extension tube


Limsbros

New Member
Dec 8, 2004
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Sembawang
#2
Try google... what is your objective or intend for using extension tube...Yes it is good for macro only if you know why you want to add extension tube. You can use it on non-macro lens or macro lens etc..
 

jeff7id

Senior Member
Oct 15, 2008
4,863
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38
#3
hi all,

would like to check if extension tube is good for macro?
There are several ways to do Macro Photography, such as usage of extension tube.

Only with a dedicated macro lens, you could achieve the 1:1 life size magnification and optimum sharpness.
 

Dec 13, 2005
117
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16
#4
Only with a dedicated macro lens, you could achieve the 1:1 life size magnification and optimum sharpness.
This statement is inaccurate and mis-leading .
Macro lenses achieve 1:1 by extension as well, so technically it is no different from use of extension tubes.
The issue of "optimum sharpness" is highly debateable.
 

wmayeo

New Member
Feb 11, 2008
1,571
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Singapore
#5
Extension tube is to assist the lens by bringing up magnification, useful for closeup photography. Of course it is good way - as in a cheaper alternative to boost magnification rather than owning a dedicated macro lens. Likely you going to manual focus your lens unless you get Kenko extension tubes. You'll lose light when you put something between your lens and camera sensor. A book that you can read up more is Bryan Peterson's Understanding Closeup Photography.
 

jeff7id

Senior Member
Oct 15, 2008
4,863
10
38
#6
This statement is inaccurate and mis-leading .
Macro lenses achieve 1:1 by extension as well, so technically it is no different from use of extension tubes.
The issue of "optimum sharpness" is highly debateable.
So how many extension tubes do you want to stack on non-macro lens to achieve 1:1 magnification ? The more tubes you stack, the lower the quality of the picture.

That's why I say to directly choose dedicated 1:1 macro lens to achieve the optimum sharpness.
 

Dec 13, 2005
117
0
16
#7
The more tubes you stack, the lower the quality of the picture.
Extension tubes do not have any glass elements so I don't know where you are getting this conclusion from.
Are you confusing extension tubes with teleconvertors (perhaps)?

Sounds like you have experience in this field, so as the TS is asking for info, perhaps it would help if you explain yourself in more details, rather than short conclusive statements, as it is difficult to understand when you are so brief.

As for how much extension is required, I believe the simple formula is:
increase in magnification = the extension distance divided by the lens focal length

You still need to know what is your lens' max magnification (at min focal distance) before you can figure out how much extension to add to get to 1:1.

This topic is best to be explained in detail by books and wmayeo has suggested a good reference.
 

#9
Dear jeff7id, the more extension tubes you add, the less light reaches the sensor. There is no degradation of image quality.
Can you please state the equipment you used? Or are you simply hypothesizing?

I've shot with 4x5's for close to 20 years. The bellows simply distance the same lens from the film plane, when extended. None of any 4x5 lenses are dedicated closeup/ macro/ micro. Yet every single one of them shoots absolutely brilliant closeup images. it's not 1:1. It's more like 25:1 (25x) magnification, especially when we were shooting for jewelery clients. Don't forget that the film is 4 inches by 5 inches large.
 

jeff7id

Senior Member
Oct 15, 2008
4,863
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38
#10
Actually, I am a portrait photographer and interested to shoot models only.
I have used macro lenses such as 60mm macro, 105mm macro for portrait purpose.
I also do close up shoot, to show the beauty of model face.

http://imaging.nikon.com/products/imaging/technology/scene/30/index.htm
Quotes from Nikon website: "Even natural portraits are possible using Micro lenses."

As for portrait, I just use macro lens and such an extension tube is not required.
That's why I recommend only a dedicated macro lens to TS.

Our shooting style is just different. Don't mean to confuse TS though....
 

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