Extension tube Canon EF25 II (review)

An alternative to getting a macro lens is extension tubes that you connect between the camera and the lens. There are many different brands and models. The reason why I chose to buy a Canon tube is because at the time I felt that it was the right thing to do. I haven't regretted it but in all fairness I probably wouldn't have regretted getting another brand either.

The reason why I chose to get a 25mm and not a 12mm was because I felt that the 25mm would work better with my other equipment. Along with my Canon EF 50mm f/1.8 II it produces great close-ups like this one of my nephew's eye. You can see my head and the camera in the reflection.

What the extension tube does is make the depth of field really short and shorten the closest focusing distance. It also makes it impossible to focus to infinity. As shown in this video. I'm using the extension tube with my 50mm lens to focus from nearest to infinity and back. Basically you change the focus distance from the near side to the far side of a penny while using the 50mm lens.

The shorter the focal length of the lens the closer you can get to the object. That means a 50mm lens is better than a 70mm lens which is better than a 200mm lens. The differences between those are shown in this video where I use the Canon EF 50mm f/1.8 II and the Canon EF 70-200mm f/4L.

There is also a limit to how close you can get. For example if I try to use the extension tube on my 30mm Sigma lens the infinity focusing distance will still be inside the front element of the lens which means it's useless.
When shooting macro most people wants to get a magnification of 1 of more. What that means is that if an object is 10mm in reality it will show up as 10mm on the sensor.
With the EF25 II extension tube you can get a magnification of 0.68 on the 50mm lens and 0.39 on the 70-200mm f/4L at the 70mm end. Magnifications are according to the table in the instructions that comes with the extension tube. According to those instructions you should be able to use it with a Canon EF 24mm f/2.8 lens and get a magnification of 1.22. Using a macro lens will get you even more magnification. The Canon EF-S 60mm f/2.8 Macro USM can get a magnification of up to 1.61. That means an object that's 10mm in reality is 16.1mm on the sensor.
As a comparison the table also has the EF12 II extension tube and with the 50mm lens I would only have gotten a magnification of 0.39 using that. So I'm guessing I made the right choice when I got the EF25 II.