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Upgrade Olympus BX40 Halogen to LED

Posted: Fri Jul 26, 2019 3:13 pm
by mrsonchus
Hi all, well the 'RetroDiode' LED upgrade for my Olympus BX40's 30W 6V Halogen arrives yesterday and it's a beauty!
Brightness is about the same or a touch brighter, but the colour of the LED is perfect, to the extent that my Canon EOS 200D auto white balance makes no change to the light colour when used with the LED-illuminated images. The LED stays exactly the same colour all the way through it's brightness range. Running temperature is way below the Halogen and the fins of the heat-sink are only warm to the touch.

A few images,
Side-by-side,
ws_retrodiode BX40 LED conversion (3).jpg
ws_retrodiode BX40 LED conversion (3).jpg (83.97 KiB) Viewed 7052 times
ws_retrodiode BX40 LED conversion (5).jpg
ws_retrodiode BX40 LED conversion (5).jpg (68.73 KiB) Viewed 7052 times
The LED's surface is correctly positioned in exactly the same place as the original Halogen's filament,
ws_retrodiode BX40 LED conversion (4).jpg
ws_retrodiode BX40 LED conversion (4).jpg (71.46 KiB) Viewed 7052 times
Fitted perfectly,
ws_retrodiode BX40 LED conversion (1).jpg
ws_retrodiode BX40 LED conversion (1).jpg (73.55 KiB) Viewed 7052 times
ws_retrodiode BX40 LED conversion (2).jpg
ws_retrodiode BX40 LED conversion (2).jpg (71.41 KiB) Viewed 7052 times
Working perfectly with a very nice white light!

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Fri Jul 26, 2019 3:49 pm
by Hobbyst46
Hi mrsonchus, this is interesting!

My small Zeiss Standard GFL never had a halogen lamp (was fabricated before halogen lamps were available, I am sure) so I replaced the incandescent by a 10W retrodiode LED. It works nicely.

Yet the Olympus BH2 which was mine on loan for a couple of days, the original is halogen, and together with the blue filter, provides fantastic bright white illumination, irrespective of the electrical power level. I wish I had such!
In the past I used an Olympus BX51 with halogen, illumination was fine.

Which retrodiode wattage is it on your new scope ? which color temperature ?

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Fri Jul 26, 2019 6:16 pm
by mrsonchus
Hobbyst46 wrote:Hi mrsonchus, this is interesting!

My small Zeiss Standard GFL never had a halogen lamp (was fabricated before halogen lamps were available, I am sure) so I replaced the incandescent by a 10W retrodiode LED. It works nicely.

Yet the Olympus BH2 which was mine on loan for a couple of days, the original is halogen, and together with the blue filter, provides fantastic bright white illumination, irrespective of the electrical power level. I wish I had such!
In the past I used an Olympus BX51 with halogen, illumination was fine.

Which retrodiode wattage is it on your new scope ? which color temperature ?
Hi Hobby' - here's a snip of the listing, a 6000K light, 800 Lumens, 10W...
Capture.JPG
Capture.JPG (51.06 KiB) Viewed 7030 times
If you're interested contact the fellow, he's called Stan and is very helpful indeed, and a very nice chap.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 2:26 pm
by Crater Eddie
That looks well made. I'm interested in your thoughts on how well / smoothly the controller works.
CE

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 4:02 pm
by mrsonchus
Crater Eddie wrote:That looks well made. I'm interested in your thoughts on how well / smoothly the controller works.
CE
Hi Ed' - that little controller works very well indeed. It has the usual not-to-zero 'feature' of these types of dimmers - i.e. it turns on/off with a nice positive 'click' rather than not clicking, to reassure that it's off before reaching going out. It's dimming range is very good: the point before it goes off is just perfect for the BX40's 4x objective, then there's a perfectly-smooth progression up to it's full-on level, which is a touch brighter than the original 30W Halogen of the BX40.

