Dear All,
What you see here is a series of different pictures made on the same Leitz Orthoplan with the same lenses i.e. Olympus DPlanApo 10x and 40x, using 2 different light sources.
Light source 1 is an Osram Mercury lamp HBO50 in a Leitz lamphouse. Light source 2 consists of 3 white power LED's in a small lamphouse covered by a diffuser that I placed directly beneath the condensor of the microscope.
The camera is a Chinese made Renusco DTM 5MP USB camera connected to a MSI laptop under Windows Vista using Scopetec Minisee as grabber.
The image I see through the oculars is comparable for both light sources except for the light intensity that is far higher for the Mercury lamp.
The pictures from both light sources are dramatically different. The mercury lamp creates tremendous interference lines in the pictures, the inexpensive LED lamp gives a perfect picture of what is visible through the oculars.
(https://www.mikroskopie-forum.de/pictures002/45221_17336618.jpg) and (https://www.mikroskopie-forum.de/pictures002/45221_39712732.jpg). This a transversal section of Ipomoea root obj.40 x followed by dog rectum 10 x resp. 40 x.(https://www.mikroskopie-forum.de/pictures002/45221_17609301.jpg) Further(https://www.mikroskopie-forum.de/pictures002/45221_50892701.jpg)
Then for the 40x: (https://www.mikroskopie-forum.de/pictures002/45221_6225957.jpg) and the mercury lamp picture:(https://www.mikroskopie-forum.de/pictures002/45221_53937671.jpg)
I have asked around among friends and collegues, but nobody can solve the problem of interference lines in the image.
Personally I think the problem is created by the high light intensity of the mercury lamp that cannot be handled by the chip of the camera: the problem is more severe at low magnification than at high magnification. However, this hypothesis does not solve the practical problem.
I might have done something completely wrong, but as yet I have no idea.
Thank you very much for help.
Leo van Griensven.
i'm not very knowledgeable about mercury-lamps, but i guess they use a pulsed power-source
if that's so, you could see the flickering of the light
Leo,
if you will orientate any polarization foil between your light source and the condenser,
afterwards turning that foil smoothly, will there any changes of the interference stripes
occur?
I would be glad to read your answer a.s.a.p.
Regards,
Joachim
Hi Leo -
My guess: Since your HBO-Lamp is driven by AC with 50 c/sec you get flickering of 100 c/sec. If my guess is correct your exposition time of picture 1 and 3 should be around 1/3 sec . Your LED uses direct current, depending on the quality of your DC source you get no flickering.
Kind regards
Rolf
Zitat von: smashIt in August 01, 2010, 20:45:17 NACHMITTAGS
i'm not very knowledgeable about mercury-lamps, but i guess they use a pulsed power-source
if that's so, you could see the flickering of the light
I use indeed AC, but if this were the reason all users of Leitz Orthoplan must experience the same problem with their digital cameras. I do not believe that such is the case. However being on this Forum I will rapidly hear whether others have identical problems.
Thank you for your answer.
Leo
Zitat von: reblaus in August 02, 2010, 01:58:01 VORMITTAG
Hi Leo -
My guess: Since your HBO-Lamp is driven by AC with 50 c/sec you get flickering of 100 c/sec. If my guess is correct your exposition time of picture 1 and 3 should be around 1/3 sec . Your LED uses direct current, depending on the quality of your DC source you get no flickering.
Kind regards
Rolf
Dear Rolf,
Thank you much for the answer. See the quote above. So far I have not heard of others. I do not know about exposition time; my USB camera grabs a frame through the software programme. It has no shutter and uses the optical system of the Orthoplan. Such a camera is only a light sensitive chip in a housing with a C mount thread (which is all you get for appr. €400).
Thanks,
Leo
Zitat von: -JS- in August 01, 2010, 23:23:47 NACHMITTAGS
Leo,
if you will orientate any polarization foil between your light source and the condenser,
afterwards turning that foil smoothly, will there any changes of the interference stripes
occur?
I would be glad to read your answer a.s.a.p.
Regards,
Joachim
Dear Joachim,
This is a smart idea. But, I have no polarization foil ? I will try to order and then try.
Thank you,
Leo
Hi Leo,
I know these stripes from my Tucsen 5MP USB-camera. They are caused by a pulsing power supply even with LEDs if you try to dimm them
using a pulse-width controlled power supply instead of a good linear controlled one.
Using e.g. a Canon S2IS I can supress the stripes by selecting a very long aperture time.
Best regards
Joachim
Zitat von: JoachimHLD in August 02, 2010, 09:18:46 VORMITTAG
Hi Leo,
I know these stripes from my Tucsen 5MP USB-camera. They are caused by a pulsing power supply even with LEDs if you try to dimm them
using a pulse-width controlled power supply instead of a good linear controlled one.
Using e.g. a Canon S2IS I can supress the stripes by selecting a very long aperture time.
Best regards
Joachim
Dear Joachim,
I will borrow one of the University's power supplies of a more modern Leitz and try at home. Hope it will work.
