MicrobeHunter.com Microscopy Forum

MicroBob wrote:I have tree different cameras and use them for the microscope in afocal mode. For each I use the best camera objective I was able to get hold of for not too much money:
Pentax Q7 - 8,5mm 1:1,9 (short because of the little focal lenght)
Nikon 1J5 - 18,5mm 1:1,8 (short because of the little focal lenght)
Sony A6000 - Pentax M 40mm 1:2,8 (a pancake design)

Bob, with which eyepiece do you use each camera objective ?

MichaelG. wrote: Note: the one on AliExpress is 500mm focal length ... I wouldn't have room to use that.

Oops, I took the diameter for the focal lenght - almost the same!

@Doron:
For the smaller cameras I have two adapters, one with an old Leitz Periplan eyepiece, higher but not high eyepoint, and one with a Zeiss Jena P non correcting high eyepoint eyepiece. For the Pentax I use a Zeiss West KPL 10 high eyepoint. The smaller cameras are very handy as they are small even with the adapter and don't put much weight on the microscope tube. For this reason I use them most. I think about a flash setup and would probably use the Sony for this as the Pentax and Nikon One systems are dead since several years. They were cheap but I wouldn't invest much money and effort in a dead end system. Both are good cameras though. For most of my everyday photograph I still use the Pentax as it has a great user interface, good but not great image quality and a lot of depth of field.

Bob

MicroBob wrote:... Probably you could even take a landscape picture with it when used off the microscope.

I tried it early this evening, Bob
... a very quick test, from the doorstep [it was raining]

With a Chinese m4/3 to T2 adapter, the focus is at about 4 metres, I think
... When we have some better weather, I will post a sample image.

MichaelG.

I wonder how the leitz 0.32x lens that they put on their slrs above a periplan eyepiece compares to using a pancake lens. I might have a chance to do some tests if all goes well, but they might offer an occasionally-affordable alternative.

Hi Dan,

A little experimenting this afternoon to answer your questions. This presumes you have the condenser with the fixed DIC prisms and phase rings, labeled "NIC/Phase Contrast"

I installed the mag changer above the DIC intermediate tube, directly under the head, and it works fine, at least visually. I didn't check the trinoc camera port. The bertrand lens will not focus on the fringe. I don't know why.

1) The condenser polarizer is only adjustable through a small range as you noted. It's really only adjustable to fine tune extinction and make up for a slightly rotated condenser. Make sure the red dot on the right side of the intermediate tube is lined up with the red dot on the stand just in front of the clamping screw. That is what aligns the slider with the turret. I tried an analyzer only slider to confirm the change in extinction with the small polarizer movement. It does pass from one side to the other of max extinction.

There is very little, if any change in the black interference fringe when moving the analyzer adjustment across the full range. I wasn't using a phase telescope however, just looking down the eyepiece tube.

2) Yes, turning the slider prism screw does give you a gradient. You should be able to, go starting screwed all the way in and backing it out, from almost white, through grey to very dark, almost black background (like dark field), through grey then slowly becoming yellow, then orange, to red, then magenta to purple and finally kind of a turquoise blue when screwed all the way out. These are interference colors and result in the "optical staining" mentioned as possible with DIC. The screw is translating one one part of the prism relative to the other.

3) The condenser probably has old, hardened grease. It should change positions easily, and not transfer excess torque to the mount. The good news is you can disassemble the condenser, clean the old grease out, and relube it very easily. The screws look like phillips but are really JIS (Japanese Industrial Standard - actually fit better than phillips). JIS screwdrivers can be found inexpensively on Amazon and are worth having if you have an Olympus scope.

It might be enough to warm the condenser gently with a hair drier or heat gun to soften the grease, but it's pretty easy to take it apart. I just decided to lube mine as it was a little stiff, too, and I shot a couple pictures I'll upload when I get a faster connection. Just remove the four very small screws on the top of the condenser, and gently pull the top off. You'll see a large central pivot screw. Remove that and the prism/phase ring disc comes up and off easily. Be careful to open the aperture iris to keep it hidden and safe. Clean the old grease off and relube. I use either Nye Damping Grease, or a good quality lithium grease. Reassemble it and you're good to go.

Tom

Hi Dan,

Here are the photos of the opened BH-2 DIC condenser.
Pretty simple. If you use a small phillips instead of a JIS, just very very careful as it won't fit quite as well as it should.

Tom

Tom, Would you happen to know if the prisms in the BH and BH2 (and less likely the BX??) NIC condensers are the same; with the main difference being the dovetail mount in the BH2?? I've seen BH setups for sale, but still hoping to find (affordably) a BH2 or BX.

PeteM,

No, I don't know off hand. I've never tried the BH system at all. The BX and BH2 condensers will interchange in the mounts, and I've been told the removable prisms are the same size, but whether they will interchange optically or not I don't know. Given the variability in the BX series - oil vs dry objective , oil vs dry condenser lens, apos vs fluorites, newer "N" infinity lenses vs older style infinity, high res prisms, normal prisms, high contrast prisms, regular or shift sliders, high res vs normal vs high contrast sliders, etc. - there's probably some useful overlap more likely I think BX to BH2 than the other way around, just due to the number of possible combinations. The BH-2 and BX sliders are physically different sizes, too, although I don't remember looking at them side by side and actually measuring them. I doubt infinity to 160 mm makes a difference, either, but it may.

I've tried BH-2 to BX phase rings and they don't work as they are not the same size, but as I understand it, shear, not size is the issue with DIC prisms.

That might be an interesting direction for experimentation. In a fit of financial foolishness a few months ago I decided I wanted to compare the Olympus BX High Resolution, Normal, and High Contrast DIC systems and have acquired a suitable number of prisms and sliders to do so. A couple more High Contrast prisms are on order from Olympus as they are just not available used. Since I already have the BH-2 NIC/Phase Contrast condenser and slider on the BHS, it would be a simple matter, though quite time consuming. to swap them for comparison. I'll have to give the idea some thought. Maybe a quick and dirty comparison is in order.

A last, but sad point: Affordable DIC is an oxymoron.

Tom

Thanks, Tom.

Thank you so much Tom. That all makes sense and is exactly what I've experienced. The tightness I was talking about was in turning the turret (the exact one you illustrated) through the detants and as you suggested, I disassembled it. I slightly unscrewed the large brass screw and put the tiniest amount of lubricant on each detant and now its smooth and does not disturb the condenser centering.