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Old May 10, 2007, 10:38 PM   #1
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"I am new to dslr's, although i have been in photography w/ advanced point and shoots "i never experienced a manual mode yet". Im expecting to learn alot, and i know i iwll have to. I enjoy photography as a hobby, although i also developed it into a business. I take pictures of famous speakers on a podium, using 8X magnification on my point and shoot camera. I looked at zoom lenses that reach that amount but they are VERY expensive. So ijust started thikning of just buying a 8X prime lens. The reason im using 8X and not mm is b/c i dont understand how to use the mm measurments, and dont even bother trying to explain it, b/c i cant get it, yet. SO, which camera would be the highest quality, that i could buy w/ 2 average lenses for my hobby, and a 8X prime lens for uder 800$, if its possible"

When i say 8X i refer to point and shoot terminology. I learned from others that im trying to say 400mm . I am shooting a target thats about 25-30 feet away, w/ a shoulders and above shot of the person. on my point and shooot i need to go to 8X optical zoom to achieve the perfect frame. And yes i mean a PRIME as in no zoom, so fixed in the "8X" (400mm (i guess)) area. I dont know if these come under 900$ for the full package. and u said ur reccomnedation was 11X zoom. would that be in term of point and shoot terminology( thats all im familiar with) cus thats alot, and to buy a 18-180 (10X) zoom lens is like 800$, sao i dont see how 300$ of zoom lesnes is 11X
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Old May 10, 2007, 11:31 PM   #2
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Arfi wrote:
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I am shooting a target thats about 25-30 feet away, w/ a shoulders and above shot of the person.
A subject about 2 feet high from a distance of 25 feet is a field of view of about 4 to 5 degrees. If you shoot landscape, that would be about a 250mm lens on a full frame dSLR, about 200mm on a APS-H dSLR, and about 150mm on a APS-C dSLR. If you shoot portrait, that would be about a 400mm lens on a full frame dSLR, about 300mm on a APS-H dSLR, and about 250mm on a APS-C dSLR.

So, the focal length of the lens you're looking for depends on the dSLR you get. If you go with a Canon EOS Digital Rebel XTi, Nikon D100, Pentax, or Sony, you won't need as long a lens as you would if you went with a Canon EOS 5D, for instance.
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Old May 11, 2007, 12:40 AM   #3
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im on a canon rebel xt and from the targets shoulder and up shot, is about 25-40 feet awayand 2 feet up

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Old May 11, 2007, 6:28 AM   #4
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"x" designations only refer to zoom lenses, and are calculated by the longest focal length divided by the shortest. It is a useless marketing term, that is rarely used in the DSLR world. Using this definition, a prime lens is technically a 1x, regardless of its focal length. Because different cameras use different focal lengths, comparing cameras based on "x" is not a good way to do it. For example, a 18-55, 70-210 and a 100-300 are all 3x zooms, but all are different lenses and give you different results.

I do understand where you're coming from. Focal lengths are easy to understand. The higher the number, the longer the reach (or more technically the narrower the view), the lower the number, the wider the view. Lenses don't really magnify the image. What really changes is the field of view. In film cameras, 50mm is considered a normal lens, ie providing the same field of view as the human eye. Since DSLR's have smaller sensors, the same focal lengths provide a smaller field of view, otherwise known as the crop factor, which is anywhere from 1.3 to 2 depending on the camera. THe XT is about 1.5, meaning a normal lens is about 35mm. There are inexpensive zoom lenses that go out to 300mm, yielding a field of view equivelant to 450mm. I would avoid the cheap mirror prime lenses. They are very slow and not suitable for indoor use and typically aren't very sharp.



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Old May 11, 2007, 8:45 AM   #5
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Arfi wrote:
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im on a canon rebel xt and from the targets shoulder and up shot, is about 25-40 feet awayand 2 feet up
A 2 foot high subject at a distance of from 25 to 40 feet away is anangle of view of 3 to 5 degrees vertically.

The Canon Lens Chart shows the angle of view of their current lenses in columns 4 & 5 (for full frame dSLRs and 35mm film cameras.) The 4th column shows the horizontal angle of view, so youwould need a 3 to 5 degree angle of viewin this column if you shot in portrait (turned the camera sideways.) The 5th column shows the vertical angle of view, so youwould need a 3 to 5 degree angle of viewin this column if you shot in landscape.

