I know they say it's not compatible, but putting the 12mm extension tube on the 17mm T/S actually does work. You have to be VERY careful as the focus point is less then a quarter of an inch from the front element. There is also a fair amount of color fringing but it also gets you a point of view hard to achieve any way other than maybe a 47mm Super Angulon on a 4X5.
When you're that close tilting doesn't have as much effect as you might think. I was more interested in just not hitting the front element. I think this opens up a whole host of possiblities for this lens.
Peter Figen wrote:
When you're that close tilting doesn't have as much effect as you might think. I was more interested in just not hitting the front element. I think this opens up a whole host of possiblities for this lens.
Especially if you start using Helicon Focus and if I had the 17 I could demo that
With the extension, you only have maybe about half an inch of focus range so Helicon Focus is not going to be much help. I do use HF but it works best when you can overlap the focus completely front to back. There's not enough working distance to do that here.
I've been wondering for years why no one makes a smaller extension. I have a Nikon tube that is either 6 or 7mm. It might be possible to to hack a 12mm Canon and shorten it and I looked into that at one point but probably got sidetracked with real work.
Actually last night I was thinking that maybe two increments of something like 6 and 9 mm would be best. I don't think you're going to get less than 6 or 7 just due to the mounts themselves.
Yeah, wide angles with tubes can be sort of fun. I was experimenting with my Sigma 15 fisheye with a 12mm tube...I can focus..at infinity the focus point is roughly 2-3mm from the front element. Here's a tiny precision screwdriver:
I just looked at my EF 12 II. Agreed, 6mm is probably about the minimum you could get to. The hard part will be dealing with how to maintain the electronic contacts. if those weren't there it would be pretty straightforward.
wide-angles on tubes are definitely cool. I have to try the fisheye, that's a good idea. MF Alt wide-angles would be easier to deal with , say like an Oly lens. they made tubes as short as 7mm, so that would be a good option possibly.
I've used the EF12 on the 50/1.0L. Even though the throat of the tube is less diameter than the rear of the lens element, it doesnt' seem to vignette.
One difference would be that the 17 T/S focuses a full 1.2 inches closer than the 17-40. That's a huge difference on a 17mm focal length. It could actually work to your advantage on the zoom, but you'd have to try it and see.
If you are wanting to try to make a short extension tube, consider not starting with an auto aperature set that has contacts. You can get a cheap set of all metal extension tubes on line from the "usual source" for $10 or $15 that do not have any contacts in them. They classically are built with a front adapter, three tubes of various lengths, and then a back adapter. Theay all screw together in various combinations to make different lengths of extension. If you leave out the tubes, and just screw the front adapter into the back adapter, you have a fairly short extension tube, but I do not think it is much different than the 12mm of a standard tube. But you may be able to modify the adapters and make one very short tube out of the parts with some mechanical work.
Keep in mind that if you end up with a short tube with no electrical contacts, you do not have any easy way to stop down a standard Canon TS-E lens. The only trick that may work is one that video users have resorted to in the past, which is to stop down a Canon lens to a known aperature using your stop down depth of field preview button, and then un mount the lens while you keep it stopped down. The aperature stays put where it was set. You would then mount the lens on the extension tube with no contacts. But that means you would need to view and focus while stopped down, which can be a serious problem for many macro and close up situations. Then again, with live view that can crank up the gain and show a dim scene farily well, it may all be workable while stopped down. In case you need it, use this crazy application as an excuse to run out and buy a 5D mkII with live view and a pretty good LCD to look at things on.
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