T490A

What equipment do you use? Post pictures and descriptions of your microscope(s) here!
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LeonhardEuler
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Joined: Thu Mar 18, 2021 12:36 pm

T490A

#1 Post by LeonhardEuler » Fri Mar 19, 2021 6:42 pm

Got and assembled my T490A microscope and a MU1000-HS camera.

I have an issue though on my monitor (not through the eyepieces), it seems like there is discoloration and I'm not sure how to fix it. Can you guys take a look at this and let me know if you know how to remedy this situation?

Image

BramHuntingNematodes
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Location: Georgia, USA

Re: T490A

#2 Post by BramHuntingNematodes » Fri Mar 19, 2021 7:02 pm

sometimes the camera grabs a slightly wider field than your eyepiece does try widening the light source as would be done for low mag objectives
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Greg Howald
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Re: T490A

#3 Post by Greg Howald » Fri Mar 19, 2021 7:25 pm

Right. Either increase magnification or open the diaphragm fully. If diaphragm is already fully open, your camera is seeing a bit beyond the field of view. The dimming in all four corners is the fringe of the circle. As it is equal at all corners the condenser is evidently centered.
Greg

Hobbyst46
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Re: T490A

#4 Post by Hobbyst46 » Fri Mar 19, 2021 8:18 pm

Greg Howald wrote:
Fri Mar 19, 2021 7:25 pm
Right. Either increase magnification or open the diaphragm fully. If diaphragm is already fully open, your camera is seeing a bit beyond the field of view. The dimming in all four corners is the fringe of the circle. As it is equal at all corners the condenser is evidently centered.
Greg
IMHO, the dark portions of the right-side corners are somewhat larger on than those of the left-side.

LeonhardEuler
Posts: 95
Joined: Thu Mar 18, 2021 12:36 pm

Re: T490A

#5 Post by LeonhardEuler » Sat Mar 20, 2021 12:35 pm

Hobbyst46 wrote:
Fri Mar 19, 2021 8:18 pm
Greg Howald wrote:
Fri Mar 19, 2021 7:25 pm
Right. Either increase magnification or open the diaphragm fully. If diaphragm is already fully open, your camera is seeing a bit beyond the field of view. The dimming in all four corners is the fringe of the circle. As it is equal at all corners the condenser is evidently centered.
Greg
IMHO, the dark portions of the right-side corners are somewhat larger on than those of the left-side.
You are correct, it is not even on all corners, it is worse on the left side, particularly in the upper left hand corner.

No idea how to fix it, I tried loosening the screw one the condenser and moving it at different angles but couldn't get the light to even out. It is very frustrating

hans
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Location: Southern California

Re: T490A

#6 Post by hans » Sat Mar 20, 2021 7:23 pm

LeonhardEuler wrote:
Fri Mar 19, 2021 6:42 pm
Got and assembled my T490A microscope and a MU1000-HS camera.
According to AmScope site for this camera the sensor is 8 mm diagonal and it comes with a 0.5X reductions lens. Didn't see a field number given for the T490A eyepieces but probably 18 or 20 mm for the 10X? That would mean the diagonal field of view seen by the camera should be close but a little less (8 mm / 0.5X = 16 mm vs. 18 or 20 mm) than what is seen through the 10X eyepiece, is that what you see?
LeonhardEuler wrote:
Fri Mar 19, 2021 6:42 pm
I have an issue though on my monitor (not through the eyepieces) ...
LeonhardEuler wrote:
Sat Mar 20, 2021 12:35 pm
... I tried loosening the screw one the condenser and moving it at different angles but couldn't get the light to even out.
These make it sound like the problem is related to reduction lens or camera but on the other hand these sorts of defects can be much more obvious in photos and harder to notice visually. Some things that might help narrow down where the problem is:
  • If you rotate the camera+lens together does the asymmetric corner shading follow the camera or the microscope?
  • How does image compare if you remove an eyepiece and move the camera+lens to one of the binocular tubes?
  • Take another test photo with the AmScope camera then without changing anything take a photo through an eyepiece with a smartphone camera for comparison.

LeonhardEuler
Posts: 95
Joined: Thu Mar 18, 2021 12:36 pm

Re: T490A

#7 Post by LeonhardEuler » Sun Mar 21, 2021 7:27 pm

hans wrote:
Sat Mar 20, 2021 7:23 pm
LeonhardEuler wrote:
Fri Mar 19, 2021 6:42 pm
Got and assembled my T490A microscope and a MU1000-HS camera.
According to AmScope site for this camera the sensor is 8 mm diagonal and it comes with a 0.5X reductions lens. Didn't see a field number given for the T490A eyepieces but probably 18 or 20 mm for the 10X? That would mean the diagonal field of view seen by the camera should be close but a little less (8 mm / 0.5X = 16 mm vs. 18 or 20 mm) than what is seen through the 10X eyepiece, is that what you see?
LeonhardEuler wrote:
Fri Mar 19, 2021 6:42 pm
I have an issue though on my monitor (not through the eyepieces) ...
LeonhardEuler wrote:
Sat Mar 20, 2021 12:35 pm
... I tried loosening the screw one the condenser and moving it at different angles but couldn't get the light to even out.
These make it sound like the problem is related to reduction lens or camera but on the other hand these sorts of defects can be much more obvious in photos and harder to notice visually. Some things that might help narrow down where the problem is:
  • If you rotate the camera+lens together does the asymmetric corner shading follow the camera or the microscope?
  • How does image compare if you remove an eyepiece and move the camera+lens to one of the binocular tubes?
  • Take another test photo with the AmScope camera then without changing anything take a photo through an eyepiece with a smartphone camera for comparison.
I did something in the software called flat field correction and that virtually eliminated the issue.

When I rotated the camera the abnormal coloring would not move along with it, to answer your question

LeonhardEuler
Posts: 95
Joined: Thu Mar 18, 2021 12:36 pm

Re: T490A

#8 Post by LeonhardEuler » Sun Mar 21, 2021 7:27 pm

Oh and BTW, the eye pieces are 23mm

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