Sony a900 - macro shots (pt II)

Received a sharper focus screen (Acute Matte "M") today from Sony for
the a900 as well as a connector set for my old Minolta flashes. So
struck the studio lights and put up a couple umbrellas with the Minolta
flashes connected to the a900.

The new focus screen is about 1 - 2 stops 'dimmer' so had to add some
ambient light to help manual focus. These did not affect exposure at 1/250.

Shot with the lens as vertical as possible this time instead of tilting
the coin (I don't have a proper macro head so achieving 1:1 focus was
more like 1:almost1 using the center column adjustment for coarse focus
(+2/-0 mm) and the lens for fine focus). The f/8 dof appears to be less
than 0.5mm when viewed full frame-full size at 95 dpi on the computer.

The first coin (tail side) was at f/8, ISO 200, 1/250
Lens: Minolta 100 f/2.8 macro (which edges out the Nikon 105 micro for
macro sharpness). Shots are MLU+cable released.

http://www.aliasimages.com/images/a9...C00423_SML.jpg
Crops at 100%
http://www.aliasimages.com/images/a9...0423_CROP1.jpg
http://www.aliasimages.com/images/a9...0423_CROP2.jpg
http://www.aliasimages.com/images/a9...0423_CROP3.jpg

Second coin was harder to get the DOF with it's higher relief, so I
stopped down w/o increasing the light (f/11 this time).
http://www.aliasimages.com/images/a9...C00428_SML.jpg
Crops at 100%
http://www.aliasimages.com/images/a9...0428_CROP1.jpg
http://www.aliasimages.com/images/a9...0428_CROP2.jpg

On to the target tests...

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"Alan Browne" wrote in message
...

Received a sharper focus screen (Acute Matte "M") today from Sony for
the a900 as well as a connector set for my old Minolta flashes. So
struck the studio lights and put up a couple umbrellas with the Minolta
flashes connected to the a900.

The new focus screen is about 1 - 2 stops 'dimmer' so had to add some
ambient light to help manual focus. These did not affect exposure at
1/250.

Shot with the lens as vertical as possible this time instead of tilting
the coin (I don't have a proper macro head so achieving 1:1 focus was
more like 1:almost1 using the center column adjustment for coarse focus
(+2/-0 mm) and the lens for fine focus). The f/8 dof appears to be less
than 0.5mm when viewed full frame-full size at 95 dpi on the computer.

The first coin (tail side) was at f/8, ISO 200, 1/250
Lens: Minolta 100 f/2.8 macro (which edges out the Nikon 105 micro for
macro sharpness). Shots are MLU+cable released.

http://www.aliasimages.com/images/a9...C00423_SML.jpg
Crops at 100%
http://www.aliasimages.com/images/a9...0423_CROP1.jpg
http://www.aliasimages.com/images/a9...0423_CROP2.jpg
http://www.aliasimages.com/images/a9...0423_CROP3.jpg

Second coin was harder to get the DOF with it's higher relief, so I
stopped down w/o increasing the light (f/11 this time).
http://www.aliasimages.com/images/a9...C00428_SML.jpg
Crops at 100%
http://www.aliasimages.com/images/a9...0428_CROP1.jpg
http://www.aliasimages.com/images/a9...0428_CROP2.jpg

On to the target tests...

Exceptionally detailed macros! The only way I could get close to that with
the D300 would be to go in at 2:1, and even then I doubt it would do it.
What I did notice before was that the Canadian coin's brass inner centre had
a oxide layer that prevented that odd dielectric effect where you get
different coloured speckles coming off the metal due to the metal's
crystaline structure being visible at high magnification. You can see this
effect with dark plastic in the sun, anodized surfaces, etc. The lack of
that effect produced a much more "life like" view because there were no out
of control specular highlights.

RichA wrote:

Exceptionally detailed macros!

Yes, I'm very pleased...

I printed the top one at 12x coin size (about 11" across). Amazing.

The only way I could get close to that with
the D300 would be to go in at 2:1, and even then I doubt it would do it.
What I did notice before was that the Canadian coin's brass inner centre had
a oxide layer that prevented that odd dielectric effect where you get
different coloured speckles coming off the metal due to the metal's
crystaline structure being visible at high magnification.

I was wondering what did that. See Eric Stevens posts/links where that
effect is quite visible.

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-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.
-- usenet posts from gmail.com and googlemail.com are filtered out.