Purpose of Canon EF 12 & EF 25

[earl_damron]

Is the purpose of these accessories simply to shorten the minimum focus distance?

In that regard, would it be comparable to picking up a macro lens?

Thanks

[mrchips]

Yes the effectivley turn a lens into a macro lens with the loss of auto focus. I use a set to turn my 28-135 IS into a macro lens but if your serious about an autofocus macro, you need to purchase a macro lens.

[Pekka]

Good reading:

http://bobatkins.photo.net/info/faq30/closeup2.htm
http://jimdoty.com/Tips/Closeup/closeup.html
http://www.camera.canon.com.my/photography/film/2000/films16/
http://www.northrup.org/equipment/extension.htm

I just ordered 77mm 500D for my 70-200. Seems to be a good choice. From worse to better in my opinion:

1. extension rings
2. closeup filters (+1, +2, +4, +8)
3. Canon 500D (2 elements)
4. Dedicated macro lens

[Rudi]

mrchips wrote:
Yes the effectivley turn a lens into a macro lens with the loss of auto focus.

You can still autofocus with the extension tubes if you have plenty of light. The reason Canon recommend NOT to use autofocus is possible actuator overload, in case someone lets the lens hunt around for focus for a long time. Trick is, if it won't autofocus the first couple of times, just switch to manual rather than let it hunt...

I regularly autofocus with the Kenko extension tubes attached. All you have to do is pick a really contrasty area to focus on, and it should work. Just remember not to INSIST on using the autofocus if there isn't enough light! :)

[earl_damron]

Thanks very much for the info guys!

[thunt]

What is the difference between the EF 12 and the EF 25? Is one better to use with bigger zooms than another?
Thanks,
T

[earl_damron]

I'm considering picking up a 500D.

Can one determine mathematically how much one of these will change the minimum focus distance? I was thinking of using it on a 75-300 IS.

Thanks

[Dick Ginkowski]

I should point out that Kenko's 12mm and 25mm extension tubes are just as good and half the price.

[Pekka]

earl_damron wrote:
I'm considering picking up a 500D.

Can one determine mathematically how much one of these will change the minimum focus distance? I was thinking of using it on a 75-300 IS.

Thanks

See http://bobatkins.photo.net/info/faq30/closeup2.htm and paragraph Q: How do extension tubes change the focusing distance of zooms and by how much compared to cu lenses?

[DoctorMoth]

I purchased the EF12 to use with a Canon 200mm 2.8L specifically, in order to use it as a macro. I was somewhat surprised to find when I got the tube that I couldn't focus any closer (or so I thought) with the lens then without it, and I lost the infinity focus totally. The little booklet/flyer that came with the tube cleared this up for me (instead of the 4.5 feet or so that I normally can focus up to with the 200mm L the tube gave me the ability to focus as close as 3.9 feet). This tube saved me a total of 6 inches. Woo hoo! I can't imagine why you would need this thing actually, at least spring for the EF 25 for forty or more bucks. I think that for the casual macro user they are basically not worth it, but for someone that has a bunch of them, and stacks them, and uses a tripod all the time, etc., they are one more tool to the macro photographer. But basically, you'll end up buying a dedicated macro lens. One more thing, you seem to lose a lot of light when you use them, my 2.8 seemingly goes to a 4 or so when I use it with the EF12, even though the tube is quite small. If you have a slower lens to begin with, you might reconsider and decide on a real macro instead. I would note that both the Canon Macros (the 100 2.8 and the 180L 3.5 ) focus without any accessories at approximately 12 inches and can also be focused to infinity. -->

[Rudi]

DoctorMoth and all,

as Pekka and others have suggested, a little research goes a long way! :)

I hope what I'm going to try and explain will make sense. If not, please feel free to ask. :D

When you have a lens, every time you move it away from the sensor plane by an amount equal to its focal length, you double the magnification. Of course, the lens is already some distance away from the sensor, but for all purposes, let's pretend you have a 50mm lens, and you use the 36mm and 12mm Kenkon ext tubes (a total of 48 mm). This should give you about double the maginification of the lens alone. As you can see, the effect will be MUCH greater than 12mm on a 200mm lens! If you used the whole set of Kenko extension tubes, the effect would be much more pronounced with the 200mm! As to the light loss, yes, there is some light loss (the light is spread thinner as you move the lens away from the camera). As most macro photography requires stopping the lens down several stops to combat the inherent shallow DOF, this really should not be much of an issue. Of course, dedicated macro lenses will always be the best (and most expensive) way to do macro, but... extension tubes have their uses.

So, I have to disagree! Extension tubes are probably the BEST way to get started in macro photography, as they will work with ALL your lenses (close-up lenses won't, only with lenses with that particular filter thread size). They are relatively cheap, and there is NO reason to buy Canon, as there are NO OPTICS inside these tubes. What's more, if you get seriously interested in macro photography, these extension tubes will come in handy with you macro lenses as well... and they will enable your seriously long telephoto lenses to focus closer, so they are handy for wildlife photography as well.

But don't just take my word for it! Do some research BEFORE buying these things (or anything else), to make sure you will be getting exactly what you want.

[earl_damron]

Pekka wrote:
See http://bobatkins.photo.net/info/faq30/closeup2.htm and paragraph Q: How do extension tubes change the focusing distance of zooms and by how much compared to cu lenses?

Wow! There's a lot of great info in this article. I was considering another question or two in this thread until I read this.

Thanks!