Snowflake macro (double om zuiko 50)

Vivalo

Olympus loser
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Nov 16, 2010
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Here's one macro shot from yesterday. Taken with OM Zuiko 50 1.4 and OM Zuiko 50 1.8 attached to it reversed. Handheld, F/5.6, iso 1000, 1/60 sec. Exact 1:1 macro ratio, I suppose.

Original camera jpeg

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Edited jpeg

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The equipment

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And another 1:1 macro shot

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Regards
Ville
 

Vivalo

Olympus loser
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Any thoughts what the focal length is when two 50mm lenses are together nose to nose? :confused:

I was wondering that when I set the mms to the IBIS. I ended up to 50mm.
 

akulya

Mu-43 Veteran
Joined
Jun 21, 2010
Messages
249
Awesome pictures, and amazing lenses!

Calculating the focal length would use a rearrangement of the formula I found here

my (perhaps wrong, anyone want to check my maths?) answer is....

f = d / [2(1+m/p)tan{2alpha}]

where...
"f" = focal length
"d" = measured linear dimension for the angle your using (i.e. if you are measuring the horizontal angle fo view, this number is the horizontal length of the sensor = 17.3mm)
"m" = magnification (with 1 being eqiv to 1:1)
"p" = ratio of apparent exit pupil diameter : entry pupil diameter
"alpha" = angle of view (the angle of view for the distance "d")

I'm not sure how you measure the apparent pupil diameters though...
:) I like this game


Code:
incidentally my rearrangement went...

alpha = 2arctan {d / [2f(1+m/p)]}

2alpha = arctan {d / [2f(1+m/p)]}

tan{2alpha} = d / [2f(1+m/p)]

(1+m/p)tan{2aplha} = d / 2f

d / (1+m/p)tan{2aplha} = 2f

f = d / [2(1+m/p)tan{2aplha}]
 

~tc~

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I'm not sure how you measure the apparent pupil diameters though...
:) I like this game
the apparent pupil diameter is the apparent diameter of the aperture opening as seen through the front (entry) and the back (exit), and they are requiring the ratio, so it looks like the equation needs to know how much of the magnification is before the aperture opening and how much is after ... Wow, looks like a giant PITA to figure out an answer to a question that doesn't need to be asked since you don't need IS when shooting from a tripod anyways.
 

Vivalo

Olympus loser
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Nov 16, 2010
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The snowflake was shot handheld, that is why I was wondering the mms.
 

lfmerrell

Mu-43 Veteran
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Jan 5, 2011
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Dallas - Fort Worth metroplex, Texas, USA
Way back in time I made a macro lens coupler from two appropriate diameter Cokin screw mounts glued face to face with crazy glue; 10 years later it is still holding together. Another option is a worm screw clamp if the lens are the same diameter, got that hint from a Popular Photography or Mechanics magazine.
 

penfan2010

Mu-43 All-Pro
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Nov 12, 2010
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NJ, USA
Vivalo - way cool, thanks for sharing. I was just about to ask you where you got the reverse lens adapter before I looked at the set up...nice one.
 
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