Glare problem with 144 LED right light for microscope

[lukego]

So where are we at now with the 8 inch beauty light? It's still worth it? Or it's not worth it for the $20 to save towards the $250 polarized ring light ?

 

I think the photo that I posted above is representative.

I'm going to upgrade to the polarized light. The beauty light avoids glare but I'm just not satisfied with the brightness. If it were significantly stronger it would probably be a viable solution but I don't want to keep spending money on cheap hacks that don't quite solve the problem. So I'll bite the bullet on the polarized ring light that should always be in the right position and easily control the level of light and shine to suit the task at hand.

Luckily I was able to cancel my order of the gooseneck lights although maybe I'll need that for high mag in the future.

[dreamcat4]

yes indeed. my impression from the photo is that the larger diameter will probably conflict with the mocroscope arm where it attaches and has the geared rail to move the head up / down. which is going to hamper the positioning / mounting and potentially somewhat get in the way.

also the dim-ness aspect is expected due to the low cost they cannot use anything but the cheapest leds. but in my mind what that calls for is homebrew replacement / modification using the same ring shell as the basis for that.

i also agree with the idea of getting the expensive polarizer. although its pretty darn expensive atm.

my other suggestion is maybe just flood your entire room with more ambient light from far away. by buying hundreds of led strips. which the isnt going to be at any single angle since it will bounce around from all walls and other surfaces in the whole room. this might be more help than the beauty light. and the cost will be less than the polarizer. (and help the polarizer too since that cuts the amount of light).

 

[lukego]

yes indeed. my impression from the photo is that the larger diameter will probably conflict with the mocroscope arm where it attaches and has the geared rail to move the head up / down. which is going to hamper the positioning / mounting and potentially somewhat get in the way.

This bit is actually okay for me because the microscope is on an articulating arm. The ring doesn't obstruct the microscope positioning.

also the dim-ness aspect is expected due to the low cost they cannot use anything but the cheapest leds. but in my mind what that calls for is homebrew replacement / modification using the same ring shell as the basis for that.

That is probably a fine idea. I'm gradually coming to realize that I'm not much of a DIY-er compared with many other people on this forum. I'm more digital than analog.

my other suggestion is maybe just flood your entire room with more ambient light from far away. by buying hundreds of led strips. which the isnt going to be at any single angle since it will bounce around from all walls and other surfaces in the whole room. this might be more help than the beauty light. and the cost will be less than the polarizer. (and help the polarizer too since that cuts the amount of light).

I have done this too actually. Since I'm working in a small room with white walls and ceiling I'm bouncing light from two color-adjustable Neewer LED panels around my room. I really like this for general strong and soft lighting of the room and work space, though i'm not sure how much impact it has on the microscope (that 144 LED ring light at close range is damn bright.)

[lukego]

I have the polarizing LED ring light now (https://www.aliexpress.com/item/4000689771351.html). I'm just playing with it and don't really have the hang of it yet.

Here's how it looks with the 0.5x barlow lens:


Here's how it looks with the 1.0x objective lens:


I've set auto-exposure in those videos but it seems superior to manual mode for me: it always chooses the maximum shutter time (~1/60sec) and then enough gain to achieve the chosen brightness level.

What do you make of it?

[lukego]

I am still waiting for the 1/3 reduction lens. This will potentially increase the field of view and catch more light. However, I do reflect that the view from the eyepieces is round and the same might be true for the camera with the 1/3 reducer. Curious to see how it looks.

[dreamcat4]

as would 0.5x barlow instead of 0.7

[lukego]

I'm super happy now! I'll make a video when I have the chance.

The killer combo for me is the polarizing ring light with the 1/3 reducer on the camera port and the 0.7x Barlow lens.

Switching from the 1/2 reducer to 1/3 is s big improvement in field of view and light level. I expected to see black around the edges but there is little or none so it's pretty optimal rectangular cropping of what I see in the eyepiece.

The 0.7x gives me enough working distance and also provided enough light even for the most extreme positions on the polarizer.

Great stuff!! The 1/2 reducer that I started with seems to have been simply the wrong tool for the job/camera and discarding a lot of light.

[dreamcat4]

cool man. thanks for coming back to let us know!

 

[jfiresto]

Good job.

I am encouraged by your success with polarized light. I have all the parts and tools to add it to a microscope, and will as soon as I finish adapting its stand and an 0.5X auxiliary lens. The lens acts more like 0.7X because it is meant for a different make and design of microscope (later Japanese instead of classic Swiss).

[sn4k3]

I'm super happy now! I'll make a video when I have the chance...

