Interesting rechargeable battery powered LED lamp

[MicroBob]

Hi together,
I just got the rechargeable battery powered LED lamp that I ordered from Aliexpress:
https://de.aliexpress.com/item/10050030 ... 4c4d1XcQoE

Not tested yet but the first impression is really good. A very compact solution for microscopy on the go and no cables to step on. It starts always on the lowest setting and the intensity is increased in steps.

After having done some tests I will report again.

Bob

[MichaelG.]

That looks very tidy, Bob

Thanks for the link.

MichaelG.

[MicroBob]

Hi together,
I have tried it on the field aperture of my Phomi one and got an equally good image as with the buikt in illumination. Tested with an achr- apl. condenser n.a. 1,4 it is ably to fully light the backlens and support th full aperture. The reflector alone would give an uneven illumination, but with a white plastic filtre (part of the set) it works nicely.

One downside is that it is a sealed construction and the rechargeable battery will be difficult to replace one day.

Bob

[apochronaut]

The wonders of China never cease. No mention of the type of battery? I thnk NiMH is still the type of choice for deep cycle?

Turns out there is a less accessorized round version with a fixed 5700 K. colour temperature and a more robust battery.
1200 mah.
https://www.ebay.com/itm/Dimmable-Water ... ect=mobile

[Dubious]

Says it's a lithium battery. My worry would be that PWM is probably used to adjust brightness and might be at a low enough frequency to cause eye strain.

[MicroBob]

PWM

Good point, I will check this!

[Hobbyst46]

I wonder about the heat sinking of the lamp. Had a very bad experience with a rechargeable LED torch light, albeit from a different brand. It became very hot to hold after about 15-20 minutes. When I tried to simultanouly charge and illuminate, it warmed even more then failed altogether for good.

[MicroBob]

I checked it for PWM-flicker: At 1200 fps I can see high frequent flicker in live view at the first and third setting. My photos with 1/50 to 1/200 second don't show signs of flicker on all four settings.

Heat generation: At just 40x40x40mm it will heat up on the highest setting. I used it as a frontal light in video conferences on the first and second setting and temperatures were ok after long use.

[Chas]

I have just got the square Ulanzi-made white-only light ( VL49 ) with a diffuser built onto the front; I wasnt expecting too much, but I think it will be very handy.
Resting on the table it illuminates the mirror really well, when the microscope is vertical. For when the microscope is tilted I have tried it on a small gorilla tripod and that seems to work well too.
If anything it is a little too bright on its lowest setting, so it might benefit from a filter.
Otherwise:
The texture of the diffuser material is undetectable when the condenser is focussed on it.
The array of individual LEDs that are behind the diffuser do show up slightly but through the eyepiece I havent noticed any uneveness.
It would now be nice to find a nice way to hold some interchangable fixed stops on the front or perhaps an iris would be better.
Its major benefit is no wires ...no extension lead...no tripping up... no "tidy up that mess"

The downside to this one is that it is doesnt have extras to confine the angle of the light, so the other version might be better.
This is the the one I got:
https://www.amazon.co.uk/ULANZI-2000mAh ... th=1&psc=1

EDIT: A new arm that holds it pointing towards the mirror, regardless of how the microscope is tilted:

Adjustable arm for light.jpg (59.27 KiB) Viewed 2237 times

Update: I have had this set-up about a month and have been using the light on its lowest output setting (it is a bit too bright at 40x or less, without a filter ) and the battery lasts many hours.
The colours seem about correct with the camera set to 'Flash' white balance . The exposure times go ~ 1/30, 1/60, 1/100, 1/125 with each increase in light output setting (thats with a coin-type 25mm lens at ISO 100) but the battery is pretty guzzled at the highest light setting.
With a 100x oil immersion lens and an Amscope camera adapter at full light output,the exposure time was around 1/15 second at ISO 100.

I tried it on a fragment of butterly wing, with the arm raised and the light shining across the stage and was pleasantly surprised :

Ulanzi light x10 Bfly wing.jpg (87.79 KiB) Viewed 2141 times

It was a lot less fuss than using a ping pong ball as a diffuser!

I dont often look at transparent or mostly-refractive things and this might the downfall of using a diffuse light source, but with coloured objects this light isnt bad:

Antenna stack Watson 100x oil objective. Width of image about 0.1mm.jpg (47.17 KiB) Viewed 2141 times

This is a stack with a Watson 100x Para and an Amscope camera adapter .. the pic was sharpened once in Irfranview after resizing.

I have tried putting field stops in front of the light to increase contrast but I havent seen any improvement.
To help in focussing the condenser I have a small circle pencilled in the middle of the diffuser.

I reckon that if there are children in the house (or 60's going on 6) and you have a horseshoe monocular this is an enjoyable combination