Bestwell Minisight grain focuser unusable?

[eyeintheworld]

I recently purchased a Bestwell Minisight grain focuser, used.

I was surprised to see that the cross hair used to focus the eyepiece is curved in, rather than straight across. Looks like maybe a finger went in there and displaced it?

I assume this will make it difficult to focus the eyepiece correctly, and thus hard to get the projected negative focus, as well.

Can anyone who uses one of these offer advice? Is there a way to salvage it, or should I try to return it?

Based on my understanding of how these work, it seems like the distance between the mirror and cross hair needs to be precisely calibrated to get the negative correctly focused on the paper surface.

Thanks!

 

[Donald Qualls]

This appears to be an aerial image focusing aid, and unless the crosshair is straight and in the (folded) focal plane at the same point as the device base, it will allow you to very precisely misfocus your negative, by exactly the amount of the crosshair deflection.

It likely is possible to repair, as the hair is probably just glued to the upper surface of the ring you see at its ends -- but it's probably better to return it and try again. The tools required to disassmeble the focuser and get the ring back to exactly the correct location aren't common.

 

[eyeintheworld]

@Donald Qualls Thanks for your reply and helping confirm my understanding. Fortunately, I was able to get a refund for the item.