Hi folks,
I'm wondering if anyone can tell me what a refractor star test looks like when the crown element has been flipped. This would mean that the flatter, front side of the crown would be turned inside, while more obviously curved inner side would be facing the sky.
Is there a more or less typical look to the star test with a lens in this arrangement? Typically, in such a lens arrangement, would the star test reveal EXTREMELY obvious diffraction rings inside of focus, while much less obvious rings outside of focus? Also, would the center rings (past the outer two) of the outside focus get mushy and just not show up too much? This star test could also simply be described as very undercorrected.
This is the exact description of my lens. At first I thought the problem might be just a too tight retaining ring that was bringing the lens elements too close together. I've tried loosening the ring and I THINK it has helped. However, I really don't think this is the problem.
Also, if the retaining ring were tightened to that degree, certainly there would be signs of pinched optics. Hwever, there are no such signs.
I just want more about this before I bother to take the lens apart and try flipping it.
Thanks,
Bruce
I'm wondering if anyone can tell me what a refractor star test looks like when the crown element has been flipped. This would mean that the flatter, front side of the crown would be turned inside, while more obviously curved inner side would be facing the sky.
Is there a more or less typical look to the star test with a lens in this arrangement? Typically, in such a lens arrangement, would the star test reveal EXTREMELY obvious diffraction rings inside of focus, while much less obvious rings outside of focus? Also, would the center rings (past the outer two) of the outside focus get mushy and just not show up too much? This star test could also simply be described as very undercorrected.
This is the exact description of my lens. At first I thought the problem might be just a too tight retaining ring that was bringing the lens elements too close together. I've tried loosening the ring and I THINK it has helped. However, I really don't think this is the problem.
Also, if the retaining ring were tightened to that degree, certainly there would be signs of pinched optics. Hwever, there are no such signs.
I just want more about this before I bother to take the lens apart and try flipping it.
Thanks,
Bruce
