Zoom vs lens size: Ok, I see these point & Shoots that say they have a 20x zoom, what does that mean in context compared to a lens? I have a 200mm lens, does a 20X reach a farther...

Brenda IS Scottish Loc: GOLDEN Colorado

Ok, I see these point & Shoots that say they have a 20x zoom, what does that mean in context compared to a lens? I have a 200mm lens, does a 20X reach a farther distance? I just don't get it. Please help me understand.

BigBear Loc: Northern CT

Brendalou1969 wrote:

Ok, I see these point & Shoots that say they have a 20x zoom, what does that mean in context compared to a lens? I have a 200mm lens, does a 20X reach a farther distance? I just don't get it. Please help me understand.

They are different classifications. 20x means it can take an image 20 x actual size. The DSL lenses are measured in mm's, which is the focal length between the front and rear lenses.

VA7RS Loc: BC Canada

The "times zoom" notation is simply the big number divided by the small one. "3x zoom" simply means the longest focal length is three times the shortest.

CaptainC Loc: Colorado, south of Denver

There is NO connection. The 20X means you multiply the widest mm by 20. Since P&S cameras have such small sensors, equating a 200 to a 20X is meaningless. If the P&S had a 35mm equivalent of 28mm at its widest, then the 20X would be a 560mm equivalent. If it were 15mm equivalent at the wide end, then 20X=300mm equivalent.

Brenda IS Scottish Loc: GOLDEN Colorado

There is just so much to learn..... I guess photography is a life long learning experience!

Aldebaran Loc: Florida

But ** I think *** 20x is much more than a 200mm. That's what you want to know , i guess. Correct me if I am wrong, you masters of photography. Oh, I see someone answered, I just know by experience.

CaptainC Loc: Colorado, south of Denver

BigBear wrote:

They are different classifications. 20x means it can take an image 20 x actual size. The DSL lenses are measured in mm's, which is the focal length between the front and rear lenses.

"actual size" has nothing to do with it. It is a range.

BigBear Loc: Northern CT

CaptainC wrote:

"actual size" has nothing to do with it. It is a range.

You are correct sir, I chose my words poorly. Thank You.

mikemilton

The other consideration is if this is optical or digital zoom or both. Digital zoom (which is quite laughable really) is just cropping

JPL

And then you can consider the sensor size you are using, it has a lot to do with how much you can crop your pics and keep up the quality. You may get a much better cropped pic from full frame dslr with 200 mm lens than uncropped with a bridge camera with 20x zoom that could equal 600 mm zoom on the full frame camera. This is because you are using a sensor in the full frame that is about 29x larger than typical bridge camera sensor. A DX sensor is about 15x larger than a typical bridge camera sensor. Size matters, but not only the 20X lens zoom number!

Crwiwy Loc: Devon UK

You need a point of reference to make sense of it.
For example - my old Olympus bridge camera at wide angle is equivalent to a 28mm lens on a full frame. I would suspect that most bridge and p&S cameras are roughly the same. Therefore a 20X zoom would give you the equivalent to 560mm on a full frame camera.
Photo software should give you the focal length used and possibly the full frame equivalent in the picture information.
Digital zooms have greatly improved since the original ones but are only really of use to catch a picture that you would not otherwise get.

Uuglypher Loc: South Dakota (East River)

A 20X prime lens on a full-frame sensor = "normal" focal length (50mm) x 20 = 1000mm.

A 20X zoom RANGE would refer to 1000mm. on top of its focal length at the widest of it wide-angle setting.

Are you dealing with a full-frame sensor or a "crop-factor" (smallr) sensor?

CaptainC Loc: Colorado, south of Denver

Uuglypher wrote:

A 20X prime lens on a full-frame sensor = "normal" focal length (50mm) x 20 = 1000mm.

A 20X zoom RANGE would refer to 1000mm. on top of its focal length at the widest of it wide-angle setting.

Are you dealing with a full-frame sensor or a "crop-factor" (smallr) sensor?

Multipliers (like 20X) are never used on SLR/DSLR lenses Those are identified by the focal length or the focal length range, i.e. 24-70. P&S cameras use the "X" and is meaningless unless you know the starting point.

Uuglypher Loc: South Dakota (East River)

CaptainC wrote:

Multipliers (like 20X) are never used on SLR/DSLR lenses Those are identified by the focal length or the focal length range, i.e. 24-70. P&S cameras use the "X" and is meaningless unless you know the starting point.

Indeed,that's right. But 5x, 8X, 10x etc are commonly used on a variety of P&S and so-called bridge and " Superzoom" cameras to indicate the RANGE of zoom...from its widest angle to "strongest" telephoto. To relate those "multiplier" designations to specific focal lengths requires knowledge of the sensor size ( and thereby knowledge of its "normal" lens' focal length by which to apply the appropriate " multiplier" to find the focal length. That will vary depending on the wide-angle starting point of the particular zoom under consideration. The original question is not insoluble; it simply requires a bit more info from which to start forming a cogent reply.

Uuglypher Loc: South Dakota (East River)

I might add that, alhough multiplier designations are not typically applied to lenses for SLR/DSLR cameras, such deignations are, indeed, useful and can be accurately applied in discussing "magnifying power" of a variety of lenses with people more familiar with telescopes, spotting scopes, and binoculars.
Again, when applied to zoom lenses and their ranges, the starting point of the zooming must first be established.
Dave G.