newbie qns: What are those lens no. for?


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kensh09

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Feb 1, 2005
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#1
i very newbie. Need to ask a stupid qns.
example Lens have 10mm-300mm, what do those numbers stands for? ;p
 

wainism

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Apr 15, 2004
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#2
those numbers stand for the focal lengths

erm, easily put, its the zoom.
10mm - wide angle
300mm - zoom

wait for the experts to get into the technicalities...
hope it helps
 

kensh09

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Feb 1, 2005
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#3
wainism said:
those numbers stand for the focal lengths

erm, easily put, its the zoom.
10mm - wide angle
300mm - zoom

wait for the experts to get into the technicalities...
hope it helps
oic....tat means if unzoom = 10mm, so if another lens which is 5mm will have wider angle rite?
300mm is how much i can zoom rite? The higher the further i can zoom.
Generally does it oso means that the greater the diff between these 2 nos. the better it is?
 

ortega

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Nov 2, 2004
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#4
Generally the greater the diff between the zoom the less lens you need to buy.
But usually, it also means that the image quality drops.

The numbers stand for the focal lenght range of the zoom lens.
There are prime lenses that are fixed focal lenght, e.g 50mm

The difference in between the numbers is the field of view that you get.
Lots of information on this on the internet, seek and you will find.

Don't worry to much about the tech bits,
shoot first!

It is better to have a great image of so-so quality that no image at all.
 

litefoot

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Jan 27, 2005
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#5
kensh09 said:
i very newbie. Need to ask a stupid qns.
example Lens have 10mm-300mm, what do those numbers stands for? ;p
Briefly its the focal length of the lens which is the distant between the plane of focus to the centre of the lens.

50mm for the 35mm format is known as the normal lens where the image is supposed to be equal to the size of our vision. Any focal length less than 50mm is known as wide angle and telephoto for range above 50mm.
 

kensh09

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Feb 1, 2005
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#7
ortega said:
Generally the greater the diff between the zoom the less lens you need to buy.
But usually, it also means that the image quality drops.

The numbers stand for the focal lenght range of the zoom lens.
There are prime lenses that are fixed focal lenght, e.g 50mm

The difference in between the numbers is the field of view that you get.
Lots of information on this on the internet, seek and you will find.

Don't worry to much about the tech bits,
shoot first!

It is better to have a great image of so-so quality that no image at all.
Saw some lens tat have fixed focus length. Does it makes the quality better compared to adjustable? Does it oso means that this len can only take picture of a fixed distance?
 

user111

Senior Member
Jul 27, 2004
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#8
not fixed distance (since u can always move about) , but fixed field of view (since the focal length is fixed)
 

ortega

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#9
kensh09 said:
Saw some lens tat have fixed focus length. Does it makes the quality better compared to adjustable? Does it oso means that this len can only take picture of a fixed distance?
Fixed FOV not fixed distance.
Normally Fixed FOCAL lenght (not focus) have less moving parts
so less things to go wrong.
Quality depends on the lens in question and what it is compaired to.

Cost of brand new lens from $200 to over $10K

Read the reviews, I am not an expert.
Buy the best that you can afford.
Best is to borrow one and fire away a few rounds, then check with your computer. if you are happy with your picture then buy lah.
 

litefoot

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Jan 27, 2005
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#10
kensh09 said:
Saw some lens tat have fixed focus length. Does it makes the quality better compared to adjustable? Does it oso means that this len can only take picture of a fixed distance?
Your question was about focal length which has nothing to do with zoom lens and its quality.

Zoom lens is like having a few lenses of different focal length in one. However, this type of lens are built with more pieces of glass (lens elements). Light are bent when passing through these elements, more elements will mean a higher loss in the details which will result a loss in constrast and sharpness. Too much bending of light will also result in image distortion etc. These short comings are overcome by lens design such as aspherical elements that reduce image distortion, better multi-coating and the use flourite compound for reducing the loss of details. In general its easier to design fixed focal length (or prime) lenses which are usually lesser elements in construction, therefore capable of better resulting image.
 

kensh09

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Feb 1, 2005
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#11
litefoot said:
Your question was about focal length which has nothing to do with zoom lens and its quality.

Zoom lens is like having a few lenses of different focal length in one. However, this type of lens are built with more pieces of glass (lens elements). Light are bent when passing through these elements, more elements will mean a higher loss in the details which will result a loss in constrast and sharpness. Too much bending of light will also result in image distortion etc. These short comings are overcome by lens design such as aspherical elements that reduce image distortion, better multi-coating and the use flourite compound for reducing the loss of details. In general its easier to design fixed focal length (or prime) lenses which are usually lesser elements in construction, therefore capable of better resulting image.
oic....now i can understand better.....so a prime lens is a len that had fixed focus lens, means cannot zoom in and out rite. Which oso means if i want a clear picture i have to move my body towards and away from the object, unless zoom lens which can be zoom. :) Right bo? :)
 

Dann

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Mar 27, 2004
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#12
kensh09 said:
oic....now i can understand better.....so a prime lens is a len that had fixed focus lens, means cannot zoom in and out rite. Which oso means if i want a clear picture i have to move my body towards and away from the object, unless zoom lens which can be zoom. :) Right bo? :)
Yo man u almost got it except for that part, You don need to move to get a clear pic, the lens can focus to get clear pics. You only move forwards or backwards to get a narrower or wider field of view. ( further to get wider view, nearer for narrower view but bigger subject.)

With a zoom lens u can stay where u r and let the lens do the walking for u. :bsmilie:
 

obewan

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Feb 11, 2005
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obe.homedns.org
#13
wainism said:
those numbers stand for the focal lengths

erm, easily put, its the zoom.
10mm - wide angle
300mm - zoom

wait for the experts to get into the technicalities...
hope it helps
ic... :think: So fisheye len belongs to which caterory ?? How many mm ?
Or is it a kind of special len ? :confused:
 

Jun 27, 2002
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here
www.9frames.com
#14
obewan said:
ic... :think: So fisheye len belongs to which caterory ?? How many mm ?
Or is it a kind of special len ? :confused:

if there is only one focal length (eg 14mm or 15mm or 16mm), its a prime lens

if there is a varible focal length, (eg 12-24mm, 10-22mm) its a zoom lens
 

litefoot

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Jan 27, 2005
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#15
Dann said:
Yo man u almost got it except for that part, You don need to move to get a clear pic, the lens can focus to get clear pics. You only move forwards or backwards to get a narrower or wider field of view. ( further to get wider view, nearer for narrower view but bigger subject.)

With a zoom lens u can stay where u r and let the lens do the walking for u. :bsmilie:
Not quite. You move to get closer or further from the subject. You cannot change the perspective of a wide angle lens by doing so.
 

litefoot

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Jan 27, 2005
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#16
obewan said:
ic... :think: So fisheye len belongs to which caterory ?? How many mm ?
Or is it a kind of special len ? :confused:
Wide angle. Usually less than 10mm.
 

ortega

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Nov 2, 2004
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#18
Yes anything less that 50mm is considered WA

He meant that the fish eye belongs to the WA cat
and that it is usually less than 10mm (not)

Current Nikon fish eye lenses

AF DX Fisheye 10.5mm f/2.8G ED
LIST PRICE : SIN$1310

AF Fisheye 16mm f/2.8D*
LIST PRICE : SIN$1330
 

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