My Kit

[zzffnn]

Rod,

Also pay attention to optical alignment / centerimg of the camera /photo tube / projection lens. I am not saying that is what was causing the issues, but it probably helps to align everything.

When you said "pay more attention to condenser position", did you mean height or centration ? I am just curious.

[rnabholz]

Rod,

Also pay attention to optical alignment / centerimg of the camera /photo tube / projection lens. I am not saying that is what was causing the issues, but it probably helps to align everything.

When you said "pay more attention to condenser position", did you mean height or centration ? I am just curious.

I saw the difference tonight by adjusting height. With each change in objective it took a small tweak.

Thanks

Rod

[zzffnn]

Yes, some people adjust Kohler ( focus of field iris) for each objective change.

[rnabholz]

Yes, some people adjust Kohler ( focus of field iris) for each objective change.

I suspect my technique could benefit from more attention to this, whether using Apos or Achros.

[apochronaut]

i did some condenser tests sometime ago and posted them on the forum. if i recall correctly the AO high N.A. achromat condensers, yours included, were very sensitive to whether they were oiled or not, so much so that there really wasn't much advantage to using one unoiled. a better option might be to find an inexpensive abbe aspheric for unoiled use, which performed, i think possibly better than the achromat under such conditions. You aren't going to get any more than a maximum of .95 N.A. out of an unoiled condenser. there is also the .90 dry achromat, which would be the best option .

[rnabholz]

i did some condenser tests sometime ago and posted them on the forum. if i recall correctly the AO high N.A. achromat condensers, yours included, were very sensitive to whether they were oiled or not, so much so that there really wasn't much advantage to using one unoiled. a better option might be to find an inexpensive abbe aspheric for unoiled use, which performed, i think possibly better than the achromat under such conditions. You aren't going to get any more than a maximum of .95 N.A. out of an unoiled condenser. there is also the .90 dry achromat, which would be the best option .

Thank you for that Apo.

If you happen to recall the title of that thread, I would be pleased to look it up.

Well, oil and I have become very friendly over the last year or so with all of the darkfield and diatom study, so I have no issue oiling it up. I bought this rig to see just how good it could be, so there is no sense in not giving it every advantage.

Thanks again

Rod

[apochronaut]

Here is the second one which references the first.

viewtopic.php?f=5&t=2904

[rnabholz]

Here is the second one which references the first.

viewtopic.php?f=5&t=2904

Thanks Apo.

I only had about 45 minutes tonight, so I returned to the same target, and shot images with the condenser unoiled and oiled. Same exposure, levels adjustment and sharpening. I offer them for comment, after going cross eyed staring at them.

AO 4 Unoiled Condenser.JPG (138.39 KiB) Viewed 11645 times

AO 4 Oiled Condenser.JPG (137.37 KiB) Viewed 11645 times

[zzffnn]

Rod,

I saw no significant difference this time.

Such intensely stained subject is not good for telling apart effective NA. I myself did a test, comparing NA 0.65 achromat vs NA 0.95 apo, using some good stained slides. I found no resolution difference, as staining itself provides enough contrast/details, such that contrast/details does not rely on NA that much anymore (unlike mounted diatoms where contrast/details is mainly provided by NA).I actually slightly prefer the depth of NA 0.65 in my test.

Put on a good Frustulia slide and I guarantee you will see big difference, unoiled condenser vs oiled. I did.

[rnabholz]

Rod,

I saw no significant difference this time.

Such intensely stained subject is not good for telling apart effective NA. I myself did a test, comparing NA 0.65 achromat vs NA 0.95 apo, using some good stained slides. I found no resolution difference, as staining itself provides enough contrast/details, such that contrast/details does not rely on NA that much anymore (unlike mounted diatoms where contrast/details is mainly provided by NA).I actually slightly prefer the depth of NA 0.65 in my test.

Put on a good Frustulia slide and I guarantee you will see big difference, unoiled condenser vs oiled. I did.

Thanks zz

I will try a more conventional test subject soon.

Rod

[apochronaut]

I agree with Fan on that. For what it is worth, #1 has slightly better contrast and sharpness.

I'm still seeing a lot of flare and chroma around the borders of the nucleii, off axis. It seems, there is some essential lack of correction in your photo lens for the apos. Can you take an afocal shot of the same subject through the compens eyepieces and compare them?

[rnabholz]

Ok guys. Two shots, same slide, 90x Apo, afocal through the 10x Compens. Carefully adjusted condenser height, Unoiled and Oiled.

First Unoiled

AO 4 Unoiled Condenser Phone.JPG (170.84 KiB) Viewed 11606 times

Oiled

AO 4 Oiled Condenser Phone.JPG (165.45 KiB) Viewed 11606 times

[zzffnn]

Oiled condenser worked better this time. Resolution difference was seen in the central region, under that "red triangle". Many dots were resolved better with oiled condenser.

[rnabholz]

Thanks zz

Here are a few more I took tonight. These are all the same set up as above, except taken through 15x Compens eyepieces.

The difficulty in using the phone with the narrow field of view of these compens eyepieces is that they only cover about one third of the phone's sensor and project a round image about 1800 pixels in diameter. Not a whole lot to work with. The images below show a bit of that, but I think are still nice.

