A small, quiet moment sits at the center of this poem: a spider has built its web right across the speaker's camera lens. Only the first of the three tanka is given here, and it works as a little scene on its own. The speaker doesn't seem annoyed. Instead, the last two lines add a playful twist. They check the memory stick for pictures of flies, as if the spider's web might have taken photographs the way it catches prey.
That joke is the heart of the poem. The camera and the web are both devices for capturing things, and the speaker half-seriously treats the spider as a fellow collector of images. The word "tiny" and the plain, matter-of-fact tone suggest affection and amusement rather than irritation.
The mood is light, curious, and observant. There is a gentle humor in the speaker's willingness to imagine the natural world quietly taking over their equipment, and a sense of wonder at how small creatures put human tools to their own use.