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DPChallenge Forums >> Photography Discussion >> What's the focal length with 4x optical
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12/07/2005 04:38:45 PM · #1
and a 2x teleconveter?
12/07/2005 04:44:47 PM · #2
I've been told before that each "x" equals 10 feet of focal length. So I'd say about 60 feet.
12/07/2005 04:57:07 PM · #3
The "X" is just a marketing term on P&S cameras. It is however, a meaningful measurement on teleconverters.

The lens on your camera has a focal length of 35-140mm, (35mm equiv), and with the 4X TC becomes 140-560mm.

Apologies if I've misunderstood your query.

bazz.
12/07/2005 04:59:29 PM · #4
Originally posted by sir_bazz:

The "X" is just a marketing term on P&S cameras. It is however, a meaningful measurement on teleconverters.

The lens on your camera has a focal length of 35-140mm, (35mm equiv), and with the 4X TC becomes 140-560mm.

Apologies if I've misunderstood your query.

bazz.

Yeah, that's what I'm asking. But it's a 2x TC not 4x.

Message edited by author 2005-12-07 17:00:13.
12/07/2005 05:30:20 PM · #5
Oooops!

Just halve both the numbers.

bazz.
12/07/2005 07:11:12 PM · #6
Originally posted by A1275:

I've been told before that each "x" equals 10 feet of focal length. So I'd say about 60 feet.


Wow, and I thought 500mm was a long lens!
12/19/2005 01:22:20 PM · #7
1x=50mm
12/19/2005 01:25:51 PM · #8
Originally posted by Brent_Ward:

1x=50mm

depends what kind of x we're talking about... 1x eye viewing is about the same as 50mm magnification. 1x in zoom means you've got a prime lens.
12/19/2005 01:28:07 PM · #9
yall got your x's mixed up. A Sigma 10-20mm super wide lens is a 2x lens. Nowhere near 100mm "2x" is supposed to be.
12/19/2005 01:28:49 PM · #10
Originally posted by jpeters:

Originally posted by A1275:

I've been told before that each "x" equals 10 feet of focal length. So I'd say about 60 feet.


Wow, and I thought 500mm was a long lens!


Doh! I mean for each x, your can zoom up to 10 feet. At least that's what some guy who was trying to sell me a teleconverter said...
12/19/2005 01:30:44 PM · #11
on your G6 (35-140mm 35mm equiv) with 2x you should have 280mm equivilant zoom.
12/19/2005 01:30:56 PM · #12
Originally posted by A1275:

Originally posted by jpeters:

Originally posted by A1275:

I've been told before that each "x" equals 10 feet of focal length. So I'd say about 60 feet.


Wow, and I thought 500mm was a long lens!


Doh! I mean for each x, your can zoom up to 10 feet. At least that's what some guy who was trying to sell me a teleconverter said...

You mean the lens extends 10 feet?
And I thought the 1200/5.6L was a large lens.
12/19/2005 01:36:08 PM · #13
The X number used by the point and shoot tells you the ratio of longest to widest focal lengths

3X could be 105/35 or 84/28 or 150/50

to get the focal length of your camera with 4x or addition 2x, just multiply these numbers to the widest focal length for your p&s
12/19/2005 01:40:27 PM · #14
Originally posted by Brent_Ward:

1x=50mm


No it isn't. The "4x" refers to range of zoom. It's the way the P&S define their lenses. The Tamron 28-75mm lens would be a 2.6x zoom in those terms. The Canon 10-22mm would be a 2.2x zoom. The Canon 100-400mm would be a 4x zoom. It's entirely independent of how wide the lens actually goes, it's just a ratio between widest and longest.

The reason they do it this way is because a "9-45mm" lens sounds wimpy, don't ya know? Even though with a P&S crop factor it's actually got some reach.

R.
12/19/2005 01:43:21 PM · #15
Originally posted by bear_music:

Originally posted by Brent_Ward:

1x=50mm


No it isn't. The "4x" refers to range of zoom. It's the way the P&S define their lenses. The Tamron 28-75mm lens would be a 2.6x zoom in those terms. The Canon 10-22mm would be a 2.2x zoom. The Canon 100-400mm would be a 4x zoom. It's entirely independent of how wide the lens actually goes, it's just a ratio between widest and longest.

The reason they do it this way is because a "9-45mm" lens sounds wimpy, don't ya know? Even though with a P&S crop factor it's actually got some reach.

R.


1x magnification = 50mm (35mm equiv)

so a 4x=200mm

I didn't realize he was talking about zoom range.
12/19/2005 01:45:10 PM · #16
1x can also refer to macro work... 4x can be achieved at 65mm ;-)

i posted the answer to the question earlier btw.
12/19/2005 01:45:59 PM · #17
What bear said - it's confusing.

It basically means that from the widest your lens goes, 4x means it will go to 4 times that. So if your cam has a built in 20mm, it will reach 80mm. If your lens has a built in 10mm, it will go to 40mm, etc. If you have a DSLR, the "_x" lens description no longer gets used.
12/19/2005 01:47:01 PM · #18
Originally posted by kyebosh:

1x can also refer to macro work


Usually for macro it's in ratio, like 1:1 and 2:1 and 1:2. :)

M
12/19/2005 01:52:14 PM · #19
Originally posted by mavrik:

Originally posted by kyebosh:

1x can also refer to macro work


Usually for macro it's in ratio, like 1:1 and 2:1 and 1:2. :)

M


Not when you get into serious macro work. I use to shoot 2x-4x all the time.
12/19/2005 01:52:18 PM · #20
Originally posted by mavrik:

Originally posted by kyebosh:

1x can also refer to macro work


Usually for macro it's in ratio, like 1:1 and 2:1 and 1:2. :)

M

ahem, both are correct. just ask canon.
//consumer.usa.canon.com/ir/controller?act=ModelDetailAct&fcategoryid=155&modelid=7325
12/19/2005 01:56:13 PM · #21
Link doesn't work. I'll believe you anyways. :)
12/19/2005 01:59:55 PM · #22
canon's site is pretty unreliable lately...
//www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=183199&is=USA&addedTroughType=search
12/19/2005 03:09:28 PM · #23
Originally posted by kyebosh:

canon's site is pretty unreliable lately...

gettin it ready for the 30D :) I hope.

I'd chime in on the topic here but all that needs saying has been said.
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