A7IV and 40 mm f:2.5 for night sky photography

Seems like the A7IV is a very good performer for night sky and astrophotography. Here is some tracked Milky Way, 30 frames each 2 minutes, stacked to a total of one hour. We can see the North America nebula as a pink slightly above the center of the frame, and some other Hydrogen Alpha areas a bit lower. I am looking forward to use this camera more for astrophotography, with the very sharp Sony G 40 mm f:2.5 lens, other lenses, and a small telescope. Quantum efficiency is excellent, and Ha-response is not bad for a non-modified camera.

Wxposure with lossless raw. The processing is straightforward: Images are stacked with Registar, then lightly processed with Adobe Photoshop. No noise removal or sharpening is applied, since this little gem of a lens has very high resolution and flat field even wide open.


Milky Way, Sony A7IV and 40 mm f:2.5 Sony G lens.

Magnar - Looks really good. Thanks for sharing! This makes me want to give some astro shoots a try. Never found time yet. Your title with 40mm f2.5 in it caught my attention and made me look. While I don't have that lens maybe the Sony 24-70 GMII at 2.8 could work out.

I appreciate the details along with the inspiration.

You've thought about this a lot. What do you think of the FE 14mm f/1.8 GM for star and aurora shooting?

BaseballShots said:

Magnar - Looks really good. Thanks for sharing! This makes me want to give some astro shoots a try. Never found time yet. Your title with 40mm f2.5 in it caught my attention and made me look. While I don't have that lens maybe the Sony 24-70 GMII at 2.8 could work out.

I appreciate the details along with the inspiration.

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The GM 24-70 mm is probably very good/excellent for this kind of photography. I have done some Aurora photography with f:4 zoom lenses, one of them the not-so-popular Sony/Zeiss 24-70 mm, with good results. My other wide zoom is the Sony PZ 16-35 mm f:4, but I haven't had the opportunity to use this video centric lens for astro. ;-)

dcstep said:

You've thought about this a lot. What do you think of the FE 14mm f/1.8 GM for star and aurora shooting?

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This lens should work like a dream for aurora photography. I know one person who own this lens, and the satisfaction level is sky high! ;-)

For wide night sky shooting I mostly use a Loxia 21 mm f:2.8 wide open, sometimes stitching two or three frames.

I would say that everything as bright as f:4 or better is ok for night sky and Aurora photography.

A small tracker is recommended, and will open up for lots of opportunities for astro shooting. Then you can go really deep with focal lengths up to 200 mm, and a bit longer with good polar alignment.

Awesome! It's very reassuring to hear usage of more typical lenses for some hobby/fun Astro work instead of only prime wide super bright lenses.

I had a great time with my copy of the new 16-35 PZ sony for some landscapes (another style I hadn't done).

BTW I'm 99% sure your posts 4-5 years ago (early 2018) on Sony GM 100-400 helped me out for my first Sony kit setup. Just wanted to say thanks for all you contribute.

Regards

BaseballShots said:

Awesome! It's very reassuring to hear usage of more typical lenses for some hobby/fun Astro work instead of only prime wide super bright lenses.

I had a great time with my copy of the new 16-35 PZ sony for some landscapes (another style I hadn't done).

BTW I'm 99% sure your posts 4-5 years ago (early 2018) on Sony GM 100-400 helped me out for my first Sony kit setup. Just wanted to say thanks for all you contribute.

Regards

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Thank a lot for your kind words! Sharing experience and discussing solutions makes any photo forum great. ;-)

Personally I am looking for what I can do with my gear, instead of searching for limitations. At work I mostly use the 24-70 mm f:4 zoom lens for reportage style work that is published widely. The challenge is how to compose and arrange the photographs so that they tell the story and draw attention, while still being trustworthy.

Magnar W said:

Seems like the A7IV is a very good performer for night sky and astrophotography.


Milky Way, Sony A7IV and 40 mm f:2.5 Sony G lens.

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Lovely photo, but I am not sure that I agree with your statement about the A7IV's astro prowess.

I often get "donut stars" with my A7IV, which are holes created in the middle of smaller stars by the Sony firmware, where I assume it misinterprets them as hot pixels.

