Calling All Lens Guru's !!

I am going to purchase either the 1.4x II or the 2x II (Canon of course)
for use on my EF 70-200L f/2.8 .
I've read all the "sticky's", searched all over the net, and can't seem to find any "reviews" of anyone using this lens-TC's combo?
There are numerous good recommendations for the 1.4x, and a few that
say the 2x is a little soft on the long end.
But all have been with other lenses.
I have not been able to find any examples of this combo anywhere ??
Any one with "real world" experience using this combo of lens and Canon 1.4x II or 2x II that is willing to "sway" my decision??
Photo examples would be greatly appreciated !!
I like the idea of the 2x as most of what I'll be using this combo for is
birding, and wildlife. (deer, bobcat, and coyote mostly at about 25-300 yards)

Is my math correct?
Effective focal length of EF70-200L f2.8 on 20D (1.6 crop factor)

w/ TC 1.4x II
70mm x 1.4 = 98mm x 1.6c f = 156.8mm
200mm x 1.4 = 280mm x 1.6cf = 448mm
effective f/stop 4~45

w/TC 2x II
70mm x 2 = 140mm x 1.6cf = 224mm
200mm x 2 = 400mm x 1.6cf = 640mm
effective f/stop 5.6~64

Thanks in advance!!
Dennis

your maths are correct ONE POINT to ber in mind the focus speed will slow down aprox 40% with the 1.4 tc and it will take the edge of sharpness .dont know the figer for the x2 tc but would think it the same
Rob.

I would go for the 1.4,this question comes up quite a lot on this forum.I was torn between the 70-200 +2x or a 100-400 but opted for the 100-400 then I got the 70-200f2.8L is and a 1.4 tcon.

Have a look at this.http://www.luminous-landscape.com/reviews/​lenses/400v400.shtml

I bought a Tamron 1.4X to use with my 70-200 f/2.8L, and I'm pretty happy with it: http://onstagephotogra​phy.com/images/hugelio​ns3.jpg

Steve

thanks Rob, and malla !!
Steve,, I knew your shot, without looking ( although I did check it out again! )
I pm'd you weeks ago, when you first posted lions. Asking permission to copy-print this outsanding image ?? Will do so through your site.
Dennis

I have both converters. I use the 2x more than the 1.4 with my 70-200 2.8L The image quality does suffer a bit (slightly more with the 2x than the 1.4x) but if you need the reach and don't want to carry another long lens (or in my case don't have one) they are a good solution. I normally carry 3 lenses (16-200mm) & both converters. On rare occation I'll even stack the converters.

Just one thing to remember, the TC actually bings the subject closer by magnifying the imge giving the lens an increased focal length... The crop factor will crop that image to give you an angle of view of a lens of 1.6 times the focal length, it will not bring the image closer like the TC will... So if you use a 2X TC on the 70-200 you will only have a 140-400 lens with the centre of the image cropped to the angle of view of a 224-640 lens not an actual 224-640 lens...

I have borrowed a 2x converter; and rented a 1.4 converter form a local store for Baseball spring training last year. I was way more impressed with the 1.4 extended pictures on my 70-200 than the 2X pictures.

If I can find a few; I will post them for you to compare. In my opinion; i'd go with the 1.4; not the 2x.

let us know which one you settle on.

This was taken with my 70-200mm f/2.8L, with a Canon 2x and Tamron 1.4X stacked. All I had to do was brighten it a tad.

Byte size: ZERO | Content warning: NOT AN IMAGE

http://www.photo.net/e​quipment/canon/tc1/