I’m a bit of a newbie, and I’ve just bought a zoom lens for my OM10. It's a Hanimex One-Touch Zoom Lens 80-200mm F4.5 Macro
It’s arrived and I’m trying to understand the scales on the lens.
I can understand the usual focusing distance scale in green and white shown in the first photo, as well as the aperture ring nearest the camera body, and the focal length scale along the yellow line down the lens centre.
The scale I don't understand is the curved red arc that peels away from the centre line, denoted "R" nearest the body. I believe it has something to do with the Macro function of the lens, as it's in the same colour as the ratios and focal length shown in picture 2.
I'd like to try and better understand the red markings on the lens. I understand that zoom lenses aren't truly macro. However, I don't know why it states f = 200mm in red, nor do I understand the curved red line and the ratios it gives in red.
The behaviour of the lens is as follows:
A: sliding the focusing ring towards and away from the body zooms in and out respectively
B: rotating the focusing ring focuses as usual