Visible below. You will need to zoom in.


Donut stars

Admittedly, this is just a snap and not a traditional astro long exposure, but it would still be nice if Sony didn't put those holes in there.

I also don't believe that this is a focus issue, as according to peaking, everything looks right.

Magnar W said:

dcstep said:

You've thought about this a lot. What do you think of the FE 14mm f/1.8 GM for star and aurora shooting?

Click to expand...

This lens should work like a dream for aurora photography. I know one person who own this lens, and the satisfaction level is sky high! ;-)

Click to expand...

You know me too. It's a great lens for Astro/nightshots

Cheers!


Photography for me is not about recreating what i saw through
the viewfinder but to show people the way i see the world.

Magnar W said:

Seems like the A7IV is a very good performer for night sky and astrophotography. Here is some tracked Milky Way, 30 frames each 2 minutes, stacked to a total of one hour. We can see the North America nebula as a pink slightly above the center of the frame, and some other Hydrogen Alpha areas a bit lower. I am looking forward to use this camera more for astrophotography, with the very sharp Sony G 40 mm f:2.5 lens, other lenses, and a small telescope. Quantum efficiency is excellent, and Ha-response is not bad for a non-modified camera.

Wxposure with lossless raw. The processing is straightforward: Images are stacked with Registar, then lightly processed with Adobe Photoshop. No noise removal or sharpening is applied, since this little gem of a lens has very high resolution and flat field even wide open.


Milky Way, Sony A7IV and 40 mm f:2.5 Sony G lens.

Click to expand...

What a lovely shot

--
Photography for me is not about recreating what i saw through
the viewfinder but to show people the way i see the world.

Hello, I zoomed into your image checking for the donut holes you mentioned and to be honest I didn’t see much (maybe it’s the limitations of my phone screen). In any event to you feel they detract form a widefield image such as the one you posted? Just curious as I’m considering this camera.

Cheers!

JayJee said:

Lovely photo, but I am not sure that I agree with your statement about the A7IV's astro prowess.

I often get "donut stars" with my A7IV, which are holes created in the middle of smaller stars by the Sony firmware, where I assume it misinterprets them as hot pixels.

Click to expand...

Your stars are slightly out of focus, and this is how the lens you use render out-of-focus light points. You don't see the stars, you actually see bokeh balls!

So it is NOT the camera, lens, nor the raw converter. It is user error.

Try this:

• Go for Maual focus
• Use loupe focus/magnifiwed view and use highest magnification
• Try to fet the stars pin sharp, not just almost sharp.

Then these "holes" will disappear completely. ;-)

JayJee said:

Visible below. You will need to zoom in.


Donut stars

Click to expand...

RichardLarssen said:

Magnar W said:

Seems like the A7IV is a very good performer for night sky and astrophotography. Here is some tracked Milky Way, 30 frames each 2 minutes, stacked to a total of one hour. We can see the North America nebula as a pink slightly above the center of the frame, and some other Hydrogen Alpha areas a bit lower. I am looking forward to use this camera more for astrophotography, with the very sharp Sony G 40 mm f:2.5 lens, other lenses, and a small telescope. Quantum efficiency is excellent, and Ha-response is not bad for a non-modified camera.

Wxposure with lossless raw. The processing is straightforward: Images are stacked with Registar, then lightly processed with Adobe Photoshop. No noise removal or sharpening is applied, since this little gem of a lens has very high resolution and flat field even wide open.


Milky Way, Sony A7IV and 40 mm f:2.5 Sony G lens.

Click to expand...

What a lovely shot

Click to expand...

Thanks a lot, Richard!

Magnar W said:

JayJee said:

Lovely photo, but I am not sure that I agree with your statement about the A7IV's astro prowess.

I often get "donut stars" with my A7IV, which are holes created in the middle of smaller stars by the Sony firmware, where I assume it misinterprets them as hot pixels.

Click to expand...

Your stars are slightly out of focus, and this is how the lens you use render out-of-focus light points. You don't see the stars, you actually see bokeh balls!

