# Stair Trail Using Slow Exposure



## monfor5 (Sep 8, 2010)

Hi All, 

This is a post from a blog I run called Landscape Photography Tips & More | The Omniscape Photography Blog.  Enjoy!  

*The Making of "Star Struck" - by Brandon Broderick*

Greetings Omniscape Photography fans, and welcome to our first blog. For this blog, Ill be discussing my landscape fine art photo entitled "Star Struck".  This photo was taken in Northern Ontario near the town of Kirkland Lake. I had always been interested in photos of the stars, and more specificly, photos of star trails. After lots of trial and error, I was finally figuring it out and decided it was time to get a bit creative with it. 





​

The night this photo was taken, there was a full moon so I had to take advantage of it. Ive taken photos of the moon before but wanted to use it in a different way this time. I set up my shot so I had the moon at my back. This would allow me to still photograph the stars and allow the moon to illuminate the foreground. This is a single 15 minute exposure. The only editing done was a slight temperature adjustment and some minor noise reduction. 

Lastly, heres a simple tip for these night shots. Always try and set up your shot before it gets dark. It is still possible to set up the shot in the dark, however I find that composing a shot and making sure focus is correct is much easier to do during daylight hours. 

*Equipment used:*
Camera: Canon EOS 5D mk II
Lens: Canon EF 14mm f/2.8 L II USM
Tripod: Gitzo GT2541 carbon fiber tripod
Tripod Head: Manfrotto 488RC2


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## Flash Harry (Sep 8, 2010)

Not long enough


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## Garbz (Sep 9, 2010)

And too much light pollution to boot. 

Here's a tip. Take a picture just like the one you did, then take about 50 in a row for half as long as you did. Stack the 50 using a maximum value algorithm, that'll create startrails and keep the sky much darker, then in photoshop blend the foreground of the original photo together with the stacked to bring out the foreground again. 

Play with stacking. It'll open up a whole new world of possibilities for you.


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## guzziknight (Sep 9, 2010)

Which program do you use for the stacking?


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## Garbz (Sep 10, 2010)

I used ImageStacker, but now I'm migrating to Deep Sky Stacker. It's free and looks like it may be more powerful. I've yet to pull something decent out of it but I have seen some amazing results from people who use it.


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## pbelarge (Sep 10, 2010)

Garbz said:


> I used ImageStacker, but now I'm migrating to Deep Sky Stacker. It's free and looks like it may be more powerful. I've yet to pull something decent out of it but I have seen some amazing results from people who use it.


 

Garbz
Could you recommend some reading/tutorials on stacking?
Thanks


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## guzziknight (Sep 10, 2010)

Looks like Deep Sky Stacker is a PC only program. Any MAC compatible ones out there?


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## Garbz (Sep 10, 2010)

I did see Keith's Image Stacker Keith's Image Stacker did have a mac version. But I have used neither the mac, nor the windows versions. 

I haven't seen much in the way of a tutorial but Keith's site also offers a nice explaination of the stacking to increase exposure technique: How Image Stacking Works along with information on why stacking 20 seemingly black images can result in an image with a lot of detail that isn't at all visible in any frame regardless of how you play with it. Contrary to popular belief, noise is our friend in this case.

The Deep Sky Image stacker website has some good background theory too: The theory or How to create better images Beyond the mathematical theory all that needs to be done is read the manuals. Each program works slightly differently, apparently you can also do this in Photoshop too using Smart Objects though I've never tried it.

What I was talking about above to extend startrails without increasing the light pollution was a function of ImageStacker (haven't looked if Deep Sky can do it too). This function takes the maximum brightness value across all photos and stacks that to the final value. Here's a 2 hour example of this maximum value process. The result is made of 200 30 seconds pictures with a 5 second cooldown time in between images. (you can break camera sensors if you overheat them, not sure if this is still a problem but it definitely was with cameras of 2+ years ago). If you zoom in all the way on the original you can just make out gaps between the stars from the individual exposure, but not on a normal sized image: http://farm2.static.flickr.com/1353/773160897_fae20200db_b.jpg


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## Josh66 (Sep 10, 2010)

Garbz said:


> If you zoom in all the way on the original you can just make out gaps between the stars from the individual exposure, but not on a normal sized image: http://farm2.static.flickr.com/1353/773160897_fae20200db_b.jpg


Even without zooming in, it still looks a little (and I mean "a little" as in, barely noticeable) jagged...  Definitely not the same as film ... but I do think you did the best that is possible with today's digital technology.
It looks good ... just not quite the same as film.

All I mean is that you can tell, within seconds, that it was captured digitally...  That doesn't mean it's bad - I like it.  All it means is that it's different.

I wonder how long it will take digital to match film in very long exposures (longer than an hour)...?


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## jake337 (Sep 11, 2010)

O|||||||O said:


> Garbz said:
> 
> 
> > If you zoom in all the way on the original you can just make out gaps between the stars from the individual exposure, but not on a normal sized image: http://farm2.static.flickr.com/1353/773160897_fae20200db_b.jpg
> ...


 
What about using multiple cameras?  They would have to be identical cameras with identical lenses and as close to each other as possible. Then stitch them together in PP. Possible???


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## Josh66 (Sep 11, 2010)

Possible, I guess - but that would be a lot of work.

The main problem is the sensor heating up, right?  I think the easiest solution would be finding a good way to keep it cool.


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## Garbz (Sep 11, 2010)

Which is why cameras dedicated to astrophotography have massive heatsinks on the back of the sensors. 

