Teleconverters

[Spargo]

How do these work exactly? Just stick it on the end of your lens and it magnifies it more? Is this one a good one: http://www.bhphotovideo.com/bnh/controller/home?O=NavBar&A=getItemDetail&Q=&sku=294242&is=REG &si=spec#goto_itemInfo

Will it fit any Canon lens?

[robertwgross]

No. The B&H item is not what you want.

There is a Canon 1.4x teleconverter for EOS lenses, except it fits only L lenses. Sigma and Tamron and all those companies sell teleconverters for EOS lenses that will fit most any EOS lens (EF type). I don't know about EF-S lenses, though, since they are different.

A teleconverter fits between the camera body and the actual telephoto lens, so it has lens and lens mount type of ends on it.

If you have a 100mm lens, then it makes it work like a 140mm lens.

They work best with a very sharp lens. If you put one on a fuzzy lens, then it makes it twice as fuzzy.

You don't get something for nothing.

---Bob Gross---

[Spargo]

Thanks. Could you point out a reasonable converter to go with the 70-200 f/4L and the 75-300 f/4-5.6 IS (both Canon)?

[Cal Maier]

The 70-200/4 L will work well with the Canon 1.4XT.C. but the 75-300IS is not designed to work with the Canon Tele-Converters and it will not mount on the T.C.

The Canon Tele-Converters are designed to work with most L series Tele -lenses and tele - zooms, but they will not mount on the Regular USM type lenses.

Cal
CPS 432

[Cadwell]

There is a Canon 1.4x teleconverter for EOS lenses, except it fits only L lenses. Sigma and Tamron and all those companies sell teleconverters for EOS lenses that will fit most any EOS lens (EF type). I don't know about EF-S lenses, though, since they are different.

---Bob Gross---

The Sigma EX teleconvertors have a similar physical design to the Canon ones and therefore they have the same lens restrictions. They will only fit lenses with a recessed rear element. I don't know about the Tamron ones.

The Sigma TCs will not work with the Canon 75-300mm. The 1.4x Sigma EX works very well with the 70-200mm f/4L.

[karusel]

Searching for comparisons of third party 1.4x TCs versus Canon (which I haven't found) I've found a comparison of Sigma vs. Tamron 1.4 (http://194.100.88.243/petteri/pont/pdf/Reviews/de_TC_vs_TC/a_Tamron_vs_Sigma_1.4x.pdf).

According to this test Tamron is a bit better and it can be used also on non-L lens, since it is built in a differend fashion.

If someone knows of a comparison between Canon and any other brand TC, please share the link.

[Spargo]

Would this be the teleconverter for NON-L lenses, such as the 75-300 f/4-5.6 IS? http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=185148&is=REG

[Savagelogic]

I'm no expert at teleconvertors, but the description says that it is for lenses f/2.8 or faster which your 75-300 f/4-5.6 IS is not. So I'd assume it wouldn't work for you, at least not what it is meant for.

[Spargo]

It says "For Telephoto Lenses 90mm & Longer with Maximum Apertures of f/2.8 & Larger"...Correct me if I'm wrong, but isn't it longer than 90mm (300mm) and has a maximum aperture of larger than f/2.8 (f/5.6)? Or is it backwards in numbers like golf where lower is larger? :P

[robertwgross]

If you check it, f/5.6 is a smaller aperture than f/2.8. Actually, two stops smaller.

---Bob Gross---

[Cadwell]

f/2.8 is a larger aperture than f/4 which in turn is larger than f/5.6. F-stops are ratios. That's why the "/" character is in there. The actual size of the aperture is given by the focal length (f) divided by the 2.8 or 4 or 5.6....

One thing you should be aware of with teleconvertors is that you lose 1 stop with the 1.4x and 2 stops with the 2x. You don't say which camera you have but I'm guessing it's a 300D/dRebel or a 10D. Those cameras cannot autofocus with a lens with an aperture smaller than f/5.6... so I do not believe that you will have autofocus with any of the TCs on the 75-300mm. A 1.4x TC will retain autofocus on the 70-200mm f/4 but a 2x TC wont.