LOMO MƂP-1

What equipment do you use? Post pictures and descriptions of your microscope(s) here!
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LomoBen
Posts: 27
Joined: Wed Mar 02, 2022 5:03 pm
Location: Reda,Poland

Re: LOMO Mbp-1

#31 Post by LomoBen » Sat Mar 12, 2022 1:05 pm

This is an example only:
https://botland.com.pl/diody-led/2498-d ... 56415.html
Because I live in Poland, this example.
But you can Google in your own country England?
Star LED 3 Watts.

rudnicki
Posts: 25
Joined: Wed Sep 23, 2020 12:36 pm

Re: LOMO Mbp-1

#32 Post by rudnicki » Sat Mar 12, 2022 1:32 pm

Attention, Russian bulbs are, if I'm not mistaken, 8V 20W. You have to find adequate power supply . I suggest you my solution. If you want to adapt the Russian illuminator, a led of one W is enough. 3W is the equivalent of a 20-30W halogen if not more.

LomoBen
Posts: 27
Joined: Wed Mar 02, 2022 5:03 pm
Location: Reda,Poland

Re: LOMO Mbp-1

#33 Post by LomoBen » Sat Mar 12, 2022 3:16 pm

Amoeba,
Have you seen this...?
https://www.youtube.com/watch?v=UQlaP-OhC2M

MicroBob
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Location: Northern Germany

Re: LOMO Mbp-1

#34 Post by MicroBob » Sat Mar 12, 2022 4:27 pm

I like the Cree XM-L2 10W and XHP 50 12V 36W LEDs. For basic bright field work 1W would be enough.For high power dark field 10W LED power is barly acceptable. I power them with a lab power supply that can supply at least 2A. For extended use at high power it is better to use stronger power supply. With strong LEDs the risk of burning them is much reduced.
I buy the LEDs on star or round boards and use heat compound and screws to mount them on the heat sink. I make the heat sinks on the lathe and try to hit a very close fit as this allows better heat transport to the stand of the microscope. I drill the heat sink from one side 3/4 through (7mm) and drill two angled holes from the edge of the LED mounting surface to meet the 7mm hole. This way it is fairly easy to place and solder the wires.

dtsh
Posts: 977
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Location: Wisconsin

Re: LOMO Mbp-1

#35 Post by dtsh » Sat Mar 12, 2022 5:14 pm

Amoeba wrote:
Sat Mar 12, 2022 10:27 am
I have come to realise that the original Russian bulb for the OI-19 is a low voltage bulb rated a 8V/20W. I initially thought it was mains rated! In that case, the sewing machine bulb I referred to earlier would DEFINITELY NOT be a suitable substitute. It is unlikely that the lamp and its components would be rated for mains voltage, the light intensity is likely to be too high, and it may get too hot. I was solely focused on the B12 mount and hadn't considered other factors. Having read excellent and the very useful information about microscopy lighting on the microscopy-uk.org website as suggested I see that very careful consideration is needed

I also now realise that the diaphragm is evidently part of a Kohler lighing system.

I would like to ask what rating of LED (wattage) is suitable for a microscope lamp? I imagine that 8W in incandescent would probably translate into less than 1W in LED lighting, although I think I saw a reference to a 2.5W LED? I am still reading up on this so I might come across the info somewhere down the line...
A number of people and manufacruters seem to be using a 3W LED, but I personally would prefer a bit more to allow for darkfield and other illumination techniques which requuire a brighter source of light. I put a 12W LED into my AO10 and tend to use it at it's lowest setting and with a 15% neutral density filter when viewing. When I'm using phase contrast or darkfield the extra illumination is nice.

