Improve 2237074: Make preview start earlier.

Change-Id: I9d7416cfd7c9cbaa3bc135ac8fd67776ec1c65e3
diff --git a/src/com/android/camera/MenuHelper.java b/src/com/android/camera/MenuHelper.java
index 453d629..0ab7612 100644
--- a/src/com/android/camera/MenuHelper.java
+++ b/src/com/android/camera/MenuHelper.java
@@ -1066,8 +1066,9 @@
                 String storageDirectory =
                         Environment.getExternalStorageDirectory().toString();
                 StatFs stat = new StatFs(storageDirectory);
+                final int PICTURE_BYTES = 1500000;
                 float remaining = ((float) stat.getAvailableBlocks()
-                        * (float) stat.getBlockSize()) / 400000F;
+                        * (float) stat.getBlockSize()) / PICTURE_BYTES;
                 return (int) remaining;
             }
         } catch (Exception ex) {