Question about enough light power for EPI DIC

[fsittony]

Hi all,
I just built my BH2 with EPI illuminator with 100W halogen light, but I still found it's not enough for darkfield or EPI DIC, it's too dark. especially the high magnificaion say 50x.
I wonder how much light power would be enough? 150W or 200W？Halogen light would be preferred as the color is better than LED.
Thanks.
Tony

[Saul]

What is your shutter speed ?

[Scarodactyl]

I would check to make sure your aperture is totally open and everything is set up right. I didn't have brightness issues with epi DIC on my bh2, though darkfield rarely gave me great results.

[fsittony]

What is your shutter speed ?

about 1/10 while ISO is 320.
The optical view is not bright enough, it's quite dim. For the camera, it's still ok to extend the shutter speed, but will it be any problem if set to seconds?
Tony

[fsittony]

I would check to make sure your aperture is totally open and everything is set up right. I didn't have brightness issues with epi DIC on my bh2, though darkfield rarely gave me great results.

Apertue is opened to just cover the image circle, and filed iris is closed a little to enhance the contrast, not too much.

How about the view from your optical eyepieces? Looks bright?
I have a retro LED lamphouse(10W) for BH2 trasmitted light. The brightness is better than the 100W halogen for transmitted DIC. Looks nice from the eyes.
I put it back instead of the EPI lamphouse, but it still looks quite dark from the optic eyepieces, brightness about the same as the original.
Tony

[Scarodactyl]

The view feom the eyepieces was fine up to 50x as I recall. I'm afraid I sold it a while back since I ended up with a Nikon system.
Dumb question, but have tou co firmed the right wattage bulb is in there? I once got an Olympus stereo base that the previous owner put the wrong voltage bulb in.

[fsittony]

The brightfield is ok. But DIC is such a light eater...
How about your Nikon system comparing to BH2, are the brightness and image quality better?
I actually DIYed the original lamphouse from 50W to 100W, replace the halogen bulb and drive the bulb with a lighting transformer and dimable switch.
Maybe I will try the 150W later. Hope the heat wouldn't be a big problem.
Tony

[Scarodactyl]

Hmm. Did you do all the filament centering and such? I was fairly impressed with the illumination on that system to be honest, that was using the bh2-uma with the original 100w lamphouse. I like the Nikon system better because of its less pronounced image doubling and the single adjustable slider is more convenient for swapping objectives in and out vs matching to one of four different prisms. For the illumination I use a fiber optic light guide from a 150w source adapted onto the end of thr illuminator, which is generally plenty bright enough.

[eKretz2]

My Vanox AH2 uses the same EPI lenses and such as the BH2, it has a built in 100W halogen illuminator. I generally don't have any issue at all getting enough illumination except for darkfield at very high magnification sometimes. What is your subject?

[fsittony]

Hmm. Did you do all the filament centering and such? I was fairly impressed with the illumination on that system to be honest, that was using the bh2-uma with the original 100w lamphouse. I like the Nikon system better because of its less pronounced image doubling and the single adjustable slider is more convenient for swapping objectives in and out vs matching to one of four different prisms. For the illumination I use a fiber optic light guide from a 150w source adapted onto the end of thr illuminator, which is generally plenty bright enough.

Ye, I did the filament centering. It's not that easy to find AC dimable lighting transformer for 150W and 200W, but there are some fiber optic illuminator marked SCHOTT on the market.
Maybe I will use that transformer like you, and see how to get it work with the UMA lamphouse. Do you mean you removed the halogen bulb from the EPI lamphouse and put a single fiber into the origin position where the bulb was?
Can you still do filament centering?

Regards the doubling, I encountered the same problem as you did. The prisms I use are ULWD T-2, T4-2, objectives are LMPLANFL 10X, NEO SPLAN NIC 20X, ULWD NEO SPLAN 50X.
Whenever I put the prism into the light path, the doubling comes. It's annoying, and not that clear as the POL. It looks embossed in DIC and have 3D effect but you can still see the doubling there.

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_DSC4848.jpg (106.21 KiB) Viewed 5418 times

I'm not sure if the ULWD prisms are wrong here with the BH2's polarizer UPO, or I should use the original N-NIC/M-NIC as the original brochure suggested.

Anyway, that's great you are satisfied with the Nikon system.


Tony

[fsittony]

My Vanox AH2 uses the same EPI lenses and such as the BH2, it has a built in 100W halogen illuminator. I generally don't have any issue at all getting enough illumination except for darkfield at very high magnification sometimes. What is your subject?

AH2 is a nice system, it's the best module among the H series. How about the EPI DIC, do you have enough brightness for that? When I slot in the polarizer, it eats lots of light just as the darkfield.
It then looks quite dark from the view, although I can slow the shutter speed to get brighter image, I'm not sure if it can resolve enough detail then.
I'm working on the leaf, and pollen at the moment. They don't reflect much light as the IC or stones.

How about your EPI DIC, do you have any doubling problem?

Tony

[Scarodactyl]

Yeah, I just 3d printed an adapter that fits into the lamp house to accept the illuminator. It is probably not positioned correctly and needs some more work, but this was an option that Nikon offered in some official form from what I can tell so it likely isn't conceptually wrong.

[eKretz2]

My Vanox AH2 uses the same EPI lenses and such as the BH2, it has a built in 100W halogen illuminator. I generally don't have any issue at all getting enough illumination except for darkfield at very high magnification sometimes. What is your subject?