Nice little box, double-sided tape onto BX frame.
ws_DSCN0368.jpg
ws_DSCN0368.jpg (50.73 KiB) Viewed 6977 times
Here's the dimmer in action, the two black wires are for the camera - nothing to do with the illumination.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 4:33 pm
by Crater Eddie
Thanks John, I had wondered if it dimmed all the way down to zero or suddenly went out at some point, that seems typical as you said.
Unfortunately the vid says "unavailable". :(
CE

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 5:01 pm
by mrsonchus
Crater Eddie wrote:Thanks John, I had wondered if it dimmed all the way down to zero or suddenly went out at some point, that seems typical as you said.
Unfortunately the vid says "unavailable". :(
CE
Urk! Try it now Ed' :oops:

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 6:44 pm
by Crater Eddie
mrsonchus wrote:
Urk! Try it now Ed' :oops:
That fixed it, thanks.
CE

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 6:57 pm
by billbillt
Hello John B..

I am glad you chose to do the LED conversion... LED lighting is the future of microscope lighting..

The Best,
BillT

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 7:06 pm
by zzffnn
John B or anyone who has retroDiode LEDs,

If you use your camera in eletronic shutter mode with the LED, do you see those frequency bands?

Thank you.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 7:17 pm
by Hobbyst46
zzffnn wrote:John B or anyone who has retroDiode LEDs,

If you use your camera in eletronic shutter mode with the LED, do you see those frequency bands?

Thank you.
When I started using the retroDiode LED fixture, with the original simple PWM dimmer (square box, off-white color) I got bands. Stan suggested to switch to a 21KHz PWM dimmer. I did so and the bands disappeared, unless the shutter speed is very high, say 1/400 s. Perhaps if I used a faster speed, say 1/1000 s, they would have disappeared, but the light beam is not that bright and the ISO setting is usually 200 and sometimes 800.
A constant current power supply would likely make a better dimmer, but I have PWM...

I wonder which dimmer/controller is in John B's new LED setup.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 7:38 pm
by zzffnn
Yes, the friend of mine who made my LED said bands came from the PWM dimmer and different pot position may produce different amount of banding.

I think most APSC sensor would be fine with iso800. Even my small micro four thirds sensor (Olympus E-M1 mk1) does okay with iso800, though not much higher.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 7:41 pm
by Hobbyst46
zzffnn wrote:Yes, the friend of mine who made my LED said bands came from the PWM dimmer and different pot position may produce different amount of banding.
zzffnn, I think that the PWM dimmer has no pot positions, it just changes the duty cycle, not the voltage or current supplied to the LED.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 7:47 pm
by billbillt
"zzffnn, I think that the PWM dimmer has no pot positions, it just changes the duty cycle, not the voltage or current supplied to the LED."

Yes.. That is what PWM stands for.. Pulse Width Modulation.. It changes the amount of duration of the on-off cycle...

BillT

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 7:58 pm
by MicroBob
Hi together,
if you are looking for an uncomplicated LED power supply these are nice:

https://www.ebay.de/itm/Regelbares-Labo ... SwIoNc9kct

https://www.ebay.de/itm/323288745987

The first one is nicer as a general purpose lab power supply.
The second one has lots of power and can be used for bulbs and LED
Both take up little space and can be used for other purposes like heat plates, little ovens, fans...

These are nice LEDs for cases where you need real power, like reflected light or high power darkfield :
https://www.ebay.de/itm/Cree-XLamp-XHP5 ... 2749.l2649

Quite a small emitter, similar to the flat filament of a bulb, and this one has a nice light temperature of 4500K.
These are clusters of 4 single LEDs that are grouped closely together, similar to the wire of a filament, and work with higher voltage and less current, so you don't need especially fat cables. To use the full power that is available you need good cooling. LEDs have an efficieny like a fluorescent lamp - not bad but not great either.

Bob

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 9:09 pm
by mrsonchus
zzffnn wrote:Yes, the friend of mine who made my LED said bands came from the PWM dimmer and different pot position may produce different amount of banding.

