first star pic oh dear

iwols

iwols

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hi all took some star pics tonight need help please

star2 by iwols, on Flickr

star by iwols, on Flickr
god these are bad,struggled with focus and funny tinge to pics
 
tinge is light pollution exacerbated by the long exposure. The blur is either camera shake or poor focusing I reckon.
Exif helps too if you want replies.
from flickr
Exif data
Camera Nikon D90
Exposure 15.6
Aperture f/4.5
Focal Length 18 mm
Focal Length 18.3 mm
ISO Speed 1600
Exposure Bias +8/3 EV
 
Thanks can I minimise the light pollution and I used a tripod with a cable release,I struggled with the focus side to be honest
 
Cameras sensors pick up light pollution very easily, but the photos show a lot for a 15 second exposure. Were they taken in a light polluted area?

The shots look unfocused, rather than suffering from camera shake. Did you use autofocus and if so what did you focus on? Auto focus system will struggle trying to focus on stars.

Try auto focussing on something distant on the horizon then switch to manual focus so the focus setting does not change or,
manually focus on something distant on the horizon, or
set the focus on the lens to infinity.

Why is there a large +ve exposure compensation? That could have boosted the effect of the light pollution.

Dave
 
The light pollution will be less on some nights, with cleaner air.
Agree main problem is not in focus.
Keep trying, the camera is clearly capable of resolving the stars.
 
You've missed focus, just need to get better on that front, that comes with practice :thumbs: as to the light pollution you can balance most of it out with a customer white balance in the 2-3000k range :thumbs:

Matt
MWHCVT
 
For focus (as I don't have live view) I focus on a distant light or something similar then switch to manual, and am careful not to change any lens settings (focal length or knock the focus). Not ideal but it does work of you're careful, live view would be a better bet if it can boost the exposure enough.

As for the orange, a Tungsten WB will get rid of a lot of it but shoot raw and then you can try get rid of some more later. I live next to the M25 so know all about light polution.

I'd also go for a longer exposure something around the 25-30s area.
 
Tringa said:
Cameras sensors pick up light pollution very easily, but the photos show a lot for a 15 second exposure. Were they taken in a light polluted area?

The shots look unfocused, rather than suffering from camera shake. Did you use autofocus and if so what did you focus on? Auto focus system will struggle trying to focus on stars.

Try auto focussing on something distant on the horizon then switch to manual focus so the focus setting does not change or,
manually focus on something distant on the horizon, or
set the focus on the lens to infinity.

Why is there a large +ve exposure compensation? That could have boosted the effect of the light pollution.

Dave[/QUOTE
Thanks guys like I said,really struggled to focus on anything even on live view,where would the 8.3 exposure bias come from,thought it would be 0 unless altered,any more comments appreciated guys
Click to expand...
 
Ploddles said:
Could you not just set the focus to 'infinity'?
Click to expand...
You'd probably get away with it if lens stopped down, but the infinity symbol on the lens is only a guide.
Lenses usually go just past infinity - sounds quite alarming - but I guess the exact infinity focus point varies with different cameras so the marked point is like an average.
 
as said shoot raw and use tungsten white balance to minimise it, then correct it completely when you process the raw later.

Focus, use manual focus, use live view, centre a bright star or constellation, then use the zoom function of live view to zoom in, focus, take a 10 second test shot, check it and adjust if needed.
I cant see any camera shake in those images, just de-focused stars, nice and round too so your not getting much "trailing".

Keep going, your on the right track and once you've nailed the focusing and post processing to adjust the white balance you'll have some nice images.
 
does anyone know where the Exposure Bias +8/3 EV came from as i didnt alter anything cheers
 
Cheers for posting your picture. I tried to do one and finished with a similar image to yourself. The picture looked very orange. Great to see a solution posted!

thanks
 
The large +ve exposure compensation is probably due to you pressing the exp.comp button by accident. Just check the LCD screen as it shows the compensation and reset it to zero.

Dave
 
im going to scottland next week, i've been before and remember the sky to be very clear at night, will i still get the orange tinge? Im going to a cottage next to glenborrodale :S
 
hi guys not the finished articel but better,any suggestions appreciated,how many stars are there:)

stars3 by iwols, on Flickr

exif data

Make NIKON CORPORATION Model NIKON D90
ExifOffset 214
ExposureTime 26
FNumber 4.5
ExposureProgram Manual
ISOSpeedRatings 1600
ShutterSpeedValue -4.70044 (26.00 s)
ApertureValue 4.33985 (F4.5)
ExposureBiasValue +0.7
MaxApertureValue 4.3 (F4.4)
MeteringMode Spot
LightSource Unknown
Flash Not fired
FocalLength 55
ExposureMode Manual exposure
WhiteBalance Auto white balance
 
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You've zoomed in a lot more than the 1st shot which has lead to some streaking. Rough rule of thumb I picked up was to keep the shutter speed faster than 600/focal length seconds (eg 600/18mm = 33.3s but 600/55 = 10.9s). If you break this you get the streaking you can see here caused by the earth's rotation. If you want/need to use a longer speed then you need to start looking at devices that move the lens to account for the earth's movement.
 
maninsuitcase said:
You've zoomed in a lot more than the 1st shot which has lead to some streaking. Rough rule of thumb I picked up was to keep the shutter speed faster than 600/focal length seconds (eg 600/18mm = 33.3s but 600/55 = 10.9s). If you break this you get the streaking you can see here caused by the earth's rotation. If you want/need to use a longer speed then you need to start looking at devices that move the lens to account for the earth's movement.
Click to expand...

