MicrobeHunter.com Microscopy Forum

Hi everyone, thank you all for your previous help in my earlier post found here: Canon Mirroless Adapter


I have since recieved my Canon M50 markII camera, and have set up my trinoc to recieve it. Pictures come out great!

So, I decided to throw my stage micrometer slide on, take some photos and calibrate it. Now, I use Fiji and a microscope measurement plugin. I have used both in the past, with my iPhone with great success.

To my surprise, after I "calibrated" and took spore measurements, all my spores in the photos were about .1µm wide! So, I knew something was off, went back, re-calibrated, but the problem persisted.

So, what exactly am I doing wrong? Am I not account for some magnifcation?

Camera is attached to this adapter

my iPhone setup was in the trinoc port, attached to a 10x eyepiece, fwiw.

Most probably the problem sits in the process not in the equipment.

Thank you for your reply, what makes me believe its not the process, is the fact that I have been able to calibrate my iPhone with the same microscope

Alexander wrote: ↑

Sat Aug 06, 2022 4:42 pm

Most probably the problem sits in the process not in the equipment.

@alexander; right you were. I was miscalculating by a decimal point.

I calibrated my Canon M3 by simply photographing the stage micrometer through each objective, then in Photoshop I created a scale bar from that image. Whenever I want to add a scale, I simply put the image with the scale bar in as a new layer, copy out the scale bar and add as a new layer, then turn off the visibility of the layer of the original image with the scale bar and flatten the image. Sounds complex, but it's simple!

http://www.rakm.co.uk/bryophyte_pages/f ... us_04.html

RichardK-M:

I also use Photoshop to put scale bars on photos using the same basic logic you do. An alternative procedure that's efficient: 1) convert distance on the photos of the stage micrometer to pixels using the Ruler tool (go to Analyze under the Image pull-down). 2) Then you can create a preset for the objective using that conversion. Once that's done, any time you want to make a scale bar for a photo taken with that objective, simply go back to the Analyze menu, do a Set scale using the preset, and then let Photoshop create the scale bar for you. Photoshop automatically puts the scale bar on a new layer. You have total control over font, font size, position, bar thickness, etc.

I validated the procedure by measuring a diatom using a calibrated reticle and comparing it to a Photoshop measurement of the diatom.

Zooming doesn't change the number of pixels in a measurement. I'm not sure about resizing, so it would be good to put the scale bar on before you resize the image.

Cheers, David