Astro Photo Question (trying this forum)...

Started 4 months ago | Questions
John Retsal Regular Member • Posts: 259
Astro Photo Question (trying this forum)...
1

[ I asked this over on the Astrophotography forum and got zero replies ]

I'm going to try my hand at some wide-field Milky Way photography.

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

Location has Bortle 2 skies (for those who know what that means), so pretty dark.

I'd be shooting at 14mm and maybe 20mm, wide open at f/4 tripod mounted, no tracking and VR off.

I'm pretty sure I need to keep my exposure times (per the NPF rule) to around 11 sec for 14mm and 8 sec for 20mm in order to have no trailing visible.

What I'm unsure about are other settings such as ISO (taking into consideration the camera's ISO Invariance) and white balance.

And a bonus question, is there any advantage in shooting in b/w in terms of the quality of the images?

Thanks all!

ANSWER:
This question has not been answered yet.
ghostfox_1 Contributing Member • Posts: 698
Re: Astro Photo Question (trying this forum)...
5

Two things, the 500 rule is less helpful, there are calculators that give you better times for less trailing out there now. I personally use the lonely specks advanced calculator.

Secondly, if you're going to shoot single frames, then I'd rather shoot at a higher iso than lower in camera, because it's going to produce cleaner stars still vs making assumptions. If you're going to stack, shoot at the lowest you feel comfortable with (I did 800 iso on my z7 to stack frames for my latest milky way pano).

And just shoot in color. I think the raws produced will be in color regardless, but you don't get a benefit otherwise.

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Z6User
Z6User Senior Member • Posts: 1,189
Re: Astro Photo Question (trying this forum)...

I don’t mean to be facetious, but the answers to your questions are out there in Google land.

Also, as alluded to by the other poster, you can take a series of short exposures using the built in intervalometer, then stack them using software that can do the alignment. You will of course lose some of the sensor area, but you will get better results. Lots of short exposures combined gives you reduced noise and more round stars.

And at the risk of stating the obvious, there are small and fairly cheap driven mounts, though quality varies, so check the reviews. Even with a mount, I believe you are best to stack lots of short exposures,

Hasn’t Starlink destroyed the night sky?

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SoCalRick
SoCalRick Junior Member • Posts: 41
Re: Astro Photo Question (trying this forum)...
2

John Retsal wrote:

...

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

...

I'd be shooting at 14mm and maybe 20mm, wide open at f/4 tripod mounted, no tracking and VR off.

I'm pretty sure I need to keep my exposure times (per the NPF rule) to around 11 sec for 14mm and 8 sec for 20mm in order to have no trailing visible.

...

I think you are going to find those exposure times to be way too short to gather enough light, especially for an f/4 lens. You might need say, 20 seconds and 6400 ISO with an f/4 lens. Using either my 20mm @f/1.8, or my 14-24 @f/2.8, I might start out at 20 seconds and ISO 1600 and adjust from there, and those are way faster lenses than the 14-30 f/4.

There are a lot of factors to consider as to what setting to use to collect the most light and not get movement in the stars, including what portion of the night sky you are pointed at. The NPF rule might help a little, but it also identifies a multiplier (K value) that might need to be used in front of the ratio. Some rule of thumb guides suggest using a K value of about 2.5 or 3 (so your exposure times may be too low).

I would suggest that the best recommendation is to experiment in the field and adjust your settings as needed to get a reasonable exposure without any visible star movement. Maybe start at 15 seconds and ISO 3200 and adjust accordingly from there.

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kayaker353 Senior Member • Posts: 1,259
Re: Astro Photo Question (trying this forum)...
1

At the risk of usurping the OP's question, I have tried a couple of astro tests.  First, technical technique, then on to real photos.  I have found that 30 seconds at F2 with the Z9  and 20 mm F1.8 and ISO 200 shows a lot of bright stars, but no tracking to speak of.  Also, there is no sense of a multitude of stars, as in the Milky Way.  Am I underexposing and need to up the ISO to get a more dramatic effect?  Also, is stacking required compared to a single shot?  Will keep experimenting until I get an attractive effect.  Would appreciate any helpful comments>

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jjuncal Regular Member • Posts: 158
Re: Astro Photo Question (trying this forum)...
2

I haven't been shooting for long with the 14-30mm that I replaced when the 14-24mm came out and only took in one occasion for astrophotography.