See, the right pieces and quality stuff makes all the difference

[lukego]

Here is a quick video of the new setup:



I'm very thankful for all the tips and feedback here. Honestly I was quite disappointed with the polarized ring light in the beginning because it did not seem bright enough for the camera port. The real problem seems to have been that I was using the wrong reducer lens and spilling most of my precious light away from the camera sensor. Having videos demonstrating how it's supposed to look really helped!

(Sorry about the focus issues towards the end, I don't have a setup yet to record and view the camera port at the same time, I'm doing everything on the HDMI output going into a capture card. Polarizer is great for finding dog hair on these old zombie boards...!)

[lukego]

Update: I waited a very long time for my gooseneck LED lights to be delivered (https://www.aliexpress.com/item/1645407423.html) and I'm getting much happier now with my picture quality and overall light level. I'm able to get a decent image on the camera without adding gain/ISO on the camera and without unwanted glare.

Here's how it looks now:



And here's another video of the same setup but with a Nikon DSLR camera instead of the dedicated microscope camera (just out of curiosity because I'm curious about the relative sensor and ISO quality.)

[lukego]

I have been happy with my video quality lately. I've been positioning the gooseneck lights really close and this delivers enough light even for high magnification. Here's a video from the camera port doing 01005.



I do still find it challenging to get enough light to the camera port for decent exposure. I'm wondering whether a camera with a more sensitive sensor might help with this in the future. I'd like to hear recommendations for cameras delivering good picture quality even when the microscope doesn't deliver too much light.

[jfiresto]

... I'm wondering whether a camera with a more sensitive sensor might help with this in the future. I'd like to hear recommendations for cameras delivering good picture quality even when the microscope doesn't deliver too much light....

What camera are you using and how big is its sensor?

This $400 microscope camera only has a 1/2.3" sensor. The sensor in a micro four thirds camera has almost four times the area which almost wins you a couple f-stops. The sensor in a full frame camera is that much larger again and almost win you a couple more. Full frame, however, usually needs a relay lens; micro four thirds sometimes doesn't.

[dreamcat4]

To take advantage of the whole sensor area on a DSLR camera, you will need the right type of a lens that is capable of magnifying and being within the allowable focussing range, for the aperture. Whilst being at the right distance away from the camera port. At the distance where the camera had been mounted.

Probably not so easy or so simple to get right. Unless you already find somebody else has done that, and they can recommend the right adapter product(s) for achieving that.

Otherwise the best microscope camera is the blue square / cube shaped ones. Which have the sony IMX290 sensor in them. They are full HD 1080p @ 60fps. With 2 variants. A version with auto exposure but FIXED focus, that is the cheaper one. Then for an extra ~$100 or so is the version that looks exactly the same, but also includes auto focus. And it's the autofocus version that Dave Jones eevBlog made his video about. Sorry I don't have a link handy. But you can find it on eevblog youtube channel.

Hope that helps.

[jfiresto]

To take advantage of the whole sensor area on a DSLR camera, you will need the right type of a lens that is capable of magnifying and being within the allowable focussing range....

The challenge in adapting a DSLR is that it needs a suitable relay lens, if for no other reason, because the mirror distances the sensor from the lens flange. If you can live without an optical viewfinder, a mirror-less camera brings the sensor within range although you may still need an expansion lens to fully cover it.

Otherwise the best microscope camera is the blue square / cube shaped ones. Which have the sony IMX290 sensor in them.

Ack. That one is 1/2.8" and even smaller than the one I linked to.

[lukego]

Thanks for helping me work this out!

I'd like to briefly step back and summarize/acknowledge that:

• I don't know much about optics but I'm impatiently waiting for a copy of Light: Science and Magic that is taking a long time for delivery. So though I may miss some of the finer points here now I'll come back later to understand fully.
• There are a lot of variables affecting picture quality: microscope head, objective lenses, auxilliary lenses, optical splitter for the trinocular ports, camera sensor, etc and I may not be considering the right one(s).
• I am mostly wondering where is the lowest hanging fruit: what could I do to get sharper images, less sensitivity to low light, better depth of field, etc?

So with that out of the way let's get back into this.

Otherwise the best microscope camera is the blue square / cube shaped ones. Which have the sony IMX290 sensor in them.

This is actually what I am using now: the Eakins autofocus camera with IMX290 sensor that Dave reviewed. However, I'm not using it with an inspection scope but rather on the camera port of an Eakins (~AmScope) trinocular microscope. So my setup is like Steve Gardner here https://www.youtube.com/watch?v=xs67D1t16wA.

