Park Edwards
Veteran
Is there a perfect distance the GG should be from an Achromat.
Achromats
- Thread starter Park Edwards
- Start date
Ted Ramasola
Veteran
Car30
Bob hart, a poster at another forum has made this measurements,
Dioptre power.------Distance from groundglass.------ Camcorder zoom for 24mm frame.
3+ ------------------Approx 10 inches-------------- not known - may vignette
4+ ------------------Approx 8 inches--------------- 54mm for Sony FX1.
7+ ------------------Approx 5 inches--------------- Approx 40mm for Sony FX1
10+ ---------------- Approx 3 inches-------------- not known - may go soft on edges.
Hope this helps
Ted
Bob hart, a poster at another forum has made this measurements,
Dioptre power.------Distance from groundglass.------ Camcorder zoom for 24mm frame.
3+ ------------------Approx 10 inches-------------- not known - may vignette
4+ ------------------Approx 8 inches--------------- 54mm for Sony FX1.
7+ ------------------Approx 5 inches--------------- Approx 40mm for Sony FX1
10+ ---------------- Approx 3 inches-------------- not known - may go soft on edges.
Hope this helps
Ted
twocik23
Veteran
"3+ ------------------Approx 10 inches-------------- not known - may vignette
4+ ------------------Approx 8 inches--------------- 54mm for Sony FX1.
7+ ------------------Approx 5 inches--------------- Approx 40mm for Sony FX1
10+ ---------------- Approx 3 inches-------------- not known - may go soft on edges."
Remember guys that Achromats aren't measure in + 9, +2, +5, etc.. , they're measured in focal length. A good fast way to calculate the focal length is to (now this isn't the most accurate way, but does work)
ie.
1000 / whatever number = Focal length
1000 / + 8 = 125mm
4+ ------------------Approx 8 inches--------------- 54mm for Sony FX1.
7+ ------------------Approx 5 inches--------------- Approx 40mm for Sony FX1
10+ ---------------- Approx 3 inches-------------- not known - may go soft on edges."
Remember guys that Achromats aren't measure in + 9, +2, +5, etc.. , they're measured in focal length. A good fast way to calculate the focal length is to (now this isn't the most accurate way, but does work)
ie.
1000 / whatever number = Focal length
1000 / + 8 = 125mm
Park Edwards
Veteran
Yeah, I know how to find the diopter from the FL but I was always curious if there was a perfect distance the GG should be from the Achromat. I just recently seen how sharp the picture it got when I put some spacers between the GG and the achromat. Appreciate the chart there guys.
-rh
-rh