What are some good tips for astral photography?

Started by renowilliams, August 10, 2013, 04:02:18 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

renowilliams

Hi All

I'm looking for some settings help for shooting the stars. I am pretty new to photography and could use some input. I plan on doing a time lapse and have played with the intervolometer, so I'm comfortable with that. Also lens choice. I have a 18-55mm and a nifty 50. My thought is to use the 18-55 but maybe I'm wrong.

Any assistance would be greatly appreciated.

Tim

Pileot

My experience is to get good light from the sky you need a long exposure. The problem is the sky moves and can blur even a 10 second exposure, depending on the quality you are looking for. If you take, say, a 30 second exposure you can actually get little streaks from the stars moving.

I would suggest get the fastest glass you have, in this case the 50mm 1.8 and shoot it wide open.
Most of the time you try to go as low ISO as you can to reduce noise but to get a short shutter speed I'd use ISO 400-800, I know on my 7D (and T2I before that) I found the noise acceptable until 800ISO. YMMV.

Lastly, just trial and error. The less ambient light the better. Bring a laptop or tablet to look at the pics in higher resolution as you take them and have fun!

TheUnkn0wn

There's a nice rule for preventing star streaks. Lets say your using your 50mm lens, 450/50 = 9. This means you can have a 9 second exposure before star trails can be seen. So the rule is divide 450 by the focal length you are using. (e.g 18mm = 25 seconds)

As for ISO you'll have to use a fairly high ISO (800-1600)

If you're doing deep sky photography I recommend you take multiple pictures so you can stack them using software like (http://deepskystacker.free.fr/english/index.html)

To reduce noise from the sensor take a dark frame after shooting, (just take a photo with the lens cap on using the SAME settings you used to take your other photos). You can then use this dark frame to subtract the noise from your images.

I think that covers the most important things.

mageye

The location is very important. I found a light pollution map. With this you can see easily where the darkest skies are. You may have to search around on google to find something for your locality.

Here is one for the UK:

(you can even zoom right in on the maps and the place names are labelled)

http://www.avex-asso.org/dossiers/wordpress/?page_id=127

One thing people can often overlook is the 'Mirror lockup'. It's a standard Canon feature on the Canon menu it locks the mirror so that it's always open thus preventing camera shake (and resulting trails/blur) caused by the shutter actuation. This makes a big difference with long exposure shots. Try it if you haven't already. (normal photo mode)
5DMKII | 500D | KOMPUTERBAY 32GB Professional 1000x |Canon EF 50mm f/1.8 II | Samyang 35mm f/1.4 ED AS UMC | Canon EF 75-300mm f/4-5.6 III | Zoom H2 (4CH. audio recorder) | Mac OS X 10.9.2 | Photoshop CC | After Effects CC | Final Cut Pro 7

xNiNELiVES

@TheUnknown
That conversion needs to be adjusted because he's on a 1.6x crop body. That 18mm is actually a 28.8mm. 450/28.8= 15.63 seconds.
Also I'm guessing you copied that name from the hacker on COD.

Now you should adjust your exposure for how bad the light pollution is in your location. If you're at a really dark location, such as Yosemite or something, choose 30", 3.5, 3200 ISO. If you don't use 3200 iso you can lose a lot of detail. It's like underexposing a photo in daylight.

I would never shoot with a 50 (80mm) for a timelapse. Only unless you have a specific foreground you want to magnify on and stars are a secondary thing.

If you go out shooting in a dark location with a 15 second exposure at iso 800 your timelapse is going to turn out crap because you won't see anything. Trust me that's what happened to me in the past. Just deal with the star trails anyways you'll never see them unless you are looking at them in a 100% crop.

Look for example at these two photos I took, the darker is in ISO 800 then second is 3200:
https://dl.dropboxusercontent.com/u/814675/IMG_3166.jpg
https://dl.dropboxusercontent.com/u/814675/IMG_3167.jpg
Both were also using 30 second exposures and an aperture of 2.8.

jose_ugs

@xNiNELiVES
Do you use any in-cam Noise Reduction?

Doyle4

Canon 5Dmkii

30second's, F/2.8 iso 1600 - there is streaks at 100% crop though, pointed out my bedroom window, had alot of light pollution though, also...SHOOT RAW!! its a must!!


Audionut

Follow the advice in this thread.

