70-200 2.8 IS II with 2x Entender

[DaVanti]

Hi Folks

Looking for some advice hopefully from someone with first hand experience.
Currently use my 100-400 mostly for motorsport,, have loved the lens since I first bought it, I find it reasonably sharp and easy to use. However most of the time am also carrying with me a 24-105 and even include the 100 macro just in case of low light situations. Thinking about carrying one lens only in most cases and have been interested in the 70-200 for a while especially after seeing results and reviews regarding its sharpness,, it looks like a brilliant lens.

What I'm considering is combining the 70-200 2.8 IS II with a 2x III Entender. This setup would cover the range that I mostly use, rarely use wide angle or even get close 50mm.
Just wondering how much the extender would interfere with picture quality?
Am hoping others use this set up and advise or at least pass on their experiences.

[pjc]

I didn't have the 100-400 so my decision to buy the 70-200 II w 2xIII was relatively easy.

I used this site to help me decide: http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=113&Camera=453&Sample=0&FLI=0&API=2&LensComp=687&CameraComp=453&SampleComp=0&FLIComp=7&APIComp=2

[DaVanti]

Thanks Peter,, I knew the extenders would degrade things but didn't realise by how much.

[ameerat42]

Now Whooo up there, guys.
What are we actually talking about? That is, what are we looking at and what are we concluding?

You first asked a "how much" question, so you would have to come up with something measurable and assessible.

Firstly, teleconverters magnify the output of the primary lens, and may add some effect of their own or that may
be negligible.

How has the simulator on that site been set up and calibrated? In addition, the images remain the same size, and then the "fuzz factor" has been superimposed. What would the fuzz factor be if you could see the original output of the primary lens?

I'm just pointing out that such a simulator has to be interpreted properly, not just accepted. When using my own lens/2x converter, I have still been quite happy (an assessment) with what I could see (a measure).

[unistudent1962]

Adding a 2x Converter to a 70-200 f2.8 gives you a 140-400 f5.6.
This is replacing a 24-105 f4 and a 100-400 f4.5-5.6, I'd see that as a very expensive step sideways, if not backwards.
If you want to use the shorter focal length you still need to take the lens off and remove the tele-converter.

[jev]

Just wondering how much the extender would interfere with picture quality?
I own a 70-200/2.8 (original, without IS), a 2xTC and the 100-400. Whilst the 70-200/2.8 is a tad sharper than the 100-400, the latter is sharper when comparing it to the combination 70-200 + TC. Note that the TC is slightly more prone to CA too.

Having said that, it is the other features that made me decide to get the 100-400: it's pull-zoom (requires some getting used to, but IMHO it works faster than rotate-to-zoom) and the (partial) weather-sealing. I never trusted the TC in even slightly moist weather conditions and I still don't like how it looks / feels (mechanically).

[Tannin]

Give some thought to using a 70-200 with a 1.4 teleconverter. Sure, it limits you to 280mm at f/4, but 280mm is a pretty fair length and the 1.4 converter has much less image-degrading effect than a 2x converter does.