Ronny,
I have been wanting to send some replies but had problems with the site. All seems fixed now.
I am going to attach a photo that my son took with his cell phone. It is taken with a close up attachment similar to those you suggested earlier. It is a different one that is actually more expensive. You can clearly see some pretty bad spherical aberration on this shot with the close up lens attachment. The particular product is: Camkix Universal 3 in 1 Cell Phone Camera Lens Kit – Fish Eye Lens / 2 in 1 Macro Lens & Wide Angle Lens / Universal Clip (Black) https://www.amazon.com/dp/B00CSJ50HY/ref=cm_sw_r_other_awd_9VcCwb7BEDGKS
Jack