It is currently Sat May 25, 2013 6:09 am

Forum rules


No more than three images or three external links allowed in any post or reply. Please trim quotations and do not include images in quotes unless essential.



Post a new topicPost a reply Page 1 of 2   [ 25 posts ]
Go to page 1, 2  Next
Author Message
 Post subject: A77 -- no ghosting!
Unread postPosted: Wed Oct 26, 2011 10:34 pm 
Initiate
User avatar

Joined: Sat Oct 08, 2011 10:41 am
Posts: 44
What about ghosting with the A77? As soon as I got my camera I had to make the best torture ghosting test; astrophotography. So I put my camera behind my highest quality Takahashi astrograph (530 mm focal length, f:5) to do some test shots. The conditions were not perfect with turbulent air. Still this test would reveale any ghosting if this was a problem.

The only finding was some very, very faint and needle thin vertical spikes from the brightest stars in the Pleiades photograph (Seven Sisters, open star cluster). This might be related to the translucent mirror. No other cameras bring this out. Not even my specialized astro camera with a cooled CCD sensor. On the other hand, spikes like these will never be a real world problem, since the bright Pleiades stars are way overexposed. For the Pleiades test I did not use autoguiding to track the stars, but later tests with perfect tracking shows the same result: no ghosting, but some extremely faint vertical spikes for the 3 brightest stars in the Pleiades.

The Andromeda galaxy photo is clean, with absolutely no hint about artifacts like ghosting or vertical spikes. Autoguiding was activated to get perfectly round and sharp stars.

The results show that ghosting is a non-issue with the A77. The Sony engineers have done a very respectable job with this!

Technique: A77, ISO 800, 530 mm focal length at f:5. The Pleiades image is one 5 minute exposure, and the Andromeda image is made up from 12 single images, each exposed for 5 minutes and then stacked to make a total of 1 hour exposure.

Also: New to this forum, but not new to photography or Minolta/Sony cameras and lenses.

Attachment:
File comment: The Pleiades, 530 mm focal length, 1 hour total exposure, A77.
pleiades.jpg
pleiades.jpg [ 131.04 KiB | Viewed 1439 times ]


Attachment:
File comment: Andromeda Galaxy, 530 mm focal length, 1 hour total exposure, A77.
m31.jpg
m31.jpg [ 133.59 KiB | Viewed 1439 times ]


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Wed Oct 26, 2011 10:56 pm 
Subsuming Vortex of Brilliance
User avatar

Joined: Wed May 30, 2007 7:38 pm
Posts: 5436
Location: Yerevan, Armenia
Magnar, excellent input and welcome.
I'm not good in astronomy, though quite good in gastronomy :wink:
Whenever a patient asks if his/her skin condition (which being unrelated to food) is related to food or not I always reply: "it is as much related to food as I am to astronomy"...
And here I see two shots which are definitely not related to skin conditions but "nevertheless" quite beautiful, specially Andromeda.
Thanks for sharing them and once again welcome.
Hope we'll see lots of shots like these.

_________________
A99 + Sony, Zeiss, Minolta, Rokinon and M42 lenses

Flickr


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Wed Oct 26, 2011 11:57 pm 
Subsuming Vortex of Brilliance
User avatar

Joined: Sun Jun 29, 2008 3:10 pm
Posts: 4599
Hi Magnar - welcome to the forum from me as well. Wonderful astronomy pictures - I hope we can look forward to many more :D . Very interesting to see how well controlled the ghosting is in the A77 in these conditions.

_________________
A100, A700, Nex 5, A99 and an ever growing bunch of lenses.


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Thu Oct 27, 2011 12:14 am 
Oligarch

Joined: Thu Aug 07, 2008 11:50 am
Posts: 203
Location: Auckland, New Zealand
Welcome!

I saw you post these on DPR, nice to you you on the (mostly) friendly forum. :mrgreen:


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Thu Oct 27, 2011 12:43 am 
Site Admin
User avatar

Joined: Sat May 19, 2007 1:14 pm
Posts: 6037
Location: Kelso, Scotland
Welcome aboard Magnar, been hoping you would arrive here one day! I have a very large infra-red lens sitting in my office, removed from a Varityper imagesetter, which I wanted to send to you to see if you could make any use of this unusual huge piece of glass for astro work. I emailed you but never got a reply so I reckoned you had changed email address.

David

_________________
http://www.photoclubalpha.com
Image


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Thu Oct 27, 2011 2:18 am 
Emperor of a Minor Galaxy
User avatar

Joined: Thu Dec 18, 2008 5:04 pm
Posts: 2017
Location: St. Louis, Missouri, USA
A welcome from me, as well. Maybe you can help me to pick out the right galaxy to be Emperor of!

I love the shots. Please post more!

Dusty

_________________
A couple of a350's, an a700, even more lenses.


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Thu Oct 27, 2011 2:34 am 
Acolyte

Joined: Fri Jun 19, 2009 5:41 am
Posts: 16
Welcome Magnar

Good news about the (no) ghosting.......

