Thoughts on 2x teleconverter?

[KJ3N]

Since buying a larger zoom lens (greater than 300mm) is pretty damned expensive, I'm thinking of adding a 2x teleconverter to increase the range of my 75-300mm AF lens.

Any particular recommendations?

[KC2KFC]

What make of camera do you own and what make is the zoom lens?

[K7SGJ]

You may also want to consider how fast your lens is. If it is an F4, for example, the converter will make it equivalent to an F8 which is kinda slow and may even affect the ability of the camera to autofocus. When I used one with film cameras, I had to have the lab do a 1 or 2 push on developing for good exposure. With EOS, you can see what's going on immediately, and make any exposure changes needed right away when shooting on manual. If you do get one. get the best optics you can. Personally, if I had a need for a longer lens, I would buy one in lieu of the 2x. The more light you can get to the CCD, the more options you will have for creativity. If you only plan to go long occasionally, and in bright light, the 2x would do. Also, when considering the 2x, don't forget to consider any filters you may be using as some of those cut down the light, too, and the 2x will double that loss as well.

[KJ3N]

What make of camera do you own and what make is the zoom lens?

Canon EOS Rebel XTi with Canon EF 75-300mm lens.


You may also want to consider how fast your lens is. If it is an F4, for example, the converter will make it equivalent to an F8 which is kinda slow and may even affect the ability of the camera to autofocus.

Not a major concern. Manual focus is usually what I use for long shots. Even with just the standard 75-300 zoom lens, I find the autofocus doesn't always do what I want it to.


When I used one with film cameras, I had to have the lab do a 1 or 2 push on developing for good exposure. With EOS, you can see what's going on immediately, and make any exposure changes needed right away when shooting on manual. If you do get one. get the best optics you can.

And that's why I'm asking. Who/what has the best optics in a 2x converter?


Personally, if I had a need for a longer lens, I would buy one in lieu of the 2x. The more light you can get to the CCD, the more options you will have for creativity.

I'm not sinking $1K+ into a lens I'm not going to use that often.


If you only plan to go long occasionally, and in bright light, the 2x would do. Also, when considering the 2x, don't forget to consider any filters you may be using as some of those cut down the light, too, and the 2x will double that loss as well.

Most of the use (probably all of it) will be outdoors. Better close-ups of wildlife, etc.

[KK4AMI]

Maybe something to be careful about.

http://forums.usa.canon.com/t5/EOS-Rebel/Will-my-70-300-Canon-Zoom-lens-a-2x-multiplier-function-on-a-new/td-p/58153

[KC2KFC]

Maybe something to be careful about.

http://forums.usa.canon.com/t5/EOS-Rebel/Will-my-70-300-Canon-Zoom-lens-a-2x-multiplier-function-on-a-new/td-p/58153

I was going to recommend the Tamron, but after reading this it looks like that would not work.

[N8OBM]

Since buying a larger zoom lens (greater than 300mm) is pretty damned expensive, I'm thinking of adding a 2x teleconverter to increase the range of my 75-300mm AF lens.

Any particular recommendations?

See if you can find one amongst your friends and try it first. All Zoom Lens are compromises. A teleconverter is also a compromise. Adding a compromise to a compromise increases the odds it will not do what you need. The best advice I can give is, If you are shooting Canon, stay with canon optics. There are some good lenses out there made by other makers but, If you stay with Canon you will always get at least good if not first rate glass. Avoid using El Craptar lenses.

From a technical standpoint your problem is this, As the lens gets longer, The different colors do not focus on the same plane. The coatings on the lens are to correct for the different wavelengths of the light that passes through it so that they will focus on the same plane. Any aberration will be multiplied by the tele-converter. In short, The longer the lens you use it with, the less likely you will be happy with the results. The hard part of making a bright long lens is two fold. First you need a big piece of high quality glass with no flaws and then you need the coatings to deposit on a big surface in a consistent manner. There is a reason fast tele photo lens are expensive.

That said, Tamron used to make a 300mm 2.8f fixed length lens that was sharp enough you could get away with using a tele convertor with and still get OK brightness and sharpness. I don't know if they still do. If you don't need it often you might look at finding a photo store that rents lenses. We had one in Ann Arbor. I used to rent that Tamron every so often. Nice glass.

[KJ3N]

See if you can find one amongst your friends and try it first. All Zoom Lens are compromises. A teleconverter is also a compromise. Adding a compromise to a compromise increases the odds it will not do what you need. The best advice I can give is, If you are shooting Canon, stay with canon optics. There are some good lenses out there made by other makers but, If you stay with Canon you will always get at least good if not first rate glass. Avoid using El Craptar lenses.

You mean like these? http://www.rokinon.com/category.php?catId=2

[N8OBM]

You mean like these? http://www.rokinon.com/category.php?catId=2

For the most part yes but, Some of the long focal length fixed aperture mirror reflex lenses are surprisingly good for the money. I don't know if these are any good but some are. I would check some of the photography mags to see how these perform.

Archie N8OBM

[PA5COR]

Since my photographic experiences are from the past, i had the Canon AE1 with Sigma 70-210 lense and Sigma 2 x teleconverter then, worked decently, still have the setup but isn't used in 10 yeaars now, selling is no option no demand for it.
Have a Canon 7 Mpix point and shoot thingy now and the phone with 8 Mpix cam build in.
Last one also makes nice HD video too.