Hi,
Today, I tried a new method for dark-field. I used a 17mm Plössl (four elements eyepiece) instead of the 24 mm I was using. I really don't know how to calculate the focal length of the eyepiece in microscopy, but I think the stock eyepiece (10 x) is about 30 mm FL, give or take. This eyepiece should give something around 18 x.
I did this because, with my homemade filter, I get the best images with the 4x objective. The idea was to get a bigger image scale using this objective. I also used the digital zoom of my phone. I know this isn't recommended because there is no resolution to gain, but I wanted the best image scale that remained sharp enough. I guess with my current equipment, this will work better than using the 10x objective.
Anyway, I think the outcome is not bad at all for a super cheap microscope and a cellphone:
https://www.youtube.com/watch?v=xu-LtFp ... e=youtu.be
Thanks in advance for watching and for your advice!