How to use an Extension tube


eys123

New Member
Nov 16, 2012
154
1
0
Bedok
#1
hi guys im just wondering how do i use the extension tube? i dont get how the mm works
 

Octarine

Moderator
Staff member
Jan 3, 2008
12,488
26
48
Pasir Ris
#2
Between lens and body?
Have a look at our macro section here. They have sticky threads and other guides.
 

eys123

New Member
Nov 16, 2012
154
1
0
Bedok
#3
Between lens and body?
Have a look at our macro section here. They have sticky threads and other guides.
i wanna know what does eat focal length of the extension do? and must i always use 3 of them? im using the kenko extension tube set
 

Edwin Francis

Senior Member
Mar 24, 2006
880
3
18
www.sgwriter.com
#6
i wanna know what does eat focal length of the extension do? and must i always use 3 of them? im using the kenko extension tube set
No you don't have to use all three. They come in 3 different lengths so you get can different magnification setups. You can use 1, 2 or all 3 of them together.

The length markings are not 'focal lengths'. They are physical lengths of each tube. Optics theory says you get 1:1 magnification when you are at 2f or 2 x focal length. So extending a 28mm lens by 28mm will give you 1:1 magnification (with the lens focused at infinity). Extending it more will increase the magnification, reducing extension will reduce magnification. Increasing magnification also results in a smaller effective aperture, darker screen image, perhaps leading to AF issues.
 

Octarine

Moderator
Staff member
Jan 3, 2008
12,488
26
48
Pasir Ris
#8
Anyone use extension tube set for Sony NEX Camera?
The same question in two diffrent threads? Please don't cross post
Equipment specific questions (Sony) are best asked in the respective equipment forums.
 

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