How to copy video files from iPhone 6 onto computer?
Mac Solution
You can use Image Capture to manage your videos and photos on your iPhone 6.
With Image capture: Choose AutoImporter from the “Connecting this [device] opens” pop-up menu to transfer images from a device to your computer whenever you connect it to your computer.
Click the icon that looks like a box with a down arrow enclosed on the lower left corner:

Select your preferred application from the list to change which application comes up when plugging in your iPhone 6:

From Apple Support:

Image Capture:
Transfer images and other items from your device
Transfer images, video clips, and MP3 sounds to your computer from
many cameras and devices that contain a camera, such as your
iPhone. Once you transfer the items, you can delete them from the device.
Connect your device to your computer, then turn the device on. If the
device is locked with a passcode, enter it.

In Image Capture, select the device in the Devices list.

Use the buttons at the bottom of the Image Capture window to view the thumbnails as a list or as icons to change the size of the
thumbnails, or to rotate or delete images.

From the Import To pop-up menu, choose where to save the images or which app to use to open the image.

To import only some of the photos, select those photos, then click Import. To import all the photos, click Import All.

Choose AutoImporter from the “Connecting this [device] opens” pop-up menu to transfer images from a device to your computer whenever
you connect it to your computer.



Select “Delete after Import” to remove the items from the device after transferring them to your computer. You can also select and delete individual items on your device, then press the delete key on your keyboard.