Earlier in the thread I found that I need a 1/3 reducer lens to have a suitable field of view on this microscope. The camera then sees approximately the rectangle contained by the circles I see through the eye pieces i.e. crops out the round bits around the edges.

Generally the view through the eye pieces is very bright - brighter than I would ideally like - while the camera can only /just/ get a proper picture without using ISO gain. So it seems like somehow less light is coming to the camera lens than to my eyes and I don't know if that's down to the reducer lens (indirectly a mismatched camera sensor size?) or due to the ratio of the optical splitter in the microscope head (unspecified, didn't get a straight answer from Eakins) or...

Any ideas? (Am I expressing myself clearly?)

[dreamcat4]

If you take apart the Eakins microscope head you will see that the 3rd port is in fact being tapped / split by a triangular prism from the left eye piece. So it would then make sense that the light reaching the camera port will be of a lower intensity. Perhaps less than 50%. But then your camera's aperture and its CCD sensor will have different values of sensitivity and gain compare to you own eyes. So it's not going to be like for like regardless of the prism thing. Plus also your computer monitor has it own brightness too.

[mawyatt]

Microscope objectives can be directly mounted to a standard DLSR with some available adapters and extensions. Finite objectives do not require another lens in the optical chain, infinite objectives do require a "tube lens" in the optical chain. Also you can use a reversed DSLR lens with an standard reverse adapter, or even stacking standard DSLR lenses. Many have repurposed old scanner & reproduction lenses for macro use, some are exceptional.

A bellows is very useful, especially with finite objectives since you can vary the magnification by simply changing the distance between the objective and the camera with the bellows.

You can find loads of information about all this over at:

https://www.photomacrography.net/index.htm
 
Another good reference is:

https://www.closeuphotography.com

Another:

http://extreme-macro.co.uk/


Here's a couple setups I've developed for focus stacking of chips I've designed or been involved with, but also useful for video. Also some notes from my notebook.

Best,

[mawyatt]

Here's some notes on using objectives with a DSLR using extensions and adapters.

Best,

[lukego]

Microscope objectives can be directly mounted to a standard DLSR with some available adapters and extensions.

I actually have a full-frame DSLR (Nikon D750) with the adapter to mount it on my microscope. I have tested it only once and I did not notice a huge difference but I haven't made a detailed side-by-side image comparison. I suppose that this means I have everything I need to compare the impact of sensor size on image quality though.

Thanks for the references!

[lukego]

This $400 microscope camera only has a 1/2.3" sensor. The sensor in a micro four thirds camera has almost four times the area which almost wins you a couple f-stops. The sensor in a full frame camera is that much larger again and almost win you a couple more. Full frame, however, usually needs a relay lens; micro four thirds sometimes doesn't.

Thanks for your insights!

To what extent can I compensate for a small sensor using a reducer lens?

I've seen a big improvement with my 1/2.8" IMX290 camera since I started using the 1/3 reducer lens. I suppose that this both gives me a wider field of view and also channels light onto the sensor (instead of spilling off the sides when the small sensor causes the image to crop.) But at what cost does this come? Is there still a significant loss of light? Loss of image clarity? Impact on depth of field? Would these aspects be better/different with a larger sensor camera that doesn't need a reducer lens? Is there a good description of the trade-offs already online somewhere?

[lukego]

Follow-on question: I have a problem that the round field of view in my eyepieces is larger than the rectangle field of view in the camera. This makes me worry that the camera will crop out something important that I see with my eyes.

Would a reasonable solution be to switch my 10x eyepieces for 15x? The idea being that this would increase the zoom on the eyepieces and in doing so reduce their field of view to be within what the camera sees.

[lukego]

Follow-follow-on question

I see other cameras like RisingCam BIGEYE 4K with Sony IMX294 4/3" sensor. Are such cameras better suited to these trinocular microscopes by virtue of their larger sensors matching the image delivered to the camera port? (Is my IMX290 1/2.8" camera better suited to other microscopes e.g. a single-lens inspection scope?)

Hard to make sense of it all! Not least the various Sony sensor product numbers... I found a complete list but I'm not sure that helps much.

[jfiresto]

... To what extent can I compensate for a small sensor using a reducer lens?

About all you can do is center the sensor with the image out of the microscope and reduce the image so that it just excites every pixel in the sensor, out to the corners. Your video above show modest vignetting at the right side corners which makes me think you are close to that. Could you post a image of a light object that shows the vignetting at all four corners?

Your reduction lens may be losing a modest amount of light, but I am pretty sure you are losing a great deal more sensitivity (many f-stops) from the small, 1/2.8" sensor.