Question about spots on photomicrographs

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tjlmicro
Posts: 12
Joined: Mon Dec 28, 2020 12:39 pm
Location: Cary, NC USA

Question about spots on photomicrographs

Post by tjlmicro »

Dear All.

I have recently noticed that there are a couple of round spots on my photomicrographs that are not coming from the subjects that I am photographing. Here is an example (see the spots indicated at the arrows).
Picture1.jpg
I don't think they are from the optics of the microscope, since I don't see them when I am examining my samples and I have carefully cleaned the substage iris, the condenser top lens, and the objective front lenses. The microscope that I am using is a Zeiss Photomicroscope III. I have a Canon 1300D camera attached to the microscope using an Amscope adapter. I have also carefully cleaned the upper and lower lenses in this adapter. However, the spots remain. Any ideas on where they could be coming from and how to resolve it? Thanks in advance for your help.

seta666
Posts: 1071
Joined: Fri Mar 19, 2010 8:50 am
Location: Castellon, Spain

Re: Question about spots on photomicrographs

Post by seta666 »

I wish only had a couple of spots!! my pictures look like lentils soup sometimes. That is dust on your sensor, your new best friend.
The bigger the effective aperture the more you will see them.

Scarodactyl
Posts: 1616
Joined: Sat Apr 14, 2018 10:26 am

Re: Question about spots on photomicrographs

Post by Scarodactyl »

Camera adapters can also show dust pretty badly. You can easily eliminate possibilities by rotating different elements and seeing if the spots move or not.

Ichthyophthirius
Posts: 1152
Joined: Thu Mar 07, 2013 5:24 am

Re: Question about spots on photomicrographs

Post by Ichthyophthirius »

tjlmicro wrote:
Sun Mar 21, 2021 9:42 am
Any ideas on where they could be coming from and how to resolve it? Thanks in advance for your help.
Hi,

Yeah, rotate all the components on you microscope individually and track down the location of the dust, but it's likely to be on the sensor.

It can be removed mechanically (lots of different methods but start with a rubber dust blower, not canned air or your mouth) or
digitally by applying an empty background image to you photomicrograph in Photoshop or DPP: https://support.usa.canon.com/kb/index? ... =ART136907 As said above, it's most visible at very high f-numbers (narrow light cones when using very high magnification objectives), so use an empty and clean slide to create the "dust delete data" file under the same conditions.

Regards, Ichty

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