Find theangle of view in the 4th or 5th column, find the focal length of the lens in the first column with that angle of view, and find that focal length in the3rd column. When you find it, go back to the first column and you'll find the focal length of the lens you need on your Rebel XT to get the angle of view you want.

For instance, I scan down the 5th column for an angle of view of from 3 to 5 degrees, and find 4°35'. In the first column, I find that is the angle of view is for the Canon EF 300mm f/2.8L IS USM, which has a focal length of 300mm. I scan the third column for "300" and find 320, which is for the EF 200mm f/2.8L II USM. So the Canon EF 200mm f/2.8L II USM will give you about the angle of view you need for what you'd be shooting IN LANDSCAPE.

BTW, for the type of shooting you'll be doing, the images will be quite forgiving of the types of imperfections one might find in a inexpensive zoom, and given what I think might be the kind of environment you'll be in (chairs and tables in the way, etc.), you might not be able to stand exactly where you want, so a zoom might help you frame your shotsbetter. The Canon EF 70-300mm f/4-5.6 USM IS is quite a respectable lens that should suit you well. It has Image Stabilization, and goes for $550 at Adorama. And if that's too steep, the Sigma AF 70-300mm f/4-5.6 APO macro is also not to be sneezed at, and Adorama has it for $200. Think about it.
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Old May 11, 2007, 9:37 AM   #6
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I still dont understand this angle chart system. I am shooting in a room full of people, but i pu my camera ontop of a table in the middle of the room, directly in front of the target. Therefore the view goes over everyone's head. Therefore i can stick w/o zoom. If a prime lens is cheaper i woud take that, but if a zoom lens would be better, ill take that. I have to get a full package, for under 900$, so price-wise, i dont know if its possable to get lenses for the hobby, and then this lens that we're talking about now (it seems like i should stop reffering to it as the 8X lens) for the business for under 900$. I could go for the nikon d40, or the XT. Whichever fits the price budget. Which one works, and what lens should i get?
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Old May 11, 2007, 1:01 PM   #7
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So, do you have a Canon RebelXT and you're just shopping for a lens, or do you need both a camera and a lens?You say "im on a canon rebel xt ...", but then you say "I could go for the nikon d40, or the XT."

If you remember your high school Trigonometry, you'll know that a2 foot high subject at 25 feet makes an anglethat hasa tangent of 2/25, which is 4.6 degrees, while a 2 foot high subject at 40 feet makes an anglethat hasa tangent of 2/40, which is 2.9 degrees. So you'll need a lens that has a vertical angle of view of 4.6 to 2.9 degrees, in order to capture an image of the speaker without chopping off the top of his or her head.

On either the XT or the D40, a 150mm lens will give you about a 4.6 degree angle of view, while a 250mm lens will give you about a 2.9 degree angle of view.

That is, if you shoot landscape! Do you shoot landscape?

If you shoot portrait, then for the XT or D40, you'll need a 250mm lens for about a 4.6 degree angle of view, and a 400mm lens for about a 2.9 degree angle of view.

Does that help?
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Old May 11, 2007, 1:17 PM   #8
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i was assuming i would get the xt. But i heard about pentax and d40. So i dont have a camera yet, and im flexible. I do portraits and landscapes
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Old May 11, 2007, 1:27 PM   #9
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Arfi wrote:
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I do portraits and landscapes
All the more reason to consider a telephoto zoom. Something that goes from 100mm to 300mm. The kit lens won't do at all for what you're talking about, so just get the body, and buy at least a100-300 zoom. You could go down to 70mm, or up to 400mm, depending on what's available in your price range, but you need to cover at least 100-300.
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Old May 11, 2007, 1:43 PM   #10
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Arfi wrote:
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i was assuming i would get the xt. But i heard about pentax and d40. So i dont have a camera yet, and im flexible.
If you haven't picked out a camera yet (and you're REALLY flexible), do your shopping for a good lens first, then buy the camera that it'll fit.

Photodo and Photozone have very good reviews on lenses, and Adorama and B & H are good on-line retailers. You might even find a very good lens used at KEH.
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