Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-05-2015, 12:10 PM   #1
Veteran Member




Join Date: Dec 2011
Location: UK
Posts: 440
Astro lens shoot out... what and why

OK this thread might have been done before, but here we go...

Enter the ring:

Pentax
DA 10-17 FE
DA 14
DA 15
DA 12-24
DA 21
FA 31
and others (including legacy etc)


Sigma
8-16
10-20
18-35

Samyang
8 FE
10
12
14
16
24


What and why?

Do you augment with Astrotracer?

09-05-2015, 12:29 PM   #2
Pentaxian
Aaron28's Avatar

Join Date: Jan 2015
Location: Huntsville, Al
Posts: 5,131
any of them really.....although a prime would be better than a zoom as in most cases they have faster/wider apertures
and certainly could use the o-gps to track for longer exposures with any of these
I use a 14/2.8 and 28/2.8 mostly but sometimes I will go long for nebula and other deep sky objects (lovejoy<comet>, Andromeda,etc some with success)
but for startrails or static star field usually on the fast and wide side
it's all preference or work with what ya got
the best is having a good and dark location with clear skies more than anything else as it's my most troubling aspect of astrophotography
09-05-2015, 12:32 PM   #3
Veteran Member




Join Date: Dec 2011
Location: UK
Posts: 440
Original Poster
QuoteOriginally posted by Aaron28 Quote
the best is having a good and dark location with clear skies more than anything else as it's my most troubling aspect of astrophotography
yes an important point

So far I've only tried the DA 15 and Samyang 16mm f2

DA 15 I've used the astrotracer and had some ok-ish results, but I need to improve

Samyang 16 I've shot without astrotracer, but had real trouble getting the focus right
09-05-2015, 01:29 PM   #4
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 11,183
I have Samyang 14mm, but I would suggest Samyang 16mm. Slightly better aperture, allows filters (not needed for astro, but still good), not as awkwardly wide, but still UWA. But yes, with Samyang the focus is a bit difficult. You can look at the Samyang lens club thread, the last page or two has some astro photos and tips. Focus can be difficult, especially since the focusing rings are often miscalibrated with Samyang lenses. You can calibrate it or just learn where true infinity is on your particular lens. You have to do that before you go out into the field at night, because it will be too difficult out there.

Btw, we have plenty threads about astrophotography, so feel free to search for those. Samyang lenses are usually favourites because they are UWA, fast aperture, very sharp, good corrections, and still affordable. Zoom lenses tend to have really slow aperture or lower image quality (if not, they will be expensive).

Keep in mind with astrophotography its all about setting up the shot. The lens is the last part of the chain. You need to set up the shot, use heavy tripod, weigh it down, find the right ISO and shutter speed, maybe take multiple frames to combine them and for NR, post process the photo, and so on. Lens is important, but it is just one of the factors.

09-05-2015, 01:39 PM   #5
Site Supporter
Site Supporter
W412ren's Avatar

Join Date: Jul 2011
Location: Fareham, Hampshire
Photos: Albums
Posts: 402
I've used a number of lenses with the O-GPS1 but the most used are:
A24/2.8 - wide enough for big constellations (and landscape without the O-GPS1)
A135/2.8 - andromeda-type targets
A28 or 35 for asterisms and smaller constellations

Most importantly; all of the above can be used with a step down ring to fit a 48mm Light pollution filter with no vignetting :-)
09-05-2015, 02:18 PM   #6
Site Supporter
Site Supporter




Join Date: Dec 2008
Location: NJ, USA
Photos: Gallery | Albums
Posts: 402
For specific deep space objects you need light gathering. In a telescope the most important aspect is the Aperture or Diameter of the objective. Thus I have used a 300mm Tamron f2.8 (sold) and 400 mm Tamron f4 for the large diameter of the objective (MF lenses). For planets, Magnification matters and long focal length is needed. For star fields and milky way, wide fairly fast prime would be best. I used OGPS with all.
this was taken with OGPS and 300mm F2.8

https://www.flickr.com/photos/33404360@N08/12116690043/in/dateposted-public/
09-05-2015, 02:28 PM   #7
Pentaxian
Aaron28's Avatar

Join Date: Jan 2015
Location: Huntsville, Al
Posts: 5,131
QuoteOriginally posted by Conqueror Quote
DA 15 I've used the astrotracer and had some ok-ish results, but I need to improve
the o-gps is hit or miss with me and even though I've had it 9 months doesn't mean I have enough experience using it (maybe a dozen + times)......sometimes I can use the max time it gives other times I back off the time it gives....sometimes great results other times I wonder why I bought the damn thing.....but I would think it work very with the da15 even it being an f4......although I have not used it with my 14/2.8 but I have with just about everything else I have (usually the 14 is on my K-r doin time lapse and the o-gps on my K-50)




QuoteOriginally posted by Conqueror Quote
Samyang 16 I've shot without astrotracer, but had real trouble getting the focus right
fortunately for me (not that I know for a fact) setting infinity on my 14 is ok and its not at a hard stop either........as suggested marking what is infinity on your 16 may prove very beneficial when it comes to shooting at night and should be a very capable lens at f2 with the astrotracer or not.......

---------- Post added 09-05-15 at 04:33 PM ----------

QuoteOriginally posted by spartan Quote
this was taken with OGPS and 300mm F2.8
nice clean image! hope to get something that good this fall when it comes back......
09-05-2015, 02:37 PM   #8
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 49,613
QuoteOriginally posted by Conqueror Quote
OK this thread might have been done before, but here we go...

