DSLR issue

[Scarodactyl]

A cheaper LED might have a lot of blue in its spectrum which could exaggerate the perceived CA. On the other hand running a 12v bulb at 6v is going to give a pretty far from neutral spectrum too I'd think.

[LouiseScot]

A cheaper LED might have a lot of blue in its spectrum which could exaggerate the perceived CA. On the other hand running a 12v bulb at 6v is going to give a pretty far from neutral spectrum too I'd think.

Hi

I don't know what LED is factory fitted to the Amscope. I think the one I've been using with the rail system is a warm white, so with reduced blue, but I'll check.

Louise

[ldflan]

A cheaper LED might have a lot of blue in its spectrum which could exaggerate the perceived CA. On the other hand running a 12v bulb at 6v is going to give a pretty far from neutral spectrum too I'd think.

No, it's not an excess of blue that's the issue in my experience. I say that because you can't simply filter out the blue/purple when an LED induces CA like this. Maybe it's the lens or lenses over the diode? Don't know.

[LouiseScot]

A final comparison! Amscope T720Q + Canon 1100d + Chinese Infinity Plan Fluor 40x: Factory LED (3W), Halogen Bulb 30W, Warm White LED (3W)
I had to place the halogen (on a heatsink) and the Warm White LED (Also on a heatsink) just atop the Kohler illuminator so illumination probably not so even or precisely centred. The factory LED illumination was Kohler adjusted. Condenser set to '40' on the scale (it could probably be set closer to '60' as it's 40/0.85 - but a small detail).

Factory LED:

IMG_0001_factoryLEDCropAuto.jpg (68.29 KiB) Viewed 1485 times

Halogen:

IMG_0004_tungsten_Cropadj_tung w bal.jpg (69.19 KiB) Viewed 1485 times

Warm White LED:

IMG_0010WarmWhiteCropAdj.jpg (68.56 KiB) Viewed 1485 times

They are each different but not hugely so (to my eyes). I'm not a very good judge when it comes to adjusting colour settings but I try... I did do some adjustments to the images - just aligning peaks in levels, overall levels, and some brightness/contrast tweaks. Exposures were different: Factory LED 1/50s; Tungsten 1/125s; Warm White LED 1/500s.

I think I'm going to put this topic to bed now, but any comments/thoughts are welcome

Louise

[ldflan]

To my eye, the tungsten halogen is vastly better than either of the LEDs. You are getting a lot of green or purple CA from both of the LEDs, and it is obscuring detail.

[LouiseScot]

To my eye, the tungsten halogen is vastly better than either of the LEDs. You are getting a lot of green or purple CA from both of the LEDs, and it is obscuring detail.

You may be right! Though (my) flaky post adjustment also plays a role... I think it would be tricky to retrofit a halogen lamp to the T720. I'm awaiting delivery of a 100x/1.30 plan fluor and I'm anticipating that will be better for viewing diatoms (100x oil certainly has been a lot better previously!). With just the 40x I've been doing extreme cropping which I shouldn't have to do at 100x

Thanks

Louise

[Hobbyst46]

Halogen is an "established" light source. No wonder that modern research microscopes are still offered with halogen as default (last time I checked - 2-3 years ago). And when they offer LED, these are expensive LED lamps, which had been optimized. For example, a very high color index. Perhaps the AmScope microscope LED lamp is less so. And contains a strong blue component.

Yet, I would try and test the setups with a micrometer stage as well, because of the complex optical properties of diatoms.

[Hobbyst46]

For example, my own new retroDiode lamp delivers neutral white light from a 95+ color index. Its output is much "whiter" than the previous one that had a strong blue component (although the blue component is useful for other purposes).

Louise, thanks for the nice comparison !

[LouiseScot]

For example, my own new retroDiode lamp delivers neutral white light from a 95+ color index. Its output is much "whiter" than the previous one that had a strong blue component (although the blue component is useful for other purposes).

Louise, thanks for the nice comparison !

Hiya

Of course, tungsten halogen run very hot - especially the 30W one I used. What did you think of the warm white LED image? That LED has reduced blue (2900-3200K). The halogen initially gave a very warm/high red image which I adjusted. Is your lamp a single LED below the illuminator? I could probably substitute a different LED for the factory-fitted one but I don't know the best one to get (that would be compatible).

Thanks

Louise

[Hobbyst46]

Of course, tungsten halogen run very hot - especially the 30W one I used. What did you think of the warm white LED image? That LED has reduced blue (2900-3200K). The halogen initially gave a very warm/high red image which I adjusted. Is your lamp a single LED below the illuminator? I could probably substitute a different LED for the factory-fitted one but I don't know the best one to get (that would be compatible).

Did you place a pale blue filter on the halogen ? that is the ordinary way (AFAIK) to achieve a near daylight background color.

My lamp is fitted into the base of the microscope, such that the LED die rests at the same point where the original incandescent lamp filament was (when it was, decades ago; much inferior to any LED). So, it is below the field aperture, and I can achieve proper Kohler illumination with those retroDidoe LED lamps.

I think that, of the three most recent images you posted, the warm white was the worst - aesthetically.

Sorry that I cannot suggest a substitute LED. But I would look for a neutral white (say 5000K).

[LouiseScot]

Of course, tungsten halogen run very hot - especially the 30W one I used. What did you think of the warm white LED image? That LED has reduced blue (2900-3200K). The halogen initially gave a very warm/high red image which I adjusted. Is your lamp a single LED below the illuminator? I could probably substitute a different LED for the factory-fitted one but I don't know the best one to get (that would be compatible).

Did you place a pale blue filter on the halogen ? that is the ordinary way (AFAIK) to achieve a near daylight background color.

My lamp is fitted into the base of the microscope, such that the LED die rests at the same point where the original incandescent lamp filament was (when it was, decades ago; much inferior to any LED). So, it is below the field aperture, and I can achieve proper Kohler illumination with those retroDidoe LED lamps.

I think that, of the three most recent images you posted, the warm white was the worst - aesthetically.

Sorry that I cannot suggest a substitute LED. But I would look for a neutral white (say 5000K).

Hi
No, didn't use a blue filter - didn't think to! I might try it though So what make/model was the 'retroDiode' LED you fitted?
Louise