Hi Giannis
More likely or not these can be found over the Internet. As far as I am aware, Sony do not make these themselves. The EnCinema SLR Lens Adapter seems to crop up a few times on my searches but it is far from cheap so expect to fork out some money for one.
What you need to consider is more than just depth of field. Whilst this may do it, it is still limited in what it will be able to do and that will be mainly quality. Since these work but using additional lenses, your image quality may not be as sharp as before, you may also encounter dark or cut off corners or even poor performance in low light. I have had a look at even the ones using mounts made for iPhones and whilst the depth looks great, the sharpness has gone which is one of the keys to a high end video. I can assure you that manual focusing on video is horrible especially with motion based subjects.
As much as I would say check out the YouTube videos, it would not really reflect what you may buy or your Handycam which you are using. Personally I feel that too shallow depth of field on video is getting a bit overdone now depending on what you are planning to video. I personally find more dynamic shots using sliders or steadycams yield far more creative results with video.
Have you got some example videos online to share? If you do find one, it would be awesome to post up a mini review or some sort since I would be very interested to read. 🙂
