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05-12-2011, 07:31 AM - 1 Like   #16
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Hi Astrophotographers !

6-7 years ago, Canon Eos 20d, 5d, etc... were fine tools for AstroPhoto,
but their very huge amount of Electronic Noise from iso 100 to 400,
made the iso 1600 setting mandatory for AstroPhotography use !
(exept during warm summer nights, say iso 800 setting ?)
Taking Pattern Noise in account, the measured DR was no more than ~9~10 EV
from iso 100 to 1600, so it was not a big problem using them at iso 1600 !
Exept the need of stacking 25-30 RAWs in DSS to get good results :
Fuji S2 Pro, Canon Eos 20d, 5d AstroPhotos : Jean Claude DIMA

As there were no change in Canon's Electronic Noise levels at low iso settings :
http://forums.dpreview.com/forums/read.asp?forum=1032&message=35842756
I decided to change back to Pentax, and bought a K-5 and a "K" T2 adapter !

Now, the Pentax K-5 is playing in a very different world than the Eos :
= a total lack of Electronic Noise at iso 80 to 400 !
= a measured DR of about 14 EV at iso 80 !
+ with the Pentax K-5 at iso 80, you'll get very tiny RAWs, about 13-15 MB,
and you'll only need stacking from 3 to 6 RAWs in DSS to get good pictures :
http://www.chassimages.com/forum/index.php/topic,118675.75.html
http://www.chassimages.com/forum/index.php/topic,118675.100.html

http://www.chassimages.com/forum/index.php/topic,118675.125.html
http://www.chassimages.com/forum/index.php/topic,118675.150.html
http://www.chassimages.com/forum/index.php/topic,118675.175.html
(say 3 RAWs for big luminous Deep Sky Objects... else 5-6 RAWs ?)
Pentax K-5 AstroPhotos : Pentax-Full-Frame-Soon

of course, you may keep shooting AstroPhotos at hight iso settings,
but for example, when shooting at iso 12800 instead of iso 80 :
-- DR is only half the iso 80 DR !
-- SNR is only half than the iso 80 value !!
-- RAW Size is about twice the iso 80 RAW Size !!!
-- you'll need stacking much more RAWs to get rid of Noise !!!!

All photos presented here are taken at sea level, in a big big city,
with such light pollution making any visual observation impossible !
I am very excited to bring my Pentax K-5 in the mountains,
where I could test its resistance at low temperatures ?
and where, of course, i will get far better pictures !




Last edited by geo444; 04-09-2013 at 11:09 AM. Reason: lost links
05-12-2011, 08:03 AM - 2 Likes   #17
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I think this needs to be an article. There's too much good, highly specialized information here to lose.
05-12-2011, 08:04 AM   #18
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QuoteOriginally posted by geo444 Quote
All photos presented here are taken at sea level, in a big big city,
with such light pollution making any visual observation impossible !
I am very excited to bring my Pentax K-5 in the mountains,
where I could test its resistance at low temperatures ?
and where, of course, i will get far better pictures !
Actually, I took mine in the mountains of Pennsylvania on a farm in the middle of nowhere. I did them while visiting my aunt one weekend.
Trust me, I know mine aren't great examples as it was a first attempt... but I'm going back to PA for memorial day weekend and hoping to give it a try again!



QuoteOriginally posted by oliver939 Quote
@Drabbit,

your pics are very nice but exif says they're from Kx.
Do you have a K5 to try to do similar photos?

Yeah, I mentioned I took them with the K-x
See above... hope to try with K-5 again soon... I live on Long Island in NY, so I don't exactly have a polution-free sky close by to try... have to wait until I can get out to Montauk or back to PA
05-12-2011, 04:10 PM   #19
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Here's a star time lapse with the K-5.

http://www.bsquires.name/ph/test4.mov

Taken May 5, 2011, 6 miles south of the Columbia River, in the Deschutes River canyon. Some light pollution, which surprised me as this is the middle of no where.

K-5, DA 15mm ltd. Set for a 20 second exposure every minute with the dark frame subtraction turned on. ISO 1600, f/4.5, one pix every minute from 10 pm until 3 am. The flash at the end is a train going through the canyon.

05-12-2011, 04:44 PM - 3 Likes   #20
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My astrophotos with K5

These are my new astrophotos captured last weekends.

1. Omega Centuari Globular Cluster - Pentax K5 + CZ 300mm + 2x TC.



2. The Milky Way - Pentax K5 + 18-55mm. 5 minutes exposure @ ISO1600



3. The panorama of the Milky Way



4. The Heart of the Scorpius



5. The constellation of the Scorpius



Thanks for looking.
05-12-2011, 05:32 PM   #21
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kamayok3: one word... AMAZING!

What are you using for tracking?
05-12-2011, 06:02 PM   #22
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I am using German Equatorial Mount for tracking. Thanks.
05-12-2011, 06:07 PM   #23
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QuoteOriginally posted by geo444 Quote
Hi Astrophotographers !

6-7 years ago, Canon Eos 20d, 5d, etc... were fine tools for AstroPhoto,
but their very huge amount of Electronic Noise from iso 100 to 400,
made the iso 1600 setting mandatory for AstroPhotography use !
(exept during warm summer nights, say iso 800 setting ?)
Taking Pattern Noise in account, the measured DR was no more than ~9~10 EV
from iso 100 to 1600, so it was not a big problem using them at iso 1600 !
Exept the need of stacking 25-30 RAWs in DSS to get good results :
Fuji S2 Pro, Canon Eos 20d, 5d AstroPhotos : Jean Claude DIMA

As there were no change in Canon's Electronic Noise levels at low iso settings :
beyond banding, is Canon DR definitely glued at 11 EV ??: Canon EOS-1D / 1Ds / 5D Forum: Digital Photography Review
I decided to change back to Pentax, and bought a K-5 and a "K" T2 adapter !

