While using zoom tool the exposure suddenly gets down and it seems ok after zoom out but after export the low exposure version gets exported.

Please provide screen captures to illustrate the problem. Please go the the menu command Help->System Info and copy and paste the information there into your reply.

This new forum is so poorly designed that many people get confused. In the first dialogbox when you create your message, you want to enter the title (although it doesn’t say that), a few words like “Problem with Zoom Tool”. In the next dialog box, you provide the details. We don’t need the exact same text twice.