MicroBob
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Location: Northern Germany

Re: LOMO Mbp-1

#36 Post by MicroBob » Sat Mar 12, 2022 6:50 pm

Of cause it is not only a question of power but also on how well it is used. If much of the light never reaches the specimen the light is wasted. In case a complete illuminator is available it makes sense to study how the light is transmitted and which size the filament has.

rudnicki
Posts: 25
Joined: Wed Sep 23, 2020 12:36 pm

Re: LOMO Mbp-1

#37 Post by rudnicki » Sat Mar 12, 2022 7:23 pm

Some photos showing how my illuminator works with a lomo microscope. The illuminator is connected to a laboratory power supply. A Chinese 30V 2A lab power supply costs in Poland 40 £. Old compact camera canon a 590 is
x2_Easy-Resize.com.jpg
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pine stem 200x
x1_Easy-Resize.com.jpg
x1_Easy-Resize.com.jpg (161.84 KiB) Viewed 3891 times
Image of the led in the eyepiece
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x4_Easy-Resize.com.jpg
x4_Easy-Resize.com.jpg (36.37 KiB) Viewed 3891 times

Amoeba
Posts: 60
Joined: Mon Nov 27, 2017 12:27 pm

Re: LOMO Mbp-1

#38 Post by Amoeba » Sun Mar 13, 2022 8:01 pm

Thank you LomoBen for the link to the video by MicrobeHunter. So Köhler illumination is about producing an even field of light and reducing glare by directing light only to where it is needed. I see there are quite a few other videos by MicrobeHunter on various microscopy topics which I will be having a look at in due course.

The information about illumination on the Microscopy-uk.org.uk seemed to suggest that a 5mm LED that emits 2000mcd would be adequate. This is about the amount of white light that is generated by an ordinary 5mm white LED. I did an experiment today using the original failed bulb as a means to mount the LED. This involved breaking the outer glass envelope but being careful not to break the insides and mounting an ordinary white LED in place of the filament on the two protruding support wires. Since I didn't have a piece of frosted glass, the LED was "frosted" using some fine sandpaper. The amount of emitted light seemed uninspiring, but after a carefully directing the beam at the mirror and some adjustment it could be made to work for brightfield. The intensity had to be turned down for the lowest magnifications, but was a bit of a struggle for the highest (x90). I didn't get the clearly defined diaphragm edges that were evident in MicrobeHunter's video (would this be due to sanding the LED?) but it was possible to adjust for best contrast and the arrangement seemed to work. This was just an experiment, so was lashed-up a bit casually although it did include a potentiometer to adjust intensity. Naturally, the final product will be wired up properly.

What now confuses me is that the conversations seems to have moved on to talking about 10W and even 36W LEDs! What is evident, is that even for comfortable viewing even for brightfield, more light is needed than a standard white 5mm LED can provide. I will probably order a couple of 2.5W or 3W LEDs on star PCBs for now. I still need to read up a bit more on darkfield and phase contrast techniques but I don't have suitable oil immersion objectives for darkfield yet.
Attachments
LED_fit_ordinary_white-1024.jpg
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Amoeba
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Re: LOMO MƂP-1

#39 Post by Amoeba » Tue Mar 15, 2022 4:44 pm

The microscope kit I bid one arrived today. There are some issues which I need help on so I have started a separate thread.

viewtopic.php?f=24&t=15161

The binocular head looks in good order and just needs a clean and a second K10x eyepiece.

The illuminator that came with it works. The bulb survived the journey and the 6.3V PSU worked just fine.

Hobbyst46
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Re: LOMO Mbp-1

#40 Post by Hobbyst46 » Tue Mar 15, 2022 5:41 pm

Amoeba wrote:
Sun Mar 13, 2022 8:01 pm
What now confuses me is that the conversations seems to have moved on to talking about 10W and even 36W LEDs! What is evident, is that even for comfortable viewing even for brightfield, more light is needed than a standard white 5mm LED can provide. I will probably order a couple of 2.5W or 3W LEDs on star PCBs for now. I still need to read up a bit more on darkfield and phase contrast techniques but I don't have suitable oil immersion objectives for darkfield yet.
1. An LED has an angle of illumination. At least, so it is with 5mm LEDs, the beam width angle can vary from 8 to 120 degrees (maybe more).
2. I have been playing a lot with 5mm LEDs and overall, their light is barely adequate for low-magnification objectives, let alone high-mag, not to mention darkfield, phase contrast etc.
3. It also depends on the distance between the LED and the specimen. The longer the distance, the stronger the LED we need. For example, if the LED is installed very near and below the field aperture, a 3W LED can be adequate (just that). However, if the LED is installed in the rear of the microscope, like it replaces a halogen external illuminator, 10W is the minimum. Just my experience.
4. The light source of the LED should be small.
5. It is possible to remove the epoxy lens of the LED by careful sawing/filing and get more intense light and a changed beam angle.

