When using EDSDK version 3.4.0 to take a photo with the Rebel T6i it can take anywhere from 2 to 30 seconds after calling EdsSendCommand(camera, kEdsCameraCommand_TakePicture, 0); for the corresponding kEdsObjectEvent_DirItemCreated to be received, signalling that the image is ready to download from the camera. Note that the camera itself takes the photo and the flash goes off almost instantly after sending the TakePicture command - it is only the kEdsObjectEvent_DirItemCreated event that is delayed for seemingly random, large amounts of time.
The delays become much longer and more frequent when connecting to a second Rebel T6i, even when only taking photos with one of the cameras. This even occurs when both cameras are ran from separate applications.
We're hoping to use both of these cameras as a part of an installation that requires we're able to download each photo from the camera within at most 5 seconds from when EdsSendCommand(camera, kEdsCameraCommand_TakePicture, 0) is called.
If anyone has any ideas on why this large delay might be occurring or any other suggestions on how to fix it, we'd greatly appreciate it!
Note: We're building 64-bit at the moment but are currently attempting to get a 32-bit build working in the meantime to see if that improves anything.
Not using live view will fix the problem. You need to download the image direct to the computer instead of saving to the SD card first as well. If ANY other camera is plugged in that is using live mode then you will continue to have the above problem unfortunately.