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07/29/2005 10:45:39 PM · #1 |
| I just bought 2 new lenses and was telling my dad abou them. I told him they were 28-70mm and 70-300mm. He asked me what their zoom rating was (as in 6x, 10x, etc) which caught me short of an answer. I told him that I didn't know and that I'd never seen a lens talked about like that. I tried looking in the manual and it told us the ratios, but not the zoom. How come lenses are not talked about in terms of their max zoom and, if one were curious, how does one figure this out? |
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07/29/2005 10:48:15 PM · #2 |
The 6x, 10x etc rating is used only in Point and Shoots and don't really tell much about the lens. A 28-70 is a 2.5x zoom (longest focal length divided by the shortest focal length).
A 70-300 is a 4.3x zoom. That way of describing zooms is just a relative measure, it does not tell you anything about the reach of the lens unless you know the actual focal length of the lens.
Message edited by author 2005-07-29 22:50:16. |
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07/29/2005 11:25:23 PM · #3 |
| I'd make something up tell them you have a 1-3X and 3-10.4X lens be sure to tell them with digital zoom it's 25X |
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07/29/2005 11:30:05 PM · #4 |
28mm is, for a 35mm camera, about 1x. So, 70mm would be 2.5x, 300mm would be about 10.7x (300/28)(relative to the method he's used to). At least that's my understanding. For the digital Rebel, 18mm is about 1x
But that's just how I understand it |
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07/29/2005 11:39:23 PM · #5 |
I think you guys are confused...cept doctornick, he's correct.
A 50-100 would be a 2x for example. A 50-200 would be a 4x for example.
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07/29/2005 11:44:49 PM · #6 |
Originally posted by deapee:
I think you guys are confused...cept doctornick, he's correct.
A 50-100 would be a 2x for example. A 50-200 would be a 4x for example. |
no, what he means is:
like on a digital camera that is a p/s, it has like 3x optical, 4x, optical, 10x optical and so forth, and he wants to know how that relates in terms of that zoom distance compared to like XX mm in an SLR lens. |
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07/29/2005 11:51:52 PM · #7 |
Originally posted by doctornick:
(longest focal length divided by the shortest focal length) |
The answer.
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07/30/2005 12:01:29 AM · #8 |
You're both right.
But usually on a P&S people look at the zoom factor to see how close the zoom will get you to something far away, rather than to see what range of focal lengths it gives you. So calling a lens that goes up to 300mm a 10x (adjust as appropriate for your sensor size) would make the most sense, even if it's a prime.
I guess to be technically correct you can tell him, "Well, if you're talking about how big it'll make the image, it's like a 10x." |
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07/30/2005 12:02:16 AM · #9 |
Originally posted by kjennings:
Originally posted by deapee:
I think you guys are confused...cept doctornick, he's correct.
A 50-100 would be a 2x for example. A 50-200 would be a 4x for example. |
no, what he means is:
like on a digital camera that is a p/s, it has like 3x optical, 4x, optical, 10x optical and so forth, and he wants to know how that relates in terms of that zoom distance compared to like XX mm in an SLR lens. |
It does not relate. A PS w/ a 10x zoom only means that the focal length of the lens on the PS when coverted to 35mm eqivalent equals 10x, or say 30-300mm. The actual lens may be much less in mm terms but coverts to that because of the chip in the camera is so small.
Maybe I just made it more confusing. |
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07/30/2005 12:17:11 AM · #10 |
A partially-correct, useful answer might be more appropriate than a correct, but useless answer.
If someone's already been told of 28-70 and 70-300, obviously he's not asking: What's: 300/70 and 70/28?
As some have already pointed out, he's most likely wanting to compare against other P&S cameras, or maybe even film ones.. The more useful answer would be to compare it against 35mm film.
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07/30/2005 12:35:16 AM · #11 |
seriously...I don't see where the confusion is coming from...a 10x lens is like 30-300, a 10-20 is a 2x a 50-100 is a 2x...where are we getting confused?
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07/30/2005 12:44:03 AM · #12 |
Originally posted by deapee:
seriously...I don't see where the confusion is coming from...a 10x lens is like 30-300, a 10-20 is a 2x a 50-100 is a 2x...where are we getting confused? |
Where we are getting confused is that in the P&S world they don't publish focal lengths, they publish "x factors". The reason is marketing; the sensors are so tiny that a 100 mm lens is significant telephoto reach, but it sounds puny to people who think in 35mm terms. So they have their own vocabulary; at "no zoom" they are all pretty much the same degree of wide angle (about 35mm equivalent, give or take) and the measure of how much reach you have is "how many x" you zoom; a 10x is way more telephoto than a 4x or a 5x.