Thank you,
Leo
Zitat von: Leo van Griensven in August 02, 2010, 08:46:18 VORMITTAG
I use indeed AC, but if this were the reason all users of Leitz Orthoplan must experience the same problem with their digital cameras. I do not believe that such is the case.
that depends on the used camera too
if the camera exposes one line of pixels, reads them out, and then continues with the next line, you will see the flickering
if it exposes all pixels at the same time, and reards them out after the exposure ends, you won't see it
Zitat von: smashIt in August 02, 2010, 16:52:40 NACHMITTAGS
Zitat von: Leo van Griensven in August 02, 2010, 08:46:18 VORMITTAG
I use indeed AC, but if this were the reason all users of Leitz Orthoplan must experience the same problem with their digital cameras. I do not believe that such is the case.
that depends on the used camera too
if the camera exposes one line of pixels, reads them out, and then continues with the next line, you will see the flickering
if it exposes all pixels at the same time, and reards them out after the exposure ends, you won't see it
Dear Chris,
You have any idea how to find out how the camera reads ? The Chinese camera was sent without any description, no software, nothing.
If that is the case, nothing will help.
If so however, I must see the same lines using all other microscopes; right?
Anyway, thanks for help.
Leo
probably it's noted in the datasheet of the sensor, but i doubt that the manufacturer of the camera will tell you which sensor they used.
Zitat von: Leo van Griensven in August 02, 2010, 18:40:15 NACHMITTAGS
If so however, I must see the same lines using all other microscopes; right?
if my theory is correct, it must be independent of the microscope, as long as you use the same lamp and camera
can you control the exposure-time or sensitivity of the camera?
if so, the line-pattern should vary when you play with it (longer exposure -> thinner stripes)
judging from your pictures increasing or decreasing the exposuretime by a factor of 20 should get rid of the stripes
or you could take a few pictures and remove the stripes by software
Zitat von: smashIt in August 02, 2010, 19:29:21 NACHMITTAGS
probably it's noted in the datasheet of the sensor, but i doubt that the manufacturer of the camera will tell you which sensor they used.
Zitat von: Leo van Griensven in August 02, 2010, 18:40:15 NACHMITTAGS
If so however, I must see the same lines using all other microscopes; right?
if my theory is correct, it must be independent of the microscope, as long as you use the same lamp and camera
can you control the exposure-time or sensitivity of the camera?
if so, the line-pattern should vary when you play with it (longer exposure -> thinner stripes)
judging from your pictures increasing or decreasing the exposuretime by a factor of 20 should get rid of the stripes
or you could take a few pictures and remove the stripes by software
Dear Chris,
We are near the solution of the problem. What I first did is increase the light of the LED and at the highest setting slow moving broad gray-black lines became visible on screen. I then went back to the HBO50 lamp and screwed field diafragm and condensor diafragm down. Then I inserted a dark filter between field diafragm and condensor and finally yes, no lines. Colors were lousy of course due to the dark filter.
To-night I will try to use the Minisee software programme to decrease exposure time and/or target setting. These are given in arbitrary units, not knowing whether the scales are logarithmic or linear. Anyway, empiry is the most important tool in experimental science and after all those years I have adapted to it.
I will let you know.
And thank you very much for your useful comments,
Leo van Griensven
Hello,
I dont understand this discussion. Its absolute normal that with an AC driven lamp you see this terrible stripes.
(https://www.mikroskopie-forum.de/pictures002/45356_42887454.jpg)
Regards
Peter
Zitat von: peter-h in August 03, 2010, 15:04:30 NACHMITTAGS
Hello,
I dont understand this discussion. Its absolute normal that with an AC driven lamp you see this terrible stripes.
(https://www.mikroskopie-forum.de/pictures002/45365_13555168.jpg)
Regards
Peter
Hi Peter,
When you have such nice slides as you do, I think it is not acceptable to have these stripes. This has to be prevented and I cannot imagine that not being possible. I use at work a Zeiss Axiophot with a 50Watt HBO lamp: no stripes. My own Reichert-Jung with halogen 100Watt: no stripes at least not when I use my Canon 1000 camera house(https://www.mikroskopie-forum.de/pictures002/45365_18891000.jpg). (1/20 sec. exp time. It is not overly sharp, but no stripes)
I am convinced that in old Leitz Orthoplans this is not common either; I believe it has to do with the USB camera getting too much light.
I will continue to try to remove it.
Cheers,
Leo
can you upload a series of 3 pictures (with stripes) without adjusting anything between them?
i just want to try something
Zitat von: smashIt in August 03, 2010, 21:20:50 NACHMITTAGS
can you upload a series of 3 pictures (with stripes) without adjusting anything between them?
i just want to try something
Dear Chris,
I have problems with this photobucket that requires small jpeg's Could you send me your e-mailaddress ? Then I'll send the files through e-mail.
leo.vangriensven@planet.com
Leo
you should have a mail in your inbox