Lens Markings

[Ollokot]

What exactly are the red markings on the distance scale of this lens,they have me confused
Best Wishes Pat,

[benm]

The red markings are for infrared photography. After focusing manually or automatically, you would note what focus distance the lens is set to and then rotate the focus ring so that that distance lines up with the red mark corresponding to the focal length the zoom is set to. A digital camera cannot do infrared photography without some modification to the sensor. It is my understanding this modification is then permanent.

Was this originally a lens for a film camera? In film days you could shoot color or BW infrared. The red marks were only needed for BW infrared photography. For color you did not have to reset the distance.

[Ollokot]

Many thanks Ben for explaining the reason for the markings.The lens is an older type first introduced in the ninety's and used on film and slr cameras.
Best Wishes Pat.