Hi!
Do you have an DSLR camera? If so, there is some great equipment you can add to your camera and get full frame reproductions of your slides. I have been looking at the Nikon ES1 from Amazon: https://www.amazon.com/NIKON-COPYING-ADAPTER-CAMERA-ACCESSORIES/dp/B001DTYMOM?pd_rd_w=4GEdF&pf_rd_p=...
A Photographer recommended it to me and I read the reviews, and it looks like it would work great.
There are scanning services you can use, if you think the project is too big. But you would lose the control over how the images are shot.
Let us know if that helps, or if you have any questions!
Michelle