I’ve been shooting at 25 seconds many frames (around 20) that I stacked and result is ok but not great to my taste.

F4 isn’t enough to gather enough light but if you want to use it I’d would rather track instead to get better results

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nflanders2 Contributing Member • Posts: 521
Re: Astro Photo Question (trying this forum)...

kayaker353 wrote:

At the risk of usurping the OP's question, I have tried a couple of astro tests. First, technical technique, then on to real photos. I have found that 30 seconds at F2 with the Z9 and 20 mm F1.8 and ISO 200 shows a lot of bright stars, but no tracking to speak of. Also, there is no sense of a multitude of stars, as in the Milky Way. Am I underexposing and need to up the ISO to get a more dramatic effect? Also, is stacking required compared to a single shot? Will keep experimenting until I get an attractive effect. Would appreciate any helpful comments>

You need to bump up ISO. I'd go with ISO 1600, maybe even ISO 3200. You should take multiple exposures (at least 10, maybe 20).

30 sec with 20mm is too long. There are calculators out there that help you calculate the right exposure time. 30 sec with 20mm will at least give you some significant trailing stars. It might be ok, if you look at the picture on your phone, but not on a larger monitor or print.

Stacking is not required, and you can create good results with a single photo. In that case, I would enable long-exposure noise reduction in camera, as it may reduce noise and detect hot pixels automatically. But I typically use stacking and sometimes even a tracker in order to get perfectly round stars.

just Tony
just Tony Veteran Member • Posts: 4,140
Re: Astro Photo Question (trying this forum)...
1

John Retsal wrote:

[ I asked this over on the Astrophotography forum and got zero replies ]

I'm going to try my hand at some wide-field Milky Way photography.

You have a very short time window at this time of year, and you will want to have a fairly low horizon to the South and Southwest.

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

It’s going to be challenging to set the focus precisely at 14mm. Very little light gets through an entrance pupil of 14/4 = 3.5mm diameter. Use the star Vega, the brightest star nearly straight up at this time of year early at night, and examine your test shots at max magnification. When you see tons of dim stars you have it.

Manual focus mode, manual exposure and VR Off are your friends.

Location has Bortle 2 skies (for those who know what that means), so pretty dark.

Nice!

I'd be shooting at 14mm and maybe 20mm, wide open at f/4 tripod mounted, no tracking and VR off.

I'm pretty sure I need to keep my exposure times (per the NPF rule) to around 11 sec for 14mm and 8 sec for 20mm in order to have no trailing visible.

Also do some exposures a bit longer. You will be using a high ISO because of f/4 (even f/2 is hard to live with on a fixed mount) which will impose a very strict limit on how large you want to display the image. The noise will impair image quality more significantly than a tiny hint of trailing.

Take a lot of shots and stack them with sequator (Windows) or Starry Sky Stacker (Mac) to mitigate the noise. Sequator can separately stack the sky and foregrounds, maybe SSS can as well.

Noise decreases as the square root of the number of stacked frames. 4 will get you 1/2x, 9 will get you 1/3x, 16 will get you 1/4x.

You will get satellites and I believe that stacking programs have the option to eliminate them. Satellites are at their worst during twilight and still so after the end of twilight, but least bad near midnight.

What I'm unsure about are other settings such as ISO (taking into consideration the camera's ISO Invariance) and white balance.

Try in advance even on light polluted skies (shorter exposures of course). Only you can judge what you like. You might go with something around 3000-4000.

If you had a tracker I’d recommend ISO 800 with exposures running to 2 or 3 minutes.

Use Daylight white balance.

And a bonus question, is there any advantage in shooting in b/w in terms of the quality of the images?

Personal preference regarding the look is as far as you need to consider it.

Don’t fail to examine shots while you’re out there, and adjust if necessary if you see issues.

