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Extension tubes - not what I expected
  
 
YonathanZ
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p.1 #1 · p.1 #1 · Extension tubes - not what I expected


Hi,

I got my Fotodiox 3-piece set extension tubes today. I've tried using the shortest piece (7mm I think) and also the longest one to focus where I wanted but they all only let me focus at a distance of about 1-5 cm, which is ridiculously close and is pretty much useless for me. I'm using them with a 50mm lens. It's pretty much like the reverse macro ring I have, which is very, very limiting. I've seen videos of people using theirs from much further (say 20cm) and I wish I knew how it can be done. The focus ring on the lens seems to have little to no effect as well.

Help.



Apr 02, 2014 at 10:10 PM
EB-1
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p.1 #2 · p.1 #2 · Extension tubes - not what I expected


That is normal. Use a longer lens if you want a longer focus distance. If you want to focus from macro to infinity, then buy a macro lens.

EBH



Apr 03, 2014 at 12:04 AM
Imagemaster
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p.1 #3 · p.1 #3 · Extension tubes - not what I expected


They are doing exactly what they are designed to do. If you don't want to be so close use them on a longer focal-length lens.


Apr 03, 2014 at 02:25 AM
YonathanZ
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p.1 #4 · p.1 #4 · Extension tubes - not what I expected


That's a shame, I was hoping to have more versatility. I only have this one lens and sometimes miss what I could do with the macro lens I had.


Apr 03, 2014 at 10:28 PM
BigSky1
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p.1 #5 · p.1 #5 · Extension tubes - not what I expected


Imagemaster wrote:
They are doing exactly what they are designed to do. If you don't want to be so close use them on a longer focal-length lens.


This may sound dumb; but, is there an "optimum" focal length for use with extension tubes? I know individual preferences will vary; but, just curious from people much more expert than me.



Apr 05, 2014 at 04:53 PM
pipspeak
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p.1 #6 · p.1 #6 · Extension tubes - not what I expected


Depends on what magnification you want. Here's a handy calculator (though note the MFD is measured from the sensor, not the front of the lens):

http://www.cambridgeincolour.com/tutorials/macro-extension-tubes-closeup.htm



Apr 05, 2014 at 05:38 PM
 

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BigSky1
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p.1 #7 · p.1 #7 · Extension tubes - not what I expected


Thanks. That's helpful. I appreciate it.


Apr 05, 2014 at 09:36 PM
Tim ONeill
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p.1 #8 · p.1 #8 · Extension tubes - not what I expected


Put them behind a midrange tele, then they are decent. On a 50, you will block all the light to the subject, unless you get a cheap ringlight to put in front. I got a cheapo ringlight from Amazon for about $30 bucks or so. Not great light, but adequate.


Apr 15, 2014 at 07:54 PM
YonathanZ
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p.1 #9 · p.1 #9 · Extension tubes - not what I expected


I only have a 50mm lens for the time being, but thanks for the advice.


Apr 16, 2014 at 02:13 PM
ZoneV
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p.1 #10 · p.1 #10 · Extension tubes - not what I expected


Most likely the shortest extension tube is longer than 7mm.
In case it is such a cheap manual extension tube set, the smallest ring has 7mm thickness + front and back mount rings adds up to 15mm extension.
Thats way too much for normal fast 50mm lenses.

For my shorter focal lenght lenses I have made an 8mm short extension tube8mm short EOS extension tube, and some time later a even shorter EF extension tube with only 6mm thickness.

I use those for the 50mm and 58mm lenses, 35mm lenses, and sometimes even 24 or 18mm wideangle lenses. To get the light onto the object is sometimes a problem - but I prefer sided or transmitted light to get more interesting images.
For more reproduction like images I use longer focal lengths.

Zeiss Contax 35mm f/1.4 wideopen on EOS 5D with DIY 6mm extension tube:




Apr 19, 2014 at 09:02 PM
YonathanZ
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p.1 #11 · p.1 #11 · Extension tubes - not what I expected


Seems like some machinery is required to make it. :\


Apr 20, 2014 at 04:37 AM
e6filmuser
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p.1 #12 · p.1 #12 · Extension tubes - not what I expected


General Gear-Talk (the clue is in the name) is not the best forum to ask specialised macro questions.

In passing, if I put a 30mm (or so) extension behind my 300mm 2.8 I get several feet of working distance.

Harold



Apr 21, 2014 at 04:13 PM





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