A77 -- no ghosting!

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Magnar Fjortoft
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A77 -- no ghosting!

Unread post by Magnar Fjortoft »

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.
The Pleiades, 530 mm focal length, 1 hour total exposure, A77.
The Pleiades, 530 mm focal length, 1 hour total exposure, A77.
pleiades.jpg (131.04 KiB) Viewed 6679 times
Andromeda Galaxy, 530 mm focal length, 1 hour total exposure, A77.
Andromeda Galaxy, 530 mm focal length, 1 hour total exposure, A77.
m31.jpg (133.59 KiB) Viewed 6679 times
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Dr. Harout
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Re: A77 -- no ghosting!

Unread post by Dr. Harout »

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.
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Birma
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Re: A77 -- no ghosting!

Unread post by Birma »

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.
Nex 5, Nex 6 (IR), A7M2, A99 and a bunch of lenses.
redsim74
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Re: A77 -- no ghosting!

Unread post by redsim74 »

Welcome!

I saw you post these on DPR, nice to you you on the (mostly) friendly forum. :mrgreen:
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Re: A77 -- no ghosting!

Unread post by David Kilpatrick »

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
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Dusty
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Re: A77 -- no ghosting!

Unread post by Dusty »

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
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Steve4D
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Re: A77 -- no ghosting!

Unread post by Steve4D »

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
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[SiC]
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Re: A77 -- no ghosting!

Unread post by [SiC] »

Great shots and a big welcome from me as well!
Eager to see some more :-)

BR,
/Zeb!
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Magnar Fjortoft
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Re: A77 -- no ghosting!

Unread post by Magnar Fjortoft »

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!
stevecim
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Re: A77 -- no ghosting!

Unread post by stevecim »

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 :)
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InTheSky
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Re: A77 -- no ghosting!

Unread post by InTheSky »

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
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Greg Beetham
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Re: A77 -- no ghosting!

Unread post by Greg Beetham »

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
agorabasta
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Re: A77 -- no ghosting!

Unread post by agorabasta »

Just got a LA-EA2 for my 5N.

So far I'm unable to register any ghosting whatsoever.
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pakodominguez
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Re: A77 -- no ghosting!

Unread post by pakodominguez »

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
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Alpha_Zagreb
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Re: A77 -- no ghosting!

Unread post by Alpha_Zagreb »

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
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