A few months after buying my Pentax K-70 digital camera I purchased a used Pentax M 200mm f/4 manual-focus lens that is nearly 40 years old. I had a gap in my lens line-up between 135mm and 300mm, so I figured this would be a cheap solution (it was only $70).
When the lens arrived it was in like-new condition, and a few test shots around town confirmed that the image quality was decent… but it really wasn't a lens that I expected to use a lot.
However, I had a soccer match to shoot that started at 1:00 PM on a blazing hot day with the sun almost directly overhead: miserable conditions for trying to get good pictures. Because I didn't have high expectations for the match I decided to shoot the first half with the 200mm, just to see what it could do. When I reviewed the shots later, I was astonished at the spectacular images that I got with it!
The lenses I usually use for field sports are the Pentax F* 300mm f/4.5 (autofocus) and the Rokinon 85mm f/1.4 (manual-focus). Compared to these lenses, the 200mm is much smaller and lighter, and the improvement in handling was definitely noticeable. This ease of handling is one reason why the lens is working so well for me. And 200mm on a crop sensor (equivalent to 300mm on a full-frame sensor) is a really good focal length for field sports.
The 200mm is also surprisingly easy to focus; much easier than the 85mm despite that len's bright f/1.4 aperture. It's so easy to focus that, at times, it feels like I'm using an autofocus lens!
But it only works as a sports lens for daylight events, where you have plenty of light to focus with, and you can stop the lens down to get excellent image quality. When I tried it at a night event, it was quite difficult to focus, and it was too slow to give me a fast shutter speed.
It should also be noted that using manual-focus lenses for fast action is a skill that has to be learned. I spent 20 years honing that skill back in the film era, so what is easy for me probably won't be easy for someone who has only used autofocus lenses. But, if you are willing to put in the effort to learn to use it, this lens will certainly deliver great results.
This is rapidly becoming a favorite lens for daylight field sports. Not too bad for a 40-year-old manual-focus lens!