Adobe Photoshop CC
About lens distortion
Barrel distortion is a lens defect that causes straight lines to bow out toward the edges of the image. Pincushion distortion is the opposite effect, where straight lines bend inward.
Examples of barrel distortion (left) and pincushion distortion (right)
Vignetting is a defect that darkens the corners of an image due to light falloff around the perimeter of the lens. Chromatic aberration appears as a color fringe along the edges of objects, caused by the lens focusing on different colors of light in different planes.
Some lenses exhibit different defects at certain focal lengths, f‑stops, and focus distances. With the Lens Correction filter, you can specify the combination of settings used to make the image.
Correct lens distortion and adjust perspective
The Lens Correction filter fixes common lens flaws such as barrel and pincushion distortion, vignetting, and chromatic aberration. The filter works only with 8‑ and 16‑bit-per-channel images in RGB or Grayscale mode.
You can also use the filter to rotate an image or fix image perspective caused by vertical or horizontal camera tilt. The filter’s image grid makes these adjustments easier and more accurate than using the Transform command.
Using lens profiles, the default Auto Correction option quickly and accurately fixes distortion. For proper automatic correction, Photoshop requires Exif metadata that identifies the camera and lens that created the image, and a matching lens profile on your system.
Select the problems you want to fix. If corrections undesirably extend or contract the image beyond original dimensions, select Auto Scale Image.
The Edge menu specifies how to handle blank areas that result from pincushion, rotation, or perspective corrections. You can fill blank areas with transparency or a color, or you can extend the edge pixels of the image.
Filters the Lens Profiles list. By default, profiles based on image sensor size appear first. To list RAW profiles first, click the pop-up menu , and select Prefer RAW Profiles.
Select a matching profile. By default, Photoshop displays only profiles that match the camera and lens used to create the image. (The camera model does not have to match perfectly.) Photoshop also automatically selects a matching sub-profile for the selected lens based on focal length, f-stop and focus distance. To change the automatic selection, right-click the current lens profile, and select a different sub-profile.
If you find no matching lens profile, click Search Online to acquire additional profiles created by the Photoshop community. To store online profiles for future use, click the pop-up menu , and choose Save Online Profile Locally.
To create your own profiles, download the free Adobe Lens Profile Creator from the Adobe website.
(Optional) Choose a preset list of settings from the Settings menu. Lens Default uses settings that you previously saved for the camera, lens, focal length, f‑stop, and focus distance used to create the image. Previous Conversion uses the settings used in your last lens correction. Any group of custom settings you saved are listed at the bottom of the menu. (See Save settings and set camera and lens defaults.)
Corrects lens barrel or pincushion distortion. Move the slider to straighten horizontal and vertical lines that bend either away from or toward the center of the image. You can also use the Remove Distortion tool to make this correction. Drag toward the center of the image to correct for barrel distortion and toward the edge of the image to correct for pincushion distortion. To compensate for any blank image edges that result, adjust the Edge option on the Auto Correction tab.
Fix Fringe settings
Compensate for fringing by adjusting the size of one color channel relative to another.
Zoom in on the image preview to get a closer view of the fringing as you make the correction.
Sets the amount of lightening or darkening along the edges of an image. Corrects images that have darkened corners caused by lens faults or improper lens shading.
You can also apply vignetting for a creative effect.
Specifies the width of area affected by the Amount slider. Specify a lower number to affect more of the image. Specify a higher number to restrict the effect to the edges of the image.
Corrects image perspective caused by tilting the camera up or down. Makes vertical lines in an image parallel.
Rotates the image to correct for camera tilt or to make adjustments after correcting perspective. You can also use the Straighten tool to make this correction. Drag along a line in the image that you want to make vertical or horizontal.
To avoid unintended scaling when adjusting perspective or angle settings, deselect Auto Scale Image on the Auto Correction tab.
Adjusts the image scale up or down. The image pixel dimensions aren’t changed. The main use is to remove blank areas of the image caused by pincushion, rotation, or perspective corrections. Scaling up effectively results in cropping the image and interpolating up to the original pixel dimensions.
- To change the image preview magnification, use the Zoom tool or the zoom controls in the lower left side of the preview image.
- To move the image in the preview window, select the Hand tool and drag in the image preview.
- To use the grid, select Show Grid at the bottom of the dialog box. Use the Size control to adjust the grid spacing and the Color control to change the color of the grid. You can move the grid to line it up with your image using the Move Grid tool .
You can save the settings in the Lens Correction dialog box to reuse with other images made with the same camera, lens, and focal length. Photoshop saves both Auto Correction settings and Custom settings for distortion, chromatic aberration, and vignetting. Perspective correction settings are not saved because they typically vary from one image to another.
You can save and reuse settings in two ways:
Manually save and load settings. Set options in the dialog box, and then choose Save Settings from the Settings menu . To use the saved settings, choose them from the Settings menu. (If you save settings outside the default folder, they don’t appear in the menu; use the Load Settings command to access them.)
Set a lens default. If your image has EXIF metadata for the camera, lens, focal length, and f‑stop, you can save the current settings as a lens default. To save the settings, click the Set Lens Default button. When you correct an image that matches the camera, lens, focal length, and f‑stop, the Lens Default option becomes available in the Settings menu. This option is not available if your image doesn’t have EXIF metadata.
Reduce image noise and JPEG artifacts
Image noise appears as random extraneous pixels that aren’t part of the image detail. Noise can be caused by photographing with a high ISO setting on a digital camera, underexposure, or shooting in a dark area with a long shutter speed. Low‑end consumer cameras usually exhibit more image noise than high‑end cameras. Scanned images may have image noise caused by the scanning sensor. Often, the film’s grain pattern appears in the scanned image.
Image noise can appear in two forms: luminance (grayscale) noise, which makes an image look grainy or patchy, and color noise, which is usually visible as colored artifacts in the image.
Luminance noise may be more pronounced in one channel of the image, usually the blue channel. You can adjust the noise for each channel separately in Advanced mode. Before opening the filter, examine each channel in your image separately to see if noise is prevalent in one channel. You preserve more image detail by correcting one channel rather than making an overall correction to all channels.
Preserves edges and image details such as hair or texture objects. A value of 100 preserves the most image detail, but reduces luminance noise the least. Balance the Strength and Preserve Details controls to fine‑tune noise reduction.
Sharpens the image. Removing noise reduces image sharpness. Use the sharpening control in the dialog box or use one of the other Photoshop sharpening filters later to restore sharpness.