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kyudave said:

thks...

18 - 55 is he zoom, then how do I calculate this zoom equivalent to how many X zoom in prosumer / consumer camera?

thks

18 - 55 is he zoom, then how do I calculate this zoom equivalent to how many X zoom in prosumer / consumer camera?

thks

Dun be confused with "35mm camera" or "35mm equivalent focal length". The former means that the camera uses a film of size 35mm.(those widely used films.) The latter is more technical. Won't go into that yet.

So for a normal 35mm camera, with starting focal length at 35mm(widely available type), a 3x zoom camera will have focal length from 35mm to 105mm (note: 105/35 = 3).

Also note that:

For a normal 35mm camera, with starting focal length at 28mm(may be a bit more expensive), a 3x zoom camera will have focal length from 28mm to 84mm (note: 84/28 = 3).

Thus the more professional way of telling pple how much zoom your camera/lens have is to quote the focal length millimetres. Pls note that the larger the number, the "further" you can see.

For your qn: 18-55mm

In the case of the Canon 300D, the sensor size is not as large as the normal film(35mm film) everyone uses. it's slightly smaller. Thus if you look at it from another way, the image is actually cropped. That's where the "cropping factor" comes in. The 300D has a cropping factor of 1.6. The cropping factor differs from camera to camera. depending on the sensor/film size.

Thus when pple say "35mm equivalent focal length", he has already taken the cropping factor into account. So the 35mm equivalent focal length of the EF-S 18-55mm is from 28.8mm to 88mm.( 18x1.6=28.8, 55x1.6=88)

AReality said:

Dun be confused with "35mm camera" or "35mm equivalent focal length". The former means that the camera uses a film of size 35mm.(those widely used films.) The latter is more technical. Won't go into that yet.

So for a normal 35mm camera, with starting focal length at 35mm(widely available type), a 3x zoom camera will have focal length from 35mm to 105mm (note: 105/35 = 3).

Also note that:

For a normal 35mm camera, with starting focal length at 28mm(may be a bit more expensive), a 3x zoom camera will have focal length from 28mm to 84mm (note: 84/28 = 3).

Thus the more professional way of telling pple how much zoom your camera/lens have is to quote the focal length millimetres. Pls note that the larger the number, the "further" you can see.

For your qn: 18-55mm

In the case of the Canon 300D, the sensor size is not as large as the normal film(35mm film) everyone uses. it's slightly smaller. Thus if you look at it from another way, the image is actually cropped. That's where the "cropping factor" comes in. The 300D has a cropping factor of 1.6. The cropping factor differs from camera to camera. depending on the sensor/film size.

Thus when pple say "35mm equivalent focal length", he has already taken the cropping factor into account. So the 35mm equivalent focal length of the EF-S 18-55mm is from 28.8mm to 88mm.( 18x1.6=28.8, 55x1.6=88)

How many times zoom equal largest focal length divided by shortest focal length.

So 18-55mm equals 3x zoom

However, 28-85mm also equals 3x zoom.

75-300m equals 4x zoom.

So when buying a digital camera, in order to appreciate the zoom, you have to know the minimum focal length of your camera.

kyudave said:

still have 1 question.

let say I have EF 28-200mm f/3.5-5.6 USM

do I need to buy other lense let say EF 28-135mm f/3.5-5.6 IS USM

which is actually the range is inside EF 28-200mm f/3.5-5.6 USM .

thks

let say I have EF 28-200mm f/3.5-5.6 USM

do I need to buy other lense let say EF 28-135mm f/3.5-5.6 IS USM

which is actually the range is inside EF 28-200mm f/3.5-5.6 USM .

thks

Although the 28-200 is convenient and cover a wide range, some people may find that the optical quality of the lens is compromised. The sharpness of the lense is compromised in order to fit such wide focal length in and the extreme ends of the lenses is not really that useful as distortions usually set in.

Also on the 28-135, there's the IS system, which allows shooting at lower shutter speed as the lens eliminates handshake during picture taking.

Whether you need to buy more lens that overlaps one another depends on how you value sharpness, convenience and money.

kyudave said:

let say I have EF 28-200mm f/3.5-5.6 USM

do I need to buy other lense let say EF 28-135mm f/3.5-5.6 IS USM

which is actually the range is inside EF 28-200mm f/3.5-5.6 USM .

thks

Primes tend to be sharper, lighter and cheaper than zooms.

Prismatic said:

How many times zoom equal largest focal length divided by shortest focal length.

So 18-55mm equals 3x zoom

However, 28-85mm also equals 3x zoom.

75-300m equals 4x zoom.

So when buying a digital camera, in order to appreciate the zoom, you have to know the minimum focal length of your camera.

So comparing 18-55 and 28-85, which one is better?

Camm said:

For 18-55mm, is 18 the minimum focal length? Y is min focal length important?

So comparing 18-55 and 28-85, which one is better?

So comparing 18-55 and 28-85, which one is better?

For comparision, on the 35mm film standard, a normal person's angle of view is about 92 degs horizontally. The angle of view of one eye is about 45 degs or so (rough guide) which is just about the angle of view of a standard 50mm lens.

A 28mm lens typical gives 65 deg.

A 20mm lens gives 84 deg.

While a extremely wide angle lens like 14mm will give 104 deg.

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