Cropping a camera source in OBS

The short answer

OBS Studio offers three common ways to crop a camera source. You can hold Alt (Option on macOS) while dragging an edge of the source in the preview. You can open Edit Transform and type exact crop values. Or you can add a Crop/Pad filter to the source. All three work the same way whether the source is a USB webcam, a DSLR or mirrorless camera on a capture card, or a camera maker's webcam utility. The main limitation is that cropping discards pixels instead of adding detail. A heavily cropped feed that is then scaled up to fill the canvas will look softer than a camera framed correctly to begin with.

Method 1: Alt-drag in the preview

• Select the camera source in the Sources list or click it in the preview.
• Hold Alt (Option on macOS) and drag one of the red edge handles inward. The handle trims that side instead of resizing the whole image.
• Release the key, then resize or reposition the cropped source normally to fit your layout.

This is the quickest method for rough framing, such as trimming empty wall space beside your head. It is less precise than typing values, so matching crops across several scenes takes more effort.

Method 2: Edit Transform for exact pixel values

Right-click the source and choose Transform, then Edit Transform (Ctrl+E on Windows and Linux). The dialog has separate crop fields for left, right, top and bottom, measured in pixels of the source's native resolution. This method suits repeatable layouts and lets you copy a transform from one source and paste it onto another. Choosing Reset Transform removes the crop, but it also resets position, scale and rotation.

Method 3: the Crop/Pad filter

Right-click the source, open Filters, and add Crop/Pad under Effect Filters. You can set left, top, right and bottom values. With the Relative option turned off, you set an output width and height instead. Negative values add padding instead of cropping. The filter belongs to the source itself, so the same crop applies wherever that source appears, and you can switch the filter off to compare the result with the uncropped image. Transform crops, by contrast, belong to each scene item and can differ from scene to scene.

Points specific to DSLR and mirrorless webcam output

• If the camera's HDMI output is not clean, on-screen indicators such as focus points or battery icons may appear in the feed. Cropping can remove overlays near the edges but not ones near the centre. Turning on the camera's clean HDMI or info-off setting, where available, is the better fix.
• Some camera makers' webcam utilities deliver a lower resolution than an HDMI capture card. Cropping leaves fewer pixels to work with, so a small crop on a low-resolution feed can visibly soften the image.
• Where possible, frame with lens focal length or camera position first and use OBS cropping for fine trimming. Optical framing keeps full detail; cropping does not.
• Check the resolution set in the Video Capture Device properties before cropping. Crop values are measured against that resolution, so changing it later can shift your framing.

What cropping does to webcam microphone audio

Cropping affects only the picture. It does not change the audio captured by a webcam's built-in microphone, a camera's microphone carried over HDMI, or a separate audio input. Gain, noise suppression and any other audio filters on the source stay in place. One related caution: if you delete and recreate a camera source to undo a bad crop, any audio settings or filters attached to that source are deleted along with it. Removing or editing the crop is the safer route. On Windows, the Video Capture Device properties also include audio options, such as whether to use a custom audio device. Those settings are separate from the crop and are worth checking if the camera's microphone is your speech source.

Evidence gaps

This guide describes OBS Studio's documented crop tools in general terms. No version-specific details, test measurements or camera-specific results were available, so menu names and options may differ slightly between OBS releases and operating systems. It does not cover how much sharpness a given camera loses when cropped, because no comparative data was available.