I may or may not be the only one here, but I currently cannot afford/don't want an auto focus 50 (or similar focal range) as I haven't seen better results beyond my Rikenon-P f2. But with diminishing eyesight, I find it increasingly difficult to focus well on people, and even harder when using my magnifier, because I have to go back and forth trying to focus the magnifier and the lens. Does anyone have any tips on how to manually focus on people faster? Because by the time I can get a good sharp shot is when they either move, or come over and start harassing me. Haha, any help/tips would be helpful.

Also, this is completely irrelevant, but some of you might enjoy it; Citizen Journalism, Recording Police, Photography is Not a Crime

Have you tried "catch in focus" ( CIF ) as a possible tool/technique ? J

I´ll add: When using catch-in-focus, then it matters which direction you turn the focus ring to focus the lens, from left or right into focus. Test which is the right direction

How do I enable catch in focus? Haha I know, stupid question. And how does it work exactly?

It's enabled as a Custom Function in the menu. Number 35 in my K-7.

The camera will not fire the shutter until it detects an in-focus object. So you just hold down the shutter and adjust focus until the shutter trips. Only works with the center point AFAIK, same as usual with manual lenses.

In my experience, it has not sped up shooting for me. I end up moving the focus ring more slowly when using CIF so as not to be caught shifting focus during capture. Others may be able to say whether or not this is a valid concern.

As to your OP, my only method for spur-of-the-moment people shots is a combination of stopping down (if possible) for more DOF, and taking a few quick shots while slightly shifting focus in between.

Funny that I randomly found this post today, as I was at the bar with my wife and some friends this evening with my K-7 and M40/2.8 and was asked by a friend for a quick shot of her and the next two people down the bar from her. DOF was a concern with the close distances involved and the spread of the subjects, combined with low light and the fact that I was in Manual mode. So did I get the shot? ...No, I didn't, haha. Two quick shots, one overexposed and both out of focus.

But since this is in the Street Photography forum, I would just recommend zone focusing ahead of time.

I was going to suggest using a camera with a true penta prism, but I see that you have a K5 already. So you have a bright finder already. If you use a wider prime lens and zone focus it at a smaller f-stop, Set the focus so the deph of field is say from 5 feet to infinity with a 50mm lens at f8. It gets better as the lenses get wider. you can just shoot away. This allows quick close shots. You can even shoot from the chest or hip this way. A wider wide angle allows for getting it all and cropping later.

Another approach is to "zone focus", by determining the distance that you like to shoot people from, and then setting the aperture and distance on the lens in order for objects within that range to be sharp, then just fire away. You then don't need to focus in the view finder, and can "shoot from the hip" or chest, or from other discrete angles if you don't want to disturb (perturb ?) the subject.

Use a depth of field chart to input your camera (for sensor crop factors) and lens focal length and particulars to determine the optimal distance and aperture settings (lots of people shoot in the f/8-f/11 range).

Online Depth of Field Calculator

Some websites that walk through this technique include:

The Ultimate Guide to Zone Focusing for Candid Street Photography - Digital Photography School
how zone focus

This is good stuff for catch those great shots.

What Santuko said. Easiest thing is to get a 24mm -28mm manual prime, set to f8 or f11 respectively, and focus a few feet out. Or if you don't want infinity in focus, drop down a stop or so and focus for the range you want to capture.