How to use extension rings

[Husky_1]

Hey everyone, do any of you guys have tips on using extension rings. In my tank, my corals are a good ways away from the front glass, so when I have these rings on I cannot seem to focus in on a coral, even if the lens is on the glass.

Also, what settings would you initially go for with ISO and Shutter Speed, how about Exposure?..Seems like I needed to bring the exposure to the + side.

My camera is a Nikon d40, and my tank is a 92corner bow. Sorry my questions were not more technical, I really don't know what to ask.

[maroun.c]

The whoe purpose of extension tubes is to let you focus much closer than the lens does alone to get more magnification. the inconveninece is that working distance is reduced with each tube you add or with longer length tubes. try only adding the shortest tube available if that still does not focus on yruo corals then you will have to move corals forward. another option would be to add teleconverters to the tubes but that will take away from Image quality. also the price of a TC with an Ext tube would be close to the price of some of the macro lenses available.
I try to keep ISO as low as I can to decrease the noise (other cameras don't suffer as much with higher Iso so others could up the ISO to more than 600 maybe but for me I try to stay around 400 max) I try to shoot with manual settings looking at the histogram as that gives me consistent results with different shots of the same coral. try to increase aperture to 8-11 to get more of the coral in focus. if you don't have much water movement and if the coral does not sway in the current you might get away with slower exposures but most of the time that will result in some blur of the image then you will need to increase yuor ISo or use some flash.
HTH

[Husky_1]

That does help a lot...Gives me a great starting point. It looks like I may only get to use these in the nano tank, and outside. I think my next purchase for Macro will be a lens and not the TC, but that will down the road.

Thanks for your help, BTW, I think I need to take a class, because I really do not know how to read the histogram.

["Umm, fish?"]

What size lens are you using the tubes with?

[Husky_1]

Hey Andy,
I am using the kit's 18-55mm lens.

["Umm, fish?"]

There's your problem. As was said before, when you add tubes you lose the ability to focus out to infinity. A 50mm lens with enough extension tubes to get it to 1:1 only has a working distance of an inch or so and that only gets worse on down toward the 18mm length.

I like working with tubes, but I don't use them on anything small than about 70mm.

BTW, I work with a flash as much as possible so I decrease my f-stop as much as possible. I like to take it to f/16.0 or even f/32.0 when the lens will allow. But, to do that you either need really long exposure times or supplemental light.

Good luck!

[Husky_1]

Thanks Andy, For $16 I had to give these things a try, maybe when I get a bigger lens I can try again. I am sure my next purchase will be a 55-200 or something similar.

["Umm, fish?"]

I have a 70-200 and I love it. I also have the 2x teleconverter to turn that into a 140-400. That makes it cover a whole lotta range.

[Husky_1]

Thats definitely nice range. Are there any disadvantages to the teleconverters?

[edwing206]

I just received my extension tubes for my camera today. I'm using my D50+ 55-200mm VR. Like Andy said, you need REALLY long exposure time. I was able to get some cool shots of some corals. I'll see if I can post some later.

["Umm, fish?"]

Teleconverters slow down your lens, so it's best to get a really fast lens to start with if you plan to use one. Also, you'll get some image degradation from them, but I don't think the Canon teleconverter with one of their good lenses degrades too much. Especially since it saves me spending a couple thousand dollars on their 400mm lens. ;)

I'd really advise spending the money on a good flash. Otherwise, it'll be really rare that you get a really sharp tank shot. Acros and montis don't look their best with flash, IMO, but everything else in the tank looks fine and the benefits of really being able to stop motion are huge.