I think most APSC sensor would be fine with iso800. Even my small micro four thirds sensor (Olympus E-M1 mk1) does okay with iso800, though not much higher.
Hi all, had a quick go at precipitating the banding effect..... Banding,

With the lamp set to about 20% the banding appeared at about 1/400sec at 800 ISO, see below, image darkened to accentuate banding - this was only seen in the taken image, not with the eye,
ws_small_1_400sec at 800 ISO 20pc lamp.jpg
ws_small_1_400sec at 800 ISO 20pc lamp.jpg (26.75 KiB) Viewed 6913 times
Here at 1/640sec and 800 ISO 20pc lamp, again darkened to show bands more clearly,
ws_small_1_640sec at 800 ISO 20pc lamp.jpg
ws_small_1_640sec at 800 ISO 20pc lamp.jpg (24.49 KiB) Viewed 6913 times
At 1/800sec, 100 ISO and 100pc lamp - no banding, darkened image again,
ws_small_1_800sec at 100 ISO 100pc lamp.jpg
ws_small_1_800sec at 100 ISO 100pc lamp.jpg (23.29 KiB) Viewed 6913 times
Here at 1/2000sec with 100 ISO and 100pc lamp, there appears a smooth gradient from the top of dark->light, but there's subtle barring.... This image has not been altered.
ws_small_1_2000sec at 100 ISO 100pc lamp.jpg
ws_small_1_2000sec at 100 ISO 100pc lamp.jpg (20.26 KiB) Viewed 6913 times
Finally, at 1/800sec, 200 ISO and 70pc lamp there are not-visible without darkening, wide bars. This image has been darkened from 'normal brightness' to show the bars,
ws_small_1_800sec at 200 ISO 70pc lamp.jpg
ws_small_1_800sec at 200 ISO 70pc lamp.jpg (67.15 KiB) Viewed 6913 times
So, on my BX40 the LED is easily bright enough and the ISO-shutter-lamp combinations that I use for my objective set from 4x to 100x work out fine - no barring at all. This may be simple luck as the three factors clearly interact and have many settings that will cause barring......
If I had a barring problem with this converter I'd buy a suitable lab PSU to power it as I think the adapter is definitely worth having as the fitting into the BX40 and the LED position is perfect - the PSU is easily replace cheaply enough as MicroBob has linked-to above.

Sorry this is a little random, if I'd made an entire and ordered set of images tonight I may have lost the willl to live half way through - I've had a very busy day...

My conclusion, a great converter, worth it's cost even if a new PSU must be added....

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 9:33 pm
by Hobbyst46
mrsonchus wrote:...
This message should be read after a 12h delay at least ;)
IMHO, the voltage-current lab PSUs shown in the photos above, can be used if and only if it can be set to a constant voltage and variable, controllable current, which can be preset to stay below a limit. As we know, the maximum continuous operating current of a LED must not be exceeded.
An alternative option, I think, is the 21KHz PWM dimmer from retroDiode.

Or maybe the simplest of all set the dimmer permanently at 100% and dim the light with ND filters, like your variable polarizer filter.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 10:11 pm
by zzffnn
Thank you very much, gents.

John B, your banding is quite subtle. My LED reveals very obvious band at most shutter speeds.

Sorry for the confusion about dimmer.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 10:16 pm
by mrsonchus
Hobbyst46 wrote:
mrsonchus wrote:...
This message should be read after a 12h delay at least ;)
IMHO, the voltage-current lab PSUs shown in the photos above, can be used if and only if it can be set to a constant voltage and variable, controllable current, which can be preset to stay below a limit. As we know, the maximum continuous operating current of a LED must not be exceeded.
An alternative option, I think, is the 21KHz PWM dimmer from retroDiode.