I like to use this calculator for exposure time: http://news.alpine-photography.com/2013/06/get-your-stars-right-tool-long-exposure.html


Canon 5D3 - Sigma 35mm f/1.4
f/1.4 - 15secs - ISO 6400

renowilliams

Thanks for all the input guys, I really appreciate it. I went out early this morning and took a few shots. I just picked up a Canon 17-85mm lens, so I wanted to try it out. Its not a particularly fast lens but I think they tuned out not too bad. I set my shutter to 20 seconds and was at 17mm. The iso was at 800 and 1600



http://www.flickr.com/photos/renowilliams/9530653904/in/photostream/lightbox/


http://www.flickr.com/photos/renowilliams/9530654178/in/photostream/lightbox/

Doyle4

Quote from: Audionut on August 17, 2013, 12:54:44 PM
Follow the advice in this thread.

I like to use this calculator for exposure time: http://news.alpine-photography.com/2013/06/get-your-stars-right-tool-long-exposure.html


Canon 5D3 - Sigma 35mm f/1.4
f/1.4 - 15secs - ISO 6400


WOW WOW WOW WOW WOW WOW!!
Man that is beautiful! im new to Astro and will defiantly be reading the guide! i was tempted to use iso6400 but was too scared incase of noise or hot pixels appearing.

Doyle4

Also, the Sigma 35mm f/1.4, is that Sigma's latest model? if so how is it?

Cheers.

Audionut

Deal with noise and hot pixels in post imo.

The Sigma?  Just buy it, buy it now  ;)
Get a dock with it too.  It's super accurate and consistent when you tweak it's AF.

@renowilliams
You haven't quite got the focus right on the stars.

Doyle4

Noticed the 30mm 1.4 is cheaper than the 35mm, is it worth the extra or going for the 30mm? Cheers

Audionut

http://www.dxomark.com/index.php/Lenses/Compare-Camera-Lenses/Compare-lenses/%28lens1%29/293/%28lens2%29/1056/%28lens3%29/1098/%28brand1%29/Sigma/%28camera1%29/870/%28brand2%29/Sigma/%28camera2%29/870/%28brand3%29/Sigma/%28camera3%29/870

DxO shows the 35mm to be superior to the 30mm in all test cases.  Sharpness, vignetting, distortion and CA.
The 35mm will also work on FF if you decide on that route in the future.

Whether that is worth the price difference, only you can decide (or your minister for finance, if you have one :P ).

P.s.  Lets take further discussion to another thread or PM please.  We've sufficiently taken this thread far enough off topic  ;)

Doyle4

Thanks Audionut for the good tip on what lens to use for astral photography ;) ha

xNiNELiVES


dmilligan

Using FPS override in ML is a very good way to get your shot in focus. Set to around 1-2fps and optimize for low light. Then manually focus using live view at 10x zoom. That should be enough to make out bright stars enough to focus. Depending on your lens you might need to use either higher or lower fps. The higher the fps you use the quicker the screen responds so the easier it is to adjust, but you have to make it slow enough to pick up enough light to focus.

Lens sharpness is not really very important for astro, noise hinders your sharpness much more than the lens does. Focal length is the most important factor to consider when buying an astro lens, and it all depends on what you want to do, there are applications for just about any length lens from 8mm to 8000mm. Wide field timelapses: 8mm fisheye, nebula/galaxys: 1000mm telescope, planetary: 2500mm+ telescope.

I don't really care for all the night exposure time calculators. IMO just use trial and error and push the exposure time until the star trails are unacceptable to you. The amount of star trail you get also depends on which direction your pointing, which these calculations don't take into effect anyway.

For timelapse I usually shoot a little bit longer shutter speed than I would for non-tracked still photos, because when reduced to video resolutions, the star trails are less noticable, and also because the scene is moving anyway (kind of like desirable motion blur in normal video).

