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Can I manually adjust the exposure time for iOS cameras?

I want to adjust the exposure of an iPhone / iPod touch camera with intimate detail. I would prefer to take a series of photos with reduced exposure time to get a sequence of images (for HDR recovery). Is it possible?

If not, what's new? It seems you can set a point of interest for the image for auto exposure. Maybe I could look for a dark / light area of ​​the image and then use this exposurePointOfInterest to adjust the exposure, but this seems like a very indirect solution that is also error prone. If someone tried an alternative, such an answer is also desirable.

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Since iOS gives control of the frame duration MinFrameDuration MaxFrameDuration

since the exposure time depends on the frame rate and frame duration By setting the minimum and maximum frame rates to a specific value, you will block the frame rate. This will affect your exposure time. It’s also a very indirect way of controlling, maybe it helps your business.

Example:

 if (conn.isVideoMinFrameDurationSupported) conn.videoMinFrameDuration = CMTimeMake(1, CAPTURE_FRAMES_PER_SECOND); if (conn.isVideoMaxFrameDurationSupported) conn.videoMaxFrameDuration = CMTimeMake(1, CAPTURE_FRAMES_PER_SECOND);
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Since you will need to reduce the shutter speed of the camera, this, unfortunately, is not possible and, more importantly, against HIG:

Changing the behavior of external iPhone equipment is in violation of the License Agreement with the iPhone Developer Program. Applications must adhere to the iPhone User Guide as described in the iPhone Software Developer License Agreement Section 3.3.7

A related article by Apple removes the Camera + iPhone application from the application store after the developer opens the hack to enable a hidden feature .

If this can be done programmatically, rather than with hardware, you may have a chance, but then it just affects the image, not the image with a long exposure.

There are several simulated slow shutter applications that get approval, such as Slow Shutter or Magic Shutter .

Related article: The new application for the iPhone camera "Magic Shutter" comes to the App Store .

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I tried to do this for my activated motion application (Pocket Sentry), and I found it impossible to do this and get approval in the app store.

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I tried to do it myself. I think this is only possible using the object of interest for exposure. I detect dark and bright spots, and then correct them.

Please Note: Detecting Bright / Dark Dots on iPhone Screen

Does anyone know a better way to do this?

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I'm not sure, but you should try using the AVFoundation class to create a camera application, following the sample apple code: AVCam sample code

And then try to use the exposureMode property of the class:

class description ActivityMode

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This is supported with iOS 8: http://developer.xamarin.com/guides/ios/platform_features/intro_to_manual_camera_controls/

Take a look at AVCaptureExposureModeCustom and CaptureDevice.LockExposure ...

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