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400mm f5.6 and Extension Tubes (1 Viewer)
- Thread starter Roy C
- Start date
bpw
Well-known member
I’m not aware of any formula, so can’t be of much help there.
The paperwork with the Canon extension tubes lists the focusing distance ranges with different lenses. With the 12mm tube, the focusing range with the 400mm f5.6 is 2.893 to 13.449 metres.
Does the manufacturer of your extension tube have this information, perhaps on their website?
The paperwork with the Canon extension tubes lists the focusing distance ranges with different lenses. With the 12mm tube, the focusing range with the 400mm f5.6 is 2.893 to 13.449 metres.
Does the manufacturer of your extension tube have this information, perhaps on their website?
Roy C
Occasional bird snapper
bpw said:
Thanks for that Paul. My tubes are Jessops (figured no glass, so what the heck!) and they do not give any info like this. Colud you possibly give me the data for a 25mm tube.
Thanks
Roy C
p.s. Had a look at your web site - great site with very fine images.
Last edited:
bpw
Well-known member
Thanks Roy,
Having looked at the stats again for each tube, I’ve noticed that Canon give two sets of figures for each tube:
EF12
Focusing Distance Ranges 2.893 to 13.449 metres
Working Distance 2.580 to 13.136 metres
EF25
Focusing Distance Ranges 2.460 to 6.610 metres
Working distance 2.132 to 6.282 metres
Working distance is given as “the distance from the subject to the tip of the lens”
Having looked at the stats again for each tube, I’ve noticed that Canon give two sets of figures for each tube:
EF12
Focusing Distance Ranges 2.893 to 13.449 metres
Working Distance 2.580 to 13.136 metres
EF25
Focusing Distance Ranges 2.460 to 6.610 metres
Working distance 2.132 to 6.282 metres
Working distance is given as “the distance from the subject to the tip of the lens”
bpw
Well-known member
Kevin said:
It is possible to use both together, or any combination of extension tubes, e.g. 2 x 25mm and 1 x 12mm. It is also possible to use these with one or both of the teleconverters!
I’ve no idea what the effect would be on the focusing range though (apart from stating the obvious).
CannOffice
Member
Extension tubes are usually used for close focusing and the degree of magnification is what most people need to be able to calculate. Divide the focal length of the lens into the extension and you get the magnification ratio. eg 50 mm lens on 100mm extension will give a ratio of 2:1 or double life size while a 100 mm lens on a 50 mm extension will give a ratio of 1:2 or half life size. When working in the field of close up or macro photography this is the information most photographers need.This would indicate the need for a fairly long extension to get in very close with a 400mm lens. I dont really see your problem as you are putting the extenson tube to enable close focusing and can take it off again to get focus to infinity.
Roy C said:
Hi Roy,
how are the Jessops extension tubes ? I was thinking of getting these but couldn't find any useful info on their website and can't be bothered queueing for half an hour at the local store. Do you know if they support EF_S lenses ? also i assume they have the electronic connection for AF ?
I also have the 400m F5.6L and find the minimum focus distance a pain in the proverbial.
Cheers,
Richard
Tannin
Common; sedentary.
A helpful and useful reply, CannOffice, but perhaps not so relevant to the Roy's concerns. Lots of people use an extension tube with a long telephoto lens to take pictures of smaller birds. With a lot of long teles, you can't fill the frame with a small bird because you can't focus close enough.
Just last weekend I was taking pictures of Buff-rumped Thornbills and, not for the first time, ran into that restriction - my 500mm lens only focuses to 4.5 metres, with the result that I had to crop the shots more than I'd like. With very small birds - thornbills, pardalotes, and the like - this is a regular problem.
I deal with it either of two ways: take the 100-400 instead if I'm after the littlies, or use an extension tube to cut the MFD down. Currently I have a 12mm tube but I plan to get a 25mm one as well. For reference, the "big 6" Canon teles have a MFD as follows:
For bird photography, the key limiting factor isn't magnification (at least not directly), it's MFD. At least that's the number you need to know if you are trying to fill the frame with a little 'un.
BTW, the whole business of messing about swapping lenses or fiddling with extension tubes is very tedious, and seems to me to be crying out for some redesign work. How hard could it be to provide a sliding extension tube at the rear end of a big telephoto lens to give you a decent MFD without removing the lens, fitting a tube, and replacing the lens? (What I'm suggesting here is essentially a modern implementation of the old bellows method.) I'm sure there are technical limitation to how far you could take that method, but even if Canon could cut the MFD of a 400 or 500 mm lens back to about half of the current amount, it would be a very real improvement. (OK, I'll stop dreaming now.)
BTW, I was sure I saw a chart of MFDs with the Canon lenses and 12mm and 25mm tubes on the web somewhere, and went searching for it the other day without success. I must have been thinking of the extension tube manual - darn it, for I have no idea where to start looking for that. You can't use Google to search for a little scrap of paper!
Just last weekend I was taking pictures of Buff-rumped Thornbills and, not for the first time, ran into that restriction - my 500mm lens only focuses to 4.5 metres, with the result that I had to crop the shots more than I'd like. With very small birds - thornbills, pardalotes, and the like - this is a regular problem.
I deal with it either of two ways: take the 100-400 instead if I'm after the littlies, or use an extension tube to cut the MFD down. Currently I have a 12mm tube but I plan to get a 25mm one as well. For reference, the "big 6" Canon teles have a MFD as follows:
- 1.8m: 100-400
- 3.0m: 400 f/2.8
- 3.5m 400 f/5.6
- 3.5m 400 f/4 DO
- 4.5m 500 f/4
- 5.5m 600 f/4
For bird photography, the key limiting factor isn't magnification (at least not directly), it's MFD. At least that's the number you need to know if you are trying to fill the frame with a little 'un.
BTW, the whole business of messing about swapping lenses or fiddling with extension tubes is very tedious, and seems to me to be crying out for some redesign work. How hard could it be to provide a sliding extension tube at the rear end of a big telephoto lens to give you a decent MFD without removing the lens, fitting a tube, and replacing the lens? (What I'm suggesting here is essentially a modern implementation of the old bellows method.) I'm sure there are technical limitation to how far you could take that method, but even if Canon could cut the MFD of a 400 or 500 mm lens back to about half of the current amount, it would be a very real improvement. (OK, I'll stop dreaming now.)
BTW, I was sure I saw a chart of MFDs with the Canon lenses and 12mm and 25mm tubes on the web somewhere, and went searching for it the other day without success. I must have been thinking of the extension tube manual - darn it, for I have no idea where to start looking for that. You can't use Google to search for a little scrap of paper!
