Canon 100-400L or 70-200L with extender

[wsbII]

Hello,
Just looking for some insight from anyone who has used the Canon extenders. I'm looking at either the 100-400L or the 70-200L f4 plus a 2.0 extender. I'd like the 2.8 (70-200), but not right now. The concern I have is over the speed of the 100-400. With a 4.5 max ap, I am just worried it will never be used unless in bright light. The constant 4 of the 70-200 is slightly better and with the 2.0 extender I can cover the same range of FL. Anyone used the extenders that can tell me if there are any downsides to using them. Does image quality suffer? Does the addition of the ring make things more cumbersome? Etc?
Thanks!
Bill

[Elmo]

The f:4 will turn into an f:8 with the 2x extender. The 100-400 will be faster and will likely have better IQ than f:4 used with a 2x.

[inkista]

100-400L.

Not only will the f/4 turn into an f/8 with a 2x tc, but on anything but a 1-series Canon dSLR, it will stop autofocusing. This is why the 2x is only compatible with the f/2.8L telephotos.

The math goes like this:

f-number = focal length/aperture_diameter.

So, with an f/4 200mm lens: 4 = 200mm/50mm.

That aperture diameter, however, doesn't change when you add a TC, even if your focal length does. So

200mm x 2 / 50mm = 400mm / 50mm = 8. So you've got an f/8 lens.

[RichardTaylor]

I have a friend who was shooting motor sport with with a 70-200 F2.8 IS L + extender. He was happy with it until he tried a Canon 100-400.
Now days he always shoots, when trackside, with a 100-400 as it is a lot more convenient use.

As far as using it in low light goes you can always use a tripod for static subjects or for some action use very high ISO and possibly a mono pod.

Here are a couple of examples , of mine, from a motor racing event last month, Using the 100-400..
I was using a 40D and mono pod. Noise reduction was used when PPing the RAW files.

(1) About 1/2 hour minutes before dawn.

Camera Canon EOS 40D
Exposure 0.01 sec (1/100)
Aperture f/4.5
Focal Length 100 mm
ISO Speed 3200
Exposure Bias 0 EV

(2) just before dawn (they were racing). The track is slightly damp from the early morning dew.

Camera Canon EOS 40D
Exposure 0.003 sec (1/320)
Aperture f/5.6
Focal Length 235 mm
ISO Speed 3200
Exposure Bias 0 EV

[wsbII]

Thank you everyone. I didn't think about the math and the shrinking of the ap. With that in mind I think it is an easy decision. Toss in the autofocus issue and it's a no brainer
Thanks!!!
Bill

Btw -nice shos Richard. I like the cars coming around the corner best.

[Thunder_o_b]

Originally Posted by wsbII

Thank you everyone. I didn't think about the math and the shrinking of the ap. With that in mind I think it is an easy decision. Toss in the autofocus issue and it's a no brainer
Thanks!!!
Bill

Btw -nice shos Richard. I like the cars coming around the corner best.

Before you spend the money on the Canon, look into the Sigma 120-400mm It is said to be equal to or better by several reviews. I have the sig, and find it to be well worth the money. I have posted several shots from it here in the forums. It is less expensive, and the warranty is far better than the Canon.

[OsmosisStudios]

Originally Posted by inkista

The math goes like this:

f-number = focal length/aperture_diameter.

So, with an f/4 200mm lens: 4 = 200mm/50mm.

That aperture diameter, however, doesn't change when you add a TC, even if your focal length does. So

200mm x 2 / 50mm = 400mm / 50mm = 8. So you've got an f/8 lens.

Someone has finally explained this! Thank you.

[inkista]

The 120-400 is probably better bang for the buck (especially since they've now fixed the issues the early batches had), It's about 90% of the 100-400 for half the price. but I still think the 100-400L is a better lens, particularly at the 400mm end, which is where you're likely to be using it the most.

[oldwolf]

What about the 70-300 L?

[Thunder_o_b]

Originally Posted by oldwolf

What about the 70-300 L?

Big money. I have thought about this lens from time to time, but all the reviews that I have read have said that the IQ is a real compromise.

EDIT: I'm such a goof, it was late last night and I misread oldwolfs post. I was for some reason seeing 28-300mm instead of the 70-300mm.

Sorry.