How much zoom is a 14-42mm & a 18-55mm lens equate to?

Question

What do the numbers mean? How do you know how much zoom?

does the "__ mm" part mean more zoom? like is "55mm" is more zoom than 42mm?

My digital non slr camera has 18x optical zoom(4.7-84.2mm) is one of these more zoom than that? Cause I don't want to get a camera with less zoom, I wanna get a better camera.

So Dr. sam, basically i cant get a lens that will zoom as far as my current 18x camera, but if i do get a digital SLR, when I crop it will be clearer than my current camera? My camera has manul settings as well, so I dont really see a big reason to spend like $800+ on a camera body & lens.

I do want a clearer picture, but my 7.1 camera is pretty clear, maybe i'll just get a non slr 10mp or so camera with the same amount of zoom or more.

Answer 1

See http://www.flickr.com/photos/samfeinstein/476181737/
and http://www.flickr.com/photos/samfeinstein/1245831147/ for a visual representation of the numbers in the answers above me.

Please refer to the numbers in the parentheses citing "equivalent" focal lengths. You need to know about this to properly compare.

In your 18x camera, there is a 1/2.5" sensor. The "crop factor" or "lens factor" in this camera is 6.03X or just about 6X. This means that the effective range on your 4.7-84.2 mm lens is about 28-507 mm.

If you are buying a digital SLR, you need to know the "crop factor" of that camera. This is easy to find in charts on-line, but it is also pretty easy to figure out. Most consumer SLR's have a 1.5X factor, but Canon's have a 1.6X factor.

In the Nikon, Pentax, etc., cameras, this means that you will need to have an actual 18-338 mm range. This is a lot. In a Canon Rebel XTi, for instance, you will need an actual 17.5-317 mm range.

Since you mention the 14-42 lens, I will assume that you have also looked at an Olympus, which has a crop factor of 2X. In an Olympus or other 2X camera, you would need a 14-253.5 mm range. By the way, Barry, on an Olympus digital SLR, the 14-42 is not so much a wide angle lens, as it is an effective 28-84 mm lens.

It would be very unusual to accomplish this range in one lens for an SLR. It is possible to nearly cover it with 2 lenses, though, as my first example above shows. This was done partly with an 18-200 mm lens and partly with a 70-300 lens. This gives an effective coverage of 27-450 mm. This is still not quite as "good" as your current camera, but since the sensor in the digital SLR's I am talking about are nearly TEN TIMES larger than yours is now, the image quality is so far superior that you would have no problem cropping the images just a little bit to give an equivalent magnification in the final image.

Mason, "zoom power" must be a function of two numbers. It makes no sense to say that one single focal length is such-and-such zoom, because it must be compared to another focal length. If you are going to say that the "X" power of a single focal length is related to some dimension of the film or the sensor, the accepted standard is that 1X is equal to the diagonal of the frame and not the length. Even this is open to question. If a 35 mm frame is 42 mm across the diagonal, this would suggest that a 42 mm lens is the standard "normal" lens. We all know that 50 mm is considered a normal lens. This suggests that the proper dimension to measure is the theoretical diagonal that would exist if the frame was square, such as a 35 mm negative being 35x35 mm. The diagonal of our theoretic square negative would be 49.5, which pretty much meets the standard of 50 mm. You can test this with a 6x6 cm frame and come out with 85 mm as the normal, which indeed it is. Well.... 80 mm for some brands.

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See: http://www.flickr.com/photos/samfeinstein/476181751/in/set-72157601339945649/ This will show you why you want an SLR sensor instead of a point and shoot sensor. AND, this P&S has the larger sensor that is nearly twice as big as yours.

As far as the lens... You can get an SLR lens that is 2 or 3 TIMES more "powerful" than your current camera, but it will cost big bucks. I am not aware of a single SLR zoom that covers as much range as your current camera. That's really only made possible by having a small sensor with a huge crop factor, by the way. It's a paradox. You get more zoom because you have a smaller sensor, but the smaller sensor gives you lower image quality.

Answer 2

OK, here's the thing.

Focal length gives you a different view depending on what sort of camera you're using, because the size of the recording medium (film or digital sensor) is different.

A 50mm lens behaves differently depending on whether you're using a "crop sensor" DSLR, "full frame" DSLR, medium format film, or large format film.

Most of the digital SLR cameras you are probably looking at are "crop sensor." This means that the digital sensor is smaller than film, but significantly larger than a compact point-and-shoot. On these cameras, a 14-42 or 18-55 both equate to a "standard" zoom. Both give you a wide angle view, and both give you a "normal" view. The 55 gets you into short telephoto/portrait territory.

Something to consider: I'm a professional photographer, and I only own ONE zoom lens (Canon 16-35 f/2.8L II), and that's a pretty recent acquisition. All of my other lenses are fixed-focal-length (also called "prime" lenses). "Zoomability" is NOT the measure of a good lens. Image quality is the most important attribute of a good lens, and this is an attribute that inevitably sacrificed in the pursuit of a lens that can "do it all." If you only plan on getting one lens, I'd discourage you from buying an SLR camera: you've just negated the single most important advantage an SLR has over a point-and-shoot.

Answer 3

Depends on the camera.
If it's a 35mm film camera, then 14 - 42 will be 0.39x - 1.17x. 18 - 55 will be 0.5x - 1.52x.
If it's a Nikon digital SLR, then 14 - 42 will be 0.58x - 1.75x. 18 - 55 will be 0.75x - 2.29x.
If it's a Canon digital SLR, then 14 - 42 will be 0.62x - 1.87x. 18 - 55 will be 0.8x - 2.43x.

mm is the focal length, not the length of the lens. Basically, to work out how much zoom (which is more basic photography that Antoni doesn't obviously know) is in a lens, you divide the focal length by the largest dimention of the film or sensor. For example, a 300mm lens used on a nikon dslr would be 300 divided by 24 (length of sensor is 24mm) = 12.5 times zoom.

Answer 4

Ok, 14-42mm is basically a wide angle lens. It's good for sports events and landscape photos. Normally, a 35 mm SLR camera comes with a 50mm lens. mm stands for milimeter. 18-55mm lens would go from wide angle to normal view. A 90-105mm lens would be good for portraiture. Anything higher than 105 mm would really bring the subject close up and would be good for distance shooting. I hope that I'm being helpful. Good luck.

Answer 5

the numbers refer to focal lenghts of zoom lenses, you know how much zoom by looking through the viewfinder

the rest of your question i dont get,

goto a camera store, get the salesperson to demonstrate the lenses to you

EDIT: focal lenght of a lens is not the lenght of the lens its the lenght from the frount of the lens to the film plane (in film cams), or to the sensor on a full frame digital, on a cropped digtal sensor its the same times by a crop factor

mm means millimeters, photography is meteric.........25mm = 1 inch

18x optical is far more than 55mm, however what camera are you getting? they all have different "crop" factors unless they are full frame............so if you get a nikon its a factor of 1.5x

1.5x 55mm = 82.5mm

if you are happy with your existing camera keep it, if you get a 55mm lens you will get no where near 18x opitical


EDIT2: masons emotive attack is sillyness,

a correction regarding canon DSLRS they have 3 crop factors

1. full frame - no crop
2. 1.3 crops
3. 1.6 crops

a