Post-processing, dark frame - tips and tricks

[wilsontie]

Date: 10/6/07
Time: around 11pm
Place: Sibu, Sarawak
Camera: Canon Powershot S3 IS
stacked: 26 frames (15s each) using Deepsky stacker

OK . my take on Shah's challenge. Using Photoshop

1. my picture of the same part of the sky lebeh kurang,




single frame  with Canon EOS 20D and canon 50mm f1.4
6s f/1.4 at 50.0mm iso800


2. Next I rotated to match wilsontie pic




3. followed by adjusting scale to match and stack onto wilsontie pic




and viola no prizes for guessing 



Anybody want to try using the skychart.

cheers

woo...bestnya!!!!!

[mymoon]

Wah... great light abg aziz. Cuba tengok berapa banyak light photon yang boleh menerjah masuk ke ccd sensor jika lens anda mampu stop sampai f/1.4 itu baru 6 saat jer tu...

Cuba imagine, let say guided 60 saat mesti kita orang semua dah tak boleh kenal pasti buruj2 dalam imej tu dah terlampau crowded dengan bintang2 dan dust

maaf tapi 6s at 50mm tidak perlu apa2 astro mount. hanya tripod biasa saje cukup. sepatutnya saya ambil 10X6s light frames,10X6s darks,10X6s flats and 10X at 1/4000s bias frames semuanya di adun dengan  deepskystaker dsb. barulah gambar jadi macam yang terpapar dlm internet.

saya pun bukan mahir sangat, maklum lah baru nak berjinak2.

untuk further reading sila click http://deepskystacker.free.fr/english/index.html

cheers

[wilsontie]

Wah... great light abg aziz. Cuba tengok berapa banyak light photon yang boleh menerjah masuk ke ccd sensor jika lens anda mampu stop sampai f/1.4 itu baru 6 saat jer tu...

Cuba imagine, let say guided 60 saat mesti kita orang semua dah tak boleh kenal pasti buruj2 dalam imej tu dah terlampau crowded dengan bintang2 dan dust

maaf tapi 6s at 50mm tidak perlu apa2 astro mount. hanya tripod biasa saje cukup. sepatutnya saya ambil 10X6s light frames,10X6s darks,10X6s flats and 10X at 1/4000s bias frames semuanya di adun dengan  deepskystaker dsb. barulah gambar jadi macam yang terpapar dlm internet.

saya pun bukan mahir sangat, maklum lah baru nak berjinak2.

untuk further reading sila click http://deepskystacker.free.fr/english/index.html

cheers

sorry nak tanya pasal deepsky stacker..sebab lepas saya stack photos with DSS,they will become almost black and white? so wanna ask why yours pictures are so colourful? Are you process them with other software after stacking in DSS?
 Thanks.

[mymoon]

sorry nak tanya pasal deepsky stacker..sebab lepas saya stack photos with DSS,they will become almost black and white? so wanna ask why yours pictures are so colourful? Are you process them with other software after stacking in DSS?
 Thanks.

http://deepskystacker.free.fr/english/index.html

DeepSkyStacker is for pre-processing steps of deep sky pictures namely
Registering and
Stacking and
Simple post-stacking processes to quickly view the final result and
Saving the resulting image to a jpeg, bitmap or TIFF and
Getting ready to start post-processing

I normally do the post processing of my pictures in Adobe Photoshop sekurang-kurangnya
http://www.astropix.com/HTML/J_DIGIT/DIGTECHS.HTM


BTW the easy way and to automatically  get the camera to do all this work for you is take one exposure of your deep-sky object (not a set of them) and use the camera with long-exposure noise reduction turned on. Then, as soon as you close the shutter, the camera will automatically take a matching dark frame, subtract it, gamma-correct the result, and save it as a JPEG file. You can still adjust the contrast of your JPEG in Photoshop and combine multiple JPEGs of the same object.

