EF extenders

[igercelman]

I would like select an extender. But I am not sure which one has better image performance, 1.4x or 2x.

Are there any exprience about Canon extenders with Canon EF 70-200mm f/4 L?

[Phil Hall]

igercelman wrote:
I would like select an extender. But I am not sure which one has better image performance, 1.4x or 2x.

Are there any exprience about Canon extenders with Canon EF 70-200mm f/4 L?

Both extenenders work well with the 70-200 IS f2.8. The autofocus may not work well with the f4 and the 2x. There should not be a problem with the 1.4x. The 1.4x is a little sharper than the 2x.

[Phil Hall]

igercelman wrote:
I would like select an extender. But I am not sure which one has better image performance, 1.4x or 2x.

Are there any exprience about Canon extenders with Canon EF 70-200mm f/4 L?

Both extenenders work well with the 70-200 IS f2.8. The autofocus may not work well with the f4 and the 2x. There should not be a problem with the 1.4x. The 1.4x is a little sharper than the 2x.

[who10]

Phil Hall wrote:

Both extenenders work well with the 70-200 IS f2.8. The autofocus may not work well with the f4 and the 2x. There should not be a problem with the 1.4x. The 1.4x is a little sharper than the 2x.



In your experience do you find the the 100-400IS appreciably sharper than the 70-200 f2.8 with a 2x extender? Do you have any example shots posted using a 2x on the 70-200 f2.8?

[CyberDyneSystems]

The 100-400IS won't autofocus with either extender. Adding the extenders increase4s the f/stop,.. which in turn disables autofocus if the f/stop is too high. I do not recall what aperture the 10D requires for autofocus,. but on most EOS camreras it is f/5.6

You can "cheat" to get it the 100-400 to work with the 1.4X,.(f/7.8 ) but I doubt it will ever work with the 2X.

Althought the 100-400mm IS looks pretty sharp with the 1.4X extender,. both Canon extenders look better with the 70-200mm f/2.8 than they do with any other zoom. They are the best match you can get. (for zooms,. primes are even better)

The 1.4X looks slightly sharper,. but the 2X is damn fine too!

On the 70-200mm f/4 I would go for the 1.4X. You are guaranteed autofocus and and the images will be sharp. You may be able to convince the f/4 lens to focus using the 2X (you will be at f/8 ) by using the tape trick,. but it is "iffy"

[Longwatcher]

My take,
I have both extenders, the 70-200/2.8L IS and the 100-400L IS.

First, I think Canon software disabled the 100-400 from working with extenders, since people can tape over the contacts and get it to autofocus. Also I have put the 2x and 1.4x on the 70-200/2.8L at the same time and it autofocused (hunted a bit, but it did it automatically). I wish they had not done this since I can always switch to manual if it won't lock up (had to do it frequently indoors with my D60 no matter which lens).

at 400mm, the 100-400 is sharper/better in my opinion then the 70-200/2.8 IS with 2x extender, however, that ever elusive bokeh thing is better on the 70-200/2.8 IS.

When you are in the 1.4x (280mm) range though, the 70-200/2.8 IS is the better choice then the 100-400.

For trivia, putting both extenders on the 70-200/2.8 IS is not as good as just using the 100-400 with one of the extenders. But using both extenders provides just a touch more detail then cropping to the same scale.

Almost forgot to answer the primary question. The 1.4x extender is far far higher quality then the 2x, which seems pretty bad, but it will give you more detail, but it really cuts into the exposure levels. Canon needs to make a 2x "L" extender.
Just my experience and opinion,