Extension Tubes - Any suggestions??

There's no major difference between the various tube sets for Canon, as long as they have the electrical contacts so the lens remains working with the body. Without that, you can't set the aperture for example. And as tubes have no optical elements inside them, they all perform the same! So a 3rd party set is typically great value as you get a set of 3 for not dissimilar price to a single Canon one.

As for matching it with the 50mm f/1.8, if you use big apertures you will notice some degradations as the magnification increases, but in practice you want a bigger depth of field anyway so stopping down negates that to a large degree.

As the magnification increases the effective f number goes up too, so you will tend to need more light or longer exposures to compensate. Personally I wouldn't trust AF in this application and would use magnified live view, but that works best with a tripod.

I did a magnification comparison with tubes a while back which I'm failing to find at the moment. I'll post it later if I manage to find it.

Edit: Can't find it on this forum but I also posted it here. Scroll down a bit there for the pics with various tubes on the Canon 50mm f/1.8.

 

Disagreeing slightly here (because you know I can't help myself, popo ), I have used generic, cheap tubes from eBay and found the contacts to be dodgy, leading to repeated error messages coming up on the camera. Pretty frustrating. And I have read on the Canon users' forum that this is not an uncommon experience. However, my Kenko tubes have remained entirely reliable. However, they also remain fairly unused.

The problem I have found with extension tubes, as with all macro photography, is that the depth of field quickly disintegrates to nothing. You get a tiny window of clarity, with the rest of the shot being out of focus. And this holds even when you stop right down. You can see this in Popo's example shots. The shorter the minimum focal length, the narrower the depth of field. This might not bother you, but it annoys the hell out of me.

One way to minimise this nuisance is to make sure that you have your subject on the same plane as your lens. So, for example, the doll's face must be exactly flat onto to the camera, not tilted up or down or in anyway away from the lens. Most of that will then remain in focus. eg



As you can see, the face is in focus, but the ears, the far side of the flowers and even the right side of the face are starting to blur out. But this was on f/4, so could have been improved by stopping down a bit.

But you couldn't get a shot like this without the tubes (or a very expensive macro lens).



But the question is, would you want to?

The other thing I used to do was use my telephoto zoom and zoom right into the subject to get a close up. The advantage of this is that you retain a lot more of the depth of field. The disadvantage is that there is a limit to how close up you can get, particularly if your telephoto lens has a massive minimum focal length, as mine does (which is 1.1m, so you are halfway across the room before you can get it to focus). So you could never get that massive Pong face shot with it. This also means that you are losing lots of light, which matters if you are a nocturnal photographer, like me. It is also a rather ghetto way of doing things. But that is how I tend to work.

Close up with my Sigma 55-200 f/4-5.6 DC Lens at its minimum focal distance but at 161mm (so could have been a little more magnified, but not much).



But, the tubes are fun to experiment with, they work jjust fine with all the auto facilities on the Canon EOSs and they are relatively cheap. So, as with most things, I guess it depends on what you need them for.

 

The set I have are like these and I haven't had problems with them. The ebay price seems to be about half that of the Kenko ones. Of course with any unbranded kit there is some risk it may perform less well than other brands.

On the (lack of) depth of field, that applies at higher magnifications pretty much regardless of the method you use to get there. It is a problem with extension tubes, close up lenses, actual macro lenses or even using teleconverters. Depending on how far you go, I'd stop down to f/8 to f/16, although rarely beyond that as the light loss gets rather extreme and diffraction softening gets excessive. This isn't hand holding territory without flash, but generally I prefer using a tripod and longer exposures. Using a longer focal length lens in theory shouldn't help if you really are using the same magnification. Without additional accessories they don't usually go to very high magnifications, so the depth of field isn't necessarily being compared like for like.

 

Not a big fan of extension tubes. They can be useful, but I wouldn't pay that much for them. The Kenkos are a good choice.

If a dedicated macro lens is out of the question, I personally prefer other solutions for higher magnifications: a 1.4x teleconverter or a multi-element diopter like the Canon 250D (Not a camera model!) that screws onto the lens like a filter. The teleconverter is more useful in a general sense and the filter is easier to mount and use. These would cost ~$100 each.

A less suggested option is to reverse-mount the 50mm onto another lens that is mounted normally. You can do this with a reverse-mount ring that costs ~$10. The rule of thumb for the magnification possible is (mounted lens FL)/(reversed lens FL). So for example, if you were able to borrow another 50mm, you could achieve 1:1 "life size" magnification. Preferably you would do this with primes only...

Either way, I would say a tripod and/or flash is essential. You're getting pretty dark when you shoot macro.

 

Has anybody tried focus stacking? I'm not into macro, but it seems to be the way to make up for the shallow depth of field when using extension tubes and the like.

I'm only really into big dolls so it hasn't been an issue for me, but I just switched to a full-frame body and now I can't get tight portraits, so I may have to get a macro myself.

 

Extension tubes are probably the easiest way to control magnification on a budget, at least for shorter focal length lenses. Close up filters work more effectively on longer focal lengths. Teleconverters offer a straight magnification boost, but mechanical compatibility is possible issue depending on the model. And if the lens doesn't have that much magnification to start with, the boost might still not be near enough. I find lens reversal just too messy overall.

Focus stacking I've only dabbled in a little for more extreme macro. It's fiddly to set up and then you need the software to crunch it. It's overkill for this application.