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Old Mar 26, 2005, 6:40 PM   #1
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Hello, all...

I'm an S1IS user that's upgrading to the 20D asap. I'm also looking at teleconverters for a zoom telephoto. I've heard all sorts of things...like any teleconverter is not worth the money, that Canon's are great and other brands show considerable distortion, that Tamrons are great and Sigmas are not, and vice versa, that 1.4 are far better than 2.0...:?

Any advice would be greatly appreciated. Thanks.




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Old Mar 26, 2005, 8:42 PM   #2
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The best lens is the one that gets used the most often!

Your first consideration is what you like to photograph. If you spend most of your time in the 35mm to 80mm focal range, then definitely look for a zoom with the range where you spend most of your time shooting.

However, if you're into shooting birds and wildlilfe, then you might be better served in the 200mm to400mm focal length.

You only need a really fast lens (F2.8 or faster) if you are shooting in low light situations like indoors, evening shots or whatever. A "faster" lens is usually indicative of a higher priced, higher quality lens.

Since your using a Canon 20D, which is a serious amateur, semi-pro camera, you shouldn't be out shopping for the cheapest glass you can find. Forget the cheap Pheonix lens.

You can consider, however, Tamron and Sigma lenses, as they offer excellent value. Maybe your photographic habits are best served by two medium priced lenses with different focal lengths, at $300-400 each, rather than one $1,000 lens.

As for teleconverters, I'm not a fan. You lose so many stops of light it's ridiculous.

To summarize, you really need to analyze the shooting you do and your budget. Read over the reviews, look at photographic samples, ask experienced people who have similar interests and the same model camera. They will quickly steer you in the right direction.

As for me, I shoot low light indoor sports (Canon 50mm F1.4 len), and outdoor sports and general portrait/family (Tamron 28-75 XR DI). Maybe one day I will get a longer telephoto if myshooting patterns warrant it.

- Terry




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Old Mar 27, 2005, 2:52 PM   #3
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A couple things to think about regarding teleconverters:
  • Canon teleconverters will only work with Canon L lenses (see their site for which ones)[/*]
  • Sigma or Tamron will work with their own lenses plus Canons[/*]
  • A 1.4x costs you 1 stop and a 2.0 costs 2 stops.[/*]
  • When using a Canon or Sigma teleconverter (which passes back aperture info to the camera) autofocus will not work on lenses whose adjusted aperture is smaller than 5.6 - so if you put a Canon 2x teleconverter on a4.0 lense you will lose auto focus. You can get around this by taping the pins so the info is not communicated. I believe the Tamron does not communicate so you still keep autofocus.[/*]
  • Assuming lenses of equal quality, a lense that is naturally 300mm will be sharper than a lense plus teleconverter combination. [/*]
  • I've seen a lot of images of photos with a 1.4x teleconverter and they still look great. i use one on my Sigma 70-200mm 2.8 lense and I still think it's sharp. Plus it gives me a lot more flexibility than if I had bought the Sigma 100-300 outright. But if you think you will always have the teleconverter on then I'd opt for a naturally 'longer' lense.[/*]
  • Although I do not have a 2.0 teleconverter I've heard enough folks say the sharpness really deteriorates. But there may be no other choice if you need a lense with 800mm or greater distance - unless you heave $6000 sitting aroundl
[/*]
Hope this is helpful
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Old Mar 27, 2005, 10:32 PM   #4
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Here's an example of a Sigma 120-300 f/2.8 shot wide open with its Sigma 2x teleconverter (ie 600mm @ f/5.6):

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Old Mar 28, 2005, 2:07 PM   #5
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MANY thanks for the insights!
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Old Mar 28, 2005, 4:39 PM   #6
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A subtle point that you might not know.
You can try to tape the pins on the teleconverter so the camera doesn't know its there and therefor will try to autofocus. But it won't work very well. In fact, it will be fairly bad. Yes, it will work... but if you are taking any kind of action shot the action will be gone before it achieves focus.

Also, the quality of the lens directly effects how much the teleconverter will degrade the quality of the picture. The teleconverter will magnify the picture and all the optical flaws in the lens.

lower quality lens = even lower quality shot with a teleconverter.
Great lens = almost great shot.

I know that I really don't see a difference when I put the 1.4TC on my 600mm lens. But that is because it is an amazing lens to start with.

Don't ignore the loss of light and aperture. Put a 1.4xTC on a f4 lens and it is an f5.6 lens. This will increase the DOF, loose 1/2 the light, and slow down the AF. Put a 2xTC on a f4 lens and it will be an f8 lens, loose 3/4th the light, and won't autofocus at all unless you trick it (and even then it will hunt and be really slow.)

Unless your subject is static, this will probably cost you the shot.

Eric
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Old Mar 28, 2005, 11:01 PM   #7
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NHL,



That's a pretty serious duck head shot!



- Terry
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