Distance to sublect with 200mm

[D-50]

I am going to shoot a concert in a concert hall this weekend specifically for one of the percussionist. He wants pictures of him. I will be in the Control/lighting booth and the theature is not huge. I am wonderig though is 200mm going to be enough to get a decent shot of him. I know Im not going to be able to get right in his face but I am looking to get shots of him where he can be clearly identified and his body and instrument fill the frame. What is the maximum distance I can be from him to get these results?

 

[JDP]

This ought to help a bit, it's Tamron's interactive Focal Length Comparison.

 

[Soocom1]

Depends really. If the lens has a large front element, there shouldn't be too much of a problem. With concert lighting, you could pick up lens flair, so I would test shoot before the event and see what the results are.