filming darkfield

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Shivs
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filming darkfield

#1 Post by Shivs » Thu Mar 18, 2021 1:06 am

Just got a darkfield condenser and I am having trouble filming it. I am using a basic omax 2mp camera, I am thinking that the camera is the problem. I have to set the exposure time up to get any brightness and the framerate tanks... since the framerate is only 12fps to begin with I dont have much headroom. Have a look at the vid:

http://office.shivs.org:5080/darkfieldtest.mp4

All of the omax (and amscope cameras seem to be just rebranded versions of the same thing) cameras have this limitation, even the much higher Megapixel versions.

something like this swift would be perfect but the price is kinda steep. Im looking to pay maybe $300-$400

https://swiftoptical.com/products/micro ... moticam-s6

PeteM
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Re: filming darkfield

#2 Post by PeteM » Thu Mar 18, 2021 1:38 am

More light is likely needed. What do you currently have?

apochronaut
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Re: filming darkfield

#3 Post by apochronaut » Thu Mar 18, 2021 1:42 am

Have you done some still photos in DF? Maybe start there if not. DF is demanding because of the extremely low light levels plus it pushes the envelope on the dynamic range of the camera because of the illumination differential between background and subject. It definitely requires a better camera.

Shivs
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Re: filming darkfield

#4 Post by Shivs » Thu Mar 18, 2021 1:49 am

Currently using this
https://www.amazon.ca/dp/B00FG89BX8/ref ... UTF8&psc=1

Not happy with it at all, would like something that can do better than 12 fps.

BramHuntingNematodes
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Re: filming darkfield

#5 Post by BramHuntingNematodes » Thu Mar 18, 2021 1:52 am

Hold on to the reduction lens though that might come in handy
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

hans
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Re: filming darkfield

#6 Post by hans » Thu Mar 18, 2021 2:52 am

PeteM wrote:
Thu Mar 18, 2021 1:38 am
More light is likely needed.
Shivs wrote:
Thu Mar 18, 2021 1:49 am
...would like something that can do better than 12 fps.
To emphasize what Pete is saying, changing cameras is unlikely to help much with frame rate. Number of photons available for the camera to detect within a given exposure time is a pretty basic physical limitation. A better sensor may improve detection efficiency and readout noise, but probably not as much as you are hoping.

Shivs
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Location: Vancouver, British Columbia, Canada

Re: filming darkfield

#7 Post by Shivs » Thu Mar 18, 2021 3:01 am

im using https://www.amazon.ca/OMAX-40X-2000X-Bi ... B005TJ5CEG with a basic amscope dry darkfield condenser. Any way to somehow increase the light output of my scope or get a better condenser?

https://www.amazon.ca/gp/product/B005OR ... UTF8&psc=1

apochronaut
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Re: filming darkfield

#8 Post by apochronaut » Thu Mar 18, 2021 3:10 am

DF demands high illumination, that's why really good DF microscopes use 100 watt halogen illuminators. Still , with up to a 40X objective most microscopes should function o.k. How is the eyepiece view? If it seems decent enough, it is probably a camera issue. DF blocks 90% of the light, so you are shooting at very low light levels with very uneven illumination. Pretty taxing conditions.

Shivs
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Re: filming darkfield

#9 Post by Shivs » Thu Mar 18, 2021 3:16 am

Eyepiece view is totally fine, I don't think you guys realize how much I hate this camera. Any recommendations? I don't want to use an SLR with mount setup, seems a bit complicated. Cameras made for microscopes that can do 30 fps at at least 5mp

BramHuntingNematodes
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Re: filming darkfield

#10 Post by BramHuntingNematodes » Thu Mar 18, 2021 3:42 am

1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Shivs
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Re: filming darkfield

#11 Post by Shivs » Thu Mar 18, 2021 3:46 am

BramHuntingNematodes wrote:
Thu Mar 18, 2021 3:42 am
https://machinevisionstore.com/catalog/details/15402

how about this one
would that reduction lens I should hang on to fit right on here?

BramHuntingNematodes
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Re: filming darkfield

#12 Post by BramHuntingNematodes » Thu Mar 18, 2021 3:49 am

Yes, it's a c-mount camera so it would.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

BramHuntingNematodes
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Re: filming darkfield

#13 Post by BramHuntingNematodes » Thu Mar 18, 2021 3:57 am

They also have the "Pro" version for $90 more which is the same camera but with some additional firmware that allows for some fine tweaking of the camera response. I am unfamiliar with exactly how that is used, so I can't really comment on it.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Shivs
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Re: filming darkfield

#14 Post by Shivs » Thu Mar 18, 2021 7:08 am

BramHuntingNematodes wrote:
Thu Mar 18, 2021 3:42 am
https://machinevisionstore.com/catalog/details/15402

how about this one
I was looking at this one which is 8MP vs 5mp for the other one but in a 16x9 aspect ratio. Would that all of that 8mp be "usable" in 16x9 vs the more square 4:3 since the image is a circle?
https://machinevisionstore.com/catalog/details/15382

Sir
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Re: filming darkfield

#15 Post by Sir » Thu Mar 18, 2021 7:19 am

Before you go out and but a new camera, I'd suggest trying a smartphone mount. It's a cheaper alternative if you already have a smartphone, and some of the latest phones provide stellar images, often with reduced noise and increased sharpness through the phone's in-built processing.

If you have a point and shoot camera lying around, an afocal setup is also possible by recording through one of the eyepieces.

Improving image quality is a never ending battle, but it's very rewarding as you continue to learn how to improve your setup. Don't underestimate the power of good slide preparation techniques as well. Good luck :D

BramHuntingNematodes
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Re: filming darkfield

#16 Post by BramHuntingNematodes » Thu Mar 18, 2021 12:53 pm

Shivs wrote:
Thu Mar 18, 2021 7:08 am
BramHuntingNematodes wrote:
Thu Mar 18, 2021 3:42 am
https://machinevisionstore.com/catalog/details/15402

how about this one
I was looking at this one which is 8MP vs 5mp for the other one but in a 16x9 aspect ratio. Would that all of that 8mp be "usable" in 16x9 vs the more square 4:3 since the image is a circle?
https://machinevisionstore.com/catalog/details/15382
You want to match up the projected real image circle as best you can to the sensor. Crop too much and your image is fuzzy. Too little and you get vignette. So I would assume not much improved performance despite the extra nominal 3 mega pixels.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Shivs
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Location: Vancouver, British Columbia, Canada

Re: filming darkfield

#17 Post by Shivs » Thu Mar 18, 2021 5:52 pm

Machine vision store doesn't ship to Canada without a bunch of hassle :cry:
I ordered a smartphone mount, I have a Samsung s20 which has an amazing camera so I'll give it a shot. I like using my big monitor to look for stuff which I why I want a good microscope camera. Smartphone screen might be to small.

Shivs
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Re: filming darkfield

#18 Post by Shivs » Tue Mar 23, 2021 11:09 pm

I ended up picking up the Amscope 18mp camera
https://www.amscope.com/cameras/usb/mic ... slide.html

18MP is probably totally overkill but it was the framerate that was the main thing for me. This one will come with the software (im pretty sure the omax camera I am using has the same software just rebranded). I also ended up bucking up for a t490 halogen so I should be set :D

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blekenbleu
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Re: filming darkfield

#19 Post by blekenbleu » Thu Apr 08, 2021 2:50 pm

Shivs wrote:
Tue Mar 23, 2021 11:09 pm
18MP is probably totally overkill
Oversampling allows better downsampling to reduce noise and optimize unsharp mask.
Optiphot 66, AO 10 and 120

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