EDSDK shooting and immediate retrieval

Question

For several days I tried to extract the captured image from the camera. Today I found

EdsSetPropertyData(cRef, PropID_SaveTo, 0, 4, 2); 

which does not save the image to the camera. But my problem is that I can not get the image from the camera. My ObjectEventHandler will never be called (sometimes during initialization it will be called for previous images). Here is my caller (in the main function):

 Camera camera = new Camera(); Thread thread = new Thread(new ThreadStart(camera.DoThings)); thread.Start(); 

And here is my class CC (camera control)

 using System; using System.Collections.Generic; using System.Linq; using System.Text; using EDSDKLib; namespace CCCBSv2 { class CC : EDSDK { IntPtr cRef; // Initilizes, takes picture and uninitilizes public void RunSeq() { uint err; err = Initialize(); if (err != EDS_ERR_OK) { return; } err = TakePicture(); if (err != EDS_ERR_OK) { return; } Uninitilize(); } public uint Initialize() { // err init uint err; // Initilize SDK. // SDK initilizion is needed to use EDSDK functions err = EdsInitializeSDK(); // In case of error pass it on... if (err != EDS_ERR_OK) { return err; } // get first camera connected to computer err = GetFirstCamera(); if (err != EDS_ERR_OK) { return err; } // Open session to camera EdsOpenSession(cRef); // Set object event handler, We need this event handler to retrieve pictures from camera err = EdsSetObjectEventHandler(cRef, ObjectEvent_All, ObjectEventHandler, IntPtr.Zero); if (err != EDS_ERR_OK) { return err; } // We don't want to save pictures to the camera so lets set save target to host err = EdsSetPropertyData(cRef, PropID_SaveTo, 0, 4, 2); return err; } // uninitilizes edsdk public uint Uninitilize() { uint err; err = EdsCloseSession(cRef); if (err != EDS_ERR_OK) { return err; } err = EdsTerminateSDK(); return err; } // gets the first camera to cRef private uint GetFirstCamera() { // Variable initilazions IntPtr cameraList; uint err; int count; // Get list of cameras; err = EdsGetCameraList(out cameraList); if (err != EDS_ERR_OK) { return err; } // Get count of cameras in list err = EdsGetChildCount(cameraList, out count); if (err != EDS_ERR_OK) { return err; } if (count == 0) { return EDS_ERR_DEVICE_NOT_FOUND; } // Get first camera to public cRef err = EdsGetChildAtIndex(cameraList, 0, out cRef); if (err != EDS_ERR_OK) { return err; } // release camera list if (cameraList != null) { EdsRelease(cameraList); } // everything went just fine return EDS_ERR_OK; } public uint ObjectEventHandler(uint inEvent, IntPtr inRef, IntPtr inContext){ switch (inEvent) { // in case of a download request case ObjectEvent_DirItemRequestTransfer: DownloadImage(inRef); break; default: break; } return EDS_ERR_OK; } // Downloads the picture from camera buffer to the computer private uint DownloadImage(IntPtr dItem) { EdsDirectoryItemInfo dirInfo; uint err; IntPtr stream = new IntPtr(); err = EdsGetDirectoryItemInfo(dItem, out dirInfo); if (err == EDS_ERR_OK) { err = EdsCreateFileStream(dirInfo.szFileName, EdsFileCreateDisposition.CreateAlways, EdsAccess.ReadWrite, out stream); } if (err == EDS_ERR_OK) { err = EdsDownload(dItem, dirInfo.Size, stream); } if (err == EDS_ERR_OK) { err = EdsDownloadComplete(dItem); } if (stream != null) { EdsRelease(stream); } return err; } // Takes picture public uint TakePicture() { return EdsSendCommand(cRef, CameraCommand_TakePicture, 0); } } } 

Answer 1

To retrieve and send events, you need a Windows message loop. The object's event handler should be called after adding this value to main() :

 while(GetMessage(&msg, NULL, NULL, NULL)) { TranslateMessage(&msg); DispatchMessage(&msg); } 

Also remember to set PropID_SaveTo to SaveTo_Host. You can see my post here .

Answer 2

I am working on the best Canon EOS support for .NET. I call it Canon.Eos.Framework . I just added support for capturing and loading any path on your computer . This structure is still in Alpha mode, but feel free to test.

Answer 3

My first assumption is that you UnInitialize the driver too quickly before the callback has a chance to be called.

TakePicture simply tells the camera to take a picture, and you return more or less instantly to disable the driver. But in fact, photographing involves moving the mechanical parts around and can take half an eternity, and by the time the camera announces this is done, the listener no longer needs to receive the message.