microscope objective post processing best practices?

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dbur
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Joined: Fri Apr 16, 2010 3:47 pm
Location: Oregon
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microscope objective post processing best practices?

Post by dbur »

This information may be around somewhere but I didn't find it with a search.

I have recently acquired the Nikon MRL00102 and am trying to use it with a Nikkor 200mm, f4 lens.

So far I'm not too impressed with my results.

There seems to be a lot of purple fringing and the stack I've tried so far didn't come out very good. I used 1.25 mil steps (~32 microns) which may be too large, but I still expected better results than I got.

I stacked with Zerene Pmap and Dmap with defaults.

What processing is recommended before stacking?
Should I be attempting to clean up the purple fringing first?
What is the best workflow and processing steps for this setup?

I know a lot of people are using this 10x objective. Has anyone done a Lightroom correction profile for it?

Thanks.

ChrisR
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Post by ChrisR »

32µm ia too big a step, so you will have a lot of OOF image, which is where the longitudinal CA shows up.
Try 10µm, or a tad better, 5.

Having said that, yes, this objective does have it, as is shown in Robert Otoole's test
http://www.photomacrography.net/forum/v ... 102#240032

I haven't found it a big problem on real subjects, unless there's a lot of fine detail over a lot of blacks. I've not tried correcting it before stacking.
If you use a brush the same colour but weak, and "Subtract" mode, ....


I just tried it on Robert's test image. Select all the purplish parts, expand and feather a little, and make from that a new layer on top to adjust them. It may not be accurate, but it certainly stops it noticing.
Chris R

dbur
Posts: 174
Joined: Fri Apr 16, 2010 3:47 pm
Location: Oregon
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Post by dbur »

I'm going to need a finer lead screw to get below 1 mil steps.

It looks like Lightroom manual purple defringing of 10, 41/63 or purple Lum -49, Sat -51 do a fair job of reducing the purple on this particular image. I think in this case the purple fringe adjustment works a bit better than the Lum/Sat adjustment. Haven't done a stack after this adjustment, just trying on a single image.

I'd prefer to do it in LR rather than have to push each image through PS before stacking.

Thanks.

dbur
Posts: 174
Joined: Fri Apr 16, 2010 3:47 pm
Location: Oregon
Contact:

Post by dbur »

I constructed a stage with ~ 200 microinch step resolution.
(http://www.photomacrography.net/forum/v ... hp?t=39021)

I took a little extra care setting up a test with some decent lighting diffusion and got a fairly good result.

10x Nikon PLAN with 200mm tube lens. 35 image stack at 200 u" steps (5 micron).

This is the ruled edge of a Starrett steel ruler. The rules are 10 mils on center. Images is ~0.085 inches across. First test with my Rube Goldberg stacking stage.

Image

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