1x4 extender c/w 75-300mm?

[fox1]

Does auto focus on this combination function
correctly.? Anyone have results? thanx..

[Daytripper]

Fox1,

Your question is impossible to answer without knowing what brand of extender you are referring to, what the maximum aperture of your lens is, and what body you are using, but seeing as how I've got nothing better to do I'll give it a go anyway... ;-)

Assuming that you are referring to the Canon extender, and a Canon lens, the short answer to your question is "No" - It won't even fit.

A 1.4x extender will cost you 1 stop, and assuming that you have a body with autofocus that is compatible with the extender you will need a lens with a maximum aperture of at least f/4 at maximum focal length. Yes there is a way to fool the camera into attempting to autofocus with smaller apertures, but if your starting at f/5.6 there is no point even trying.

The best place to start looking for info like this is Canon's website at http://www.usa.canon.com/eflenses/lineup/index.html - Look up the 1.4x and 2x extenders for a list of compatible lenses and cases where you can expect autofocus to function.

Best of luck,
Pete

(Edited for 1.4x instead of 2x)

[DonCoon]

fox1 wrote:
Does auto focus on this combination function
correctly.? Anyone have results? thanx..

Well, it depends how I translate your question.

I assume you're asking if a 1.4x teleconverter works with a Canon 75-300mm f/4-5.6 lens. If not, just ignore what I say :)

My short answer is "yes" in the right conditions. And I understand the Canon TCs have problems.

But I have a Tamron 1.4x TC and use it on my 75-300. To get AF to work properly, I set the aperture manually to f8 at 300mm and f5.6 at the short end. I hear all sorts of reports that it won't work but my 10D doesn't seem to have a problem.

That said, you will notice image degradation with a TC in varying degrees.

Just my limited experience.

[scottbergerphoto]

The Canon 1.4X II Extender is not compatible with that lens. Follow this link and click on compaibility chart to see which lenses are compatible.
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=220456&is=USA
Scott

[fox1]

scottbergerphoto wrote:
The Canon 1.4X II Extender is not compatible with that lens. Follow this link and click on compaibility chart to see which lenses are compatible.
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=220456&is=USA
Scott

Thanks Scott and everyone else for the input..

Looks like I'll have to buy that 100-400 L after all. :D

[Belmondo]

fox1 wrote:
Looks like I'll have to buy that 100-400 L after all. :D

Admit it. You planned it this way, right?

[sjprg]

Try a Sigma 50-500mm before you do. I think you will be very pleasently supprised.

[scottbergerphoto]

fox1 wrote:
scottbergerphoto wrote:
The Canon 1.4X II Extender is not compatible with that lens. Follow this link and click on compaibility chart to see which lenses are compatible.
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=220456&is=USA
Scott

Thanks Scott and everyone else for the input..

Looks like I'll have to buy that 100-400 L after all. :D

The 100-400 IS L is a wonderful lens. Here's an example of what it can do:

http://www.pbase.com/image/20905204.jpg
Get that credit card warmed up!
Scott

[defordphoto]

DonCoon wrote:
And I understand the Canon TCs have problems.


Really. What would those problems be?

[DonCoon]

RFMSports wrote:
DonCoon wrote:
And I understand the Canon TCs have problems.


Really. What would those problems be?

What I guess I meant is that I understand they electronically block you from using them on lenses not meeting their specs. Whereas I can use my Tamron 1.4x by setting the aperture to f8 and the lens will AF.

It's been awhile so I'll apologize if my facts are askew.

[jameseba]

I have tried out the Canon 100-400L and Sigma 50-500. I like Sigma over Canon because it is confortable and cheaper. The sharpness is not much different. I am planning to get Sigma this Friday, I hope.

[brettwmd]

I use the Tamron 1.4x with my 75-300mm IS. Autofocus is slower than normal, but it works!

Brett W.

[fox1]

belmondo wrote:
fox1 wrote:
Looks like I'll have to buy that 100-400 L after all. :D

Admit it. You planned it this way, right?

Scots always looking for cheaper alternatives. :D

[fox1]

sjprg wrote:
Try a Sigma 50-500mm before you do. I think you will be very pleasently supprised.

Or ruptured!

Handy for touting around the discos,
especially with the lens hood attached! :D :D :D