Extension tube ef12II or ef25II ???

[mikes2994]

I have a efs 55-250mm canon lens, in the manual it says its compatible with these 2 extension tubes (ef12 II and ef25 II) I am confused which one is better to take pictures of farther objects ( ex 100yds away) thanks for any advice.

 

[paulk_68]

I have a efs 55-250mm canon lens, in the manual it says its compatible with these 2 extension tubes (ef12 II and ef25 II) I am confused which one is better to take pictures of farther objects ( ex 100yds away) thanks for any advice.

An extension tube helps bring objects closer to you, like when taking macros. Teleconverters are used for bringing objects that are far away, closer. That is the simple explanation. To the best of my knowledge, Canon does not make a teleconverter that is compatible with any of the EF-S lenses.

Edited to clarify a little- Extension tubes shorten your focal length, and teleconverters increase your focal length.

Below are a couple of images of my 30D set up for taking pictures with extension tubes, macro lens, and reversed 50mm lens.

 

[Steph]

Extension tubes shorten your focal length

Strictly speaking that is not true. Extension tubes decrease the minimum focusing distance allowing to get closer to the subject and therefore obtain greater magnification. You also lose the ability to focus at infinity when using extension tube.

 

[Overread]

!! impressive setup Paul! Out of interst is all that tape around the flashmount area just to help hold the angle mount steady? I have tried similar setups with my 580M2 and found that the weight of the flash tends to pull most small heads downwards (ballheads are no use at all).

As for extension tubes they are for mostly macro use - giving you a reduced minimum focusing distance so that you can get closer, at the cost that you will lose focsuing on further off subjects (a few feet to only a few inches depending on the lens and tubes). Also the amount of increase you get in magnification is proportional to the focal length of the lens and the tube length - the longer the lens the more tube length you will need to get to a fixed magnification point.

What does increase your focal length and will give you closer shots of further off subjects is a teleconverter (or extender as canon call them to be difficult) however its important to note that your image quality will take a noticable hit with one of these, especialy on a lens such as yours with a very long zoom range. Personaly I would say that you are likly toget better shots from cropping than you would from using a teleconveter - also canon brand ones will not fit your current lens - they only fit onto select L grade lenses. Kenko and Sigma make their own teleconverters which get very good reviews, though I have no idea if they will fit your lens either

 

[paulk_68]

Extension tubes shorten your focal length

Strictly speaking that is not true. Extension tubes decrease the minimum focusing distance allowing to get closer to the subject and therefore obtain greater magnification. You also lose the ability to focus at infinity when using extension tube.

Yes, that is exactly right. Thank you Steph for clearing that up,.. it was way past my bed time when I posted :blushing:

!! impressive setup Paul! Out of interst is all that tape around the flashmount area just to help hold the angle mount steady? I have tried similar setups with my 580M2 and found that the weight of the flash tends to pull most small heads downwards (ballheads are no use at all).

Overread, the tape (and small flat piece of wood) is to keep the flash & shoe from moving side to side on the bracket. When I get focused on something, I tend to become oblivious to my surroundings and bump into things with the softbox.

The pictures of the spider mite and gnat were taken with the set-up http://www.pbase.com/paulket/macros The DOF is incredibly narrow with the set-up.