First stack with Mitutoyo 10x

Images taken in a controlled environment or with a posed subject. All subject types.

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hero
Posts: 72
Joined: Mon Jul 17, 2017 12:38 pm
Location: California

First stack with Mitutoyo 10x

Post by hero »

Here's a specimen of metazeunerite on fluorite, FOV approx 3mm.

Mitutoyo BD Plan APO 10x + Raynox 150 reversed, but the tubes weren't flocked, I'm using the wrong tubes, and the setup kinda sags. Oh, and the lighting setup is awful. The component images are on the soft side and I had to use pretty aggressive sharpening. Once I have everything flocked and figured out the proper distances, I hope to make better images.

~ 100 images stacked with Zerene. Pmax leaves some artifacts in the highlights but the result is better than with Dmap.

What I want to know is what that mysterious orange goo might be, located about 1/4 of the distance from the left border and 2/5 from the bottom. It's obviously not soft, but for something that small to show a structure like that is quite unusual to me.

Image

100% crop:

Image

rjlittlefield
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Post by rjlittlefield »

The image seems to have come out well, despite all the concerns.

Can we see a 100% pixels crop of the goo?

--Rik

hero
Posts: 72
Joined: Mon Jul 17, 2017 12:38 pm
Location: California

Post by hero »

Thanks Rik for all your help in sourcing all the necessary pieces. What's curious to me--and what I think you've been trying to tell me all along but I was too obtuse to realize--is that the spacing of components isn't really all that critical. The 80-20 rule seems to apply; you can get most of the way there just from the basics, and the rest is just tweaking.

Here's a 100% crop of the orange goo...it has a luster and morphology that is unusual to me at this scale but I suspect it is some iron oxide mineral. There are other tiny features on the matrix that share an organic character, but even these are too small to image clearly at 10x.

Image

hero
Posts: 72
Joined: Mon Jul 17, 2017 12:38 pm
Location: California

Post by hero »

So I discovered that I've been setting the (reversed) Raynox-to-sensor distance much too short, resulting in a number of problems for my full-frame sensor. I estimate the total extension was somewhere around 140-150 mm, possibly less, but I didn't get an accurate measurement before modifying my setup.

Effectively, I was pushing down the Mitutoyo on FF, getting less than 10x, getting hard vignetting in the corners, and seeing severe astigmatism in the image periphery...and wondering why my setup was not meeting expectations.

I realized (after searching through too many forum posts!) that what I needed to do was empirically adjust the amount of extension so that the reversed Raynox was at infinity focus...I don't know why it took me so long to figure this out. I'm going to also try mounting the Raynox in the normal orientation and see what happens, because I suspect there's some pretty strong field curvature on FF in the periphery when reversed, which isn't a problem so much as a point of confusion when I review the stacks, since the corners aren't focused where I'm expecting them to be.[/list]

Beatsy
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Location: Malvern, UK

Post by Beatsy »

Nice shots. As Rik says, you wouldn't know the setup was less than optimal.

I've seen *very* similar "goo" when photographing rusty nails and screws up close. So the iron oxide origin sounds most likely to me. Perhaps just moisture in the air reacting with some water soluble component which swells and/or bubbles up as a result and carries oxides along with it (?).

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