EF 12 II Extension tube vs. EF 25 Extension tube

Discussion in 'Canon EOS' started by danny_best, Oct 12, 2006.

  1. I ordered the Ef 12 II extension tube from B&H and have not received it yet, and i found out that there was
    a larger extension tube ( EF 25). My Question is should i keep the Ef 12 tube or return it and pay the 40$
    more for the EF 25? I have Rebel Xt with 28-135mm Canon IS, 100mm Canon Macro, 100-400mm
    Canon L Is lens.

    I asked a question the other day about adding a canon 1.4x extender to my 100-400 lenses and the
    responses i got were great i wanted to say thank you. Alot of the comments said that it the AF would hunt
    if attached to the extender. I am kinda new to photography and I'm not up on all the terms and didn't
    quite know what that ment.

    They also said to tape down the 3 left most pins on the extender. Would i use regular tape? And would this
    cause any problems

    Sorry for the loaded questions. I'm making these purchases because i will be taking photography classes
    next semester and i want to have some good hardware. I have found this site to be very helpful. I will be
    writing again to ask about what lenses you may recommend that i get, a( shoot alot of outdoors and some
    of my sisters volleyball games) and a flash mount for my camera for my 430 flash.
  2. You will lose AF using a 1.4x on a 100-400 IS on a Rebel XT. If you tape the pins then you can get the camera to attempt to AF. This is unlikely to be very acceptable (similar tricks lead to disappointing behaviour on my 20D and that has better AF than a Rebel XT) but might work if you have a lot of light and a high contrast subject.
  3. Without knowing what you want the extension tube for I can't say which is better. The EF25II is longer than the EF12II. Both feature new digitally optimized air ;) Actually the only difference with the original versions is that the new versions let you mount EF-S lenses. I use a set of three Kenko tubes and they work fine for me with light lenses but will not mount EF-S lenses.

    AF quits on most Canon bodies if the camera detects that the maximum aperture is slower than 5.6. The net result is using a 1.4x on any lens slower than f4 you will lose AF. Certain high end bodies will AF at f8 using the centre sensor.
  4. Autofocus is useless for macro work, unless you're one of those bug hunters with the 180mm lens and a ring flash. Get the extension tube you need for the magnification you require. Since it's hard to know in advance what magnification you will require, it's best to have both tubes.
  5. Autofocus is useless for macro work, unless you're one of those bug hunters with the 180mm lens and a ring flash.
    Oddly, I find AF quite useful with a 100 mm macro lens, in quite a few situations other than insect photography (although it is often useful for that, too).
  6. In case you didn't know, extension tubes are also stackable, meaning you'll be able to focus even closer still, meaning even greater magnification. So if the 12 doesn't cut it for you, get the 25 in addition to it, and then you can choose between 12mm, 25mm, and 37mm of extension. For what it's worth, I have 2 25's and a 12 that I use in various combinations.

    Oh, and I think it's Kenko that puts out a set of tubes of various sizes that I believe were a lot cheaper than Canon's. While I ended up with the Canon's before I found out about the Kenko's way back when, extension tubes are probably the only accessory I'd have no qualms about using a 3rd party vs a genuine Canon.
  7. Unless you are only planning to use the tube with very shot lenses you will want both. I have two 25mm and one 12mm, I might use them in any combination or all together, there is no problem with this despite Canon not recommneding it.

    You can calculate the magnifiction the tubes will give with the lens focussed at infinity as M=E/F, where E is the total of the tubes length and F is the lens focal length. The magnification will increase further when the lens is focussed closer but this is tricky to calculate with moder internal focus lenses.

    The 100mm macro gives about 2.2:1 with the stack of three tubes and set to clossest focus.
  8. If you won't ever need to mount them to an EF-S lens, the Pro-Optic set of 3 EOS mount extension tubes can't be beat for value. Cheap price, but unlike some cheapies they have full electronic coupling plus they're nice and solid too.
  9. Hi,

    Extension tubes in various lengths are very handy to have in your camera bag. They will improve the close focus of a long lens, or make for macro capabilities when used on many "non-macro" lenses. I always have a set with me and have used them on many different lenses and cameras over the years.

    For my Canon system, I currently have two 25mm, three 12mm and a Kenko set with 12, 20 and 36mm in it (these are approx. lengths, without actually going and looking ;-). Singly or in combination these give a lot of options.

    Basically, the longer the lens' focal length, the more tube length you will need to get into true macro territory (say 1:2 or greater magnification, which is 1/2 life-size) if that's your goal. But, to some degree this depends upon the lens and the camera being used. For example, some lenses already focus quite closely, or some D-SLRs have effective magnification built into them (1.6X lens factor on Rebel/10D/20D/30D etc.) And, you can use the tubes in combination with the 1.4X extender to get even greater magnification.

