Canon 2X telextender on EF 70-200 with 20D?

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Has anyone here used a Canon 2X telextender on the EF 70-200 with a
20D?

Or for that matter the Canon telextenders on at all?


******************************************************************

"The past is foreign country: they do things differently there."

_The Go-Between_
L.P. Hartley
1895 - 1972

Archived from groups: rec.photo.digital (More info?)

> Has anyone here used a Canon 2X telextender on the EF 70-200
>with a 20D?

For unknown reasons I assumed you meant the f/4 in my previous answer
.... if you're using the f/2.8 then it will hold autofocus with the 20D
and a 2x since min aperture is still f/5.6 ... I have this lens and
have used it with a 2x occasionally, wide open it has a bit of light
fall-off in the corners with full frame cameras (film or the 1Ds), with
the 20D you probably won't notice much since it's cropped already.

Archived from groups: rec.photo.digital (More info?)

I have used the 2x on my EF 70 - 200 F4 L on a 10D and now a 20D. You can
forget autofocusing. Even when taping a pin as per an article that appeared
on a net site, the autofocus is so slow as to be useless. If you are happy
with manual focus (as I have been for certain applications) then I have not
noticed much of a degradation in performance. However, sometimes the
focusing is out and this is user error not the optics and people blame the
converter.

regards

Don from Down Under
"John A. Stovall" <johnastovall@earthlink.net> wrote in message
news:7l8v1193sc06damvifl8agmlfpqcitg0rp@4ax.com...
> On 25 Feb 2005 14:06:29 -0800, "Bill Hilton" <bhilton665@aol.com>
> wrote:
>
>>> Has anyone here used a Canon 2X telextender on the EF 70-200
>>>with a 20D?
>>
>>For unknown reasons I assumed you meant the f/4 in my previous answer
>>... if you're using the f/2.8 then it will hold autofocus with the 20D
>>and a 2x since min aperture is still f/5.6 ... I have this lens and
>>have used it with a 2x occasionally, wide open it has a bit of light
>>fall-off in the corners with full frame cameras (film or the 1Ds), with
>>the 20D you probably won't notice much since it's cropped already.
>
> I'm looking at using it on the EF 70-200 F/4.0L.
> ******************************************************************
>
> "The past is foreign country: they do things differently there."
>
> _The Go-Between_
> L.P. Hartley
> 1895 - 1972

Archived from groups: rec.photo.digital (More info?)

In message <a_OdnWY-4q6BAr3fRVn-ug@comcast.com>,
"emski" <emski@comcast.net> wrote:

>> Has anyone here used a Canon 2X telextender

> I did use on 100-400 5.6 L ..no AF, IS was working slow, all over quality
>not satisfied.So went back to the store

There's nothing wrong with the quality of the Canon 2x TC, or the Kenko
Pro 300 (or Tamron SP, which is the same). You were probably expecting
miracles beyond the laws of physics if you were not satisfied. A TC is
only useful when you can get enough light, and the prime optics are
sharp, and you have sufficient shutter speed.

For the 100-400, the f5.6 becomes f11, and you need to halve the maximum
exposure time for hand-held shots, as well, so you lose 3 stops in low
light. On top of that, the 100-400 is not at its sharpest at f5.6, and
another stop or two down is needed for maximum sharpness. I only use
the 100-400 with my 2x under very bright conditions.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

Archived from groups: rec.photo.digital (More info?)

DM wrote:
> I have used both with the f2.8 70-200 (see my reply to your earlier
post).
> The 1.4x is a QUALITY piece of kit and the images it captures still
retain
> sharpness of the L lens. The 2x is not so hot. I does enable you to
'get
> that bit closer' but is simply not sharp enough. You get better
quality by
> cropping a 1.4x image to give the same 'view' than shooting it with
the 2x.

It's not because that the 2x is not sharp, but the 70-200 zoom is not
sharp enough to be used with a 2x. 200/2.8 prime + 2x is sharp, much
sharper than cropping.

Archived from groups: rec.photo.digital (More info?)

Can you back that up with a sequence of shots of the same subject first with
a 1.4x Extender & then the 2x? (Because I can)

The lack of sharpness has nothing to do with the f/2.8 70-200 as you state.
The difference is between the 2 teleconvertors.

And if you think it's my imagination, this is a similar point of view from
www.the-digital-picture.com/

"There is noticeable degradation in image quality when using the 2x -
noticeably more than with the Canon Extender EF 1.4x II. Sharpness and
contrast suffer noticeably. The best results will be made using a very sharp
lens such as the Canon EF 300mm f/2.8 L IS USM Lens."

Regards

DM

<bj286@scn.org> wrote in message
news:1110235290.661776.224040@o13g2000cwo.googlegroups.com...
> DM wrote:
>> I have used both with the f2.8 70-200 (see my reply to your earlier
> post).
>> The 1.4x is a QUALITY piece of kit and the images it captures still
> retain
>> sharpness of the L lens. The 2x is not so hot. I does enable you to
> 'get
>> that bit closer' but is simply not sharp enough. You get better
> quality by
>> cropping a 1.4x image to give the same 'view' than shooting it with
> the 2x.
>
> It's not because that the 2x is not sharp, but the 70-200 zoom is not
> sharp enough to be used with a 2x. 200/2.8 prime + 2x is sharp, much
> sharper than cropping.
>

Archived from groups: rec.photo.digital (More info?)

roadwarrior wrote:
> There is indeed "some" halation when using a 2.0xII teleconverter on
ANY
> Canon compatible lens with the possible exception of some primes.
With
> the zooms and all the elements involved it seems indeed there is a
price
> to be paid in contrast/sharpness and as I mentioned a phenomena
called
> "halation" which appears as a ghosting of the image. The 100-400L for

> example @400 is superior to the 70-200 2.8L IS and 2.0xII
teleconverter
> combo. It is "usable" but NOT optimal.....I'll leave it at that......

And 200/2.8 prime + 2x is sharper than the 100-400, which according to
the above is sharper than 70-200/2.8 + 2x.