<!--
{
  "availability" : [
    "iOS: 27.0.0 -",
    "iPadOS: 27.0.0 -",
    "macCatalyst: 27.0.0 -",
    "tvOS: 27.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "AVFoundation",
  "identifier" : "/documentation/AVFoundation/AVCaptureDevice/Format/supportsExposureModeCustom(lensAperture:duration:iso:)",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Method",
  "symbol" : {
    "kind" : "Instance Method",
    "modules" : [
      "AVFoundation"
    ],
    "preciseIdentifier" : "c:objc(cs)AVCaptureDeviceFormat(im)supportsExposureModeCustomWithLensAperture:duration:ISO:"
  },
  "title" : "supportsExposureModeCustom(lensAperture:duration:iso:)"
}
-->

# supportsExposureModeCustom(lensAperture:duration:iso:)

Reports if the given set of exposure parameters are supported by this format.

```
func supportsExposureModeCustom(lensAperture: Float, duration: CMTime, iso ISO: Float) -> Bool
```

## Discussion

The intended use of this method is to query which combinations of “Auto” parameters (`AVFCapture/AVCaptureLensApertureAuto`, `AVFCapture/AVCaptureExposureDurationAuto`, `AVFCapture/AVCaptureISOAuto`) are supported by this format.
If you pass a numeric constant it will be range checked against the parameter’s supported min and max. However you can also pass the “Current” constants (`AVFCapture/AVCaptureLensApertureCurrent`, `AVFCapture/AVCaptureExposureDurationCurrent`, `AVFCapture/AVCaptureISOCurrent`) to generically query locked vs. auto parameter support without picking arbitrary lock values.

> Example: to query support for “shutter priority” where the exposure duration is locked but auto-exposure continues to manage aperture and ISO:
> 
> ```swift
> format.supportsExposureModeCustom(lensAperture: AVCaptureDevice.autoLensAperture, duration: AVCaptureDevice.currentExposureDuration, iso: AVCaptureDevice.autoISO)
> ```

Devices that have fixed aperture will have equivalent support for `AVFCapture/AVCaptureLensApertureAuto` and `AVFCapture/AVCaptureLensApertureCurrent`.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)