    When an extension tube is installed on a lens it will no longer focus to infinity. This is okay, since the whole point is close-focus or macro. Nice thing about extension tubes is that they have no optical elements. Adding optics to the front or rear of any lens will nearly always degrade the image in some respects, a little or a lot depending upon the quality of the optics and how well they are matched to the lens being used. Extension tubes leave the lens' optical formula intact and simply can't cause these sorts of problems.

    To give you some ideas, I've used 12mm on an EF 20/2.8 and had flower petals in focus while they were actually touching the front element of that lens. A 50/1.4 becomes a neat close-focus or macro lens with 12 to 25mm of extension. EF 85/1.8 also works well with 25 or more mm of extension. (Another approximationi is that to get to 1:1, or life size, you need total extension equal to the focal length of the lens. I.e., use 50mm of extension on a normal 50mm lens. However, again, it depends upon the actual lens & camera in use.)

    It's been pretty well addressed already. But, the 1.4X Extender "costs" you one stop of light, which is lost when light is passing through that lens' optics. When installed on lenses that are already only around f5.6, your camera will have trouble AFing with the 1.4X installed and only effective f8, thus the hunting. Plus, the 1.4X can only be installed and is designed to work with longer lenses. In your kit, likely only the 100-400, but it sounds like that's the lens you want to use it on. Be prepared to manually focus the lens when racked out to 400mm with the 1.4X installed. (I hope you have it on a tripod, too, even with I.S., since this is the equivalent of nearly 900mm telephoto on a full-frame camera! 400mm x 1.4 x 1.6 = 896.)

    Note, there is some light fall-off when using extensions, too. So, a tall stack of them might cause similar difficulty with AF. However, a lot of folks don't use AF with macro photography, anyway. I.S. is likely to be less than effective when very close-up, too.

    Stacking a bunch of extension tubes together will likely slow AF and/or I.S. due to all the extra electrical connections being made. The tiny trickle of power passing between lens and camera body has to cross those connections. The more connections there are, the less efficient it is, so communication and power functions slow down.

    Canon's tubes are very well made, mostly metal and I think the electronic contacts are gold plated. Kenko's seem fine, too, but are polycarbonate bodies, and probably not gold plated contacts (Hey, they gotta save $ somewhere, to sell them so much cheaper). Besides the 3-tube set offered (which is a sort of traditional way these tubes have been offered) Kenko also makes 12mm and 25mm individual tubes, which might be higher quality in some ways, aren't much cheaper than the Canon tubes.

    You can get into all kinds of math and calculations of magnifications with various combos of tubes and lenses. However, I just suggest experimenting and learning what to expect with a few key combos. This might be more practical out in the field.

    If it's an area of high interest to you, there are some really good books out there about using many methods to shoot macro or near-macro close-ups. If I recall, Tim Fitzharris has written one or two specifically about the subject. John Shaw's "Close-Ups in Nature" is excellent. And George Lepp's "Beyond the Basics" gets into the subject in some detail.


  10. Danny, if I were you I would just return the Canon extension tube and get the Kenko extension tube set. For the same price as the Canon, you get 12, 20, and 36mm Kenko tubes in the set. These tubes don't have glass like the Canon tubes. Therefore, you won't be compromising IQ by going third party. Are you intending to use the extension tube w/ your 100-400 IS to do some macro photography?

    As far as putting tape on the TC, I used regular scotch tape, and it worked fine. Again...AF will work, but it will hunt...meaning it will have a hard time focusing...and it's possible it may not find the correct focus at all.
  11. " return the Canon extension tube and get the Kenko extension tube set"

    I had a set of Kenko tubes but changed to Canon after I had the lenses fall off unexpectedly three times, the last time my 300 f4 fell into sand narrowly missing the nearby bog. The other two times were with my 100mm macro.

    The problem is the Kenko tubes do to lock firmly and have weak springs on the release leavers. The Canons are much more solidly made and lock tightly.