But I assume we  want to do things the hard way. Why? Konon nya to be able to stack (combine) multiple images with maximum precision and control and also to avoid having to spend as much time on dark frames as you do on actual exposures tapi masa yang sama di habiskan didepan computer tak dikira.

ha ha ..we are suckers for control and pantang di cabar



Hope this is of help.

cheers

[wilsontie]

sorry nak tanya pasal deepsky stacker..sebab lepas saya stack photos with DSS,they will become almost black and white? so wanna ask why yours pictures are so colourful? Are you process them with other software after stacking in DSS?
 Thanks.

http://deepskystacker.free.fr/english/index.html

DeepSkyStacker is for pre-processing steps of deep sky pictures namely
Registering and
Stacking and
Simple post-stacking processes to quickly view the final result and
Saving the resulting image to a jpeg, bitmap or TIFF and
Getting ready to start post-processing

I normally do the post processing of my pictures in Adobe Photoshop sekurang-kurangnya
http://www.astropix.com/HTML/J_DIGIT/DIGTECHS.HTM


BTW the easy way and to automatically  get the camera to do all this work for you is take one exposure of your deep-sky object (not a set of them) and use the camera with long-exposure noise reduction turned on. Then, as soon as you close the shutter, the camera will automatically take a matching dark frame, subtract it, gamma-correct the result, and save it as a JPEG file. You can still adjust the contrast of your JPEG in Photoshop and combine multiple JPEGs of the same object.

But I assume we  want to do things the hard way. Why? Konon nya to be able to stack (combine) multiple images with maximum precision and control and also to avoid having to spend as much time on dark frames as you do on actual exposures tapi masa yang sama di habiskan didepan computer tak dikira.

ha ha ..we are suckers for control and pantang di cabar



Hope this is of help.

cheers

what kind of camera that come with "automatically take a matching dark frame, subtract it, gamma-correct the result, and save it as a JPEG file“?anyway  thanks for answering my question

[mymoon]

what kind of camera that come with "automatically take a matching dark frame, subtract it, gamma-correct the result, and save it as a JPEG file“?anyway  thanks for answering my question

For the Nikon coolpix cp995, a P&S I bought in 2001 with the NR on, any shot 1/15 sec or longer the camera will surreptitiously gather a dark frame of the same duration and use any speckles on that to remove any speckles on the shot.

click   http://www.pk3.org/Astro/index.htm?astrophoto_dc_vs_wc.htm and scroll down the page to see its effectiveness.

with most DSLR either Nikon or Canon the feature will be buried in the menu. It is by Default disabled. You have to turn it on.

I believe for the Canon 300D this feature is missing. I may be wrong. Any owner care to verify.

cheers

[botok]

Tak tahu betul atau tidak, tapi rasanya hampir semua consumer level camera yang ada noise reduction (kamera apa yang takde noise reduction sekarang ni??) semuanya ada proses dark frame subtraction yang diambil selepas sahaja light frame diambil. Kalau kamera tu ada option untuk off noise reduction proses mungkin boleh hentikan dark frame subtraction prosess tu.

[wilsontie]

Tak tahu betul atau tidak, tapi rasanya hampir semua consumer level camera yang ada noise reduction (kamera apa yang takde noise reduction sekarang ni??) semuanya ada proses dark frame subtraction yang diambil selepas sahaja light frame diambil. Kalau kamera tu ada option untuk off noise reduction proses mungkin boleh hentikan dark frame subtraction prosess tu.

so..means that i no need to take anymore offset, dark frames...?since camera already do dark frame substraction.
AND which results is better: we take dark frame and then substract ourselves OR let the camera do the things?

thanks for answering

[botok]

Dunno which one is better, manually done or built-in feature in camera? Saya akan cuba buat perbandingan nanti bila langit kawasan utara ni clears up.

[wilsontie]

Dunno which one is better, manually done or built-in feature in camera? Saya akan cuba buat perbandingan nanti bila langit kawasan utara ni clears up.

ok..wait for your good news
yup these few days sibu and miri also raining every day...

[kamayok3]

Dunno which one is better, manually done or built-in feature in camera? Saya akan cuba buat perbandingan nanti bila langit kawasan utara ni clears up.

Manual done always better....... 

Regards,

Tommy

[nsyahron]

Manual done always better....... 

Regards,

Tommy

Tommy,  do you take darks at every session or you use a Master dark?

[kamayok3]

Manual done always better....... 

Regards,

Tommy

Tommy,  do you take darks at every session or you use a Master dark?

Already answer you through PM... Check it out.

Tommy

[botok]

Tommy pm i sekali la i pun nak tau jugak..

[kamayok3]

Tommy pm i sekali la i pun nak tau jugak..

hahahah.....okok...PM u sekali. Simple answer saja. Sudah senttttt................

Tommy