question about 150 apo componon hm

**Songyun** · 12-Oct-2011, 06:24

What is the translucent plastic part on the rear cell for?

**aduncanson** · 12-Oct-2011, 06:35

Do you mean the window that illuminates the diaphragm?

**ic-racer** · 12-Oct-2011, 07:12

I suspect the rear element blocks the little window that brings in light to illuminate the aperture. The plastic piece funnels light around the rear element to get to the aperture illumination device on the barrel.

**Songyun** · 12-Oct-2011, 19:11

Originally Posted by ic-racer

I suspect the rear element blocks the little window that brings in light to illuminate the aperture. The plastic piece funnels light around the rear element to get to the aperture illumination device on the barrel.

I see, thanks!