I've never had a prime lens and the difference is amazing. I've also never had a lens that can open that wide and am having a pretty good time experimenting. It feels solid in your hands, a good weight but not heavy. The diaphragm is comfortable to use. I gave it 3 stars for durability because while I'm sure it's perfectly durable for the lens, I don't want anyone to think it shouldn't be treated with care. Caution: If you are using a newer camera, be sure to read how to use the lens with your camera. I had to do some research to find out. PentaxForums is a great resource. Also, this is an old lens that doesn't have autofocus. However, the aperture can be adjusted by the camera when set to "A". Works great on my K-70. I would say this was the best photo item I have ever bought.
Nikon 35mm f/1.8G Auto Focus Lens for Nikon DSLR Cameras - Black (Model 2183)
125 Review
Canon EF 40mm f/2.8 STM Lens - Fixed Black (6310B002) for US Cameras
76 Review
Nikon 50mm f/1.8D Lens: Perfect for Nikon DSLR Cameras!
97 Review
Canon EF 50mm f/1.8 II Fixed Lens - Discontinued by Manufacturer
93 Review