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Archive 2008 · Real World Focal Length Difference onLong End?

  
 
thekid1
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p.1 #1 · Real World Focal Length Difference onLong End?


My son is now into crew/rowing. I am looking at lenses for a longer reach. I have the 70-200 and was looking at the 1.4x or 100-400. On a 1.3 crop it is 364 vs 520. It sounded like a lot but I went to a couple of sights that compare focal length and the difference did seem that big. The differences in focal length at the short end made a big difference but seem to have less of an impact at the long end. I have a Mark II and a Rebel. With the 1.6 crop that could take my 70-200 out to 448.

I was just wondering if at the long end, a difference in focal length of 350 vs 450 is a big difference in actual practice.



Nov 19, 2008 at 02:19 AM
Ian.Dobinson
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p.1 #2 · Real World Focal Length Difference onLong End?


AS you go longer then every mm makes less of a difference as its a smaller % of the focal length (10mm at the Ultra wide is a world of difference but would hardlet be noticed at 400mm).
But I can say the difference between my 70-300 and the 100-400 I had for a while was noticable which may be because the 70-300 isn't 300 and the 100-400 is I dont know.
If you can then get the 100-400 as its a very good lens and still offers some versitility.

It seems in this game that wide is not wide enough and long is not long enough.



Nov 19, 2008 at 03:26 AM
Andrew J
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p.1 #3 · Real World Focal Length Difference onLong End?


The object size difference to you would be approximately 7x vs 9x magnification. For many that would be nothing to sneeze at.


Nov 19, 2008 at 05:30 AM
srene
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p.1 #4 · Real World Focal Length Difference onLong End?


highly recommend the canon 100-400. If you dont want to spend over 1K, the sigma 50-500*

*it is a 6.3 at 500 I believe. Also does not have i.s.
If anything you can always rent the lens before buying at lensrentals.com excellent company.

hope this helps
Rene



Nov 19, 2008 at 05:41 AM
thekid1
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p.1 #5 · Real World Focal Length Difference onLong End?


Thanks for the responses.
I was just wondering if the difference is a full head shot vs getting half a body or even more. Renting one first is something I might consider since I have a friend who has the 1.4x extender I can borrow.



Nov 19, 2008 at 10:06 AM
Pixel Perfect
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p.1 #6 · Real World Focal Length Difference onLong End?


thekid1 wrote:
My son is now into crew/rowing. I am looking at lenses for a longer reach. I have the 70-200 and was looking at the 1.4x or 100-400. On a 1.3 crop it is 364 vs 520. It sounded like a lot but I went to a couple of sights that compare focal length and the difference did seem that big. The differences in focal length at the short end made a big difference but seem to have less of an impact at the long end. I have a Mark II and a Rebel. With the 1.6 crop that could take
...Show more

On the same camera - so we don't have to worry about pixel density differences, the 100-400 @ 400 will be a lot better choice than a 70-200 + 1.4. and will put 2x as many pixels on the subject and the subject will look ~ 40% bigger.

Comparing the Rebel (8MP) and the 1D II is a bit different as the pixel densities need to be taken into account. The 8.2MP Rebel has 60% higher pixel density than the 1D II and is thus effectively a sqrt(1.60) = 1.28x TC in itself compared to the 1D II. Thus if you use a 70-200 + 1.4x =112-280 on the Rebel it would be like a 112-280 x 1.28 = 143-358 on the 1D II. So you'd need the 100-400 on the 1D II to do any better in reach (or a 70-200 + 2x) than the rebel.

Using the 100-400 on the rebel would be like using a 128 - 512 on the 1D II.

Why don't you see if the 70-200 + 1.4 on the rebel is long enough and has good enough AF. Ideally if you have the money the 100-400 on the 1D II will be a better combo in reach and AF.

Pixel density is more useful than FOV when comparing different cameras to assess reach.



Nov 19, 2008 at 07:39 PM
Matt Philbin
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p.1 #7 · Real World Focal Length Difference onLong End?


It took me a little while to find this, but maybe it will help...

http://www.usa.canon.com/app/html/EFLenses101/focal_length.html



Nov 19, 2008 at 08:59 PM
Tony B
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p.1 #8 · Real World Focal Length Difference onLong End?


Alternatively
http://www.tamron.com/lenses/learning_center/tools/focal-length-comparison.php



Nov 20, 2008 at 03:39 PM
dfresh
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p.1 #9 · Real World Focal Length Difference onLong End?


Tony B wrote:
Alternatively
http://www.tamron.com/lenses/learning_center/tools/focal-length-comparison.php


I like that one, I recognized that bridge from Florence, Italy immediately since I shot it once too



Nov 20, 2008 at 03:47 PM
thekid1
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p.1 #10 · Real World Focal Length Difference onLong End?


Thanks Whayne for the suggestion. I think I will start with the 1.4x and the Rebel and see how that works. I have never shot a rowing event but I am assuming it will be easier than shooting basketball and the Rebel performance will work.

The Tamron site for focal length comparison is what really caused me to ask the question in the first place. On the picture with the clock, the difference between 300 and 400 did not seem huge and the difference between 400 and 500 was not that much.




Nov 20, 2008 at 11:37 PM





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