So it is NOT the camera, lens, nor the raw converter. It is user error.

Try this:

• Go for Maual focus
• Use loupe focus/magnifiwed view and use highest magnification
• Try to fet the stars pin sharp, not just almost sharp.

Then these "holes" will disappear completely. ;-)

Member said:

Visible below. You will need to zoom in.


Donut stars

Click to expand...

Click to expand...

Just to add to that, while I have next to zero experience with astrophotography, no camera removes hot pixels from 1/30s exposures. That is done from dark frames taken at much longer exposure times (1s on my A7C). And of course, long exposure noise reduction can be turned off.

kolyy said:

Just to add to that, while I have next to zero experience with astrophotography, no camera removes hot pixels from 1/30s exposures. That is done from dark frames taken at much longer exposure times (1s on my A7C). And of course, long exposure noise reduction can be turned off.

Click to expand...

That's correct. There are different kinds of in-camera noise reduction:

• Long exposure noise reduction - can be turned on/off and kicks in from about 1 second. This is a "dark frame", with the same duration as the photograph, and is used immediately after exposure to subtract noise. The camera will be buissy during this operation - 60 sec exposure, then 60 sec dark frame subtraction afterwards where everything is locked.
• High ISO noise reduction - in-camera setting, depends on camera model and file type, etc.
• Spatial filtering, "star eater" that kicks in at 3.4 sec for many newer Sony camera models, and after up to 30 sec for older models. This removes hot pixels and very faint stars, and is most noticeable when using wide and ultra wide lenses. The night sky and brighter stars will look great, though.

None of these will introduce "donut stars".

Actuallty, to feed the "star eater" you need a very sharp lens, and for longer exposures you also need a tracker to avoid the slightest sign of star movement/star traces. For the picture below the stars are sligthly stretched, enough to avoid much of the "star eater defect" - just to illustrate how little impact spatial filtering has for real world night sky shooting with the camera on a tripod.

[ATTACH alt="24-70 mm f:4 lens at 24 mm wide open. The "star eater" have consumed everything that reminds about hot pixels, but there are plenty of brighter stars left. By the way, who want the frame filled with tiny, white dots/faint stars that look just like hot pixels?"]3165687[/ATTACH]
24-70 mm f:4 lens at 24 mm wide open. The "star eater" have consumed everything that reminds about hot pixels, but there are plenty of brighter stars left. By the way, who want the frame filled with tiny, white dots/faint stars that look just like hot pixels?

Magnar W said:

kolyy said:

Just to add to that, while I have next to zero experience with astrophotography, no camera removes hot pixels from 1/30s exposures. That is done from dark frames taken at much longer exposure times (1s on my A7C). And of course, long exposure noise reduction can be turned off.

Click to expand...

That's correct. There are different kinds of in-camera noise reduction:

• Long exposure noise reduction - can be turned on/off and kicks in from about 1 second. This is a "dark frame", with the same duration as the photograph, and is used immediately after exposure to subtract noise. The camera will be buissy during this operation - 60 sec exposure, then 60 sec dark frame subtraction afterwards where everything is locked.
• High ISO noise reduction - in-camera setting, depends on camera model and file type, etc.
• Spatial filtering, "star eater" that kicks in at 3.4 sec for many newer Sony camera models, and after up to 30 sec for older models. This removes hot pixels and very faint stars, and is most noticeable when using wide and ultra wide lenses. The night sky and brighter stars will look great, though.

None of these will introduce "donut stars".

[ATTACH alt="24-70 mm f:4 lens at 24 mm wide open. The "star eater" have consumed everything that reminds about hot pixels, but there are plenty of brighter stars left. By the way, who want the frame filled with tiny, white dots/faint stars that look just like hot pixels?"]3165687[/ATTACH]
24-70 mm f:4 lens at 24 mm wide open. The "star eater" have consumed everything that reminds about hot pixels, but there are plenty of brighter stars left. By the way, who want the frame filled with tiny, white dots/faint stars that look just like hot pixels?

Click to expand...

Yes, and "high ISO NR", unlike the other two, only effects jpegs, not raws.