AH2 is a nice system, it's the best module among the H series. How about the EPI DIC, do you have enough brightness for that? When I slot in the polarizer, it eats lots of light just as the darkfield.
It then looks quite dark from the view, although I can slow the shutter speed to get brighter image, I'm not sure if it can resolve enough detail then.
I'm working on the leaf, and pollen at the moment. They don't reflect much light as the IC or stones.

How about your EPI DIC, do you have any doubling problem?

Tony

I haven't noticed any doubling except when the prism is translated way off from the optimal area, so I don't think so, but I'm not looking at the same subjects as you guys. I generally am looking at metal stuff.

Here are a couple quick sample images of a yard leaf in pol and DIC - DIC looks almost exactly the same in terms of lighting. This is with the lamp on the 'low' setting. I think the analyzer on my scope maybe has some additional waveplate on board, as I don't get so much of the rainbow effect as you guys. I also don't have a stacking setup yet so forgive the small DOF.

50x pol



100x pol



100x DIC

[fsittony]

Yeah, I just 3d printed an adapter that fits into the lamp house to accept the illuminator. It is probably not positioned correctly and needs some more work, but this was an option that Nikon offered in some official form from what I can tell so it likely isn't conceptually wrong.

Got it. Thanks.
Tony

[fsittony]

My Vanox AH2 uses the same EPI lenses and such as the BH2, it has a built in 100W halogen illuminator. I generally don't have any issue at all getting enough illumination except for darkfield at very high magnification sometimes. What is your subject?

AH2 is a nice system, it's the best module among the H series. How about the EPI DIC, do you have enough brightness for that? When I slot in the polarizer, it eats lots of light just as the darkfield.
It then looks quite dark from the view, although I can slow the shutter speed to get brighter image, I'm not sure if it can resolve enough detail then.
I'm working on the leaf, and pollen at the moment. They don't reflect much light as the IC or stones.

How about your EPI DIC, do you have any doubling problem?

Tony

I haven't noticed any doubling except when the prism is translated way off from the optimal area, so I don't think so, but I'm not looking at the same subjects as you guys. I generally am looking at metal stuff.

Here are a couple quick sample images of a yard leaf in pol and DIC - DIC looks almost exactly the same in terms of lighting. This is with the lamp on the 'low' setting. I think the analyzer on my scope maybe has some additional waveplate on board, as I don't get so much of the rainbow effect as you guys. I also don't have a stacking setup yet so forgive the small DOF.

50x pol



100x pol



100x DIC

Above pictures are a noteboook RAM, and it is flat so I don't need to stack...I also haven't built the stacking system either, but if working with leaf, pollen, or such stuff, stacking seems to be a must.
Leaf and pollen generally don't have much DIC effect. It looks almost the same under 100x pol vs. 100x DIC.

How about your metal stuff, can you take a picture of it under DIC vs. POL for comparison?
What are your DIC prisms, are they ULWD or N-NIC?
I doubt the doubling effect is the nature of DIC as it creates the embossed effect, just a guess...

For metal stuff, DIC should have strong effect. Do you have the tint plate? It strengthen the DIC effect a lot.

IMG_20211117_101434.jpg (138.91 KiB) Viewed 5343 times

Thanks.
Tony

[eKretz2]

Yes, with metal it is very strong. Here is an example of a razors edge I've posted before. This is a Feather razor blade with a very highly finished bevel. Under regular brightfield or pol the surface texture of the last portion of the bevel is not visible. Under DIC it is plainly visible.



And a few cheek cells from another thread I took as a quick comparison.



I have both a full and ¼ wave plate but they're not set up to use yet. The one in your photo appears to be a neutral density filter, I'm sure you're aware already that's not the same as a tint (wave) plate. If you're using that it would explain the dimness.

Edit: I just saw the lambda - didn't notice that before.

[fsittony]

Right, DIC can reveals some details while POL and brightfield cannot, it has better 3D effect.
Thanks for the pictures. They look better than mine. The edges look clear.

I only use the middle lambda tint plate for DIC, just put it into the slot.It boosts the DIC effect. Forget about the ND12...blocks the light too much. I am still in eager of more light...

UTP.jpg (79.81 KiB) Viewed 5305 times

How do your DIC prisms look? Are they N-NIC or M-NIC type like below?

NIC.jpg (55.64 KiB) Viewed 5305 times

Tony

[eKretz2]

I've got 3 different types. They all seem to produce about the same quality of image, but I like the latter two best since the prism can be completely removed from the path to use darkfield, pol or brightfield with a quick flip or slide. The former style only allows translation of the prism, although the translation is much easier to fine tune since it's translated by a fine thread screw. I also have all T-2 prisms on the flip-out (second type) style except for one which is a T4-2. I don't care for that one, like the T-2 better. The T-2 give a nice even color or grayscale across the field, where the T4-2 is banded through several colors even on an almost completely flat surface. As near as I can tell the only difference between M-NIC and N-NIC prisms is that one can be used for 27mm threaded objectives and one can't. The former don't appear to be usable for darkfield or pol (nor clear brightfield) however as the prism isn't able to be removed from the light path without completely removing it from the scope.

[fsittony]

That's a full collection, pretty detailed comparison between the 3 types of prisms. Great information. It's true the flip-out style is more convenient for a quick transition.
I'm now using the middle on as you attached, T4-2 for 20X and the rest all T-2. Got my headache with the doubling issue. Brightfield, darkfield, pol produce the clear image while DIC not so good.

IMG_20211118_093542.jpg (176.61 KiB) Viewed 5263 times

Objective is Lmplanfl 10x, I tried ULWD NEOSPLAN also, the doubling issue under DIC is about the same.







DIC is obviously not clear as other modes.

Tony