Extension tubes or Macro lens?

[IPT]

I already have a good Canon setup (28-135IS, 70-200 f4L, 300 f4L, and a 5D body), but I would like to get "closer". The 28-135 has a min focusing distance of 1.64'. Assuming you wanted to take some intimate shots of SPS (maybe even 1:1's) in a 50 gal reef tank would you get extension tubes (12, 20, and 36mm tubes by Kenko @169$) or will I need to shell out for the 100mm Macro lens? How much will the 36mm tube shorten my focusing distance by (the 100mm Macro by Canon has a min focusing of 5.9" and wll get 1:1)?

[BlueCorn]

I use both the 100 macro and a set of tubes. I think that it's worth having both.

[gregr]

Both here too. I believe the best you can get with the 28-135 and a 36mm extension tube is roughly 3/4 lifesize and I guess that's not bad. I used to use a 300f4 with tubes (and a 1.4x converter or even 2x) for bugs and snakes- that was a great set-up- superbly sharp with a decent working distance. But that wasn't for aquarium photos (it would get you even less magnifnication obviously, but it's great for bugs and such)- a 100mm macro lens is the best choice for corals because with the zoom and tubes you will have very slow shutter speeds. Even with the 100mm macro lens you'll be wanting more speed. Add the speed issue to the magnification issue and the macro lens wins.

[louist]

Extension tubes will help you get close. The calc goes like this:
Magnification = total length of extension / focal length

So, to get 1x @ 28mm, you will need 28mm worth of extension, while @80mm, you will need 80mm worth of extension. The light lose from 25mm worth of extension is almost 2 stops, which equates to ~4x longer shutter speed, then take the working distance into consideration.

Tubes are great for normal kind of macro photography and especially for flowers, butterflies etc, but IMO, it isn't that suitable for aquarium photography. Well, unless you line all your corals up along the sides of your tank!

PS. 25mm extension tube with the lens set to 28mm is almost impossible to use. When I used to use a 25mm tube with my 28-80, I was mostly using 50 to 80mm. Anything under that, and the working distance is extremely prohibitive.

[NoSchwag]

Are all brands created equal? I see a set for 130.00 at someplaces, and much less at others.

[BlueCorn]

There's no real reason to go expensive with ext. tubes. Canon air isn't any faster than Tamron or Kenko air. That's really all they are, it's an extension between the camera body and the rear of the lens.

[GuOD]

beeryguy which tubes would you recommend i pick up for my 30d+100mm?

[BlueCorn]

I use a Kenko set (12, 20 and 36) but like I said, it really doesn't matter. Air is air.

[GuOD]

might order them from bh today :D

what mag. can the 100 macro get to with tubes?

[Ebn]

If you stack all 3 of them, you'll get nearly 1.7x lifesize.

[GuOD]

Thanks!

I think I'll order em :) Always wanted to get even closer!

[returnofsid]

If you stack all 3 you'll be limiting your available light to an extreme also though.