You will see that I am still getting some color - I have no Apochromat experience, so I don't know what is reasonable to expect. I welcome your thoughts please.

AO4 4881.JPG (75.51 KiB) Viewed 11597 times

AO4 4897.JPG (129.83 KiB) Viewed 11597 times

AO4 4902.JPG (61.9 KiB) Viewed 11597 times

AO4 4892.JPG (101.43 KiB) Viewed 11597 times

AO4 4908.JPG (111.57 KiB) Viewed 11597 times

[zzffnn]

Rod,

The diatom images look good to me. Don't worry too much about it.

I would suggest getting your DSLR there first. Most smartphone lens has a very wide angle and thus high curvature, which makes it hard to beat a prime lens of normal focal length. I remember a slight misalignment of my phone lens caused some edge degradation before, though not sure if you have it there.

Don't forget diatoms frustules are basically glass pieces, the thicker/more spherical/more irregular they are, the worse aberration they cause. Rhopalodia side view (your photos #1) is probably pretty thick, as is the diatom in your photo #4.

Crowded areas of a strew mount may not play well with color reproduction either. Ask Charles to carefully arrange some Frustulia for you

Colorless subjects can also reveal colors anywhere from your optical train, from light source bulb to camera sensor.

The green filter that I am sending you should cut off 90% of non-green colors, which will help, if you obsess with chromatic aberration.

Sorry, I am not the best person to ask for telling optical aberration. I usually don't pay much attention to them. Mostly I want apos because of their high resolution, which helps identify biological features. I have yet to produce a nice still photo as fine as yours.........

[billbillt]

These turned out very good!.. The only improvement to me would be some image stacking with the diatoms...

BillT

[rnabholz]

Rod,

The diatom images look good to me. Don't worry too much about it.

I would suggest getting your DSLR there first. Most smartphone lens has a very wide angle and thus high curvature, which makes it hard to beat a prime lens of normal focal length. I remember a slight misalignment of my phone lens caused some edge degradation before, though not sure if you have it there.

Don't forget diatoms frustules are basically glass pieces, the thicker/more spherical/more irregular they are, the worse aberration they cause. Rhopalodia side view (your photos #1) is probably pretty thick, as is the diatom in your photo #4.

Crowded areas of a strew mount may not play well with color reproduction either. Ask Charles to carefully arrange some Frustulia for you

Colorless subjects can also reveal colors anywhere from your optical train, from light source bulb to camera sensor.

The green filter that I am sending you should cut off 90% of non-green colors, which will help, if you obsess with chromatic aberration.

Sorry, I am not the best person to ask for telling optical aberration. I usually don't pay much attention to them. Mostly I want apos because of their high resolution, which helps identify biological features. I have yet to produce a nice still photo as fine as yours.........

Thanks zz

You make good points about the variables in play.

I am generally happy with the images and the views visually.

As to the DSLR, it is still my goal to get it working. I discovered that the projection lens looks like it may have some damage from fungus. The seller threw it in on the deal as an afterthought, I doubt he knew.

I may see if I can find a replacement, or may have to consider another approach.

Thanks

[rnabholz]

These turned out very good!.. The only improvement to me would be some image stacking with the diatoms...

BillT

Thank you Bill. I will take some stacks one I get things sorted a bit.

Rod

[gekko]

First, beautiful work, Rod, as always.

I am totally unqualified to comment on differences between oiled and dry condenser use on account of my bad vision, so, not surprisingly, I cannot discern any difference whatsoever in your examples. But my question is this: you can make the comparison with the condenser iris (as viewed at the back focal plane of the objective) the same size under both conditions, or you can compare them with the optimum opening of the iris in each case (so it would be open more in the case of the oiled condenser). Those are two "defined" states for the comparison in my view. I don't which one you used.

Sorry if the following is unrelated to the posts above, in which case please overlook it. On the subject of color fringes, my understanding (subject to correction the the experts) that an apo objective will produce CA from areas above and below the plane of focus (and this is normal). It is corrected for the plane of focus (same is true of achromats, as far as I know).

zzffnn: if you don't mind telling, where did you get that green filter that blocks most of the other colors? I have a Nikon interference filter (marked "GIF"), but it lets in a very wide spectrum (which rather surprised me). I now use a sandwich of inexpensive blue and green plastic and gel that does a much better job (much narrower bandwidth). Thanks for any suggestions.

[zzffnn]

gekko,

I was told by Dave J Jackson of Better Microscopy that Lee #124 gel filter works best for our purpose:
http://www.ebay.com/itm/231869474670

We looked through Lee filter's web page (and their spectrum data) and found #124 as the best fit.

You want an efficient (high pass) filter that passes only green light (with minimal blue/purple or yellow/red). Wide pass spectrum is fine, as long as it is only green, without other colors. Yellow or red will degrade image quality. Many green filters actually pass quite a bit of other colors, even though they all look green.