Sometimes it's cool to shoot timelapses when the moon is full or almost full. It looks like a daytime scene but with stars. You also don't have to worry about light pollution. So start there if you can't get somewhere dark (or it's the wrong time of the month, like right now).


xNiNELiVES

Quote from: Audionut on August 17, 2013, 12:54:44 PM
Canon 5D3 - Sigma 35mm f/1.4
f/1.4 - 15secs - ISO 6400
https://dl.dropboxusercontent.com/u/34113196/Camera%20stuff/MilkyWay.jpg

Ummm how did you get that much color in your image? My milky ways always turn out orange to yellow. I never get that blue and purple color.


dmilligan

Quote from: xNiNELiVES on August 22, 2013, 06:59:40 PM
Ummm how did you get that much color in your image? My milky ways always turn out orange to yellow. I never get that blue and purple color.

orange/yellow is more true to what is actually there, if humans had cones sensitive enough to see color at this low of an intensity, that is how we would see it. I think a lot of photographers tint their milkyway photos into the blues just because most people expect things in the sky to have a blue color (b/c it is blue during the day). Personally I prefer the more accurate rendering, WB set to daylight (totally neutral).

falkor

on my 3rd attempt i got this image (which is also clickable to fuller sizes in a new tab)


my 1st attempts failed due to being in the city.
-take a black photo to be able to remove most noise later (use a lens cap for a single shot)
-tripod
-low f-stop (mine above is 3.5)
-hi iso  (above = 1600)
- 18mm lens
-30second exposure from a 2 second delay (i had no Magic Lantern at the time, and no intervelometer either)   
point there is to never actually touch your camera...as it will shake.

canon 60d, no, mode off, size is 5184 x 3456, taken July 28th 2013 and is 21.9mb.

   i did have to edit my truck wheel arches darker and i use a blue flashlight (for hunting and tracking blood) for the tint inside the cabin... the white light is from a bigger flashlight...

hope that helps
~falkor

Pelican

EOS 7D Mark II, EOS 7D, EOS 5, EOS 100 + lenses (10mm to 300mm), 600EX, 550EX, YN600EX x 3
EOScard, EOS DSLR firmwares, ARMu, NiControl, etc.: http://pel.hu/down

Audionut

Nice shots guys.  I'm heading out to an area with very low light pollution again tonight.  I hope to get some good captures :)

I'll be following these tips also.

Audionut

Haven't been able to get deep sky stacker working how I want it yet.  But here is a single frame from my adventures.

Canon 5D3
F/2.8 - 2 min exposure - ISO 1600


This was using my brother in laws Tonika 11-16mm f/2.8 @ 16mm on the FF body.

xNiNELiVES

Nice, what edits did you do besides the obvious saturation push?

Audionut

WB/Tone/Clarity/Vibrance

The adjustments vary depending on the lens/body/exposure.

Here it is direct from camera.


glubber

Has anybody tried making a star-timelapse using silentpics?
Even with applying NR and heavy tweaking in Lightroom on the DNGs the results are unusable.
While doing a timelapse with CR2 and the same exposure values (13"/f2.8/ ISO1600) look very pleasing.

I know about the lineskipping with "simple" silentpics, but is it just a WONTDO or have simply done wrong?  :-\
EOS 550D // Sigma 18-200 // Sigma 18-70 // Canon 10-18 STM

dmilligan

@glubber,
Night photography is incredibly demanding on the camera. I can't imagine some liveview hack being useful for it in any way. People are so afraid to use their shutters and I don't really understand why (yes I know shutters do eventually wear out). At night you must do everything you can't to get every last ounce of performance out of you camera just to get a picture that's not terrible. That means use the shutter.

For me time under the stars is very precious and I want to make the most out of it. I wouldnt even consider wasting precious time with silent pics or even shooting on jpeg quality. Do the math on how much it costs per hour to take 30s exposures assuming your shutter wears out after 100-150k uses and it costs $200 to replace and I think you may see my point.


Quote from: Audionut on September 12, 2013, 04:42:38 AM
Haven't been able to get deep sky stacker working how I want it yet.  But here is a single frame from my adventures.

This was using my brother in laws Tonika 11-16mm f/2.8 @ 16mm on the FF body.
I've never had success stacking wide angle shots that aren't tracked (and if you can track there's not much reason to stack, just take a 10 or 20 min exposure). If you think about it it makes sense why. Wide angle lenses introduce significant distortion. This means as the stars move in your frame, stars in different places are going to move different amounts, in slightly different directions. This makes registration extremely difficult b/c the software has to take into effect distortion (I'm not sure if DSS can do this, I know that the software I use, pixinsight, pretty much chokes on them and it is significantly more advanced than DSS), not just linear translation and rotation. I read about some guy who managed to do some wide angle stacking with some rather sofisticated math/custom software he designed to take the distortion into account. And even then the results where not particularly impressive, very blurry toward the edges (where distortion is the greatest).

