A lens SD1 owners won't use.
This really inexpensive Holga lens for Pentax works on SD cameras.
This lens is rated at F8 but is seems much slower than that. $15 new on eBay.
I bought it just for fun. It puts the challenge back into taking pictures. The viewfinder is very dim with this lens.
I can see that is some situations this lens might make rather artistic images.
This was taken with Pentax K5 and maximum Lightroom corrections for vignetting and CA were applied. Live view was used to focus.
Perfect fit on SD15
No corrections made on these images.