I actually remember seeing on a website someone built a cooled enclosure that keeps his 350D at around -10degC and below. All in the name of reducing noise while tracking stars with his telescope, Quite overkill


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## ecr111 (Sep 12, 2010)

Garbz said:


> Which is why cameras dedicated to astrophotography have massive heatsinks on the back of the sensors.
> 
> I actually remember seeing on a website someone built a cooled enclosure that keeps his 350D at around -10degC and below. All in the name of reducing noise while tracking stars with his telescope, Quite overkill



Cool stuff.

It's quite common among the hardcore computer enthusiasts to cool their processors in pursuit of a few more gigs of speed with liquid nitrogen.  -55C or lower.

So, I'm not surprised that there are such photography folks and they actually end up with something others can appreciate in the end.


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## Garbz (Sep 13, 2010)

Yep. Though with computers the theory is grounded with personal insantiy (much like the competition to see who can put the biggest exhaust on a car without dragging it along the bitumen) 

In reality I say quite overkill, but there's a solid theory backing for it. Johnson Noise is noise that is generated across a resistive element due to temperature. The resistive element can't be effectively removed without limiting how well the signal from the sensor to the camera is amplified, so one other way to attack the problem is to cool the sensor down. That's one of the reasons why the Spitzer space telescope is cooled with liquid helium to about 4 degK *drool*


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## ecr111 (Sep 13, 2010)

Oh, I get the theory.

I am a retired Electrical Engineer and directed testing of military grade hardware I designed from -55C to +100C .

It's all great stuff for me.


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## edouble (Sep 13, 2010)

You guys highjacked the life from the original post lol


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## ecr111 (Sep 13, 2010)

edouble said:


> You guys highjacked the life from the original post lol



LOL, sorry, but when I clicked the link I got the offer to buy the photo for $140.
So, I don't feel_ too_ bad.

But, back on topic.
I'm going to the Tennessee mountains and would like to try to get a Milky Way image.
Should I use the better IQ 17-55 f2.8 or the nikon 10-24 for the extra wide 10mm?.


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## Garbz (Sep 14, 2010)

You know stacking is a wonderful thing, but you can't beat light capturing ability. I'd sooner take the 17-55 for it's half a stop faster aperture. Though given the amazing pictures 10mm produces I think this is a tough call.


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## ecr111 (Sep 14, 2010)

Garbz said:


> You know stacking is a wonderful thing, but you can't beat light capturing ability. I'd sooner take the 17-55 for it's half a stop faster aperture. Though given the amazing pictures 10mm produces I think this is a tough call.



I assume you mean 10mm in general and not the Nikon in particular.
So far I have not been to sure with the 10-24 I have, but I have not given it that much opportunity either.

And though this is a star trail thread  I will be doing wide view and long exposure, so I would think star trails shouldn't be too apparent (?).

BTW, how high can I set the ISO on my D300s?
I'm thinking 1600.
Or, should I go higher and use long exp. NR?


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## monfor5 (Sep 14, 2010)

Hi Guys, 

Just checked back to see if there were any questions about what I posted, but see that the thread has taken off in a new direction so I'll leave it be!  

Take care!


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## Garbz (Sep 15, 2010)

I did mean the Nikon but really the point is the same for all of them. More light = more stars. 

The startrails should be apparent. One thing to note is that the process should change considerably depending on what you're photographing and where. 

Regardless of what you do long exposure NR is not only bad, it will flat out spoil the image. You can't stack since it creates an equal exposure for processing purposes. That means any star trails will look like dashes. In any case the "Dark Frame" is exactly what this is for when using Deep Sky Stacker. It does long exposure noise reduction except gives you the option of when to take the exposure (during the shoot is not ideal).

So what are you going for?
- Shooting pictures of stars? Crank up the ISO, take lots of short pictures, don't let the stars trail, align the images and stack the result to bring out the detail and reduce noise in the dark pictures you're taking.
- Shooting startrails in the city? Go really low ISO, take exposures long enough till you can't tolerate the background light pollution, give a few seconds gap and start the next exposure, stack the result with a "maximum brightness" type algorithm to ensure that the startrails come out but the background brightness doesn't increase. 
- Shooting startrails in the bush? Play with a low to medium ISO, take exposures long enough till you can't tolerate the noise or sensor bleeding, again give a few seconds cooldown time between exposures, stack again with maximum brightness type algorithm to ensure the startrails come out, adjust levels afterwards since the noise in this case will appear to disappear by raising the brightness of the blacks.


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## Studio27 (Sep 16, 2010)

Hi Guys, 

Do you need a specific lens to capture star trails? Or can you use the standard kit lens? If so  can anyone recommend settings to use and/or lenses that will capture the star trails. I have a d5000, so if ne one owns one and and can help that'll be fab! Thanks


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## Garbz (Sep 16, 2010)

As mentioned ability to capture light is key. Yes there is an ideal lens. The Nikkor 24mm f/1.4G is the ideal lens. That said I could actually buy a car for the same money. 

You'll get limited results with a standard kit lens. You will need to increase the ISO to capture fainter stars which will result in more noise, but as always it's a matter of compromise.


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## JacJac (Dec 10, 2010)

hi all, i'm new the the DSLR world and learning different techniques of photography.
i have just learnt how to take these awsome startrail photos with alot of trial and error and finally got the image i wanted.
have a look and tell me what you think and how i can improve any feedback positive or negative welcome and feel free to browse through my other photos 
Jacqui Hunt's Photos | Facebook

thanks 
Jacqui


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## Namibia (Dec 10, 2010)

guzziknight said:


> Looks like Deep Sky Stacker is a PC only program. Any MAC compatible ones out there?


I have downloaded trial version of aperture 3 on my mac - and it has a stack function


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## Sw1tchFX (Dec 10, 2010)

instead of stacking, you can also go out when there's a new moon, and if your lens is bright enough, they don't even need to be trails.


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