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Old Mar 14, 2007, 6:29 PM   #1
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suposing 2 lenses with 200mm focal leght... the 70-200mm and a 28-200mm will the 200mm be equal in both? will i see the same in both or in the 70-200 i will see far because it starts in the 70mm
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Old Mar 14, 2007, 6:35 PM   #2
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you will get the same results at 200 no matter what. 200 is 200.

now i have seen some 28-200 have problems at the 200 end getting a "crisp" images. i prefer two lenses unless you do alot of hiking/ walking and want more versatility.
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Old Mar 16, 2007, 10:28 AM   #3
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Yep,

200 is 200. On any lens it should appear the same. However, as ecap suggested, a 28-200 may be softer at maximum focal length because maxlight transmission is made more difficult by the added range. Really, it is a choice between performance and versatility.

I prefer 18-55 and 70-300 lenses, because these lenses can cover allot of ground when used together. Plus, I haven't seen a 70-210 lens that has an f-stop that's any better than a plain-jane 70-300 (F4-5.6).



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Old Mar 16, 2007, 10:51 AM   #4
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An-D wrote:
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Plus, I haven't seen a 70-210 lens that has an f-stop that's any better than a plain-jane 70-300 (F4-5.6).
There are a number of zoom lenses in the 70-200mm range that offer f/2.8 throughout their focal range. Virtually every major camera manufacturer offers at least one zoom like this, because these types of lenses are necessary for low light sports in order to get faster AF and faster shutter speeds for less motion blur. Ditto for the 3rd party lens manufacturers. For example, the Sigma 70-200mm f/2.8 EX series lenses are very popular with shooters that need faster shutter speeds in low light.

These f/2.8 lenses are at least twice as bright as a consumer grade 70-300mm lens (f/2.8 is exactly twice as bright as f/4), with even more difference in brightness as you zoom in.

So, a 70-200mm f/2.8 would you to get shutter speeds at least twice as fast for any given lighting and ISO speed as a lens that only has f/4 available. You'd get shutter speeds 4 times as fast as a lens that only has f/5.6 available (f/2.8 is 4 times as bright as f/5.6).

A brighter lens can also help a camera's Autofocus to "see" better in low light, with faster AF and less hunting (because it's brighter and the AF sensors get more light).

Even if you used a 1.5x TC to extend the range of a 70-200mm f/2.8 out to 300mm, you'd still get shutter speeds twice as fast at 300mm compared to a zoom with a largest available aperture of f/5.6 on it's long end (since you'd lose one stop of light with a 1.5x TC which would give you f/4 at 300mm on a 70-200mm f/2.8, versus the f/5.6 you'd have with a consumer grade Zoom.

In addition to shutter speed and Autofocus issues, some photographers may appreciate the shallow Depth of Field they get shooting at a wider f/2.8 aperture.

There is a reason that these lenses are larger, heavier and more expensive. They're brighter (and usually of higher quality). ;-)

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Old Mar 16, 2007, 11:02 AM   #5
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D3v1l wrote:
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suposing 2 lenses with 200mm focal leght... the 70-200mm and a 28-200mm will the 200mm be equal in both? will i see the same in both or in the 70-200 i will see far because it starts in the 70mm
Yes, and no. ;-)

The angle of view you'll have at 200mm should be roughly identical (sometimes the manufacturers do round the focal length a bit one way or the other, but they should be very close).

However, some lens designs change the effective focal length with focus distance. So, if you're focused on a closer subject, you may have a wider angle of view (less apparent magnfication) with some of the internal focus lens designs that are becoming more popular, versus some other lens designs.

Hardly a week goes by that I don't seem someone complaining that "my new [insert lens here] is really only a 150mm lens versus a 200mm lens, or something to that effect, when they compare it with another lens they have with the same focal length, if they're focusing on a closer subject with two different lens designs.

So, there can be differences between the angle of view you'll have with two different lenses set to 200mm, depending on your focus distance. The ratings assume that you're focused to infinity (in which case the angle of view between two lenses with the same focal length on the same camera should be comparable). But, with closer subjects, your angle of view may appear to be signficantly different between two lenses set to the same focal length.

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