Foveon sensor looks at The Great Nebula in Orion

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DavidWright2010 Senior Member • Posts: 2,755
Foveon sensor looks at The Great Nebula in Orion
6

Since I'm mostly doing astrophotography these days, I'm using different cameras. But while I was waiting for the Moon to set tonight. I got out the SD1M and the Sigma 150-600 mm (C) lens.

After the obligatory Moon shots, where I used AF to get a sharp Moon image, I switched to manual focus and slewed the mount over to Orion. I was going to use the focus obtained on the Moon, since the SD has no live view to fine focus on a star.

I took a series of 30 second exposures wide open (f/6.3), until I got bored with pressing a button every minute. (14 exposures)

Then I processed and stacked these images.

For a comparision, I had a series of 30 sec exposures with a Pentax camera and a 360 mm F/5.9 OTA. I had used the intervalometer function in the Pentax to run off a series of 60 such exposures; I selected 14 at random and processed them as well.

Here we are - Foveon on left, Bayer on right:

And while this result isn't terrible, the Orion Nebula is the brightest deep sky object in the Northern Hemisphere.

I was also interested is seeing how the 150-600 mm lens did on stars, so here is the full-sized stacked image:

The full non-Foveon image of Orion - 60 exposures of 30 sec each - can be found here.

David

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xpatUSA
xpatUSA Forum Pro • Posts: 18,928
Re: Foveon sensor looks at The Great Nebula in Orion

An excellent demonstration of why I don't do astro, if you see what I mean. I just don't have the kit or the patience.

Interesting that the Merrill image looks "better" but the Pentax captured more stars (bottom right).

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SigmaChrome Forum Pro • Posts: 13,306
Re: Foveon sensor looks at The Great Nebula in Orion

Thanks David, that's a really useful comparison.

The SD1M image is actually surprisingly good - compared to what I expected to see. But it does seem to have missed focus somewhat.

Did you do anything to reduce the green and magenta splotching?

What did you use to do the stacking?

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applemax Regular Member • Posts: 446
Re: Foveon sensor looks at The Great Nebula in Orion
5

Hello!

xpatUSA wrote:

Interesting that the Merrill image looks "better" but the Pentax captured more stars (bottom right).

No, sorry, it does not look "better". Just look at those broad purple vertical bands below the nebula all the way down to the bottom of the image. These are artifacts the Foveon sensors produce with low light/high ISO and which can't be reduced by image processing without removing the nebula altogether. If one would post such an image on an astronomy forum one would probably get banned for lifetime...

Don't get me wrong, this is not intended as critique. But I am also an amateur astronomer and really have tried everything with my Sigma cameras over the years. Apart from taking pictures of the moon (for which these cameras work nicely) every other attempt at astrophotography is just a waste of lifetime.

For 1/2 the price of a pre-owned SD1 Merrill (are there any new ones left?) one can find a large choice of perfectly astro-capable cameras. I got myself a Canon EOS 6D full frame camera for that purpose. There are not too many clear nights and there is no point in wasting them using tools that are not up to the job.

Regards

Max

D Cox Forum Pro • Posts: 28,261
Re: Foveon sensor looks at The Great Nebula in Orion

applemax wrote:

Hello!

xpatUSA wrote:

Interesting that the Merrill image looks "better" but the Pentax captured more stars (bottom right).

No, sorry, it does not look "better". Just look at those broad purple vertical bands below the nebula all the way down to the bottom of the image. These are artifacts the Foveon sensors produce with low light/high ISO and which can't be reduced by image processing without removing the nebula altogether. If one would post such an image on an astronomy forum one would probably get banned for lifetime...

Don't get me wrong, this is not intended as critique. But I am also an amateur astronomer and really have tried everything with my Sigma cameras over the years. Apart from taking pictures of the moon (for which these cameras work nicely) every other attempt at astrophotography is just a waste of lifetime.

For 1/2 the price of a pre-owned SD1 Merrill (are there any new ones left?) one can find a large choice of perfectly astro-capable cameras. I got myself a Canon EOS 6D full frame camera for that purpose. There are not too many clear nights and there is no point in wasting them using tools that are not up to the job.

Regards

Max

Anyway, isn't "better" a greater number of captured stars ?

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OP DavidWright2010 Senior Member • Posts: 2,755
Re: Foveon sensor looks at The Great Nebula in Orion

applemax wrote:

Apart from taking pictures of the moon (for which these cameras work nicely) every other attempt at astrophotography is just a waste of lifetime.

FMax

Yes, this is my opinion, too.

David

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OP DavidWright2010 Senior Member • Posts: 2,755
Re: Foveon sensor looks at The Great Nebula in Orion
1

SigmaChrome wrote:

Thanks David, that's a really useful comparison.

The SD1M image is actually surprisingly good - compared to what I expected to see. But it does seem to have missed focus somewhat.

No live view...

Did you do anything to reduce the green and magenta splotching?

No.

What did you use to do the stacking?

Deep Sky Stacker.

David

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jande9
jande9 Senior Member • Posts: 1,592
Re: Foveon sensor looks at The Great Nebula in Orion

I like the sharpness of the sigma picture but its too bad about the blotching.  What iso were you using?

Jan

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atom14
atom14 Senior Member • Posts: 2,561
Capolavoro, David Wright!

I really L KE the subtle tonality you got in the compared Foveon image.

atom14.

OP DavidWright2010 Senior Member • Posts: 2,755
Re: Foveon sensor looks at The Great Nebula in Orion

jande9 wrote:

I like the sharpness of the sigma picture but its too bad about the blotching. What iso were you using?

Jan

I don't think it matters, but ISO 100.

Don't compare the detail - they are different focal lengths.

Here's a small region of Orion with advantage Bayer (800mm) over Foveon (600mm):

David

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MOD rick decker Forum Pro • Posts: 17,427
Re: Foveon sensor looks at The Great Nebula in Orion

Very nice...Thanks David

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