Fortunately tracking is not very difficult esp. with wide angle lenses b/c you don't have to be all that accurate. I use my telescope's equatorial mount, which would probably only cost around $150 by itself (my scope and everything was like $400). You could probably put together a simple barn door mount for less than $50.


Audionut

I actually didn't have much trouble in aligning the images.  My main concern was getting the required information in the tiff file.  I just can't seem to get the tone adjustments out of the tiffs as I can with the original raw files.  This is probably from my own lack of understanding of all the options in DSS.

Wide angle with tracking mount would simplify matters greatly.

RenatoPhoto

Quote from: dmilligan on September 12, 2013, 10:52:12 PM
@glubber,
I've never had success stacking wide angle shots that aren't tracked (and if you can track there's not much reason to stack, just take a 10 or 20 min exposure).

Here is a stack of 20 photos taken with 5D3 without telescope mount or tracking, just used my Canon EF 300mmf/4+2X = 600 f/8.  (I wish i had the f2.8, but cant afford it)
Image taken at 2 seconds (lots of blurr) ISO 6400

DSS aligned them pretty well and got rid of tons of noise.

http://www.pululahuahostal.com  |  EF 300 f/4, EF 100-400 L, EF 180 L, EF-S 10-22, Samyang 14mm, Sigma 28mm EX DG, Sigma 8mm 1:3.5 EX DG, EF 50mm 1:1.8 II, EF 1.4X II, Kenko C-AF 2X

dmilligan

Explain to me how a 300mm lens is considered wide angle.  Last time I checked they were called super telephoto. He's using an 11-16mm lens, your using a 300mm difference is night and day. Yes stacking anything more telephoto than about 50mm works fine, I do actually successfully stack photos from my nifty fifty. I was talking about wide angle lenses, which have way too much distortion to align and stack

RenatoPhoto

Quote from: dmilligan on September 13, 2013, 04:45:47 PM
Explain to me how a 300mm lens is considered wide angle.  Last time I checked they were called super telephoto. He's using an 11-16mm lens, your using a 300mm difference is night and day. Yes stacking anything more telephoto than about 50mm works fine, I do actually successfully stack photos from my nifty fifty. I was talking about wide angle lenses, which have way too much distortion to align and stack
I did not mean to offend you!  I have done some stacking of fisheye and still works, it certainly helps reduce noise.
http://www.pululahuahostal.com  |  EF 300 f/4, EF 100-400 L, EF 180 L, EF-S 10-22, Samyang 14mm, Sigma 28mm EX DG, Sigma 8mm 1:3.5 EX DG, EF 50mm 1:1.8 II, EF 1.4X II, Kenko C-AF 2X

dmilligan

Sorry that came off a little snipy.

No doubt it helps with noise, but how do you align them? Alignment algorithms typically work by analyzing distances and angles between stars and matching them up to stars in other frames. If distances and angles are changing due to distortion, the algorithms are going to have trouble matching stars. Also, typically these algorithms are only capable of applying linear corrections to the images such as translation, rotation, and scale. Distortion requires nonlinear corrections to be applied to images, which like I said is possible, but only with some rather complicated math and modeling of the distortion created by a specific lens. And nonlinear transforms are also going to reduce resolution as you move out from the center of the image.

Watch how the stars move on a fisheye timelapse to see what I mean.

RenatoPhoto

Quote from: dmilligan on September 13, 2013, 06:24:13 PM
No doubt it helps with noise, but how do you align them?

I dont know but DSS does a great job IMHO, but I am not an expert by a long shot.  I have played with this software and always the outcome (Autosave.tiff) seem a lot better than any single image so in my opinion it works but maybe not to perfection.
http://www.pululahuahostal.com  |  EF 300 f/4, EF 100-400 L, EF 180 L, EF-S 10-22, Samyang 14mm, Sigma 28mm EX DG, Sigma 8mm 1:3.5 EX DG, EF 50mm 1:1.8 II, EF 1.4X II, Kenko C-AF 2X

fotojohni

The fps over ride is an absolute must!!

http://www.jakeevansphotography.com/85/

Also, ettr as much as you possibly can. Then crush in post.  I suggest using a wide angle prime because of the reduced vignetting when stopping down.  Vignetting is the biggest enemy, next one is sharpness in the corners.  Look for a lens without a curved plane of focus. 

It can be very difficult to deal with the shadow areas in the photo.  You can try to speed light them, but it usually looks like shit.  You have to be creative.   

The most important thing is to take some time to analyze the scene and compose shots effectively.