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The "butterflies" thread has inspired me to get my act together and take some proper images. I spent a couple hours (!) last night trying to take a picture of a flower, but at the magnifications I am working at, I need the optomechanical equipment in my lab to keep everything stable. To see why, here's the flower:
http://a.imageshack.us/img686/2918/dsc00403t.jpg
It looks ok, but that's my limit. Here's a 100% crop of the same flower, using the 16mm Luminar:
http://a.imageshack.us/img153/2244/16flower.jpg
I got lucky with this shot- notice the miniscule depth of focus.
So today, I set up everything on some rail and took images of a 1/32" ball bearing sitting on some foam. I illuminated it with a LumenPro metal halide source coupled into a liquid light guide- no diffuser. The light is so bright the glint off the bearing was enough to blind me. Here it is with the 63mm, stopped down most of the way:
http://a.imageshack.us/img266/6576/dsc00468xc.jpg
And here it is wide open, followed by a 100% crop-
http://a.imageshack.us/img266/2705/dsc00461i.jpg
http://a.imageshack.us/img294/1764/63mmball.jpg
The detail is quite good, and there is little chromatic aberration- dig the bokeh!
Now stepping up the the 25mm: again, full frame and a 100% crop
http://a.imageshack.us/img840/4047/dsc00465e.jpg
http://a.imageshack.us/img294/5230/25mmball.jpg
Again, the image is quite sharp, but the depth of focus is so small that the detail appears out of focus.
Now the 16mm:
http://a.imageshack.us/img294/6281/dsc00470eo.jpg
http://a.imageshack.us/img840/1953/16mmball.png
This is where things get interesting- the depth of focus is negligible, and what you are seeing in the crop is not blur, but speckle. The magnification and sharpness of this lens is sufficient to resolve speckle from an extended, broadband source.
Just for fun, I stuck on a 16x epiplan objective and took an image of one of the plastic foam flecks. The full-frame image is rather dull, but the 100% crop shows an interesting optical effect: diffraction off the sharp edge and interference:
http://a.imageshack.us/img251/2343/16xfoam.jpg
The colors are real, not chromatic aberration. I suspect they are interference fringes caused by a varying thickness of the 'flake'. The diffraction off the edge is pretty cool, too (IMO)- I count 7 periods.
Something I find interesting in this sequence, is that there is a definite change around 10X magnification- the images change from being recognizable (but magnified), to unfamiliar and confusing. Hopefully there's enough time left in the summer to explore this a little more...
http://a.imageshack.us/img686/2918/dsc00403t.jpg
It looks ok, but that's my limit. Here's a 100% crop of the same flower, using the 16mm Luminar:
http://a.imageshack.us/img153/2244/16flower.jpg
I got lucky with this shot- notice the miniscule depth of focus.
So today, I set up everything on some rail and took images of a 1/32" ball bearing sitting on some foam. I illuminated it with a LumenPro metal halide source coupled into a liquid light guide- no diffuser. The light is so bright the glint off the bearing was enough to blind me. Here it is with the 63mm, stopped down most of the way:
http://a.imageshack.us/img266/6576/dsc00468xc.jpg
And here it is wide open, followed by a 100% crop-
http://a.imageshack.us/img266/2705/dsc00461i.jpg
http://a.imageshack.us/img294/1764/63mmball.jpg
The detail is quite good, and there is little chromatic aberration- dig the bokeh!
Now stepping up the the 25mm: again, full frame and a 100% crop
http://a.imageshack.us/img840/4047/dsc00465e.jpg
http://a.imageshack.us/img294/5230/25mmball.jpg
Again, the image is quite sharp, but the depth of focus is so small that the detail appears out of focus.
Now the 16mm:
http://a.imageshack.us/img294/6281/dsc00470eo.jpg
http://a.imageshack.us/img840/1953/16mmball.png
This is where things get interesting- the depth of focus is negligible, and what you are seeing in the crop is not blur, but speckle. The magnification and sharpness of this lens is sufficient to resolve speckle from an extended, broadband source.
Just for fun, I stuck on a 16x epiplan objective and took an image of one of the plastic foam flecks. The full-frame image is rather dull, but the 100% crop shows an interesting optical effect: diffraction off the sharp edge and interference:
http://a.imageshack.us/img251/2343/16xfoam.jpg
The colors are real, not chromatic aberration. I suspect they are interference fringes caused by a varying thickness of the 'flake'. The diffraction off the edge is pretty cool, too (IMO)- I count 7 periods.
Something I find interesting in this sequence, is that there is a definite change around 10X magnification- the images change from being recognizable (but magnified), to unfamiliar and confusing. Hopefully there's enough time left in the summer to explore this a little more...
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