Hi,
I done a simple test at various f-stop (F1.8, F2.0, F2.2, F2.5, F2.8, F3.2, F3.5 and F4.0) and below is the result showing part of the image at the edge. The image of the test shot (60s exposure @ ISO800) is at actual size and no processing had been done.
The test shot show that at F3.5 or slower, the stars image looks the best.
Have a nice day.
Canon EF 50mm f/1.8 II lens for Astrophotography
- weixing
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Canon EF 50mm f/1.8 II lens for Astrophotography
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- Canon EF 50mm f/1.8 II Test Shot
- EF50F18LensTest.jpg (89.75 KiB) Viewed 15936 times
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- Canon EF 50mm f/1.8 II
- ef_50mm_f18_ii.jpg (12.62 KiB) Viewed 15936 times
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance."
- weixing
- Super Moderator
- Posts: 4708
- Joined: Wed Oct 01, 2003 12:22 am
- Favourite scope: Vixen R200SS & Celestron 6" F5 Achro Refractor
- Location: (Tampines) Earth of Solar System in Orion Arm of Milky Way Galaxy in Local Group Galaxies Cluster
Hi,
Below is the full image (no other processing done other than scaling down the image) at F1.8 and F2.8.
Can see the that the stars got tail even the image is scale down at F1.8, but the stars look ok at F2.8 when scale down.
Have a nice day.
Below is the full image (no other processing done other than scaling down the image) at F1.8 and F2.8.
Can see the that the stars got tail even the image is scale down at F1.8, but the stars look ok at F2.8 when scale down.
Have a nice day.
- Attachments
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- 60s Exposure @ ISO800 F2.8
- EF50-F2_8.jpg (50.79 KiB) Viewed 15930 times
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- 60s Exposure @ ISO 800 F1.8
- EF50-F1_8.jpg (42.79 KiB) Viewed 15931 times
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance."
- weixing
- Super Moderator
- Posts: 4708
- Joined: Wed Oct 01, 2003 12:22 am
- Favourite scope: Vixen R200SS & Celestron 6" F5 Achro Refractor
- Location: (Tampines) Earth of Solar System in Orion Arm of Milky Way Galaxy in Local Group Galaxies Cluster
Hi,
Also, I think the pink and greenish colour at the edge is cause by the vignetting of the LPR filter when the lens is at faster f-stop... you can see some pink and greenish colour on the LPR filter if you look through it at an angle.
Have a nice day.
I think it is cause by the uncorrected aberrations of the lens at wide open and vignetting cause by the LPR filter which is smaller than the lens.what caused those streaking effect at larger aperture?
Also, I think the pink and greenish colour at the edge is cause by the vignetting of the LPR filter when the lens is at faster f-stop... you can see some pink and greenish colour on the LPR filter if you look through it at an angle.
Have a nice day.
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance."
- weixing
- Super Moderator
- Posts: 4708
- Joined: Wed Oct 01, 2003 12:22 am
- Favourite scope: Vixen R200SS & Celestron 6" F5 Achro Refractor
- Location: (Tampines) Earth of Solar System in Orion Arm of Milky Way Galaxy in Local Group Galaxies Cluster
Hi,
Have a nice day.
I have mark (by the white box) the location of where the test shot was taken from on this F3.5 image.could you please indicate where the test shots came from the full frame?
Have a nice day.
- Attachments
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- 60s Exposure @ ISO 800 F3.5 (location of test shot mark by white box)
- EF50-F3_5.jpg (58.95 KiB) Viewed 15895 times
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance."
- weixing
- Super Moderator
- Posts: 4708
- Joined: Wed Oct 01, 2003 12:22 am
- Favourite scope: Vixen R200SS & Celestron 6" F5 Achro Refractor
- Location: (Tampines) Earth of Solar System in Orion Arm of Milky Way Galaxy in Local Group Galaxies Cluster
Hi,
Anyway, below is the center of test shots... 300x300 pixels at the center. The open cluster in the image is the M6 butterfly cluster.
Have a nice day.
Center is usually ok even at wide open.did you do a comparison of the centers to see if it's usable larger than f/4?
Anyway, below is the center of test shots... 300x300 pixels at the center. The open cluster in the image is the M6 butterfly cluster.
Have a nice day.
- Attachments
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- Canon EF 50mm f/1.8 II (300x300 pixels of the image at the center)
- EF50F18LensTest-Centre.jpg (70.02 KiB) Viewed 15881 times
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance."