I just published a review of the Saramonic SR-AX101 and SR-AX107 Audio Adapters at GoodAudioTracks.com.
If you're trying to record good audio on a DSLR, these adapters can help solve these issues:
- You can't use microphones with XLR connectors. That leaves out hundreds of high quality professional microphones and limits you to mics with a 3.5mm connection.
- You can't use more than one mic at a time, no backup and no way to get good audio with two people.
- Even if you have manual level control for audio, you can't set audio level independently for each mic.
- You may not have audio meters or headphone output, so you have no way to monitor the sound level and make sure you get a good recording.
- You may be stuck with auto gain control on your camera that ruins any chance of getting a good recording.