You would think that they would be compatible with the name similarities. I spent the day yesterday, bright, sunny, not too cold, outside, along the Lake Huron Shoreline testing out my several new (used) film bodies. The day was so bright, that my glasses became VERY dark. Too dark to see well enough to focus and even had a difficult time seeing the lighted LED's in the viewfinder of my FM2. Guess I'll have to get some normal glasses too. Never had this problem as noticeably as yesterday, but this is the first time I went out in the bright with these particular glasses. Never even thought of that as an important factor. Live and learn.