Lenses are bad

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This topic contains 2 replies, has 3 voices, and was last updated by  Chuck Young 1 week, 6 days ago.

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  • #29248

    lreinhar
    Participant

    I had great fun putting my Deluxe Foldscope together, but neither lens is clear. Each lens has a black “amoeba-shaped” spot in middle of the field, and the rest of the field is “crazed”. Could the lenses have been damaged in the manufacturing process?

    I am giving four other Foldscopes as Christmas presents, and I am afraid that the kids will be as disappointed as I am.

    Can I get replacement lenses?

    I am open to suggestions for how to view objects with the Foldschope.

    Thanks.

    • This topic was modified 1 month ago by  lreinhar.
    #29771

    Anonymous

    Hi Ireinhar,

    I’m sorry to read that your foldscope’s lenses are dirty. Have you tried to clean them up with the cotton swab ?

    What about the other foldscopes ?

    #30000

    Chuck Young
    Participant

    I am having a similar problem with lenses. I find that the focusing wedge is useless; the lens must be VERY close to the slide for focusing, closer than can be achieved with the focusing wedge in place.
    I found an alternate way to check lens performance without assembling the entire foldscope;
    see my note below. I checked the lenses on 2 classroom sets (40 lenses total).
    My suspicion is that there is a problem with the production run of the lens mounts.
    I doubt that (at this price) anyone tested the individual lenses.

    I am also finding that the slots for the slides in the foldscope are not long enough. I had to lengthen the slots with an exacto knife.

    Chuck Young

    *I will describe my attempts to check my two boxes of Basic Classroom FoldScopes.
    I think my procedure is quite simple.
    My light source is the overhead lamp in our dining room. I redirect the light by placing a hand mirror one the table so the light from overhead lamp is in my eyes.
    I am using:
    one of the fern rhizome prepared sample slides, and
    one of the magnetic coupler washers and
    one lens in its black holder.
    I also have a package of blank microscope slides with cover slips.

    I place a magnetic coupler washer on the table, black side up.
    I place the prepared slide on the magnetic coupler washer, label and sample side up. I center the sample over the hole in the magnetic coupler washer.
    I place the lens on the slide, silver side down. So, I have a sandwich of magnetic coupler, prepared slide and lens The magnets hold the sandwich together.
    I hold the sandwich up to the light, and hold it close to my eye. Sometimes I have to readjust the sandwich to center the sample on the lens. I can see the cells of the sample. For some of the lenses, the focus is good. In this particular lens,
    the focus is kind of poor. I can improve the focus by prying the lens away from the slide OR by adding one or two cover slips between the lens and the microscope slide.

    I tested all 40 of the lenses on my classroom FoldScopes. Three or four of them gave the best images; very much in focus, good contrast, etc. Most gave reasonably good images that could be improved using the cover slips. A couple of them gave images that were out of focus and couldn’t be improved with the slide cover slips.

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