A guy on e-bay was selling 6 lamps for one of my projectors so i snapped them up but he said he has no idea on how many hours each one has.

I know the hours on the one in my projector (about 150) so i thought maybe i could compare them to mine.

I thought maybe i could use a camera and just take some still images and compair each one to mine?

Any other ideas?

If the lamp has more hours it will be a little less bright correct?

There is no way to tell with any reasonable accuracy the hours on a lamp. You could look at it and guess, but you could be off by 100, 1000 or any amount.

Yes, a lamp that is used will be less bright than a new one. But by how much? Lamps age differently. And how calibrated are your eyeballs in terms of brightness or contrast?

Bottom line, you could guess, and that's about it.

There is no way to check the hours on a bulb. You can tell if they are blown but thats about it. A bulb that looks brand new could have up to 1000 hours on it.

There is no way to tell with any reasonable accuracy the hours on a lamp. You could look at it and guess, but you could be off by 100, 1000 or any amount.

Yes, a lamp that is used will be less bright than a new one. But by how much? Lamps age differently. And how calibrated are your eyeballs in terms of brightness or contrast?

Bottom line, you could guess, and that's about it.

Thats where the camera snapshots come in. Ill try it when i get them and take some shots and then post em here and we can see what or if we notice anything.

You can get a light meter fairly cheap to see if the bulb is not outputting at 100% but that doesnt actually tell you how many hours the bulb has been used or has left.