Now, the Pentax K-5 is playing in a very different world than the Eos :
= a total lack of Electronic Noise at iso 80 to 400 !
= a measured DR of about 14 EV at iso 80 !
+ with the Pentax K-5 at iso 80, you'll get very tiny RAWs, about 13-15 MB,
and you'll only need stacking from 3 to 6 RAWs in DSS to get good pictures :
... Pentax me revoila : mon K5 arrive juste !
... Pentax me revoila : mon K5 arrive juste !
... Pentax me revoila : mon K5 arrive juste !

(say 3 RAWs for big luminous Deep Sky Objects... else 5-6 RAWs ?)
Pentax K-5 AstroPhotos : Pentax-Full-Frame-Soon

of course, you may keep shooting AstroPhotos at hight iso settings,
but for example, when shooting at iso 12800 instead of iso 80 :
-- DR is only half the iso 80 DR !
-- SNR is only half than the iso 80 value !!
-- RAW Size is about twice the iso 80 RAW Size !!!
-- you'll need stacking much more RAWs to get rid of Noise !!!!

All photos presented here are taken at sea level, in a big big city,
with such light pollution making any visual observation impossible !
I am very excited to bring my Pentax K-5 in the mountains,
where I could test its resistance at low temperatures ?
and where, of course, i will get far better pictures !

For a bit of camera trivia, the EOS 20Da was made specifically for astrophotography. The IR filter on it passed over 2.5x light ~ 656 nm wavelength.

05-15-2011, 03:01 PM   #24
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Awww. I just got my K5 recently, still trying out what I can do with it, and am currently for a week's vacation on La Palma (Canary Islands) - which is Europe's choice for many of their largest optical telescopes. At 2.4km altitude, there's a high chance of clear skies all year around, and the towns below even are required by law to keep their lights down (no upward lights or beams, for instance). I now run into this thread thinking of the possibilities - only to realize that we're close to full moon right now. Sigh. Well, it makes for great night shots of the landscape, at least
05-17-2011, 02:31 AM   #25
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Pentax K-5 for Astrophotography

QuoteOriginally posted by Blue Quote
... the EOS 20Da was made specifically for astrophotography. The IR filter on it passed over 2.5x light ~ 656 nm wavelength.
... and one of the first DSLR (w/ Fuji S3 Pro) to implement Live-View !

but their Canon CMos Sensor were very noisy at iso 100 :
Sensor Data for Canon EOS_20D
... about 10 times the noise level of the K-5 :
Sensor Data for Pentax K-5
result was heavy banding noise :
http://www.chassimages.com/forum/index.php/topic,110389.msg1976362.html#msg1976362



Last edited by geo444; 05-17-2011 at 02:51 AM.
05-17-2011, 03:54 AM   #26
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anyway, most of astrophoto pictures seen on the web are form Canon cameras.

i wish we can see more K-5 ones to see what it can do
05-17-2011, 04:12 AM   #27
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Pentax K-5 Astrophotography

QuoteOriginally posted by oliver939 Quote
anyway, most of astrophoto pictures seen on the web are form Canon cameras.
i wish we can see more K-5 ones to see what it can do

right... but the opposite would have been very surprising !?

- Canon's Eos from 20d represent ~30% of DSLR market share since 2004 !!

- vs Pentax K-5 represent... ~0.2% of DSLR market share since... 2011 ?




Last edited by geo444; 05-17-2011 at 04:33 AM.
05-17-2011, 02:46 PM   #28
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QuoteOriginally posted by kamayok3 Quote
These are my new astrophotos captured last weekends.

1. Omega Centuari Globular Cluster - Pentax K5 + CZ 300mm + 2x TC.
Fabulous shot. Which 2x TC are you using, the Tokina?

Here on the coast of California, the bright moonlit nights were followed by rain and overcast, so there has been no opportunity recently to take more sky photos. Unlike much of the rest of the US, when it rains here the lightning is rare, otherwise I'd be shooting it. The K-5, with its weatherproofing, is the perfect camera for getting shots of lightning.
05-23-2011, 05:41 AM   #29
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just a quick question - for the wide angle shots of the milkyway etc using normal camera lenses rather than telescopes - presumably you mounted the camera onto telescope mount so it would track during long exposures - when getting a telescope do you need to look for any specific mount that is capable of mounting a camera aswell as the scope?
05-26-2011, 08:33 AM - 1 Like   #30
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Pentax K-5 Astrophotography

QuoteOriginally posted by stormcloud Quote
- for the Wide Angle shots of the milkyway etc using normal camera lenses rather than telescopes - presumably you mounted the camera onto telescope mount so it would track during long exposures -
you don't need tracking on an APSc Camera...
- until ~20 second exposure at ~28mm focal
- until ~25 second exposure at ~24mm focal
- until ~30 second exposure at ~20mm focal


QuoteOriginally posted by stormcloud Quote
- when getting a telescope do you need to look for any Specific Mount that is capable of mounting a camera as well as the scope ?
a Specific Mount is an EQuatorial Mount, you cant get it together with
the Scope (Reflector or Refractor) or separately
then 3 ways mounting your camera :
- Camera mounted to the Scope with a T2 Adapter = Prime Focus
- Camera with a Lens, attached to the Scope = Piggyback
- Camera with a Lens, attached to the Mount with a Special Plate


Last edited by geo444; 05-26-2011 at 08:39 AM.
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