Hi guys! I used it in film production, but now is it reliable to use? If the answer is Yes please comment on the usage of it as the recorder on reel tape or as the portable mixer. How to sync with the video? considering (Sony HD vcr) new models

The Nagra 4.2 is still very reliable as a recorder. However, the question is whether or not it is practical.

What the Nagra does very well is to record good audio (the 4.2 is monaural, not stereo nor 2-track) and records a sync pulse on the audio to keep it is sync for playback or transfer. When the audio is played back, with the internal synchronizer (resolver) turned on, the audio plays back in perfect speed sync for video, or mag film for FILM.

If the Nagra is being used for film (to be edited in video), then the audio must be pulled down in speed by 0.1%, either by using an external sync reference of 59.94 or by modifying the file within the editing software itself. If the Nagra is being used with video, then no pulldown is necessary.

The Nagra 4.2 does NOT record SMPTE timecode, so you must use a clapstick slate and manually align the audio in sync with the picture during editing.

The problem with the Nagra is that:
1) It is only monaural. It does accept two inputs (three with an adapter), but all of these are mixed down to a single track.
2) Audiotape is extremely rare and hard to find. Read expensive.
3) The machine is heavy and bulky.

As much as I have loved using the Nagra over the years, these days you would be much better served using a portable, digital recorder. Use those recorders with a good, portable mixing panel. For ENG, the ENG-44 from Sign Video is excellent for the money. Mixers from Sound Devices and Shure are great, though more costly. If you are not needing over-the-shoulder portability, then use a Mackie or Behringer mixing board (priced from $140 to $500).