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Old Dec 12, 2008, 8:21 AM   #1
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What would give the best results

Using the same lens to achieve the same distance

A fullframe body with a 200mm f/2.8 & 1.4x teleconverter
A APS-C body with a 200mmf/2.8
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Old Dec 12, 2008, 8:42 AM   #2
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Every time you add extramagnification to a lens, you degrade its sharpness (depending on quality and matching of the various glass). In the scenario you set, at least with my cameras, the technically and theoretically"sharper" shot will be with the aps-c body but you will be hard-pressed to notice it with "L" glass. At least IMHO.
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Old Dec 12, 2008, 9:27 AM   #3
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Like hgernhardtjr said any time you add a piece of glass you take a hit:
http://www.photozone.de/canon-eos/19...review?start=1

-> This is for the 70-200 f/2.8 L non-IS (which is sharper than the IS version) data for adding a 1.4xTC. Not only the MTF (i.e. sharpness) suffers, but you're also degrading the CA and distortion characteristics of the lens according to the plotted data... which is something you don't want to do on a FF - Stick with APS-C if you prefer the tele side!
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Old Dec 12, 2008, 9:33 AM   #4
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... The vignetting too (is worse @280mm)
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Old Dec 12, 2008, 10:03 AM   #5
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NHL wrote:
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Like hgernhardtjr said any time you add a piece of glass you take a hit:
http://www.photozone.de/canon-eos/19...review?start=1

-> This is for the 70-200 f/2.8 L non-IS (which is sharper than the IS version) data for adding a 1.4xTC. Not only the MTF (i.e. sharpness) suffers not, but you're also degrading the CA and distortion characteristics of a lens according to the plotted data, which is something you don't want to do on a FF - Stick with APS-C if you prefer the tele side!
The thing is i've got a Canon 5D and a Canon 200mm f/2.8 , for almost the same price i could chose between buying a 1.4x teleconverter or a Canon EOS 1000D Rebel XS .

See what i mean :roll:
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Old Dec 12, 2008, 10:09 AM   #6
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guillermovilas wrote:
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for almost the same price i could chose between buying a 1.4x teleconverter or a Canon EOS 1000D Rebel XS .

See what i mean :roll:
It's actually much worst for the 200L f/2.8 by adding a 1.4x TC than the zoom:
http://www.photozone.de/canon-eos/17...review?start=1

I would buy an extra APS-C camera instead!
-> If anything you got a spare camera + a higher 1.6x than 1.4x (and no 1 f-stop loss)
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Old Dec 12, 2008, 10:47 AM   #7
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something else to keep in mind here. The aps-c sensor does not, in fact, "give you more reach". What it does is put more pixels on your image. THis is great for small objects like birds. Many birders prefer the aps-c sensor for perched birds for this reason. However, focus accuracy comes into play too. And lenses only accurately focus so far. I have both aps-c and aps-h cameras - I've shot over 50,000 frames with each type primarily for sports work. From my experience I don't get ANY better shots with an aps-c camera with my human subject further away. As an example the working limit for quality sports photos of a human subject with a 200mm lens in my experience is about 25 yards. That was true with an apsc as well as the aps-h. If anything I might get a LITTLE farthur with the aps-h because it has a better focus systm. Now, when shooting small birds the extra MP for the same field of view is a great bonus. So, shooting a bird with two such cameras and my 100-400 at say 15 yards, in good lighting I get better results with aps-c as there are more pixels on my subject and I'm well wthin the focus limits of the lens in both cases. Just something else to consider.
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Old Dec 12, 2008, 11:22 AM   #8
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JohnG wrote:
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something else to keep in mind here. The aps-c sensor does not, in fact, "give you more reach". What it does is put more pixels on your image. THis is great for small objects like birds. Many birders prefer the aps-c sensor for perched birds for this reason. However, focus accuracy comes into play too. And lenses only accurately focus so far. I have both aps-c and aps-h cameras - I've shot over 50,000 frames with each type primarily for sports work. From my experience I don't get ANY better shots with an aps-c camera with my human subject further away. As an example the working limit for quality sports photos of a human subject with a 200mm lens in my experience is about 25 yards. That was true with an apsc as well as the aps-h. If anything I might get a LITTLE farthur with the aps-h because it has a better focus systm. Now, when shooting small birds the extra MP for the same field of view is a great bonus. So, shooting a bird with two such cameras and my 100-400 at say 15 yards, in good lighting I get better results with aps-c as there are more pixels on my subject and I'm well wthin the focus limits of the lens in both cases. Just something else to consider.
Well i'm not looking at shooting birds but motorbike riders around a race track :roll:
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Old Dec 12, 2008, 11:30 AM   #9
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guillermovilas wrote:
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Well i'm not looking at shooting birds but motorbike riders around a race track :roll:
Well the XS focus performance will be a step back from the 5d. Not sure how the xsi would stack up against the 5d. You'll also get much better bokeh with the 5d for the panning shots. I woul really not recommend using the xs for sports photography. The 200mm 2.8 is a very sharp lens. I know several sports photographers on another site that use it often and love it. I personally would go for the TC route - better than using the xs body for sports work. Still not ideal but for your stated purposes I think it's the better option of the two.

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Old Dec 12, 2008, 1:54 PM   #10
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I don't know it's hard to say... since there's many factors involved here

It might really be a toss up:
1. With a 1.4x the AF may slow down a bit on the 5D plus
2. You're now at f/4 which disable the 5D high-precision AF sensor so might not be as accurate as an Xs on f/2.8
3. The MTF (i.e. sharpness) is really much worse with a 1.4x on the 200 f/2.8L than on the zoom - just check it out below:

200mm f/2.8 f/4 f/5.6 f/8
Center 1785 1901 2067 2034
Border 1651 1858 1977 2006

w/ Canon 1.4x f/4 f/5.6 f/8
Center 1565 1736 1728
Border 1481 1612 1584


-> The 200 f/2.8 might edges out the 70-200 f/2.8 L, but fare much worse with a 1.4X on as indicated by the previous link
:
70-200 @ 280mm f/4 f/5.6 f/8
Center1728 1910 1921
Border 1652 1740 1770
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