With Quick Mask there is no some extra benefits. Benefit is that You can paint over image with black or white and see Your mask immediately at full size view on screen. Benefit is also that You are controlling which parts will be hidden and which visible in other words mask do not depend on automatic features in Photoshop which in most cases makes selections based on levels.
The button for Quick Mask Mode is below the Forground and Background color, the icon for it looks like a circle within a square.
A number of tasks. Cut and past, copy, make a mask for example
Just like the mask in the real life.The mask option also works the same way.The mask option in the Adobe Photoshop allows you hide the part of the picture or graphics created using Photoshop.You club the mask option with other options available to create new effects.Mask option works the same way in each and every other soft-ware of Adobe.
You first need to create a "mask" (Photoshop has a special name for these that I don't recall at this moment). Then using the mask you can tell Photoshop to convert the unmasked portion of the photo from color to black and white.
Photoshop have Horizontal Type Tool and Horizontal Type Mask Tool which you can use to type text in Photoshop.
Dialog in which you can improve selection actually layer mask and remove all selection or layer mask imperfections using several commands like feather,smooth, contrarst..
Mask will be saved as Alpha channel in CHANNELS panel (Window > Channels).
There is no such thing as the Quick Mask in Majora's Mask.
By pressing edit in Quick Mask Mode button which is below foreground/background color. When you finish, press one more time and you will exit quick mask. Selection will be created based on your painting in quick mask mode.
You need mask for complicated selections. If you have a bunch of objects in composition, you could use mask for faster and more productive work.
Softening, you can soften edges of selection using Feather command from select > Modify > Feather or From Refine Edge dialog Select > Refine Edge. Feather also appears on Properties panel in Photoshop CS6 or Masks panel in previous versions to soften edges of pixel based or vector mask (you must select mask on Layers panel first).
There are 2 ways I will recommend you: select trees and mask them using layer mask or use cloning tools like Clone Stamp or Healing Brush Tool to replace trees with some other parts from your photo.