Canon 2x Extender

Joe S · Sep 19, 2008

Has anyone else had a problem getting crisp clear focus with this? I am getting rather frustrated with the quality of the images through it.

an example of the soft focus

Camera: Canon EOS Digital Rebel XTi Exposure: 0.004 sec (1/250) Aperture: f/5.6 Focal Length: 400 mm ISO Speed: 1600 Exposure Bias: 0/3 EV Metering Mode: Pattern

The focal settings were AI Servo with the focal area set to full range , I may try center focal point next, or sell it and pick up the 1.4x. Any suggestions are more than welcome.

soylentgreen · Sep 19, 2008

Unfortunately, that is inherent with all teleconverters, especially the 2x. You are losing 2 stops of aperature and autofocus in most cases. Better quality is to be had with the 1.4X. What lens are you using? Hand-held, tripod? At 400mm, a solid tripod will help immensely even with IS. 1/250 is a bit slow for moving subjects like you have also so the softness can come from that. Try the 1.4x, but faster glass is the true solution.

Big Mike · Sep 19, 2008

IS that a true 400mm lens, with the 2X adapter as well?...or is it a 200mm lens with the 2X? What lens?

Brian Austin · Sep 19, 2008

soylentgreen said:
Unfortunately, that is inherent with all teleconverters, especially the 2x. You are losing 2 stops of aperature and autofocus in most cases. Better quality is to be had with the 1.4X. What lens are you using? Hand-held, tripod? At 400mm, a solid tripod will help immensely even with IS. 1/250 is a bit slow for moving subjects like you have also so the softness can come from that. Try the 1.4x, but faster glass is the true solution.

The 2xTC isn't the best example of Canon optics, imo. The 1.4x is much sharper.

That said, the shutter speed comment above, regardless of IS, is right on.

Joe S · Sep 19, 2008

the lens is a Canon 70-200mm f2.8 L IS USM

Brian Austin · Sep 19, 2008

Joe S said:
the lens is a Canon 70-200mm L IS USM

Which also means you're shooting wide open. This lens' sweet spot is typically 2-3 stops higher, ime. That doesn't help with the 2xTC.

Joe S · Sep 19, 2008

ok, I understand the shutter speed issue, I tried to correct this with the high ISO because I was loosing light quickly. The sun was already below the horizon, maybe during the best light I will have better results at a higher shutter?

And I will try to keep from shooting wide open when possible, thank you.

Any further insight is more than welcome.

oh, and I was on a monopod

Dao · Sep 19, 2008

What is the distance between your camera and your subject(s)? If it is about 50 feet, then the total DOF is about a feet (with F5.6). And sometimes, you may not be able to get the subject or all the subjects in focus.

Joe S · Sep 19, 2008

Dao said:
What is the distance between your camera and your subject(s)? If it is about 50 feet, then the total DOF is about a feet (with F5.6). And sometimes, you may not be able to get the subject or all the subjects in focus.

the shot above was most likely at least 50 feet away, I was at the end line and they were past midfield so that may well be 60-70 feet away so that raises another excellent point. Thank you Dao

DeadEye · Sep 19, 2008

I use that exact combo a lot. 70-200 and a 2x ( not mkII) I am told the MK II is much better. Anyhoo ~ if you want it sharp you GOTTA stopp down to f8 and bump up the asa if you need to freeze action .

Big Mike · Sep 19, 2008

Most lenses are better when stopped down, but this is one of the best telephoto zoom lenses around. Even at F2.8, it's usually pretty good.

You might consider loosing the TC and just shooting at 200mm...then cropping afterward. It won't help if you are making large prints, but for smaller prints and web viewing, it should be fine.

Also, are you using mode 2 on the IS? It's meant to be used when on a mono-pod so that it only corrects for motion on one plane. If in mode one, it might actually be giving you blur.

table1349 · Sep 19, 2008

Keep in mind as well, and extender, be it the 1.4X or the 2X will affect the auto focus speed as well. The are not really suited to fast action photography. The 2X is also not really suited for anything less than the 300mm and is better on the 400mm and above.