Extension tubes

[vader88]

Right now I just have a kit lens 18-55mm and I ordered a 50mm 1.8 which will be here next week. I plan on picking up a dedicated macro lens sometime in February ( tax time ) but would like to so some macro things before then.

If I picked up the Kenko tubes, would they still be useful after I have a macro lens. Don't mind spending the money on it if it still can be put to use.

canon 450d

 

[Mr31415]

You can use extension tubes but in my mind they degrade image quality a lot, especially when not used with exceptional optics. On a 500mm F4 lens it works well, on a kit lens I doubt you will get good results.

 

[vader88]

I had planned on using it with the prime.

 

[Misled]

An extension tube doesn't degrade image quality. It may show problems with cheep glass, but even with cheep glass they can produce incredible results. An extension tube has no glass. It's basically a spacer that moves a lens further away from the camera's sensor. This allows the lens to focus at a closer distance. It will decrease the amount of light available to a sensor and also decrease the DOF. A 50mm is a bit wide, but I've used them with a cheep sigma 28-90.

 

[Almondsaz]

I shoot canon and have always had a set of Kenko extension tubes. In the begining I used them frequently, but then I got into the macro with the 60mm macro and 100mm macro from Canon - love them both for different reasons. If I was only going to buy one, it would definitely be the 100mm prime.

 

[vader88]

I had the 100mm macro, but sold it a while back. When I buy again, I'm between that lens or the tamron 90mm.

 

[Mr31415]

An extension tube doesn't degrade image quality. It may show problems with cheep glass, but even with cheep glass they can produce incredible results. An extension tube has no glass. It's basically a spacer that moves a lens further away from the camera's sensor. This allows the lens to focus at a closer distance. It will decrease the amount of light available to a sensor and also decrease the DOF. A 50mm is a bit wide, but I've used them with a cheep sigma 28-90.

I beg to differ. Optical elements within a lens are designed for use based on the manufacturers specification. By using extension tubes you basically use only the central portion of the lens elements of the lens it is attached to, for projecting a full frame view. This basically enlarges any and all defects - and all lenses have a maximum resolution limit.

I have used extension tubes with a wide variety of lenses. In each and every case the image quality one gets from a lens + extension tube is always worse than the lens itself. Attached to an expensive Canon 100mm IS F2.8 macro lens, it produces horrible softness and various aberrations. Yet without the extension tube the image quality of the 100m lens alone is superb.

The only time I found it useful is for use with something like a 500mm F4 lens to photograph hummingbirds. It allows larger magnification while keeping a set distance. It works because the amount of magnification you get is not that much with a long focal length lens like a 500mm. The shorter the focal length of the lens, the more you magnify any defects in the lens when using an extension tube. At least that is my first hand experience using L glass.

 

[Misled]

I can't say if it has something to do with L glass, or your application of the lens and tubes you used. I shoot with Nikon. This was with a sigma 28-90 with the macro switch on and a full set of tubes without electronics. A flash was also used.

I used these before owning a true macro. I've also used them since with the Nikon 105 and thought they really weren't as good as with the Sigma, but for more a DOF reason. I don't know whether you shoot with FF or a crop body, but it may be possible that using a crop body with a FF lens makes some difference. But if you work with them. They speak for themselves.

One more for fun. This was with a 30mm Kenko extension and a Nikon 105mm.

 

[smoq]

Extension tubes extend the magnification ratio beyond 1:1, but they also shallow the depth of field significantly. Here's a picture taken with all three of them and a 90mm macro lens:

 

[JaYbIrD1969]

It would be interesting to see someone conduct an experiment. A series of photos with and without tubes. Compared with the exact same composition. With no post processing. Obviously the magnification would differ, but the image quality can be compared.

 

[smoq]

It would be interesting to see someone conduct an experiment. A series of photos with and without tubes. Compared with the exact same composition. With no post processing. Obviously the magnification would differ, but the image quality can be compared.

There's no image quality drop when using extension tubes, the only two problems are extremely shallow depth of fields, where macro focusing rail is really helpful and lens is more sensitive to distortion when it's not perfectly perpendicular to the glass

 

[vader88]

I ended up grabbing the Tamron 90mm .. so far so good. I may still grab some tubes.

 

[Misled]

I may still grab some tubes.

For the cost of a set of tubes, there's no reason not to. No matter what anyone says, the tubes will allow you to get closer and increase the magnification of a given lens. The Tamron will allow you to get 1 to 1. That's it. Adding tubes to it can get you to 3 to 1 or even more. It's a bit of a learning curve and takes a bit of practice, but anything worth while is.

 

[maroun.c]

I beg to differ. Optical elements within a lens are designed for use based on the manufacturers specification. By using extension tubes you basically use only the central portion of the lens elements of the lens it is attached to, for projecting a full frame view. This basically enlarges any and all defects - and all lenses have a maximum resolution limit.

I have used extension tubes with a wide variety of lenses. In each and every case the image quality one gets from a lens + extension tube is always worse than the lens itself. Attached to an expensive Canon 100mm IS F2.8 macro lens, it produces horrible softness and various aberrations. Yet without the extension tube the image quality of the 100m lens alone is superb.

The only time I found it useful is for use with something like a 500mm F4 lens to photograph hummingbirds. It allows larger magnification while keeping a set distance. It works because the amount of magnification you get is not that much with a long focal length lens like a 500mm. The shorter the focal length of the lens, the more you magnify any defects in the lens when using an extension tube. At least that is my first hand experience using L glass.

I disagree with the idea of using only the central portion of the lense. What's happening is that the lights is going through all the optics inside the lense the same way as it would if the lense is on extension tubes or not.. the only difference is that the added distance of the path when placing the extension tubes allows the widening path to widen further before hittin your sensor which increases the magnification.
It is true that you'll find more failed pictures with the added extension tubes but its not due to using only the central portion of the lense (which isn't a bad thing as you only use that portion when you close down your aperture anyway), it is due to how close you are to your subject which minimizes your Deapth of field. at that stage its very easy to miss the focus.
Also the slightest motion is more visible due to the added magnification.
I have played with extension tubes, reversing ring where you have a lense fixed backwards over another lense, even toyed with extension tubes behind the set... at that stage I was definitly using only the central portion of the 2 lenses (due tot he much longer path if not to a closed down aperture) and I managed some nice shots with that setup. It of course required use of a focusing rail and a very sturdy tripod, an off camera multiple flash lighting setup....