Or maybe the simplest of all set the dimmer permanently at 100% and dim the light with ND filters, like your variable polarizer filter.
Hi Hobby! :D :D :D

Yes, the 100% on plus the variable ND filter is my preferred method. With the larger field-diaphragm port of the BX40 the v-ND is a lovely tidy fit. It's absolute simplicity to turn the filter-glasses for a perfect intensity. The LED runs quite cool - at most just about warm - to the touch of the heat-sink. The colour of the light, nominally 6000k, is perfect too - Neither the camera or photoshop make any changes when I select WB correction. I also find that I get better results (in terms of sharpening that is) when I turn off all in-camera sharpening then perform a subtle sharpening if the subject warrants it, within PSE.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sat Jul 27, 2019 10:28 pm
by mrsonchus
Hobbyst46 wrote:
I wonder which dimmer/controller is in John B's new LED setup.
When I spoke to Stan before my purchase he said it was indeed the 21kHz model. Presumably this was a change to the small black one I have, from the former 'off-white' version which was larger. I used to have the (my own purchase online) large off-white dimmer and it did give awful banding on anything much below about 95% LED-power (on my stereo 'scope).
The one that now comes with RetroDiode lamps seems a great improvement - not perfect but much improved, if you intend to actually use the dimmer with the LED I suppose, for photography that is.

When using the BX40's Halogen on full it still needed a blue filter, which then significantly reduced the brightness for photography, when used with the variable ND filter. The BX40's one shortcoming may be the 30W Halogen - slightly under-powered maybe when roaming into DF or phase?

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 12:19 pm
by Hobbyst46
For the record, I was able to double-check the halogen illuminator of the Olympus BH2 that I tested a couple of days ago. It is a 100W 12V lamp. No wonder it was SO bright, even for darkfield. Maybe it has been fitted as custom upgrade from an (original?) 20-30W lamp...

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 12:48 pm
by 75RR
Best way to avoid banding is not to use Pulse width modulation (PWM).

Much better to use a Direct Current Driver instead.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 12:51 pm
by MichaelG.
Hobbyst46 wrote:For the record, I was able to double-check the halogen illuminator of the Olympus BH2 that I tested a couple of days ago. It is a 100W 12V lamp. No wonder it was SO bright, even for darkfield. Maybe it has been fitted as custom upgrade from an (original?) 20-30W lamp...
I sincerely hope that it is not a DIY substitution ... the power supply and wiring may not handle the higher current :o

Here is a proper 100W lamphouse for reference:
https://www.ebay.com/c/1840457573

MichaelG.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 12:52 pm
by mrsonchus
75RR wrote:Best way to avoid banding is not to use Pulse width modulation (PWM).

Much better to use a Direct Current Driver instead.
Looks interesting 75' - how is it used?

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 1:00 pm
by MichaelG.
75RR wrote:... Much better to use a Direct Current Driver instead.
and, for those of an inquisitive nature, here is the DataSheet:
http://www.leddynamics.com/wp-content/u ... kBlock.pdf

MichaelG.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 1:04 pm
by Hobbyst46
MichaelG , it is the same as in the photo. A standard proper upgrade , not DIY.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 1:07 pm
by 75RR
mrsonchus wrote:
75RR wrote:Best way to avoid banding is not to use Pulse width modulation (PWM).

Much better to use a Direct Current Driver instead.
Looks interesting 75' - how is it used?
Here is some literature on it:

http://www.leddynamics.com/buckblock-a009

http://www.leddynamics.com/wp-content/u ... kBlock.pdf

It is DC IN / DC OUT

You would need to match the mA output with that of your LED.

This one has 3 models: 1000mA, 1400mA and 2100mA

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 1:11 pm
by MichaelG.
Hobbyst46 wrote:MichaelG , it is the same as in the photo. A standard proper upgrade , not DIY.
Thanks for the reassurance ... I had obviously misinterpreted your earlier post :oops:

MichaelG.

Re: Upgrade Olympus BX40 Halogen to LED

Posted: Sun Jul 28, 2019 1:22 pm
by mrsonchus
Thanks 75'.