Dave did mention that green interference filter (GIF) usually works very well for our purpose. I don't already have a GIF and the other option is a $42 Olympus GIF that is only marginally more efficient (16% vs 10% of Lee, calculated from 300 nm visible spetrum). Dave did think the Olympus is necessary for me (even though I said I don't mind paying a mere $34 more), since my light source has a good output of 5000 lumens. That was why I bought the Lee filter. Can you find your Nikon GIF's exact spectrum?

[gekko]

Rod, forgive me for hijacking your post. I didn't mean to, it just happened .
zzffnn, many thanks for your very helpful reply. My Nikon GIF filter passes also yellow and some red (I used an inexpensive spectroscope to test it). I've not been able to find a curve for spectral response of my Nikon filter. Thanks again: you've given me excellent information as well as the link.

[zzffnn]

gekko,

Lee #124 passes around 5%-10% of yellow, but it is the best compromise of all Lee filters, per Dave Jackson: http://www.leefilters.com/lighting/colo ... &filter=cf

#735 was our second best choice, but ruled out due to low pass efficiency.

Dave also ruled out Moss Green, as it passes too much red.

[rnabholz]

First, beautiful work, Rod, as always.

I am totally unqualified to comment on differences between oiled and dry condenser use on account of my bad vision, so, not surprisingly, I cannot discern any difference whatsoever in your examples. But my question is this: you can make the comparison with the condenser iris (as viewed at the back focal plane of the objective) the same size under both conditions, or you can compare them with the optimum opening of the iris in each case (so it would be open more in the case of the oiled condenser). Those are two "defined" states for the comparison in my view. I don't which one you used.

Sorry if the following is unrelated to the posts above, in which case please overlook it. On the subject of color fringes, my understanding (subject to correction the the experts) that an apo objective will produce CA from areas above and below the plane of focus (and this is normal). It is corrected for the plane of focus (same is true of achromats, as far as I know).

Thank you gekko.

I probably am not much of a scientist, as my protocols aren't well conceived.

In this comparison, I was attempting to answer Apos interest in seeing afocal images out of concern that the lens in the camera adapter may have been causing issues. I took the opportunity to add the oiling comparison. I set up Kohler for both states, and obviously changed more than one variable. So maybe it just demonstrates my best afocal effort in both states.

You reminder about colour correction only applying to the focal plane is appropriate and agrees with zz's point.

Thanks for your interest.

Rod

[rnabholz]

Gekko, no worries about the new line of discussion. This thread has covered a lot of ground, all of it, including green filters, is interesting. Go for it!

Rod

[apochronaut]

The afocal images show a dramatic reduction in chroma and flare. They are very good, whereas the original shots of stained slides, you posted taken through the # 635 photo lens are terrible. So I would assume therefore, that your photo lens is not compatible with the apochromat objectives. Chroma and flare, seriously diminish off-axis resolution, so with the photo lens you are using, you would be better off using achromats, than apochromats for photography. The 635 photo adapter, is always pictured with achromats fitted in the stand.
I can find no reference to an apostar being fitted with the model 635 camera adapter or a modified version of it. Photomicrography for research purposes, in the day those were made, was still an elaborate time consuming process and for the research apochromats, aimed at professionals, who were used to a system, they had a unit model 682, which was a substantial stand with an aerial camera that was mounted over a phototube( the one I emailed you the measurements to). There was also the model 1300 Orthophot, which was more substantial yet and had a built in cine camera and illuminator. In both cases the microscope was fitted right to the base of the photographic unit, similar to the way the ortho-illuminator accepts the stand. I 'm pretty sure, if you send the photo unit back where it came from and replaced it with the aformentioned photo tube and a 5x compens lens, all will be well. Alternately, perhaps the existing lens an be removed and replaced with a compatible photo lens.
If I get a chance I will try to do some comparison images between a 5x compens and the # 1054 photo lens, I have been using( see recent AO 4 phase comparison post). The 1054 may not work well.for the apochromats but by the time those were made, the compensating features had been worked into the eyepieces. By the time the infinity apochromats came along , the same eyepieces were used for achromats and apochromats.

[rnabholz]

Thanks Apo.

That's a bit disappointing. It would have been nice had it worked out that simply with the camera adapter.

I think pursuing the photo tube and 5x makes the most sense, although that likely means a custom made tube.

Darn, but thanks.

Rod

[apochronaut]

Am I correct in assuming that the the lens is fixed into the adapter, inside a rather narrow passage, like the later ,similar adapters? Any way of removing enough of the optical parts to drop an eyepiece in there, so you still have the adapter's convenience?
I will check with the recently arrived machinist in a few days and see what he will want. The tube is simple and has only one thread, so it shouldn't be a lot......and the measurements are known.

[rnabholz]

I will have to check for sure later when I am home, but my impression is that the opening is quite narrow, I don't see an option involving inserting an eyepiece as viable.

I think the photo tube is likely the best option.

In anticipation, I grabbed this last night, a 5x compens

Look at this on eBay http://www.ebay.es/itm/291891687098

If your man can do the tube that would be great. Let me know.

Thanks

Rod

[apochronaut]

Good snag. That guy has a lot of unusual stuff.

[lScopysScopegScope]

Such a classic looking beaut.