topic SX50 - setting for taking star pixs? in Point & Shoot Digital Cameras

SX50 - setting for taking star pixs?

ladebug79 — Wed, 14 Aug 2013 06:11:47 GMT

I've played with the Tv, Av and Manual settings. How can i take pixs of the Milky Way? I have amazing pixs of the moon, but can't seem to find the right mixture of settings for stars. Specifically, time lapse to capture the stars. Thanks.

Re: SX50 - setting for taking star pixs?

hsbn — Wed, 14 Aug 2013 20:15:23 GMT

It will be noisy but do-able without any extra gears. In short, try to set it for ISO3200 or ISO6400, with widest aperture and widest zoom and shutter speed for 25sec. You will need a dark sky.
A long answer, in order to capture stars as dots or milky way, you'll need the shutter speed that is faster than 600/focal length (in your case, widest zoom on your camera is 24mm; so 600/24 =25 second). Since you cannot do a lot with the shutter speed, you'll have to change Aperture and ISO in order to maintain the overall exposure. So you can start with ISO3200 and go to ISO6400 and see how it goes. But normally, if you have a dark sky, 25sec exposure at F2.8 and ISO3200 will give you a nice exposure of the milky way.

Here my shot over the weekend with the setting I just gave you.

Re: SX50 - setting for taking star pixs?

TCampbell — Thu, 15 Aug 2013 04:11:16 GMT

You'll need to consider a few factors:

1) urban light pollution reflects off dust particles and creates an astonishing level of background glare which washes out stars and reduces your ability to see the milky way at all (or if you can see it, you might not be able to make out any distinctive structure in the milky way). Finding a good "dark sky" location will help (and if you live in or near a city or suburb, this can mean driving for hours to find a dark sky location.) You can do a Google search with terms like "dark sky map north america" to help find suitable locations -- just be warned, these are getting VERY hard to find these days.

2) The Earth is spinning ... faster than you might guess. As we spin from west to east it creates the illusion that the stars are moving from east to west. The focal length of your lens establishes an "angle of view" (i.e. the area of the sky that you can see). The narrower that angle of view (e.g. the longer the focal length of the lens) the faster the stars will appear to be moving relative to your image size. This means you want the WIDEST POSSIBLE angle (lowest possible focal length).

3) I take my images of the night sky using a full frame DSLR and a 14mm ultra-side angle lens. This gives me an "angular" field of view which is 104 degrees wide and 81 degrees tall. At that angle, I've noticed that if my camera is stationary on a tripod, I can take an exposure for about 45 seconds before stars beging to become elongated because of their motion as they move across the sky (more accurately as OUR EARTH moves while trying to view them.) If I set the exposure for 60 seconds, I can then start to see the stars beginning to elongate (they start to form "star trails").

With YOUR camera, the 35mm "equivalent" focal length at it's widest angle is equal to about 24mm. That gives you an area of the sky which is approximately 73 degrees wide by 53 degrees high. At that focal length you will likely find that the max exposure time you can take before the stars begin to appear elongated is in the neighborhood of 25 to 30 seconds.

The site I use to calculate the angular field of view is: http://www.tawbaware.com/maxlyons/calc.htm

Re: SX50 - setting for taking star pixs?

tnicoson — Thu, 15 Aug 2013 22:36:49 GMT

After reading hsbn's post, I removed my somewhat pessemistic initial reply, but I still think she is not going to have much luck at this with the camera she has. She is using a PowerShot SX50HS. I do not believe is has a "B" (Bulb) time exposure mode, so she is going to be limited to a max exposure time of 15 seconds with a max aperature of f3.4. Even if she can figure out a way to extend the exposure time, with that aperature, she is almost 2/3 of a full stop down from the recommended f2.8, which may put her well beyond the recommended 25 second max exposure time to avoid star trails. With the an exposure time limit of 15 seconds, it's probably not even worth the effort, but if she can find a way around that, it would probably be worth a try though.

hsbn:

Would be interested to know what equipment you were using.

Regards,

Ted

Re: SX50 - setting for taking star pixs?

tnicoson — Thu, 15 Aug 2013 23:28:59 GMT

Ohhhh ! Wow !

I just found a statement on Page 150 of the SX50 User Guide that for shutter speeds slower than 1.3 seconds, the ISO is automatically reduced to 80 and "can not be changed". I checked this out on my SX40, and it drops ISO to 100 at 1 second, and it applies to both Shutter Priority (Tv) and Manual Modes. From other statements regarding these settings, I gather that the noise ruduction algorithm can not handle the noise at long exposures with high ISO settings, so I guess that makes this entire discussion a wash - for the SX40/50 anyway.

Sorry, ladebug !

Regards,

Ted

Re: SX50 - setting for taking star pixs?

ladebug79 — Fri, 16 Aug 2013 00:14:24 GMT

I live in Pahrump, NV by Death Valley. Amazing stars (no noise polution) and very clear Milky Way. A guest **bleep** a pix with about 10-15 second exposure time (digital camera) of us sitting on the deck with stars galore all around us. You could see us and the stars as it were daylight almost. He had a little camera (no super lenses) and propped the camera on a chair...so I figured my Canyon could do the same, if I could get the shutter to stay open for 10-15 seconds.