    I know others are very happy with Kenko tubes although they also report the lock is not tight, but for me that was too much risk. Its more the down time than the cost of repair which insurance might cover.
  12. Bummer, Lester. I wouldn't have given such a tube a second chance, let alone a third! The Pro-Optic set (even cheaper than Kenko!) I had didn't present such a problem. Snug fit and tight lock.
  13. The Pro-Optic set (even cheaper than Kenko!) I had didn't present such a problem. Snug fit and tight lock.
    Well.... maybe you got a good copy of these tubes. I tried a Pro-Optic set once, along with a Kenko set. Both flexed visibly when I hung a heavy camera (1D II) on them, off of a tripod- mounted 500 mm lens. Both caused a few ERR99s due to electrical contact breaks. And neither struck me as being robustly built, at least in comparison to the (admittedly outlandishly expen$ive) Canon tubes.
  14. Seeing your gear list, it seems to me that where you are going to come up short is in wide angle. You already have a 100mm macro lens, and it takes lots of extension to get anything close to macro at the longer end of the 100-400. The 28-135 is not wide angle on your camera. To get the equivalent of 28mm FF, you need around 17mm, like the 17-85IS, which is Canon's 28-135 equivalent for 1.6 crop factor cameras. Or maybe the EFS 10-20mm for very wide. If you're trying to avoid "digital only" lenses like Canon's EFS series, then something like Sigma's 12-24 might work. In any case, with 28mm (FF equivalent to 44mm) as your widest lens, I think that is where you are going to be lacking. I have a 100-400 and the Canon 1.4xII. With the three pins covered with tape, the lens tries to AF, but it is frankly terrible. Interestingly, though, when I attach my cheap Tamron 1.4x (standard version, which lacks the extra three contacts) with the 100-400, the AF works fairly well, given sufficient light. Also, it works better with the superior AF of the 20D than with the Rebel XT. Remember also, that not having communication between the lens and extender means your EXIF data with the image will be wrong. With the Canon extender connected normally, your EXIF will report 560mm and F8 for a picture taken at full zoom and wide open. With the taped contacts (or the Tamron extender), the EXIF will say 400mm F5.6. The problem I have with that is when I see a bad picture, I wonder if it was with or without the extender. All that said, I have not been happy with many of my 100-400-plus-extender pictures. Alone, the 100-400 is fine. I think I get better printed results just using it as is and using skillful cropping/resizing in Photoshop in lieu of the extender. I've attached a picture I downloaded from another forum showing the taped contacts.
  15. I will buy a macro in the end, but in meantime I use 2x 12mm tubes and 3x 25mm tubes as well as a 500D closeup lense, all or in various combinations.
    I 1st bought a 25mm tube, liked it, but then realise I need the 12mm also. The 500D magnifies quite a lot, so for a dragonfly, I rather use the 12mm only, than the 500D or 25mm tube.
    This pic was taken with all these attached to 350D & 70-200IS lense.
    I never had the need to tape any pins.
  16. Chris, I guess you do not understand what the pin taping is about. It has nothing to do with extension tubes. The second part of Danny's question was about using a 1.4x extender on the 100-400 F5.6. Canon's consumer cameras (10D, 20D, 30D, Rebel, Rebel XT, Rebel XTi, and 5D) have autofocus designed to work with lenses of maximum aperture 5.6 or larger (smaller number = larger aperture, so 4 is larger than 5.6 and 2.8 is larger than 4). If the camera detects a lens with an aperture smaller than 5.6, it disables autofocus. Note that Mfrs like Sigma design some of their lenses to "lie" to the camera. For example, the 50-500mm is actually F6.3 at 500mm, which would cause the above cameras to turn of AF, but the lens tells the camera it is F5.6, and AF works. Tele-Extenders, through their magnification, modify the effective maximum aperture of the lens to which they are attached. Higher end extenders are wired to pass that information to the camera. For example, when you put a Canon 1.4x extender on a 500mm F4L lens, the camera will see the lens as a 700mm F5.6, and everything is fine. AF still works, and the EXIF data will reflect that shot with 700mm and F5.6. Put that 1.4x extender on a 400mm F5.6, though, and there is a different story. The 1.4x magnification makes the lens effectively 560mm F8. The camera detects the F8 maximum aperture and shuts down AF. This is because the AF in Canon's consumer grade cameras is not sensitive enough to work at very small apertures. However, Canon's approach is a bit conservative, as the AF can work in bright light, so we look for ways to "fool" the camera. One way is to block the three pins that communicate the extender's presence. In such a case, the camera sees the 400mm F5.6--unaware of the extender. Yes, it's darker, but the camera AE will compensate with a slower shutter speed. Of course, as a result the EXIF will be incorrect, but we don't care. We just want AF. Another way to "fool" the camera is to use one of the 3rd party extenders which don't have the extra three pins, which is theoretically the same as taping the pins on the others. The Tamron standard 1.4x extender does not have the 3 extra pins. Their "Pro" version, however, does. With the Tamron extender, the camera will still try to AF, although without really good light it is pretty hopeless. Again, we are talking about Tele-extenders...not extension tubes. Why does one use a Tele-extender? Because the lens he has is not long enough. If your lens is a short telephoto, like a 70-200, your best bet is to just get a longer lens. 1.4x on a 200 gives you only 280mm; 2x gives you only 400mm. And for shooting wildlife, 400mm is a short lens. If you only need 400mm once in a blue moon, then using an extender makes sense. If you plan to shoot birds every weekend, then you start with a 500mm or 600mm and then add a 1.4x extender.
  17. Be aware that although the tape trick works the AF control loop will no longer be critically damped. This means it will tend to under and over shoot the ideal focus reducing the hit ratio.

    If you use AF Servo and hold the AF continuously you will see the lens hunt from side to side, hopefully it will converge on correct focus. Some people have reported that this does not always happen and there have been one or two reports saying the AF motor has been trashed this way.

    I sometimes use the 300 f4 IS with the EF 2X II and manual focus fine, it just takes a bit of practice.

Share This Page