Optical zoom on SLRs?

Question

I usually deal with point and shoot cameras but lately have been interested in buying a SLR for better image quality. This might be a dumb question but usually when we look at the camera features for P & S they usually mention something about the optical zoom ( 3x , 6x , etc.) but there is no specification on the SLR cameras. (i was looking at the Canon EOS Rebel XT), my question is how far can we usually zoom in with SLR cameras, because i'm interested in taking close up pictures of objects from far away distance.

Answer 1

Since with a SLR or DSLR camera, the photographer is free to buy interchangeable lenses and those lenses are by nature optical, there is no reason to state an optical zoom ratio.  

SLR's and DSLR's are designed for photographers, by definition, already know what each focal length means to their photography, so something like 11x is not necessary to put in front of say the Nikon 18-200 mm VR lens because the photographer already knows they are dealing with a medium wide angle to medium telephoto lens without being told.  And if they need a different lens, like a 12-24 mm super wide angle it is not necessary to tell them it is a 2x lens .. it is immaterial.  It is only when the camera has a lens that cannot be exchanged with another that this optical zoom notation becomes important.

For this reason, it is usually important that someone buying a SLR or DSLR be willing to take some kind of photography class to learn how to use all the features on such a camera, but not something they would have experienced using a P&S camera.  Classes can save a lot of frustration and resolve many of the misunderstandings caused by the folks who market P&S cameras ... pixel count comes to mind ... they have successfully made the pixel a gold standard ... it is more like a tin standard, since there are three more important factors in camera design that will help the buyer determine which camera will produce the highest resolution images.

First is the lens quality

Second it the analog to digital conversion electronics

Third is the size of the sensor

Finally at number four, the pixel count.

Answer 2

SLRs or DSLRs do not have optical zoom ratings, because it changes with each lens.

For a better idea of how close you can zoom in with different lenses, check out this webtool.  Grab the arrow on the sliding scale at the bottom and move it to different focal lengths to see the effect.  For reference, your Canon Rebel XT usually comes with an 18-55mm lens.  

http://www.tamron.com/lenses/learning_ce...

Answer 3

This camera has 3x Optical Zoom and is reasonably priced. Or you can go directly to Amazon and get great discounts and free 1 day shipping. Good luck.

Answer 4

For reference the zoom of the lens is simply the big number divided by the little number. so for an 18-55 lens it is 55 / 18 which is simply 3X zoom. Why the apparently low numbers? Because with SLR cameras you have a choice. If the current lens doesn't do it for you, then you change it! By making lenses with a smaller zoom, it's actually possible to make them better quality, because there is not so much compromise to work at a wide range of focal lengths. Having said that, you can buy 18-200mm or 28-300mm lenses, so that is quite a large 11.1X zoom.

Moving into SLR photography you need to forget about this magic zoom factor and concentrate on focal lengths.

A focal length of 50mm is regarded as "Normal" and all other references are drawn from here. This is something supposedly similar to what the human eye sees. Normal focal lengths are used for portraits, although up to 85mm is still considered a portrait lens.

Any number lower than 50mm is considered a wide angle lens, and any number over 50mm is considered telephoto. SLR lenses can have fixed focal lengths, or they may zoom. An 18-55mm lens is wide angle to normal zoom lens. A 70-200mm lens is a zoom telephoto lens. Notice how a lens can be a zoom lens but not necessarily a telephoto lens, this is a popular misconception.

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