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Optical Zoom, imperative?
Ok, what I know∨ think I knowOptical Zoom is a number that you get by dividing the range of a lens.Like:35-70mm 70/35=2x75-300mm 300/75=4x100-400mm 400/100=4x.

21-35mm would be 35/21=1.6x is that correct or would you round it up and just say 2x..

Assuming that I have the above information correct.My question is&. How is this imperative?Is this for marketing or is there a real benefit to having this information?.

Looking for the Light!Thank you for your time,Tony..

Comments (8)

I think that the idea of quoting a "times zoom" came in with fixed lens compact cameras. The wide end was mostly about 35mm (or equivalent with digital cameras) so you knew that a 4x zoom was about 35-140, 6x times 35-210, etc..

I don't remember times zoom ever being quoted for SLR/DSLR lenses, just the focal length range, and it still doesn't really get quoted today. For both DSLR's and compacts it is somewhat useful in that the greater the times zoom, probably the worse the optical quality will be, especially at the two extremes..

Chris R..

Comment #1

You're correct with your math, although I am also not sure about the zooms that are not a whole number. I think they might leave it as is. It is a marketing technique. The DSLR crowd never really mentions zoom factors..

I don't actually know what you mean by imperative though. For some reason I've never really understood the meaning or use of that word, or at least the way you're using it...

Comment #2

Thank you both very much.My quest for the deep hidden meaning of optical zoom has come to an end:).

I was only using the word imperative to mean importance or the definition absolutely necessary or required...

Comment #3

Acoomer wrote:.

Thank you both very much.My quest for the deep hidden meaning of optical zoom has come to anend:).

I was only using the word imperative to mean importance or thedefinition absolutely necessary or required..

Do you mean "imperative" to have optical zoom, as opposed to digital zoom found in most P&S (point and shoot) cameras? In that context, imperative has a little clearer meaning. as Digital Zoom is pretty useless in terms of getting a decent quality picture. In choosing a camera that has both optical and digital zoom, the only zoom factor that should be considered is the optical zoom..

The digital zoom will "zoom" in closer, but there is big price to pay in picture quality. Optical zoom uses the lens to zoom in and out and so picture quality stays relatively equal throughout the optical zoom range; the digital zoom uses in-camera digital manipulation to make the image "look" bigger, but this image is an in-camera enlargment of what the optical lens is seeing, this is why it looks terrible..

Albert-OColoradoPlease visit me athttp://www.berto.zenfolio.com.

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Comment #4

I was only asking is it absolutely necessary to understand the optical zoom factor for a lens. I was trying to find out how knowing a lens is 4x or 11x was important. If you just look at the factor 11x or 4x this really doesn't tell you allot about that lens except one has a greater focal range than the other. Also Apon first glance you may think the larger number would mean that it is better or can zoom farther. When in reality the 4x has the greater focal distance..

18mm-200mm 11x100mm-400mm 4x.

To sum it up:.

I was just wondering how this is important to know and from what I have been told it is just marketing..

One more thing ...I wasn't worried about digital zoom on a DSLR.

Thanks,Tony..

Comment #5

Cosilver wrote:.

Do you mean "imperative" to have optical zoom, as opposed to digitalzoom found in most P&S (point and shoot) cameras? In that context,imperative has a little clearer meaning. as Digital Zoom is prettyuseless in terms of getting a decent quality picture. In choosing acamera that has both optical and digital zoom, the only zoom factorthat should be considered is the optical zoom..

Very good point. Some cameras quote - for marketing purposes - hugely inflated zoom figures..

Say the lens has a 3x Optical zoom. Nothing inherently good or bad about that. And then add in some marketing-speak, use an additional 2x digital zoom. That is merely cropping and resampling the image which anyone can do for themselves in software. Suddenly the camera is described as having 6x zoom. And to achieve this 75% of the information from the sensor has been discarded.



This type of usage is used especially in video cameras, where to be fair it may have some validity, as it simplifies the procedure. But the image quality of digital zoom remains poor..

In still cameras, optical zoom is the only type of zoom that matters. Certainly I've seen people defend digital zoom and present sample images, but it remains merely a convenience, similar to having a camera with the built-in ability to generate sepia-toned monochrome images, something that would usually be better done in post-processing.Regards,Peter..

Comment #6

Acoomer wrote:.

I was only asking is it absolutely necessary to understand theoptical zoom factor for a lens. I was trying to find out how knowinga lens is 4x or 11x was important. If you just look at the factor 11xor 4x this really doesn't tell you allot about that lens except onehas a greater focal range than the other. Also Apon first glance youmay think the larger number would mean that it is better or can zoomfarther. When in reality the 4x has the greater focal distance..

18mm-200mm 11x100mm-400mm 4x.

To sum it up:I was just wondering how this is important to know and from what Ihave been told it is just marketing..

One more thing ...I wasn't worried about digital zoom on a DSLR.

Ah, now I understand your question. Yes, the zoom factor (4x, 11x, etc...) is pretty useless and really not used at all in the DLSR world. I was not sure if you were referring to a DLSR or P&S in your post, so by way of the question, I thought you were referring to P&S cameras..

Albert-OColoradoPlease visit me athttp://www.berto.zenfolio.com.

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window..

Comment #7

Acoomer wrote:.

I was only asking is it absolutely necessary to understand theoptical zoom factor for a lens. I was trying to find out how knowinga lens is 4x or 11x was important. If you just look at the factor 11xor 4x this really doesn't tell you allot about that lens except onehas a greater focal range than the other. Also Apon first glance youmay think the larger number would mean that it is better or can zoomfarther. When in reality the 4x has the greater focal distance..

18mm-200mm 11x100mm-400mm 4x.

To sum it up:I was just wondering how this is important to know and from what Ihave been told it is just marketing..

This may not be what you were really asking, but since this is the beginners forum I'll mention it. Quite often it is considered that the ability of a zoom lens to magnify is the most important feature..

Say for example there are two lenses, both 5x zoom. One goes from 50mm to 250mm. And the second goes from 15 to 75mm. Which is better?.

Again, marketing has it's influence, it may be thought that the lens which goes to 250mm is much better than the one which only reaches 75mm. But consider the wideangle portion. Which is more useful, a lens with a maximum wideangle setting of 50mm, or one which goes all the way to 15mm? In very many situations, this would be incredibly useful and more versatile..

This is often overlooked and the market does little to clarify, frankly because such a lens would probably be technically more complex and difficult to make.Regards,Peter..

Comment #8

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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