All of a sudden, things are looking up around here! :lol:

Fantastic examples/work, and for some reason your images seem to look much better here than on DPR? Your recent stunning aurora images would look great here too!

Have you had much chance to try your a77 out on other (non-astro) subject matter. Interested to hear your impressions?


Regards
Steve


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Thu Oct 27, 2011 8:00 am 
Imperial Ambassador
User avatar

Joined: Fri Sep 05, 2008 7:16 am
Posts: 498
Location: Hammarö, Sweden
Great shots and a big welcome from me as well!
Eager to see some more :-)

BR,
/Zeb!

_________________
Sony A700, KM D7D & VC-7D, M Dynax 500si
KM 17-35 F2.8-4 D, M 50 F1.7 RS, M 135 F2.8, M 28-100 F3.5-5.6 D, M 100-200 F4.5, T 70-300 F4-5.6 Di USD, S 18-55 F3.5-5.6 SAM, S 18-70 F3.5-5.6
Dörr D-AF42
Sammy Gio & broken SE Satio


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Thu Oct 27, 2011 4:54 pm 
Initiate
User avatar

Joined: Sat Oct 08, 2011 10:41 am
Posts: 44
Thanks a lot to all of you! This looks like a nice forum for more serious discussions about gear, and I will not double post in the future since many of you already are reading/using the Dpreview forum. For me real life experience is what photography is about, so I am looking forward to discuss how we can get the most out of our cameras and lenses! And now I will continue the torture tests of my A77! If I find something of interest, I will for sure share this with you!

To David K.: Nice that you remember me! Thanks! This large infra-red lens looks very interesting! Probably I am getting a cooled astrocam for near infrared photography later this winter (some of my books sell very well)! I have had some trouble with my web/e-mail provider some time ago, so I have moved to a much more reliable service -- my e-mail adress is the same as earlier! I will mail you later this weekend!


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Fri Oct 28, 2011 12:18 am 
Imperial Ambassador

Joined: Fri Aug 22, 2008 8:22 am
Posts: 568
Location: Australia
Always wanted to try Astro. shots, I even have a T-mount for the alpha sitting in my camera bag. just don't have a telescope :)


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Fri Oct 28, 2011 4:59 am 
Viceroy
User avatar

Joined: Wed Oct 08, 2008 4:23 am
Posts: 858
Location: Montreal, Quebec, Canada
Welcome Magnar,

This astronomy photo are amazing. I would be very happy if some day I'm able to do this kind of technical picture.

We are waiting so see more and more of those fabulous skills and picture.

It will be very interesting to have a picture of your current setup to do this work.

Regards,

Frank

_________________
Frank
A900, NEX 7 & 5 user( and too much Minolta lenses...)


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Fri Oct 28, 2011 12:41 pm 
Subsuming Vortex of Brilliance
User avatar

Joined: Sun May 27, 2007 3:25 pm
Posts: 5356
Location: Townsville, Qld. Australia
And a hearty welcome from me as well Magnar, I’m always up for a nice M31 image and that is a splendid rendition; I like the Pleiades as well with the hot B’s shining their blue light through the interstellar dust cloud, that was well captured, I can’t see any obvious SLT ghosts anywhere so it’s looking good for the A77.
Greg


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Tue Nov 08, 2011 11:13 pm 
Viceroy

Joined: Wed Oct 22, 2008 7:41 pm
Posts: 1163
Just got a LA-EA2 for my 5N.

So far I'm unable to register any ghosting whatsoever.


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Tue Nov 08, 2011 11:28 pm 
Minister with Portfolio
User avatar

Joined: Tue May 22, 2007 5:38 pm
Posts: 2136
Location: NYC
agorabasta wrote:
Just got a LA-EA2 for my 5N.

So far I'm unable to register any ghosting whatsoever.

Nice!
how about the rest: AF speed and accuracy, contrast, etc

_________________
Pako
------------
http://www.phototeka.net/qosqo.php


Top
 Profile  
 
 Post subject: Re: A77 -- no ghosting!
Unread postPosted: Wed Nov 09, 2011 2:55 am 
Initiate

Joined: Sun Nov 06, 2011 10:40 pm
Posts: 42
Magnar Fjortoft wrote:
For me real life experience is what photography is about, so I am looking forward to discuss how we can get the most out of our cameras and lenses! And now I will continue the torture tests of my A77!


I just wanted to bold this what Magnar said. Nothing without practice.

Don't know a lot about astrophotography, but this looks very good to me.

p.s. don't know why, but these two pictures remindes me on the cover of the legendary croatian rock band Film (eng. movie): http://i46.servimg.com/u/f46/12/06/02/77/film-112.jpg


Top
 Profile  
 
Display posts from previous:  Sort by  
Post a new topicPost a reply Page 1 of 2   [ 25 posts ]
Go to page 1, 2  Next


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  


Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
twilightBB Style by Daniel St. Jules of Gamexe.net