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OP John Retsal Regular Member • Posts: 259
Re: Astro Photo Question (trying this forum)...
1

just Tony wrote:

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

It’s going to be challenging to set the focus precisely at 14mm. Very little light gets through an entrance pupil of 14/4 = 3.5mm diameter. Use the star Vega, the brightest star nearly straight up at this time of year early at night, and examine your test shots at max magnification. When you see tons of dim stars you have it.

Manual focus mode, manual exposure and VR Off are your friends.

Here are a couple of shots I got the other night. EXIF data included

Oh as for focus, with Z lenses if you disable the setting to remember last focus point, when you first turn the camera on, it's focused at infinity.

Cassiopeia/Perseus region.

Sagittarius  region

Randy_A Regular Member • Posts: 114
Re: Astro Photo Question (trying this forum)...
1

John Retsal wrote:

just Tony wrote:

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

It’s going to be challenging to set the focus precisely at 14mm. Very little light gets through an entrance pupil of 14/4 = 3.5mm diameter. Use the star Vega, the brightest star nearly straight up at this time of year early at night, and examine your test shots at max magnification. When you see tons of dim stars you have it.

Manual focus mode, manual exposure and VR Off are your friends.

Here are a couple of shots I got the other night. EXIF data included

Oh as for focus, with Z lenses if you disable the setting to remember last focus point, when you first turn the camera on, it's focused at infinity.

Cassiopeia/Perseus region.

Sagittarius region

As your second photo kind of indicates, I feel an ISO of 3200 or above will be important - especially with the f4 aperture of the 14-30. When I was at Grand Canyon last Oct, I used ISO 3200 - and that was with an f2.8 lens (Sigma Art 24-70mm @24mm). I also chose to stack as well. Here's a Flickr link to my one Milky Way shot - from the South Rim, so I didn't have the opportunity to capture the canyon below the horizon.

Link: Grand Canyon South Rim Milky Way

And as was mentioned in another earlier reply, use Daylight for White Balance.

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Randy A

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photobob1950 Regular Member • Posts: 435
Re: Astro Photo Question (trying this forum)...

Hello John

Good timing on your question! Our photography club held an Astro evening last week, I'm in Queenstown, New Zealand.

I have only shot astro a couple of previous times, so I'm no expert, but I do know what works.

Same lens as you - the 14-30mm f/4 and Z6. Manual focus, VR off.

White balance on Auto and adjusted in post to suit. Shot in RAW.

I use On1 and these images had what little noise was present reduced further with the No Noise AI feature.

20 sec, F4, ISO 3200. Added 1.3 stops in PP. A couple of photographers in front of me fooling around with light painting.

20 sec, F4, ISO 1600 (!). Added 0.5 stops in PP. I reduced the ISO to 1600 because the shore lights were blowing out at ISO 3200. I asked my model to keep still for 20 seconds.

OP John Retsal Regular Member • Posts: 259
Re: Astro Photo Question (trying this forum)...

photobob1950 wrote:

Hello John

Good timing on your question! Our photography club held an Astro evening last week, I'm in Queenstown, New Zealand.

I have only shot astro a couple of previous times, so I'm no expert, but I do know what works.

Same lens as you - the 14-30mm f/4 and Z6. Manual focus, VR off.

White balance on Auto and adjusted in post to suit. Shot in RAW.

I use On1 and these images had what little noise was present reduced further with the No Noise AI feature.

Beautiful images.  Thank you for sharing.

just Tony
just Tony Veteran Member • Posts: 4,140
Re: Astro Photo Question (trying this forum)...

John Retsal wrote:

just Tony wrote:

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

It’s going to be challenging to set the focus precisely at 14mm. Very little light gets through an entrance pupil of 14/4 = 3.5mm diameter. Use the star Vega, the brightest star nearly straight up at this time of year early at night, and examine your test shots at max magnification. When you see tons of dim stars you have it.

Manual focus mode, manual exposure and VR Off are your friends.

Here are a couple of shots I got the other night. EXIF data included

Oh as for focus, with Z lenses if you disable the setting to remember last focus point, when you first turn the camera on, it's focused at infinity.

At least close anyway. I always check focus if for some reason I needed to switch the camera off - I advise minimizing that. You should also recheck focus as the camera (it's mostly about the lens actually) cools down during the session. It doesn't take much to soften the focus on a star, and it seems slightly off in the second shot.

