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08-29-2018, 05:37 AM   #1
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SR and ext tubes

I do a fair bit of macro shooting, using mostly bellows of late, but also with ext tubes.
My question is, what focal length should be input for the SR to function correctly.
So, for example, if using 50mm of tubes, should the focal length just be increased by 50mm or is there a different formula because of the magnification factor ?
Bellows then produce a different dilemma as it has varying degrees of extension.
Is it a case of trial and error, whatever works for you or is there an actual system for working it out ???
For most of my macro shooting, I use a ringflash and inputting the focal length + the amount of ext seems to work, I ask this question in relation to no flash being used

Any thoughts

08-29-2018, 06:02 AM - 1 Like   #2
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I've struggled with this, but most of the macro work I do involves a tripod by the time ext tubes are involved. With the tripod sr is typically turned off.
08-29-2018, 06:07 AM - 1 Like   #3
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I try to keep the shutter speed higher than 1/(focal length + extension tube), but I put the focal length into the camera because lens identification is easier that way afterwards
08-29-2018, 07:14 AM   #4
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QuoteOriginally posted by UncleVanya Quote
I've struggled with this, but most of the macro work I do involves a tripod by the time ext tubes are involved. With the tripod sr is typically turned off.
Keep this up and you will easily exceed the 180 post Mark

I get that.
As most of my macro shooting is out in bushes and ditches, a tripod is extremely limiting.
And for the most part I do use flash.
Just for those times I don't, I was trying to figure out if there was an actual answer other than what seems to be trial and error.

---------- Post added 08-29-18 at 07:18 AM ----------

QuoteOriginally posted by othar Quote
I try to keep the shutter speed higher than 1/(focal length + extension tube), but I put the focal length into the camera because lens identification is easier that way afterwards
Ok, so you don't change the fl from what ever lens you're actually using.

When using bellows and the sigma 105mm macro I usually put in a value of 180mm which has led to questions about how good the 180mm macro is,
I wish I knew

08-29-2018, 07:45 AM - 1 Like   #5
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QuoteOriginally posted by dick897 Quote

Ok, so you don't change the fl from what ever lens you're actually using.
Correct. That of course leads to the problem, that I can rarely tell which extension tube I used
08-29-2018, 07:54 AM   #6
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QuoteOriginally posted by othar Quote
Correct. That of course leads to the problem, that I can rarely tell which extension tube I used
If you're taking things slowly enough to use extension tubes, one could argue that you should be taking physical notes on which tubes you're using.
08-29-2018, 08:14 AM - 1 Like   #7
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QuoteOriginally posted by pathdoc Quote
If you're taking things slowly enough to use extension tubes, one could argue that you should be taking physical notes on which tubes you're using.
I often change the lenght of the extension back and forth during photographing and I never had the patience to go through all the pictures and add this information afterwards. To be honest I don't really care which extension tube got me the picture as long as I like the outcome
08-29-2018, 08:19 AM   #8
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QuoteOriginally posted by othar Quote
I often change the lenght of the extension back and forth during photographing and I never had the patience to go through all the pictures and add this information afterwards. To be honest I don't really care which extension tube got me the picture as long as I like the outcome
Same as that.
Even more so with the bellows, as I'd have to carry a ruler as well.

---------- Post added 08-29-18 at 08:22 AM ----------

QuoteOriginally posted by pathdoc Quote
If you're taking things slowly enough to use extension tubes, one could argue that you should be taking physical notes on which tubes you're using.
To be perfectly honest, I have never taken notes on what extension I've taken any shot at.
Iď have an idea of what I was at but with bellows it can change shot to shot

08-29-2018, 08:46 AM   #9
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Since it takes time to change the tubes and lens(es) and set the focal length why not take the time to jot a few notes in a notebook or on your tablet/smartphone or a voice note.

Or change the copyright or filename setting on the camera.
08-29-2018, 08:55 AM   #10
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With the bellows it's just like focusing,
Only takes 2 secs to change the length.

But to get back on track
What I'm trying to find out is,
Is there a correct method / formula
Or is it just guess work or whatever works best for you. ?
08-29-2018, 08:55 AM   #11
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QuoteOriginally posted by Not a Number Quote
Since it takes time to change the tubes and lens(es) and set the focal length why not take the time to jot a few notes in a notebook or on your tablet/smartphone or a voice note.

Or change the copyright or filename setting on the camera.
For what goal, I won't like the picture any more just because I have all the information on the extension tube (and the exact aperture while we are at it )?
08-29-2018, 08:58 AM - 1 Like   #12
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QuoteOriginally posted by dick897 Quote
Keep this up and you will easily exceed the 180 post Mark

I get that.
As most of my macro shooting is out in bushes and ditches, a tripod is extremely limiting.
And for the most part I do use flash.
Just for those times I don't, I was trying to figure out if there was an actual answer other than what seems to be trial and error.
I have tried using magnification factor with 1:1 treated as 2x focal length with reasonable success but the tests may have used a 50mm with 50mm of extension so the resulting SR FL was 100 just like your method.

Honestly I've never seen any theory that accounted for SR and Macro.

As for the duplicates the forum was incredibly slow this morning and kept failing to show the post. Also I'm one of the people granted auto entry this month due to past posting. This month I checked and I was averaging around 300 posts every ten days. But not by duplicates, at least not intentionally! Lol.
08-29-2018, 09:36 AM   #13
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QuoteOriginally posted by othar Quote
For what goal, I won't like the picture any more just because I have all the information on the extension tube (and the exact aperture while we are at it )?
For what goal? Keeping an accurate record of what you did.
08-29-2018, 09:53 AM   #14
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QuoteOriginally posted by Not a Number Quote
For what goal? Keeping an accurate record of what you did.
And experimenting and learning what works in what situation. Different people work differently in this respect.
08-29-2018, 10:32 AM   #15
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QuoteOriginally posted by UncleVanya Quote
I have tried using magnification factor with 1:1 treated as 2x focal length with reasonable success but the tests may have used a 50mm with 50mm of extension so the resulting SR FL was 100 just like your method.

Honestly I've never seen any theory that accounted for SR and Macro.

As for the duplicates the forum was incredibly slow this morning and kept failing to show the post. Also I'm one of the people granted auto entry this month due to past posting. This month I checked and I was averaging around 300 posts every ten days. But not by duplicates, at least not intentionally! Lol.
Thanks for that.
I've never seen a definitive answer to this question either.
Which led me to asking it.
I had presumed that there would be an answer though.
I'll experiment and see if I can find something that works for me or just use flash.

That is some post count.
I wouldn't have that much in the years I'm on here. But then I was a long time lurker
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