So the OP's father was, in fact, asking for an equivalent; "How does this lens compare to my 5x Cannikon P&S for telephoto reach?" In P&S terms, the 300mm = roughly 9x zoom, I think.
Robt.
Message edited by author 2005-07-30 00:46:27.
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07/30/2005 12:47:34 AM · #13 |
Originally posted by deapee:
seriously...I don't see where the confusion is coming from...a 10x lens is like 30-300, a 10-20 is a 2x a 50-100 is a 2x...where are we getting confused? |
Because in the P&S world, where NovaTiger's dad is used to seeing things like 3x and 10x, that number is used to tell you how big the lens will make something. A 10x zoom on a P&S camera will let you get a much larger image of the tiger at the zoo than a 3x zoom would. So when he asks for that info about the lens, he's interested in comparing it to the P&S world.
In other words, he's really asking about the maximum focal length, converted to terms that he's used to. |
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07/30/2005 08:23:29 AM · #14 |
Originally posted by bear_music:
Originally posted by deapee:
seriously...I don't see where the confusion is coming from...a 10x lens is like 30-300, a 10-20 is a 2x a 50-100 is a 2x...where are we getting confused? |
Where we are getting confused is that in the P&S world they don't publish focal lengths, they publish "x factors". The reason is marketing; the sensors are so tiny that a 100 mm lens is significant telephoto reach, but it sounds puny to people who think in 35mm terms. So they have their own vocabulary; at "no zoom" they are all pretty much the same degree of wide angle (about 35mm equivalent, give or take) and the measure of how much reach you have is "how many x" you zoom; a 10x is way more telephoto than a 4x or a 5x.
So the OP's father was, in fact, asking for an equivalent; "How does this lens compare to my 5x Cannikon P&S for telephoto reach?" In P&S terms, the 300mm = roughly 9x zoom, I think.
Robt. |
I think most P&S cameras do indeed publish focal lengths, both in absolute terms and in 35mm equivilents. And all the online tests give them as well. It's there, but it's just not the first thing you read. deapee is correct to say that the zoom rating is max focal length divided by min focal length. Any other way of interpreting it is dependent upon which camera you are talking about regardless of whether you are referring to the lens system of a P&S or a DSLR's interchangeable lenses. A 10x zoom lens will get you a 10 times closer view at the long (telephoto) end of it's focal length range than at the short (wide angle) end regardless if you are talking about a Sigma 50-500mm attached to a DSLR or the lens system in a my old Canon Pro 90 IS.
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07/30/2005 09:16:55 AM · #15 |
Originally posted by coolhar:
Originally posted by bear_music:
Originally posted by deapee:
seriously...I don't see where the confusion is coming from...a 10x lens is like 30-300, a 10-20 is a 2x a 50-100 is a 2x...where are we getting confused? |
Where we are getting confused is that in the P&S world they don't publish focal lengths, they publish "x factors". The reason is marketing; the sensors are so tiny that a 100 mm lens is significant telephoto reach, but it sounds puny to people who think in 35mm terms. So they have their own vocabulary; at "no zoom" they are all pretty much the same degree of wide angle (about 35mm equivalent, give or take) and the measure of how much reach you have is "how many x" you zoom; a 10x is way more telephoto than a 4x or a 5x.
So the OP's father was, in fact, asking for an equivalent; "How does this lens compare to my 5x Cannikon P&S for telephoto reach?" In P&S terms, the 300mm = roughly 9x zoom, I think.
Robt. |
I think most P&S cameras do indeed publish focal lengths, both in absolute terms and in 35mm equivilents. And all the online tests give them as well. It's there, but it's just not the first thing you read. deapee is correct to say that the zoom rating is max focal length divided by min focal length. Any other way of interpreting it is dependent upon which camera you are talking about regardless of whether you are referring to the lens system of a P&S or a DSLR's interchangeable lenses. A 10x zoom lens will get you a 10 times closer view at the long (telephoto) end of it's focal length range than at the short (wide angle) end regardless if you are talking about a Sigma 50-500mm attached to a DSLR or the lens system in a my old Canon Pro 90 IS. |
This is true in OUR world but it's not true in their world, "they" being casual users of P&S cameras. It's like two different vocabularies sharing common words. Dollars-to-donuts, what I described is what the OP's dad was asking, and the answer I proposed ("It's like 9X, dad.") is the one that will answer his question most directly.
You are of course correct that in our world a 70-200 zoom, for example, is approximately 3X.
Robt.
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07/30/2005 09:29:50 AM · #16 |
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