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Old Feb 8, 2006, 11:44 AM   #1
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Just wanted to know what a 28-80 and 70-300mm lese REALLY meanes! I need it explained like a 8 yr. old please. Thanks guys....

M
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Old Feb 8, 2006, 12:31 PM   #2
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The focal length is the distance from your lens to the sensor in your camera.

So a 28-80 lens, with it's zoom control, lets you control the distance between your lens and yoursensorsurface between 28mm and80mm.

Generally, the farther away the lens is from your sensor (ie. 80mm), the narrower the point of view.

To the extreme, if you wanted to focuson a bird, and just the bird, at 100 meters away, you mightuse a 600mm lens.

The lens surface would be 600mm away from your sensor, and it would literallyfocus the light such that just the bird is in focus,and everything else would be cropped away.

So a 70-300mm lens would start at 70mm away from your sensor, and zoom out to 300mm away from your sensor.

Generally the smaller (ie 28mm) the focal length, the wider the view.

The longer the focal length (ie 300mm) , the narrower the view.

The above is a very simplistic discussion which doesn't take into account crop factors, and many other technical issues, but at least it gets you pointed in the right direction.

-- Terry






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Old Feb 8, 2006, 12:34 PM   #3
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M.A.W. wrote:
Quote:
Just wanted to know what a 28-80 and 70-300mm lese REALLY meanes! I need it explained like a 8 yr. old please. Thanks guys....

M
Hi M

These are descriptions of the focal lenght of the lens. The human eye is the equivalent of 50mm, so a 28-80 would be a lens that can zoom through from half the size your eye would see the world to 1.5.

And 70 to 300 would pick up where the first left off and go all the way to 6 power magnification.

However, neither description mentions the light gathering ability of these lenses. That would be called the "aperture." Meaning how large can the lens open up to gather light.

Dave
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Old Feb 8, 2006, 4:30 PM   #4
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Ok now can you explain it like a 5 year old. I dont get it. Is there math involved or somthing that im just not getting?

I understand the part about how far the lense is from the sensor, i get that but how does it blur everything else out?

If the lense says its a 5.4-16.2 the close point is 5.4mm from the sensor and then 16mm from the sensor right? but that doesnt really tell me anything. 5.4 would be macro? say 6" from the camera? and 16.2 would be zoom? or what?

ok you say a bird that is 100 meters away that makes me think distance FAR away so you want a long lense like a telescope looking at the moon LOOONG. You sugest 600mm lense that makes sence.

but where im confused is when i see these people at football games and tennis match that use the 20 foot long lense and they are just 10-20 meters away from the player. Wouldnt that be to close?
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Old Feb 8, 2006, 5:37 PM   #5
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Thank you...thank you...thank you!!!! I am purchasing a Nikon D70s with those two lenses in the package. I am an AVID WATERFOWLER and want to get some picture of the outdoors and what I experience on a day to day basis. Any other advice you think I shoul know.....give it to me......I am a puppy when it comes to this stuff!!!!

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Old Feb 8, 2006, 8:21 PM   #6
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Okay Bower, you got half of the equation happening.

You've figured out that your lens says 5.4-16.2, that you are moving your lens surface anywhere from 5.4mm to 16.2mm away from the sensor.

Okay 16.2mm would be the zoom (long) end.

5.4mm would be the wide end.

When your sensor is only 5.4mm away from the lens, it's the wide angle end.

Think of yourself inside a barn, looking out the barn door.

The closer you get to the barn door, the more you see to the right and left (THE WIDE ANGLE).

Same thing with your sensor. The closer to sensor to the lens, the WIDERANGLE is sees.

Now back away from the barn door towards the other end of the barn.

The view out the barn door is getting NARROWER AND NARROWER as you back away from the barn door.

Same thing, when you ZOOM out, your sensor is getting farther and farther away from the lens opening, and you are seeing less and less!

Now, these people that use super huge lenses to take a picture of somebody 20 feet away?

They are doing that for STATUS. My $5,000 600mm white Canon lens is worth more money than yours. lol.

Seriously, a sports photographer will often have more than one camera around his neck, one with a short zoom, and another camera on a monopod with a long zoom.

I hope this helps. It's a lot of typing to explain this.

Terry


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Old Feb 8, 2006, 8:41 PM   #7
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Don't worry much about all the numbers: get the camera and start shooting. Look around your back yard for something that is about the size of a duck/goose/swan/... An old bucket will work just fine.Take pictures of it from various distances with both lenses and at various focal lengths (zoom). That way you can pay attention to your new camera and not to the subject.

You will figure it out real quick.
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Old Feb 9, 2006, 12:15 AM   #8
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Terry,
I certainly hope that comment about why sports people have 600mm lenses is a joke. Where I come from "lol" means "lots of luck"... maybe it means "lots of laughs" to you? Being one of those people who have a 600mm lens (and knowing people who shoot sports with it) that is down right insulting.

The reason for having a 600mm lens while shooting tennis is because you're photograping the player on the other side of the net. The same thing is true for football. That is a very long and very wide field. The market for sports photos demands full frame images of players and that requires magnification. No sports photographer can afford to buy a $7,200 (Canon) or $9,000 (Nikon) lens for status.

M.A.W.
How serious are you about watching and photographing waterfowl? Do you have binoculars? What power are they? As was said by DBB, the human eye sees at around 50mm. So a 2x Binocular would be the same as a 100mm lens. My 8.5x binocs are the same as a 425mm lens. Unfortunately lenses that go out to 400mm and beyond are quite expensive (which is why I ask how serious you are.)

Personally, I'd suggest you think along the lines of what BillDrew said. Get a reasonable zoom lens or two and take pictures. See what you like to shoot. You'll find that you won't be able to do things that you want to do (for example, shoot macro.) Once that happens, then you'll have a better understanding of your needs and you'll know more about photography and you'll be in a better position to know what to buy next.

Does that help?

I basically do only bird photography. Anything with feathers. I don't have kids, I make a good living. So I've been able to save up and buy really good gear. But depending on where you live, what birds you want to photograph, and your standards you don't have to be crazy like me and spend lots of money. Does good gear help? Yes. But it isn't required to have fun and produce good images.

Eric
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Old Feb 9, 2006, 3:04 AM   #9
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This is what im talking about! they are like 5 feet away! i dont get it, are they like shooting macro like shots?







This one takes the cake, the lense is mounted to the tripod and the camera is hooked to that. Who needs a tripod for the camera when the lense is what needs the support? jeesh, it seems silly.





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Old Feb 9, 2006, 6:04 AM   #10
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Most of those lenses aren't terribly long telephotos, they look like 70-200 zooms to me, and are mounted on 1D bodies which mean that they would not be suitable for shooting birds at any distance beyond 3-4 meters. The bird lenses are really big!

The reason they are so big is that they are terribly fast telephotos, meaning they have a very wide maximum aperture (f-stop). The f-stop is the ratio between the aperture and the focal length.

It does look kinda silly, but if you want the best quality and zoom flexibility available that's what you have to use - otherwise someone would be using different gear right?
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