I've bought another old manual focus Minolta lens

Now that I have purchased (for a reasonable price on eBay) my third manual focus Minolta lens, I feel I officially have a "collection".  This assumes I am allowed to call 3 or more of anything a collection!

Seen below are, left to right: 100mm F3.5 macro (newly acquired), 50mm F3.5 macro, and 35-70mm F3.5 macro zoom.  Also pictured below are the adapters (about $20 each on eBay) that allow me to use the lenses joyfully on my two mirrorless interchangeable lens cameras, a Sony and an Olympus. 

In addition to making nice images (with limitations due to old technology and being designed for film), I have "collected" these lenses because they look and feel great.  The focus rings are smooooth and the lenses are all metal.  

I love all the markings you find on the lens barrels as you focus (or zoom on the 35-70) and the lens telescopes out..., although other than the distance scale, the f-stop, depth of field scale, and the focal length adjustment on the zoom lens, I frankly don't know what some of the other markings mean.  One guess is that some of them relate to light gathering adjustments that are made as focus changes. Since I use a live histogram on the camera all the time, I don't really need the information on the lens barrel to make EV adjustments. Other markings are clearly related to magnification ratios at different focusing distances.

UPDATE

I received some additional information by email from my friend Dennis Mook.
Dennis first owned Minolta gear in 1971 and still has the Minolta SRT-101 camera plus Minolta Rokkor 55mm F1.7 lens it came with.

Here is what he writes about the various markings on the lenses:

As far as your lenses, on the zoom, the red lines reflect where one would correctly focus the lens if one were using infrared film.  Infrared light focuses in a different plane than visible light.  The three lines reflect three different focal lengths.  So what you would do is to focus the camera thought the lens, then move your focus point over to the appropriate red line, depending upon the focal length in use. 

On the macro lenses, the white markings reflect magnification of the image when using the lens alone.  As you can see, it only focuses to 1:2, or half life size.  Minolta also made an extension tube so the lens could focus to life size, or 1:1.  The markings off to the sides are the required exposure compensation for different magnifications.  When these lenses were manufactured, almost no camera automation existed. The rule of thumb that I remember was you had to open up two stops for a life sized or 1:1 magnification. 

The curved lines are depth of field scales (for 35mm sized film or sensors; they won't apply to other sized file or sensors) for pre-focusing and/or zone focusing. 

Dennis

Check out Dennis' wonderful photography blog at www.thewanderinglensman.com and/or his Web site at www.dennismook.com)