how to select tele convertor?

[Jim Manjooran]

I have a Canon 55-250, f/4-5.6, ISII lens and was wondering what kind of tele convertor would suit it....and if there some budget options too.

Thanks for the help.

Jim

[Rajan Kanagasabai]

Hi

Depends on what body you use with this lens which eventually decides on whether Autofocus would work with a TC or not.

I did have this lens a few years ago (a friend of mine is using it these days) and if i remember right i used to have a EF 12 II convertor for the same.

The quality loss at the high end with the TC was quite a bit to comprehend with when i was using it on a 400D body.

regards
Rajan

[Jim Manjooran]

thanks Rajan...
I have a Canon 600D..
How about the Kenko teleconvertors for the lens and this camera..?
They seem to be priced reasonably...
Kenko MC7 AF 2.0 DGX Teleconverters (For Canon) Lens?
or
Kenko MC4 AF 2.0 DGX Teleconverters (For Canon) Lens?

The Canon teleconvertors which they call extenders are meant for L series lenses ..so they wont work with the Canon 55-250, f/4-5.6, ISII lens that I have here?..

What would be the good way to go?

[Rajan Kanagasabai]

Hi Jim

You are right. This will not work on a Canon TC. In fact, i got mixed up between the 55-250 and the 70-300 on my earlier post on the EF 12 II extender, which i had used with the 70-300 a few years ago.

Since this post, i got the 55-200 back from the friend and tried mounting with a Canon TC on a 5 D MII & a 5D MIII. IT simply would not mount for the rear portion of the 55-250 is elongated and would not couple with the TC. Looks like the lens is designed for small APS-C sensors and it physically would not mount on the larger sensor camera's.

I am not sure of the Kenko's, but i strongly feel that even if it does work, you may have 2 issues to comprehend with. (1) Autofocus: May not work or even if you tape the pins, it will slow it down considerably (2) There is sure to be loss of details for even the 70-300, with a TC at the high end had picture quality issues.

Any TC results in atleast a one stop penalty. Assuming the Kenko works with the 55-250, the enhanced focal length of 350mm will be highly handicapped with the reduced apreture of F8 which in turn means that the combo will need abundant light for a decent photo.

Hope this helps

regards
Rajan

[Sabyasachi Patra]

There are a few things to consider when you are using a teleconverter (TC)/extender. With a 1.4x TC you will lose 1 stop light and with a 2x TC you will lose 2 stops.

When using TCs start with the highest quality lens. Else, the quality drops significantly.

I have lost tons of money in buying and then selling at a loss many lenses and have realised that it is always better to buy only the best quality. It is better to have a longterm horizon in mind. Lenses depreciate less and will retain its value for a long time.

[Jim Manjooran]

thanks Sabyasachi...thats a good tip...what you say makes a lot of sense..a superior lens with a tele-convertor makes better sense..rather than getting into a rushed purchase with a regular lens...thanks..