A lens that does its job well. That's all in one sentence. This is really great for a vintage lens. Creates a really great look in the lens and is impressively sharp. I managed to fit it into 100x the price. Pros: - Maintains a relatively clean aperture throughout. - Doesn't distort the edges as much at low aperture - Nice form factor. Cons: - It's a photo lens. You can just slap the lens and shift the whole focal length, mm and aperture. As you approach higher f-stops you start to distort due to lens error.