MicroBob
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Location: Northern Germany

Re: LOMO MƂP-1

#41 Post by MicroBob » Tue Mar 15, 2022 6:41 pm

A true Köhler setup projects the rectangular filament in the image plane, slightly defocussed. But many microscopes don't have a true Köhler setup, they use a frosted lens in the light path as the light source, it doesn't matter much how it is illuminated from behind as long as it is evenly illuminated. A good idea is always to check whether a new illumination seup actually supplied the condenser so it reaches it's nominal aperture.

Amoeba
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Re: LOMO MƂP-1

#42 Post by Amoeba » Tue Mar 15, 2022 10:13 pm

Amoeba wrote:
apochronaut wrote:
Wed Mar 09, 2022 9:21 am
Not too many of it's ilk have a dovetailed nosepiece or rotating stage. Lomo objectives are easy to find cheaply and sets could be assembled in several nosepieces for very low cost. Water immersion, apochromat, pol. With a binocular head and 18mm eyepieces it could be a quality versatile scope with an understage led added.
Having the dovetailed slide nosepiece is a bit of a gamechanger ; 3 scopes in one, so to speak and sturdy. The only drawback is that it isn't going to be plan.
... It does indeed look like the nosepiece can easily be removed and replaced with another by slackening off a couple inside the head once the eyepiece barrel is removed. I had not even noticed that this was possible. One could build up a set of eyepieces ready to go on alternative nosepieces as you suggest.
It seems I was wrong about this. The nosepiece just slides off. There are no screws to undo. On the near identical microscope that I have just received, it comes off relatively easily, but on this one it was rather tight and needed quite a bit of effort to move it, but it does just slide off. I also see that little adjuster can be used to align it. Something new learned. :-)

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woyjwjl
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Location: Wuhan, China

Re: LOMO MƂP-1

#43 Post by woyjwjl » Fri Mar 18, 2022 2:36 am

MicroBob wrote:
Tue Mar 15, 2022 6:41 pm
A true Köhler setup projects the rectangular filament in the image plane, slightly defocussed. But many microscopes don't have a true Köhler setup, they use a frosted lens in the light path as the light source, it doesn't matter much how it is illuminated from behind as long as it is evenly illuminated. A good idea is always to check whether a new illumination seup actually supplied the condenser so it reaches it's nominal aperture.
The filament position of bh2-bhs is fixed by screws and cannot be adjusted (although frosted glass can be removed). I consulted the manual and there is no requirement for filament focusing. Does this mean that BHS does not need to be adjusted.
Micrographers from China, thanks to the forum for providing a platform for exchange

MicroBob
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Re: LOMO MƂP-1

#44 Post by MicroBob » Fri Mar 18, 2022 10:00 am

On my Zeiss Jena NF I have the choice to swing in a ground glass or not. In one case the filament is the light source, in the other the ground glass right before the lamp. If the ground glass is not switchable it is part of the light path and should stay in there.

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woyjwjl
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Re: LOMO MƂP-1

#45 Post by woyjwjl » Fri Mar 18, 2022 2:56 pm

MicroBob wrote:
Fri Mar 18, 2022 10:00 am
On my Zeiss Jena NF I have the choice to swing in a ground glass or not. In one case the filament is the light source, in the other the ground glass right before the lamp. If the ground glass is not switchable it is part of the light path and should stay in there.
Well, I see. Thank you for your answer.
Micrographers from China, thanks to the forum for providing a platform for exchange

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