Anyone know how this lens and 1.4x or 2.x TC interact with each other? I'm planning on getting this lens in the next month or two, and I'm thinking about selling my cheap Quantary 2x TC and getting one of the Canon TC's. Other than the loss of speed by adding a TC, how does it affect the IS, focusing and image quality? The TC would be uses with this lens, along with my Sigma 170-500mm.

I have read the reviews on this lens and only a couple of them mention using it with a TC.

>> how this lens and 1.4x or 2.x TC interact with each other?
Other than the loss of speed?
Even a Canon converter will affect quality. The loss of speed will affect the AF which may be slower, depending on light levels, and less accurate.

http://www.cps.canon-europe.com/kb/detail.jsp?faqId=1110

I've tried the 2x TC and mine might be dodgy, but I'm not very impressed - even on that L series lens. Compared to a 400mm lens, even another 400mm zoom. But I found it adequate and better than missing the shot, while being cheaper than a 400mm lens.

A friend has the 1.4x and I've tried borrowing that for a few shots and it seems far better quality with the same lens/body. So I'd say it's worth it for the 1.4 teleconverter.

It seems not to affect IS in my experience, I ws able to shoot handheld at 200mm with 2x on my 20D which adds another 1.6 crop factor.

BTW: Canon TCs do not seem to work with all L series lenses.
Canon website says "Extenders are only compatible with selected EF lenses, including the EF 70-200mm f/2.8L USM, EF 70-200mm f/2.8L IS USM, EF 70-200mm f/4L, EF 100-400mm f/4.5-5.6L USM, EF 400mm f/4 DO IS USM and fixed length L-series lenses of 135mm or higher."

As you can see from the Canon web site http://www.canon.co.uk/for_home/product_finder/cameras/ef_lenses/extenders/extender_ef_14x_ii/index.asp the front end of the converter protrudes into the lens body, so any lens that has rear elements flush with the lens body, or not recessed far enough, just won't work with the converters.

So check your Sigma lens to make sure it is compatible in design with the Canon converters.

Michael, are you still considering this combo? I have both the zoom and the 2xII and I might be able to dig up some test shots.

Hey Loupey,

Yes, I am considering this set up. Hopefully I will be able to make the purchase within the nex month or so. I would love to see some shots if you have them handy.

Thanks!

O.K. Attached is the 70-200 f/2.8L IS at the 200mm end for both shots from the same shooting location (one is with the 2x = 400mm). I shot these two on two different but similar days and at two different apertures - the 200mm shot at f/5.6 (2 stops below wide open) - the 400mm at effective f-stop of f/8 (1 stop below wide open).

Although I cannot recommend either components at this point as I am still field testing them, I can say that neither the AF nor the IS appears to be adversely affected with the inclusion of the TC. As for image degradation, it is difficult for me to see much at all at the long end of this zoom. In photoshop, to compare the 400mm image at 100% verses the 200mm image at 200% to get the same subject size, the 200mm image actually looks worse due to the pixilation. However, at the 70mm end of this zoom, you can see significant degradation. But I doubt that you would be using the converter to get 140mm anyways.

As Paul stated eariler, the Canon converter does extend beyond the lens mount so be careful if you plan to use it with your Sigma. The front element of the 2xII protrudes about 7mm beyond the front face of the lens mount. Also, your AF may not work with the Sigma with this TC.

Similar scenario, both at 200mm. Shooting distance about 120'.

Hope it helps. Yeah, my neighbors think I'm pretty goofy - they just don't ask anymore.

In both your tests, the top image enlarged section appears sharper to me.

Paul, at least with the 10D's resolution, its a close call between the 200mm and 400mm shots when comparing the same subject size. That's why I kept the 2xII. I'm wondering if the 5D's improved resolution/noise characteristics would change that. Of course when comparing results 100% to 100%, the 2x results are aways slightly degraded (although less than I anticipated).

I'll have a try this weekend and see if I can get decent images with the TC.
Of course even with IS on the 70-200, hand holding a 400mm is tricky !
But I have one or two shots from F1 testing with that combination that worked.
But for me it's barely acceptable quality - better than not getting the shot - just.

There still seems to be quite a few people looking so I'll post one more example.

The top photo was shot with the 70-200 at 200mm and the 2xII, handheld (IS on).

The bottom photo is a 100% section of the same shot. Good detail on the veins of the leaf.

Michael - you also asked about extension tubes with this lens. That's precisely what I am currently testing. Leaving the 70-200 mounted on the tripod, and simply detaching the body to swap in the 2x or tubes. Yes, not on par to using dedicated primes, but a great (light) way to stalk.

Although I wouldn't recommend riding an MTB at the same time:D

Looks like either your 70-200 or 2xTC (or both) betters mine.
I don't have results this good.

Thanks for the examples Loupey! I can't wait till I can finally add that lens to my kit!

Looks like either your 70-200 or 2xTC (or both) betters mine.
I don't have results this good.

Could be. Any converter will push the resolution/contrast limits of the main lens - a 2x more so than the 1.4x. Any defect is going to jump out with the teleconverter. I've heard other people (even the salesman who sold me the 2x) say the results aren't very good. Fortunately, the local store where I have always bought my gear has a liberal 14 days for a full refund and 30 days for full exchange ;)

Test, test, test. Only a few lenses have made it past my 15/31 day trials.

Here's another question for you. I went to a camera store to get my hands on one of these lenses and take a few test shots with it. The salesman told me to make sure that the IS switch on the lens AND the bower to the camera are both turned off for at least 30 seconds before taking the lens off the camera. He said you want to make sure there is no communication between the two when you take the lens off. Have you heard anything about this?

He also said that leaving the IS switch on, while the camera is off will drain the batteries. Is that true? Just wondering.

The manual for the zoom states, "The image stabilizer operates for as long as the light meter timer is displaying an exposure value, even when your finger is off the shutter button. Do not remove the lens while the stabilizer is in operation..."

No where can I find a reference about 30 seconds.

As for the power drain while the camera is off, nothing states this and I can't image that it is true as the body powers the IS. If the body is off, I don't think that there can be a power drain through the IS.

Thanks again Loupey. the part about the IS operating while the camera is displaying an exposuer value makes sense to me. I thougth 30 seconds sounded kind of odd. I didn't think te lens would drain the battery if the camera was off either. I will have to download the manual for this lens and read up on it before I order it.

I've got the 70-200 and I can reassure you on that.
When the camera is off, even if it's switched on ans it's timed out (mine is set to 1 minute) then the lens isn't taking power.
When it's switched on, the lens isn't taking significant power until you tell it to.
When you start focussing with a half-press on the shutter button, then it takes power to run the focussing motor, and if the IS is switched on, then it runs the IS system.
That lasts for about 6 seconds after you take your finger off the button, then you'll hear the IS actuators switch off with a little "clunk" as the camera switches off unused electronics.
The camera is pretty smart about conserving power that it doesn't need as long as you aren't messing with it :)

30 seconds wait to change lenses? I can't find that anywhere in the manuals.