Orion 9 image mosaic with airglow

[gregbradley]

Another mosaic I did of the Orion arm and again picked up some nice airglow.

Polarie, Sony A7r, Novoflex adapter, Nikon 14-24mm F2.8ED at 14mm/F2.8, RAW, long exposure noise reduction on, vivid, auto white balance.

From my dark site in remote NSW.

http://www.pbase.com/gregbradley/image/154149469/large regular size

http://www.pbase.com/gregbradley/image/154149469/original large size

I'll post different landscapes in the future, scouts honour!


Greg.

[dutch2]

Stunning image, well done.:thumbsup:

[gregbradley]

Thanks Ingrid :)

Greg.

[Ross G]

Looking good Greg.

The new Sony seems to be performing very well.

Ross.

[matt34]

Nice Work Greg. really like the air glow.

Why the use of the long exposure noise reduction? Are you finding better results with the new camera than with software processing?

[Bassnut]

Top work Greg. No obvious noise, good tracking and stiching,air glow adds a nice ambience.

[gregbradley]

Thanks Ross. The Sony is basically the same performance with subtle differences to the Nikon D800e in a smaller package. A bit easier to focus with the high quality electronic viewfinder, a bit brighter, auto white balance works much better and images are a bit noisier (still not much noise) but with higher contrast. Otherwise essentially the same.



The air glow was quite noticeable on several nights. Perhaps its like that there most nights. One night when there was aurora in the south the airglow was super green.

With regards to long exposure noise reduction I have been told you can get better results with long exposure noise reduction off with the Sont. I have taken with and without but didn't really check it too hard. The Nikon D800e had a small amount of amp glow so I tended to use long exposure noise reduction to get rid of that. I'll have to check it out.



Thanks Fred. Airglow is an interesting phenomena.

Greg.

[traveller]

Nice work Greg,
I read somewhere that with fast lenses (2.8 and faster), it's a good idea to stopped it down by 1-2 stops to increase sharpeners. Does this hold true in your opinion?
Cheers,
Bo

[RickS]

It's no wonder we get gradients even under dark skies. Another lovely image, Greg!

[gregbradley]

Thanks Bo. I have found lenses faster than F2.8 tend to show bad coma or chromatic aberration below F2.8. For example the Samyang 24mm F1.4. F1.4 was a writeoff, but aberrations eased around F2 but F2.8 they were better. Also I think a super sharp lens is not totally required for this type of image compared to a daylight landscape. The Nikon 14-24 is sharp in the centre at F2.8 and a little softer in the corners but pretty good really. The best of any other wide angle lens I have used. I'd like to see some images by Carlo using his new Zeiss 15mm. That could be spectacular.

It depends on the lens. Reviews often go over this point and some start to sing at F4 or even F5.6. But then of course you need to track the mount to compensate by doing 90 seconds or more exposure time to get the exposure back up.

Its not a bad strategy to stop down (or use aperture rings to achieve it and remove diffraction spikes from the iris blades) and shoot longer at lower ISO for lower noise, better signal to noise ratio and sharper images. But then you really need to shoot the landscape portion as a separate run with no tracking to retain sharpness and combine the sky and the landscape in Photoshop (not as easy as it sounds as often there are stars low in the sky showing between branches of trees etc).

So you would have to keep that later processing step in mind when framing the scene so you can avoid these issues. A panorama head would help as well here to get rid of parallax error. I used a dovetail plate to mount the camera that is fairly long so I am close to the correct pivot point (called nodal point) to remove parallax errors which can increase distortions even in a stitched panorama.



I know. I sometimes would get a green gradient in some images at my dark site and wondered how that could possibly be when it has almost zero light pollution there.

Greg.

[traveller]

Thanks Greg (as always)
Bo