Star Trails

[cmor]

My first star trail attempt. Its not perfect but I wasn't sure I would get anything so I'm happy with it. I have another one burning right now, I'll post it when its together. Lets see what you got. 30 min at f5 looking down the valley at crystal.

[grizzle6]

Love the color. Nice job.

[cmor]

Thanks

You can see purple corners in the top of the photo though, I get this hot sensor noise even with a dark frame. I pp'ed them a little bit but don't have a good plan yet on how to get rid of the in photoshop and don't know how to prevent in on the camera. It was taken at about 0 C.

[Tippster]

Probably has something to do with it being a CCD camera and there not being enough shielding in those corners of the sensors or something. It might be an "energy leak" from the camera itself "fogging" the sensor.

[cmor]

Probably has something to do with it being a CCD camera and there not being enough shielding in those corners of the sensors or something. It might be an "energy leak" from the camera itself "fogging" the sensor.

Yeah I think it is an "energy leak" as opposed to a light leak. Its on a sony a200. so how do i get rid of it?

[Hugh Conway]

how do i get rid of it?

get a new camera

[cmor]

so round 2 did not work out quite as well:



more purple corners as well, looks like im doomed to them for a while.

[grapedrink]

so round 2 did not work out quite as well:



more purple corners as well, looks like im doomed to them for a while.

i have that problem with my 30d which is a cmos sensor, except i took a 2 hour not a 30 min. at 10 min i have no problems. try this instead, put your camera on 30s exp, use a cable release and lock it down in continous shooting mode, then use a stacking software to combine the hundred or more shots you end up with..

[Eldo]

What lens are you using? Because the second shot definitely has some flare issues. (Although that purple corner seems to be something else.)

Take off any protective filter you have on the lens and if it is a zoom lens try shooting not at full wide angle. If either of those fix the problem then you know it's not a sensor issue.

I really like the first photo.

[cmor]

What lens are you using? Because the second shot definitely has some flare issues. (Although that purple corner seems to be something else.)

Take off any protective filter you have on the lens and if it is a zoom lens try shooting not at full wide angle. If either of those fix the problem then you know it's not a sensor issue.

I really like the first photo.

I'm using a sigma 10-20mm. It actually controls flare very well, but the small amount it picks up is amplified in the long exposure. I tried with and without a protective filter, and didn't see much difference. It was actually really bad until i turned one of the house lights off.

It was more near the 10mm range though, maybe narrowing it down a bit will help.

[cmor]

i have that problem with my 30d which is a cmos sensor, except i took a 2 hour not a 30 min. at 10 min i have no problems. try this instead, put your camera on 30s exp, use a cable release and lock it down in continous shooting mode, then use a stacking software to combine the hundred or more shots you end up with..

Apparently the a100 and a200 are afflicted as well. I think I'm going to try the interval, we'll see if its clear enough tonight. heres a bit of a tutorial including the interval idea:

http://stevencastle.wordpress.com/20...ls-on-a-d-slr/

Theres a link to a program to combine them there as well.

[truth]

I'm not sure how or why you chose to shoot at f5 but that seems really open. I'd shut that way down to control the overexposure and saturation while bumping up the exposure length. That said the 2nd image really pushes the relative brightness of the sky vs. the house. The house lights are simply way too hot to be able to balance with the sky. The first image maintains this balance nicely but the trails are just too short.

[Tippster]

I'm not sure how or why you chose to shoot at f5 but that seems really open. I'd shut that way down to control the overexposure and saturation while bumping up the exposure length.

That depends on the lens sometimes. Lenses suffer from Diffraction at small apertures, causing the shot to become softer or muddied looking, especially at long exposures. The trick is to find the sweet spot for each lens.... how one does that other than by trial and error I have no idea.

Here's a pretty good explanation/demo: http://www.luminous-landscape.com/tu...fraction.shtml

[altabird92]

imo, the optimum f stop is 2-2.5 slower than max aperture

[Damon]

CMOR, the purple is amp noise/glow. I'm pretty sure there is no fix to it, and CCD sensors are more prone to it then others. Shoot wider then normal and crop in post.

What are the cats doin up? And your one of those badasses with a cabin on gold hills, I always loved that location.

[Crystal_Mt_Dreamin]

I love star trail shots, just not very good at them. No patience I guess.

Took this one in mex last summer


Here's one taken on film up at Yosemite a few years back. Terrible scan job, but there are actually star trails in the pic.

[squirrelmurphy]

that palm tree shot is fukkin awesome!

[cmor]

So I tried the interval idea, but when I combined them in both the startrails app and photoshop the foreground doesnt show up, any ideas? they also look a bit jaggedy, i wonder if thats from the combo process

almost 2hours at 30s intervals:

[Damon]

Take a single picture with the mountains exposed correctly - lay it over in post. The stars look awesome, I prefer the sky being black then city orange.

What ISO is that? It's weird that there is amp glow even at 30s.

[cmor]

There is a little amp glow in the upper corners, its at iso 100. As you can see in the first photo though the mountians should come out. And I took a test shot at 3200 iso for about a minute and the mountains showed up fine.

iso 3200:

[Eldo]

...when I combined them in both the startrails app and photoshop the foreground doesnt show up, any ideas?

That is the downside of the stacking solution, it only works for the stars and not subject matter in the frame that is in near darkness, since 30 seconds is not a long enough exposure.

Also, I think the jaggies are probably from very slight camera movement at the beginning and end of each exposure, which you would probably not even notice with a long exposure. But combine numerous exposures and you will see it along the entire star trail, as if the camera was jostled every 30 seconds. Using a very sturdy tripod and shooting with mirror lockup might help with that.

I hope everyone appreciates the fact you are standing outside for hours working out the kinks in this process for us.

[cmor]

That is the downside of the stacking solution, it only works for the stars and not subject matter in the frame that is in near darkness, since 30 seconds is not a long enough exposure.

Also, I think the jaggies are probably from very slight camera movement at the beginning and end of each exposure, which you would probably not even notice with a long exposure. But combine numerous exposures and you will see it along the entire star trail, as if the camera was jostled every 30 seconds. Using a very sturdy tripod and shooting with mirror lockup might help with that.

I hope everyone appreciates the fact you are standing outside for hours working out the kinks in this process for us.

I'll try mirror lockup, as for the sturdy tripod, well, for $20 you don't get much.

It was cloudy tonight, so I tried a shorter exposure at iso 3200, the nr reduction seemed to knock out most of the amp glow, im not sure why. I think a bit more pp might be able to bring this one out a bit.

[NashBoarder]

My first attempt at Star Trails. Kilimanjaro with a 1.5 hour exposure.

[4-TEEF]

Strong work CMOR. Bummer about the leakage in the corner. I hate to say it but it seems like that camera is not a real good match for long exposures.

[aepeak]

bump.

my first attempt at star trails. i realize the picture is awful. tips on how to shoot star trails please.

photo info:

shutter: 239.6
aperture: f/3.5
exposure: manual
focal length: 18 mm
iso speed: 800

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