G
Chosun Juan
Which Super Telephoto ??
Replies
18
Views
16K
Chosun Juan
Chosun Juan
G
Canon EF 400mm f2.8 L IS II USM advice
2
Replies
32
Views
19K
Froggy
F
Hor Kee
Canon EF 400mm F4 DO lens + Canon 60D combo - advice needed
Replies
6
Views
4K
skywatcher
S
marek_walford
40D f5.6 400mm 1.4x converter
Replies
7
Views
3K
Roy C
Roy C

Users who are viewing this thread

Total: 2 (members: 0, guests: 2)
Back
Top