Cassiopeia/Perseus region.

Sagittarius region

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OP John Retsal Regular Member • Posts: 259
Re: Astro Photo Question (trying this forum)...
1

just Tony wrote:

John Retsal wrote:

just Tony wrote:

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

It’s going to be challenging to set the focus precisely at 14mm. Very little light gets through an entrance pupil of 14/4 = 3.5mm diameter. Use the star Vega, the brightest star nearly straight up at this time of year early at night, and examine your test shots at max magnification. When you see tons of dim stars you have it.

Manual focus mode, manual exposure and VR Off are your friends.

Here are a couple of shots I got the other night. EXIF data included

Oh as for focus, with Z lenses if you disable the setting to remember last focus point, when you first turn the camera on, it's focused at infinity.

At least close anyway. I always check focus if for some reason I needed to switch the camera off - I advise minimizing that. You should also recheck focus as the camera (it's mostly about the lens actually) cools down during the session. It doesn't take much to soften the focus on a star, and it seems slightly off in the second shot.

I did check focus (using rear LCD screen zoomed all the way in) and I couldn't get it any sharper. Also, to avoid any accidental movement, I power off and back on between shots.

That is looks off in the 2nd shot must be an artifact of this website or the device your viewing this on.  On my 5K monitor they're both equally sharp.

Floodblue Junior Member • Posts: 45
Re: Astro Photo Question (trying this forum)...

kayaker353 wrote:

At the risk of usurping the OP's question, I have tried a couple of astro tests. First, technical technique, then on to real photos. I have found that 30 seconds at F2 with the Z9 and 20 mm F1.8 and ISO 200 shows a lot of bright stars, but no tracking to speak of. Also, there is no sense of a multitude of stars, as in the Milky Way. Am I underexposing and need to up the ISO to get a more dramatic effect? Also, is stacking required compared to a single shot? Will keep experimenting until I get an attractive effect. Would appreciate any helpful comments>

In PP just ramp your exposure up a lot and whites as necessary and do local edits on the milky way and I think you'll be surprised how much is hidden there in the data. 30 seconds is a little long for 20mm if you're not using a tracking mount.

Ernie Misner
Ernie Misner Veteran Member • Posts: 9,346
Re: Astro Photo Question (trying this forum)...

John Retsal wrote:

just Tony wrote:

John Retsal wrote:

just Tony wrote:

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

It’s going to be challenging to set the focus precisely at 14mm. Very little light gets through an entrance pupil of 14/4 = 3.5mm diameter. Use the star Vega, the brightest star nearly straight up at this time of year early at night, and examine your test shots at max magnification. When you see tons of dim stars you have it.

Manual focus mode, manual exposure and VR Off are your friends.

Here are a couple of shots I got the other night. EXIF data included

Oh as for focus, with Z lenses if you disable the setting to remember last focus point, when you first turn the camera on, it's focused at infinity.

At least close anyway. I always check focus if for some reason I needed to switch the camera off - I advise minimizing that. You should also recheck focus as the camera (it's mostly about the lens actually) cools down during the session. It doesn't take much to soften the focus on a star, and it seems slightly off in the second shot.

I did check focus (using rear LCD screen zoomed all the way in) and I couldn't get it any sharper. Also, to avoid any accidental movement, I power off and back on between shots.

Besides focus, I have had some soft star shots due to mist that forms on the front lens element at night at higher altitudes.  Putting a disposable hand warmer on the lens can prevent that from happening.  I am going to try that next time.

That is looks off in the 2nd shot must be an artifact of this website or the device your viewing this on. On my 5K monitor they're both equally sharp.

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Ernie Misner
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Light pollution does not only erase our view of the stars. Scientific evidence suggests that artificial light at night has negative and deadly effects on wildlife, including amphibians, birds, insects, and mammals. ~ Bin Chen

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Ernie Misner
Ernie Misner Veteran Member • Posts: 9,346
Re: Astro Photo Question (trying this forum)...

