Zoom Lens Colour Intensity

[Guest stevey]

I have a large zoom lens, 10mm - 300mm. Take 17:00 today without a cloud in the sky, at 10mm I am experiancing dull colours and at 200mm or so I am experianced dull colours of the same intensity. I take it that the iris is not fully open at 10mm as it has got wider towards 200mm and the end of the zoom range to maintain the colour intensity?

If I put my hand in front of the camera, the grass that can be seen between my fingers looks more vibrant and greener like real grass - remove my hand and it fades back dull again. I take it that I have to adjust ALC and LEVEL - but what do I exactly adjust on the lens, or do I adjust the camera instead?

Thanks,

Steve

[Doktor Jon]

stevey,

Assuming that you have your AI lens correctly wired, and the camera set to AI iris operation (from what you've described so far, it sounds like you have), turn the lens 'ALC' pot to Av. (average), and then gently adjust the 'Level' pot until you achieve a correctly exposed image.

When you put your hand over the lens, you were forcing the iris to open, hence the correct (or more likely slight over exposure) of the grass, seen through the gap in your fingers.

If you haven't already done so, it would be prudent to adjust the lens back focus before you finally set the 'Level' pot to it's optimum setting.