iOS 7 added the ability to apply filter when taking photo with the Camera app. To select a camera filter style, tap on the three-circle filter icon in the lower-right corner of the Camera app. A total of eight filters is displayed with a live preview for your selection with the middle tile None being “no filter”.
Tap to select the filter. When there is a selected filter, the three-circle filter icon is in red-green-blue color. Once a filter is selected, the Camera app will apply the filter in subsequent shots. To take your picture without any filter, simply select the None filter. The three-circle filter icon is in greyish color when there is no selected filter style.
Camera filter with its unique look is not suitable for all occasion. If you have forgotten to turn off the filter or simply want to remove a filter, you can edit the photo using Photos app to remove the filter and restore it to the original image.
Locate the picture in Photos app and tap the Edit button at top-right corner to edit the picture.
Tap on the three-circle filter icon at the bottom to edit the filter. The current active filter will be selected by default. Slide the filter bar and select None.
Tap on the Apply button at top-right corner to apply the filter edit. And then tap the Save button to save the changes. This will remove any filter and revert the picture to the image without filter.
This removal will only work for pictures taken with the filters bundled with the Camera app. It will not remove filters taken from third party apps such as Instagram.
The picture must also remains inside your iOS device. If the picture is moved out of iPhone and then copied back, the Photos app for iOS would no longer be able to remove the filter.