javierpuga
Newbie
I have a "Focus Scope" focus finder:
http://www.bhphotovideo.com/c/product/123618-REG/Tundra_Security_97FS_Focus_Scope.html
i got it used in a bundle with a bunch of other used darkroom equipment. I understand how to use it, but my problem is that it doesn't seem to be accurate. I will focus an image until i see the grain through the lens, but then, after taking it away, just using my eye, i can see the image is way out of focus.
You can pull the top part of the lens out, so the eyepiece is farther from the mirror, i thought this would adjust it, but it makes it even more out of focus. i would need the lens to be closer to the mirror, if that makes sense.
either way, how could it not be accurate, it's just a lens and a mirror, right? is there something i'm missing? thanks
http://www.bhphotovideo.com/c/product/123618-REG/Tundra_Security_97FS_Focus_Scope.html
i got it used in a bundle with a bunch of other used darkroom equipment. I understand how to use it, but my problem is that it doesn't seem to be accurate. I will focus an image until i see the grain through the lens, but then, after taking it away, just using my eye, i can see the image is way out of focus.
You can pull the top part of the lens out, so the eyepiece is farther from the mirror, i thought this would adjust it, but it makes it even more out of focus. i would need the lens to be closer to the mirror, if that makes sense.
either way, how could it not be accurate, it's just a lens and a mirror, right? is there something i'm missing? thanks
d_ross
Registered User
perhaps post a picture of yours here, as it's hard to say without seeing it. but most likely the top piece isn't actually all the way in, mine has a little groove either side of the insert that matches with two little rails on the inside of the bottom part, and it needs be inserted fully to be accurate.
javierpuga
Newbie
it looks identical to the one in the b&h picture. just checked, and mine definitely does not have any grooves or rails.
it's just confusing because it's such a simple contraption, i can't imagine it not working properly.
like i said, i acquired it used, so i'm not sure if it was always inaccurate, or if it's something that happened over time.
it's just confusing because it's such a simple contraption, i can't imagine it not working properly.
like i said, i acquired it used, so i'm not sure if it was always inaccurate, or if it's something that happened over time.
d_ross
Registered User
if its not adjustable then it should be right, still they are cheap to buy, and invaluable tool I think.