Yes Chris I did zoom in a bit more just so I could see a star to focus on,even with live view and zooming in i could not see a star to focus on ,on the screen it was just plain black
 
iwols said:
Yes Chris I did zoom in a bit more just so I could see a star to focus on,even with live view and zooming in i could not see a star to focus on ,on the screen it was just plain black
Click to expand...

You need to find a brighter star then :naughty:

In all seriousness, use live view and zoom in, then manually adjust to focus. If the stars are out it should be dark enough to see them in live view, by manually focusing and looking at the screen you should see stars.

Keep at it, you are getting better results. :thumbs:
 
Dexy101 said:
You need to find a brighter star then :naughty:

In all seriousness, use live view and zoom in, then manually adjust to focus. If the stars are out it should be dark enough to see them in live view, by manually focusing and looking at the screen you should see stars.

Keep at it, you are getting better results. :thumbs:
Click to expand...

thanks just need to see some clear sky through the rain here in yorkshire
 
Its not pretty up here either at the moment, looking forward to the long cold dark nights and clear skies again back home for some decent skies.
 
Your first shot was out of focus and looks like it was a bit cloudy (or could be reflections), your 2nd one looks in focus but there is a bit of star trail but at least they are getting better.

I use the (optical) viewfinder to manually focus and frame roughly, then switch to liveview to do final focus (zoomed in of course). I assume your D90 can zoom during liveview, not sure being a Canon user myself? Choose a bright star to focus on, makes life a lot easier.

Also if you have got a lens hood, use it, it will help to reduce reflections and flare from stupid street lights. Oh and also remove any filters on the lens if one is fitted.

Once you are sorted in a light polluted area, you can take your kit with you if you go to a dark site and get some cracking shots.

Learn to find Polaris (North Star) and point your camera towards it if you want to make concentric star trails.
 
SLRUser said:
Your first shot was out of focus and looks like it was a bit cloudy (or could be reflections), your 2nd one looks in focus but there is a bit of star trail but at least they are getting better.

I use the (optical) viewfinder to manually focus and frame roughly, then switch to liveview to do final focus (zoomed in of course). I assume your D90 can zoom during liveview, not sure being a Canon user myself? Choose a bright star to focus on, makes life a lot easier.

Also if you have got a lens hood, use it, it will help to reduce reflections and flare from stupid street lights. Oh and also remove any filters on the lens if one is fitted.

Once you are sorted in a light polluted area, you can take your kit with you if you go to a dark site and get some cracking shots.

thanks for the great advice as usual guys

Learn to find Polaris (North Star) and point your camera towards it if you want to make concentric star trails.
Click to expand...
 
Very nice shot, I like the centralised point on the north star... takes a bit of time for all those 350'odd shots - did you do them manually or did you have an automated trigger?
 
ive also bought the same for the nikon nice piece of kit for the price once i work out how to use it properly
 
groovyf said:
Thanks :)
I had an automated trigger attached for this. One of these: http://www.ebay.co.uk/itm/Timer-Rem...=Camera_Camcorder_Remotes&hash=item3f0c9a1f04

I had to spend a little time getting used to how to best set the remote timer, (instructions weren't the best... but as it came from China I wasn't expecting the best english translation...)
Click to expand...

I just put it on continuous burst and hold down the shutter with a pebble and a rubber band. Less chance of gaps, but the band has pinged off a few times. A locking remote would be better, but it doesn't need to be a timer one.
 
maninsuitcase said:
I just put it on continuous burst and hold down the shutter with a pebble and a rubber band. Less chance of gaps, but the band has pinged off a few times. A locking remote would be better, but it doesn't need to be a timer one.
Click to expand...
^^ liking the ghetto-technique!

iwols - look forward to seeing your achievements with the automated trigger.
 
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This is one of mine

Dark Forest by 42zx, on Flickr

Using infinity focus and being far enough away from light pollution are important things to get right with these kind of shots.

On most lenses infinity focus (if not marked) is all the way to the end of the focus ring then back a little bit, try focusing all the way both ways until you get it.

Above was taken about 10 miles from town in the dead of winter, also found a place surrounded by hills to help block the light pollution.

25 Seconds, ISO 3200, f/3.5.
 
42zx said:
This is one of mine

Dark Forest by 42zx, on Flickr

Using infinity focus and being far enough away from light pollution are important things to get right with these kind of shots.

On most lenses infinity focus (if not marked) is all the way to the end of the focus ring then back a little bit, try focusing all the way both ways until you get it.

Above was taken about 10 miles from town in the dead of winter, also found a place surrounded by hills to help block the light pollution.
thanks for that and sharing that great pic,still finding live view a pain on my d90 even on a bright star,and magnified on the screen just doesnt seem to show the star,still using the view finder for focus cheers
25 Seconds, ISO 3200, f/3.5.
Click to expand...
 
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