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HaruhikoT wrote:
Thanks to many informative comments from you, I've just made some changes on my simulation settings to improve its accuracy.
Results (e.g. astigmatism) are slightly changed from my initial post.
In addition, new settings can handle not only Symmetrical but also Retrofocus design!
Here are my current simulation settings.
I also wrote Quick Guide to use OSLO free edition, so now you can simulate by yourself.
I hope this would help you to know optimal PC filter for your own various lenses.
Please note I'm just a hobbyist not a pro of optics, so if you find any mistakes or better settings, please feedback.
----------- save txt below -----------
// OSLO 6.6 0 0 0
LEN NEW "PC1.5m+G21+1.85mm" 21.5 8
EBR 3.839
ANG 45.0
DES "OSLO"
UNI 1.0
// SRF 0
AIR
TH 1.0e+20
AP 1.0e+20
NXT // SRF 1
GLA BK7
RD 778.5
TH 3.0
AP 25.0
NXT // SRF 2
AIR
TH 16.4
AP 25.0
NXT // SRF 3
AIR
TH 1.3
AST
NXT // SRF 4
AIR
LMO EGR
DRW ON
NXT // SRF 5
AIR
LME
TH 18.5
PFL 21.5
NOT "PERFECT"
NXT // SRF 6
GLA BK7
TH 1.85
AP 22.0
NXT // SRF 7
AIR
PY 0.0
AP 22.0
NXT // SRF 8
GLA BK7
AP 22.0
END 8
DLNR 0 5
DLNR 1 5
DLMN 1 -1.0
DLMX 1 1.0
DLNR 2 5
----------- save txt above -----------
Quick Guides:
1. Save txt above as *.len.
2. Install OSLO EDU and start GUI.
3. Select "open an existing.." and choose the *.len file
4. Choose GW (Graphics Window) and click the 4th-9th icons from the left.
You can see various analysis including astigmatism.
To adjust scale, right-click in the window and choose Re-calculate.
5. You can change P-C filter's parameter by modifying *.len file. See below:
NXT // SRF 1
GLA BK7 <- Filter's Material
RD 778.5 <- Filter's Curvature radius
TH 3.0 <- Filter's Edge thickness
AP 25.0 <- 1/2 of Filter's Diameter
6. You can also change Cover glass thickness. For Leica/Kolari, use 0.8.
NXT // SRF 6
GLA BK7
TH 1.85 <- Cover glass thickness
7. You can also change Primary lens parameter. See below:
From Zeiss G21 technical sheet I got:
Angular field= diagonal 2w 90°
Focal length = 21.5mm
Exit pupil Position = 10.7 mm in front of the last lens vertex
Back focal distance = 12.1 mm
Entrance pupil Position = 16.4 mm behind the first lens vertex
I set ANG as 45.0 (1/2 of angular field)
I set 21.5 to "PFL" in SRF 5.
I set 16.4 to "TH" in SRF 2.
Aperture stop is placed 1.3mm (10.7+12.1-21.5) in front of perfect lens.
So I set 1.3 to "TH" in SRF 3.
This helps the case the focal length is not equal to exit pupil distance.
I set EBR(entrance beam radius) as 3.839 which comes from 21.5mm(fl) / 2.8(fno) /2.
Haruhiko
...Show more →
Thank you Haruhiko. I got the the OSLO a couple of days ago but haven't figured out how to use it yet. This text base config really helps.
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