Kenko DG extension Tube on Canon 100mm 2.8

[derrickdehaan]

In reference to Kenko DG Auto extension tubes. I see decent reviews, but I am hesitant because some say that the

tubes require you to get almost too close to the subject. I want to try shooting bugs and flowers. I would be using

these tubes with the Canon 100mm f/2.8 on a 400D, with a MT-24ex. I am wondering if I would have to get so close

that i would not be able to use the lens mounted flash. I would like to hear any kind of feedback from those who use

extension tubes on this subject or any other problems I may have overlooked.

 

Thanks,

 

Derrick

[tommyinca]

You don't need the tube for the EF100mm/2.8. This is the reason you buy this lens in the first place (so you don't

have to put up with a tube). Just use it as it is for now until you are good at 1:1 macro.

[zml]

If you want to go beyond 1:1 magnification with that lens, extension tubes will do that for ya. The lens booklet/manual shows min/max focusing distances and image magnifications with the 12 and 25 mm extension tubes.

[thomasmckown]

I actually use a 400D and Canon 100mm macro. I bought the Kenko extension tubes when I got the lens. I like the extensions tubes pretty well, although I have not actually tried using the tubes with a ring light yet. I really like how close you can get, especially with all three tubes in the kit, the detail is amazing. I wish I could be of more help other than telling you they work great, at least without a flash. I can tell you though, that it is really cool to be able to get so close.

[mark u]

Roughly speaking you'll lose 3-4cm of working distance with the full set of tubes (less with other combinations) for a maximum magnification of just under 2. That should be no problem with the MT24EX.

[derrickdehaan]

Mark, that is the answer I'm looking for. The budget is just getting a little tight right now and I didn't want to pull the trigger on the tubes only to find out that the MT24-ex wouldn't be able to light the subject.

 

thanks,

 

Derrick

[sarah_fox]

I have the Kenko set, and it works fine for me. There's one report of someone's lens having fallen off of a Kenko tube, but that sounds like user error to me (lens wasn't locked).

 

You can only get just so short a tube, as you're having to stack mounts. Even so, the 12mm tube gives you comfortable enough working distance for macro work. A few days ago I posted a few sample images from a 50mm lens on a Kenko 12mm tube. You can find them on the classic cameras forum, with a thread titled "cat's eye lens experiment" or something of the sort. As I recall, the lens' focus was set to about infinity for those shots.

[alan_myers]

Hi Derrick,

 

Huh?

 

The Kenko extension tubes work fine. They are mounted behind the lens so they have nothing to do with mounting the MT24EX on the front of the lens.

 

But, I ditched the original lens mount system of the MT24EX a long time ago. I use it with a Lepp/Stoboframe Macro bracket that's far more flexible and gives much better lighting effects. The original front-of-lens mount really limits the positioning of the flash too much for my liking.

 

For that matter, an awful lot of the time I just use a single 550EX on an off camera shoe cord, hand held, usually off to the side and slightly above my subject. Works great. It's like a great big "soft box" with macro sized subjects and the light wraps around them very nicely.

 

You only need the extension tubes on 100/2.8 is you want significantly higher magnification for some reason. To give you some idea, I recently used it with a 20 or 25mm tube for a "head and shoulders" shot of a praying mantis. Extensions wouldn't be needed for most flowers, unless you are trying to get just some of the little details hiding inside, or they are particularly small flowers. Last weekend I was shooting the centers of old roses with the 100/2.8, without any added extension. Also wouldn't be needed for "full body" shots of, say, most moths and butterflies.

 

Figure it this way, the lens goes to 1:1, and your D-SLRs sensor is roughly 15mm x 22mm, so that's the area you can photograph with the lens. That's approx. 2/3 inch by 7/8 inch.

 

WIth a 100mm, a 12mm extension isn't usually significant, although it might be with a 50mm. The longer the lens, the more extension you need to have much effect.

 

I had the Kenko 36mm behind a 500/4 + 1.4X teleconverter recently. It was just enough to let me get the shot, improving close focusing of the lens (which, thankfully, didn't fall off) so I could be about 3 inches closer to the subject (a hummingbird on her nest).

 

I've used 12mm on a 20mm lens, and had flower petals that were touching the front lens element in focus.

 

I use the Kenko set alongside two Canon 12mm and one Canon 25mm. They are totally interchangeable as far as I'm concerned (but if you use an EF-S lens, make sure any extension tubes can accomodate it). The set is the best deal, last time I looked at prices it was about $160 for the set of 3, compared to about $125 for one Canon 25mm. The tube set gives you seven possible combinations, with 12mm, 20mm and 36mm tubes. Canon themselves doesn't offer a tube set, only individual tubes.

 

Canon tubes are made of metal. Supposedly the Kenko's are high impact plastic. I can't tell the difference.

 

I think Adorama has their own house brand of extension tubes, which I'm sure would be fine even though less expensive then even the Kenko set. B&H might too, but I can't recall ever seeing any. Again, if you need it to fit EF-S lenses, confirm that they will (but I've heard that someone handy with a Dremel tool can make any tube fit EF-S).

 

Do not buy those $30 tube sets off everyone's favorite auction site. They lack the electronic connections for auto focus (no big deal) and aperture (way big deal) control of the lens. The biggest problem is you have to shoot with the lens wide open all the time. Not a good thing with macro, where you need to stop down to get adequate depth of field.