[font:Comic Sans MS]First generation is poor, very poor with respect to image clarity. When we speak of 1st generation, we are generally referring to older units, which tend to be buggy, buzz and hum. Some of this white noise bleeds into the image. I wouldn't think that any manufacturer is building 'new' 1st generation units. I will say that anything is possible with Chinese trinket factories willing to fill any junk niche that is open.
The second generation series would be a starting point, however at your distance of ~50yards, it will be still very grainy. Depending on what type of 'surplus' device you go with, most offer very little in the area of true magnification. The units are already extremely heavy (3-4lbs) and I suppose that there is already enough built into the unit with the image intensifier that that inhibits much more in being able to offer anything in the way of magnification. Whatever you decide, make sure you spring a few extra dollars and acquire an infrared illuminator for indoor use (or for moonless nights, when minimal ambient light is utilizable).
If you've got the $$$ to dedicate to such a play toy, consider 3rd generation and avoid Russian and/or Sino surplus units.
Hope this helps.
To sum up: 1st generation=junk
2st generation+higher priced but still junk.
Leon[/font]