Enter the ring:

Pentax
DA 10-17 FE
DA 14
DA 15
DA 12-24
DA 21
FA 31
and others (including legacy etc)


Sigma
8-16
10-20
18-35

Samyang
8 FE
10
12
14
16
24


What and why?

Do you augment with Astrotracer?
The faster the better, as a rule of thumb, since that will allow you to use lower ISOs.


Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

09-05-2015, 03:20 PM   #9
Site Supporter
Site Supporter
W412ren's Avatar

Join Date: Jul 2011
Location: Fareham, Hampshire
Photos: Albums
Posts: 402
QuoteOriginally posted by spartan Quote
this was taken with OGPS and 300mm F2.8
Nice image.
Just for comparison this is the same subject. A135/2.8 at F4 for 30 seconds.
ISO 800. I think the astrotracer function does a good job.
M42 in the constellation of Orion by -Wargus-
09-05-2015, 04:19 PM   #10
Pentaxian
FantasticMrFox's Avatar

Join Date: Oct 2014
Location: Munich
Posts: 2,325
QuoteOriginally posted by Na Horuk Quote
I have Samyang 14mm, but I would suggest Samyang 16mm. Slightly better aperture, allows filters (not needed for astro, but still good), not as awkwardly wide, but still UWA. But yes, with Samyang the focus is a bit difficult. You can look at the Samyang lens club thread, the last page or two has some astro photos and tips. Focus can be difficult, especially since the focusing rings are often miscalibrated with Samyang lenses. You can calibrate it or just learn where true infinity is on your particular lens. You have to do that before you go out into the field at night, because it will be too difficult out there.
Yes, in regard to total light intake for astro photography the Samyang 16 mm f/2 seems to be the real deal. Looking for an astro-/landscape-lens, I am saving up for it. Ideally I would like something wider (14 or even 10 mm), but it's the only UWA Samyang that takes filters. It also seems to not suffer from the weird moustache distortion that the 14 and 10 mm feature, making it suitable for architectural work.

But I wonder why everyone is having issues with focusing and trying to find infinity on their focusing ring? I simply use live view, find a bright star, then twist the focusing ring to the point where the star's diameter is smallest.
09-05-2015, 04:49 PM   #11
Pentaxian
Aaron28's Avatar

Join Date: Jan 2015
Location: Huntsville, Al
Posts: 5,131
QuoteOriginally posted by FantasticMrFox Quote
UWA Samyang that takes filters
when I saved up for the bower 14/2.8 I did not consider filters nor did I think I would ever have any interest in using any......only concern was wide field at night.....so no big deal
however in the past few weeks I have become interested in using a polarizer or ND filters! (even ordered a cheap set to learn with) so it is a big drawback to learn/use with the 14 and slightly regrettable in hind sight but I have plenty of other lenses to use
09-05-2015, 05:07 PM   #12
Pentaxian
FantasticMrFox's Avatar

Join Date: Oct 2014
Location: Munich
Posts: 2,325
QuoteOriginally posted by Aaron28 Quote
however in the past few weeks I have become interested in using a polarizer or ND filters! (even ordered a cheap set to learn with) so it is a big drawback to learn/use with the 14 and slightly regrettable in hind sight but I have plenty of other lenses to use
Yes, it's a shame. I cannot really afford one lens each for landscape and night sky work. It's a shame the Samyang 12 mm f/2 doesn't exist in Pentax mount. It's fast (f/2 vs f/2.8 for the 10 and 14 mm versions), significantly wider than the 16 mm and it takes filters.

Buuut no Pentax version
09-05-2015, 06:57 PM   #13
Site Supporter
Site Supporter




Join Date: Mar 2008
Location: Prince George, BC
Photos: Gallery | Albums
Posts: 3,085
Coma aberration is the worst for astro work. Avoid all lenses exhibiting it.
09-05-2015, 09:09 PM   #14
Pentaxian
calsan's Avatar

Join Date: Nov 2008
Location: Perth, Australia
Photos: Gallery
Posts: 1,462
QuoteOriginally posted by jbinpg Quote
Coma aberration is the worst for astro work. Avoid all lenses exhibiting it.
^ This!

Also, I have found a normal focal length to be easiest to work with, wide often means having to deal with trees or other obstructions.
09-06-2015, 12:33 AM   #15
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 17,005
QuoteOriginally posted by jbinpg Quote
Coma aberration is the worst for astro work. Avoid all lenses exhibiting it.
Where do you go to find this info?
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
astro, astrotracer, da, infinity, k-mount, night, o-gps, pentax lens, results, slr lens, time, times, uwa
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Point And Shoot Competition #89 - Shoot What You Want. MikePerham Pentax Compact Cameras 55 05-03-2015 12:31 PM
Point And Shoot Competition #88 - Shoot What You Want. barondla Pentax Compact Cameras 69 04-02-2015 08:27 PM
Astro - New Camera and Lens - Just a little one interested_observer General Photography 5 01-17-2015 12:46 AM
Lens mystery: Why is "Asahi" and "Takumar" blacked out? Edgar_in_Indy Pentax SLR Lens Discussion 17 08-01-2014 05:15 AM
What would you suggest as the first non-kit lens purchase and why? OldNoob Troubleshooting and Beginner Help 38 11-30-2013 05:13 PM



All times are GMT -7. The time now is 09:32 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top