Eggs on Oak leaf?

[Pizzazz]

Hi Pirates!

Using my Mitty 10x with mixed lighting from my Fostec Ace optical. One light is diffused through sail cloth, the other unfiltered.

This is a dead Oak leaf and I thought this may be fungus on it, but my mentor, Chris-S, indicated it may be eggs.

So,

Thoughts?

[NikonUser]

My thoughts: not eggs, maybe fungus, but pollen seems most likely

[Pizzazz]

A lot of the dead leaves have strange gray circles on them. I assume some kind of decomposition activity. Here you can see the edge.

I did this stack with the adapter ring for the Mitutoyo REVERSED; I threaded
it on the INSIDE of the step-down ring, assuming I may get a little more
punch in the focus, since placing the step down ring on top of my UV filter
introduces a soft focus due to the objective being further from the front
optic. Again, I am assuming the UV filter affects the point of focus by
adding distance.

[rjlittlefield]

A lot of the dead leaves have strange gray circles on them. I assume some kind of decomposition activity. Here you can see the edge.

This sounds right. About the small bright blobs, I agree with NikonUser that they look like pollen. Two lobes separated by a crease does not match any eggs I know.

... placing the step down ring on top of my UV filter
introduces a soft focus due to the objective being further from the front
optic. Again, I am assuming the UV filter affects the point of focus by
adding distance.

This part does not sound right. I assume that you're using your Mitutoyo as it's designed to be used, with the rear lens focused at infinity. In that configuration, the focus relationships will not be changed by inserting a filter between the objective and the rear lens. That's why microscope manufacturers switched to infinity optics in the first place: so they could easily stick components behind the objective without altering focus arrangements and dragging objectives away from their design points. If you're getting loss of contrast when you insert a filter, it's probably due to added reflections from the filter surfaces, not from any change in focus.

By the way, what's the function of the UV filter in this setup?

--Rik

[Carduus]

Could be pollen from a member of the Pinaceae (e.g. pine, spruce, fir, larch). I think I can see the distinctive double air-sacs on some of the grains.

[Chris S.]

... placing the step down ring on top of my UV filter introduces a soft focus due to the objective being further from the front optic. Again, I am assuming the UV filter affects the point of focus by adding distance.

This part does not sound right. I assume that you're using your Mitutoyo as it's designed to be used, with the rear lens focused at infinity. In that configuration, the focus relationships will not be changed by inserting a filter between the objective and the rear lens. That's why microscope manufacturers switched to infinity optics in the first place: so they could easily stick components behind the objective without altering focus arrangements and dragging objectives away from their design points. If you're getting loss of contrast when you insert a filter, it's probably due to added reflections from the filter surfaces, not from any change in focus.

By the way, what's the function of the UV filter in this setup?

--Rik

Mike is partly conveying my suspicions, though some "game of telephone" alterations may be entering the picture. (I've conferred with Mike by phone, and have viewed some of his images not posted to the forum.)

His original inclusion of the UV filter was an oversight, and one that I can empathize with. I've myself included, in a macro assembly, an item I had long used and mentally tuned out--and upon discovery given myself a mental dope-slap. When Mike first noted the presence of the UV filter, and removed it, his results improved markedly. He attributed this improvement to decreased reflections. It was I who responded, "Maybe so, or maybe not."

Mike is using a Micro Nikkor 200mm f/4 IF-ED lens as his converging lens. Some time ago, I also experimented with my specimen of this lens as a converging lens for Mitutoyo objectives, before I integrated an official Mitutoyo tube lens into my setup. One thing I noticed with this Nikkor, in this configuration, was that when I added a polarizing filter between the Nikkor converging lens and Mitutoyo objective, resolution dropped dramatically. It wasn't so much a loss of contrast as a general fuzziness. My sense was that the additional distance between objective and converging lens was at fault. While certainly true that Mitutoyo objectives are designed to permit considerable distance between objective and converging lens, the Micro Nikkor was not designed to be a converging lens. I did not wish to take time for further testing, and moved on to an integrated Mitutoyo tube lens, which I find to be very tolerant of having a polarizing filter inserted between tube lens and objective. But was the image degradation the result of added distance between optics, internally reflected light, or something else? I don't know. Had I cared to investigate further, there were obvious ways to test. But time has value, and we have to choose our experiments.

When Mike removed the UV filter from his setup, he showed me before and after images, and we discussed the matter by phone. The improvement was substantial. Mike suspected that the improvement came from the elimination of internally reflected light. I responded that this might indeed be the case, but that the benefit might instead have arisen from decreasing the distance between the converging lens and objective.

Leaving this question open may have benefit: Mike is currently conducting tests that move his objective even closer to the Micro-Nikkor 200mm converging lens. Whether or not this proves beneficial is an interesting question, if one intends to use this particular lens for converging Mitutoyo objectives.

It may indeed prove the case that added reflections, not added distance, are the factor in the decreased quality seen with Mike's UV lens in place. This would surprise me not at all--and would allow Mike to say to me, "I told you so." But he is too nice a fellow to do that.

Cheers,

--Chris

[Pizzazz]

Rik/Chris

First, you guys ROCK!. Second, I would never entertain a "told-you-so" response. This forum, and the members' feedback, provides a unique and
very much appreciated educational experience. The fact that you take the time to become involved with my work is greatly appreciated.

I plan on submitting another stack with the adapter ring in its correct position and we can compare.

The end-game would be having the ability to place a polarizer filter behind the objective, as I can understand the benefits of this in some situations. However, I am a long way from
doing so as I am still trying to dial in my setup and process.

Thanks for the GREAT feedback.

Mike

[Pizzazz]

Here is a shot with the adapter ring in its normal aspect. I will keep the adapter ring in its normal position from now on a I do not see any real difference.

[baro-nite]

Agreed it looks like pine pollen. We get clouds of the stuff in springtime. Out of curiosity I did a stack last year, not very interesting but does show the shape and color. (This was an experiment using a 10x objective on 300mm, for 15x.)