Floodblue wrote:

kayaker353 wrote:

At the risk of usurping the OP's question, I have tried a couple of astro tests. First, technical technique, then on to real photos. I have found that 30 seconds at F2 with the Z9 and 20 mm F1.8 and ISO 200 shows a lot of bright stars, but no tracking to speak of. Also, there is no sense of a multitude of stars, as in the Milky Way. Am I underexposing and need to up the ISO to get a more dramatic effect? Also, is stacking required compared to a single shot? Will keep experimenting until I get an attractive effect. Would appreciate any helpful comments>

In PP just ramp your exposure up a lot and whites as necessary and do local edits on the milky way and I think you'll be surprised how much is hidden there in the data.

Yes to working with a slightly brighter image, then using a bit of dehaze right in the milky way area.  The hues and contrast really start to pop.

30 seconds is a little long for 20mm if you're not using a tracking mount.

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Ernie Misner
http://www.flickr.com/photos/erniemisner/
Light pollution does not only erase our view of the stars. Scientific evidence suggests that artificial light at night has negative and deadly effects on wildlife, including amphibians, birds, insects, and mammals. ~ Bin Chen

 Ernie Misner's gear list:Ernie Misner's gear list
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Ernie Misner
Ernie Misner Veteran Member • Posts: 9,346
Re: Astro Photo Question (trying this forum)...

They seem to be heavy into deep space photography on the astro forum, and have some serious knowledge.

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Ernie Misner
http://www.flickr.com/photos/erniemisner/
Light pollution does not only erase our view of the stars. Scientific evidence suggests that artificial light at night has negative and deadly effects on wildlife, including amphibians, birds, insects, and mammals. ~ Bin Chen

 Ernie Misner's gear list:Ernie Misner's gear list
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BasilG Forum Pro • Posts: 10,016
Re: Astro Photo Question (trying this forum)...

I would suggest shooting RAW (white balance less critical) and using a stacking software. With an f/4 lens, you're somewhat limited otherwise; with stacking, you'll be able to get very good results.

Bill Ferris
Bill Ferris Veteran Member • Posts: 9,136
Re: Astro Photo Question (trying this forum)...
1

John Retsal wrote:

[ I asked this over on the Astrophotography forum and got zero replies ]

I'm going to try my hand at some wide-field Milky Way photography.

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

Location has Bortle 2 skies (for those who know what that means), so pretty dark.

I'd be shooting at 14mm and maybe 20mm, wide open at f/4 tripod mounted, no tracking and VR off.

I'm pretty sure I need to keep my exposure times (per the NPF rule) to around 11 sec for 14mm and 8 sec for 20mm in order to have no trailing visible.

Personally, I use the "500 rule" as a guideline. Divide 500 by the focal length you're using to get a maximum exposure time that won't produce objectionable star-trailing. That term, objectionable, is key. It's a subjective threshold that might be too short or too long according to your aesthetic. A 30-40 second exposure at 14mm should produce a pleasing night sky result. A 25-ish second exposure should deliver the goods at 20mm.

For reference, my favorite photo of comet NEOWISE from the summer of 2020 is a 4-second, untracked exposure made at 200mm. Not to get too deep into the weeds on that one, but it's a stacked image made from eight exposures of the comet at ISO 12800. I did the stacking in Photoshop and it really does a nice job of mitigating noise visibility.

If the subject of the photo is a constellation or a bright star that you want to capture with diffraction spikes, then I would recommend observing the 500 rule a bit more closely. However, the more the stars function as framing for another subject, the less important it is to avoid any visible trailing at all costs. If your subject is the summer Milky Way, choose settings that capture the breadth, depth and color of that display. If there's a bit of star-trailing, who cares. The stars are supportive elements in the scene. If your subject is a bright comet, ignore the 500 rule and choose settings that put the comet front & center. Nobody's going to be looking at the stars. They're all going to be wow'd by the comet

What I'm unsure about are other settings such as ISO (taking into consideration the camera's ISO Invariance) and white balance.

I'll often shoot at ISO 6400 with a full-frame body. As mentioned, I used ISO 12800 for comet NEOWISE.

And a bonus question, is there any advantage in shooting in b/w in terms of the quality of the images?

Thanks all!

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Flagstaff, AZ
http://www.billferris.photoshelter.com

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