Here are my moon pictures:

https://www.facebook.com/media/set/?set=a.10200667897635067.1073741835.1089524853&type=1&l=b5dd42e34d

Thanks for all the suggestions. I'll keep trying. Any and all suggestions are welcome. Is this something that could be 'adjusted' with a software change? ~k

Re: SX50 - setting for taking star pixs?

tnicoson — Fri, 16 Aug 2013 03:01:39 GMT

ladebug

Tim was talking about LIGHT polution, but I don't think you need to worry too much about that where you are at. The NOISE we were talking about is "digital" noise generated by the electrons in the camera's own image sensor during very low light conditions. It is sort of equivalent to the "snow" on an old analog TV without an antenna. This noise becomes more prevalent as the camera's image sensor sensitivity setting (ISO) is increased. It shows up in the finished image as a graininess. Most digital cameras have some type of post exposure processing that reduces this noise, and that is where the problem comes in with the SX50. I have the same problem with my SX40. Apparently your friend had a camera with a more generic noise reduction "algorithm" that allowed a long exposure with a high image sensor ISO sensitivity. The Canon SX40/50 cameras have a very sophisticated noise reduction algorithm that can become overloaded at the extremes of ISO sensitivity combined with long exposure times. The camera automatically reduces the ISO sensitivity to minimum (80) when you set the shutter speed to longer than 1.3 seconds. In MANUAL or Tv mode, you can set the shutter speed to 15 seconds, but at ISO 80, I don't think you will get much. Yes ! Canon could change this by modifying the camera's firmware, but I doubt very much that they would, as this would allow the noise reduction algorithm to lock-up the camera in the extremes.

Regards,

Ted

Re: SX50 - setting for taking star pixs?

rockyraybell — Sat, 04 Apr 2015 00:08:41 GMT

Yes you can, but you'll need a hack to override the camera iso and shutter speed limits. Google CHDK

In some ways the 40 was better for night shots, but you can do it with the 50. Look for users on flickr that use the 50. I've taken shots of aurora's and meteors with both the 40 and 50. Better off with a better camera, but it will work. Unless there's a moon figure 1600 or 3200 and limit it to 25 seconds, 20 and less is better for sharpness. Start zooming in and it changes everything.

Re: SX50 - setting for taking star pixs?

Shineman — Sat, 13 Aug 2016 05:25:21 GMT

The pronlem is is that the SX50 HS has no bulb or way of setting time exposure, so I don't know what mode to shoot in: Manual, AV or Program? I have tried nut am still having limited success. Am I missing somthing? Please clarify...

Re: SX50 - setting for taking star pixs?

rockyraybell — Sat, 13 Aug 2016 07:01:56 GMT

With CHDK you menu into a settings window for setting exposure, and pretty much everything else. For instance you can run your iso higher than 100 when exceeding 1 sec. You can run whatever you want. But... I would save it for cool temps. You can toast the sensor when running at a high iso and long exposure. Doesn't mean it will happen, but it can. I have a sx60, there is no hack available for it. I would rather have a 40 or a 50 than the 60 with the extra zoom. It's a lousy night camera, but ok during the day. I've got some night shots, aurora's, etc., on flickr at https://www.flickr.com/photos/rockyraybell/

Have shots with all three cameras there. I probably won't do anymore night stuff until I can get a dslr. One second just doesn't cut it.

Re: SX50 - setting for taking star pixs?

Shineman — Sat, 13 Aug 2016 15:02:15 GMT

Ok, thank you so much. I will run CHDK and see what I can do!

Re: SX50 - setting for taking star pixs?

Browneyedgranny — Tue, 04 Aug 2020 19:19:51 GMT

I have this safe camera and it only goes from 1/2000- 15 sec. with aperture ranges 3.5-8 and the iso can be set at 80-6400. And one tip, I just discovered. If you have the DR correction on, the iso only guess to 1,600. I knew my camera went to 6400 she finally discovered why it wasn't.

Re: SX50 - setting for taking star pixs?

Browneyedgranny — Tue, 04 Aug 2020 19:31:51 GMT

Yes. True. I've tried and was wondering what was happening. Then I watched when I tried changing the exposure time the iso changes from my set 6400 down to 80 when I get to more than 1 sec. That's aggravating. If it's a manual setting why isn't it letting that be changed.

Re: SX50 - setting for taking star pixs?

rockyraybell — Tue, 04 Aug 2020 21:33:15 GMT

It's not made for it. That said I used the 40, 50, and 60 for night shots. There's a hack for doing it and it works fairly well but eventually you'll toast the sensor. That is why I had all three. The 50 was the better one for me. I've got a dslr now, but wish I still had a working 50 or 60 for some stuff. You can find the hack by googling chdk. Lot of info out there on it. The hack is put on the sd card, the card made bootable and away you go. Gets around the ISO issue so you can run high ISO's for long exposures. I've got stuff on flickr you can look at to get an idea of what you can do. You may find focus can be a real pain from what I remember. Also, there's something called the 400, 500, and 600 rule for avoiding star streak. Divide one of those by the focal length and it will give you an about how long you can expose without the streak. A 50 mm would be about 8 seconds. Wide open landscape on the 50sx would be 20 seconds or less, though that varies a bit depending on what part of the sky you're shooting because the speed of rotation is slower as you move towards the poles. Like a merry go round. I've got some stuff on Flickr from all three camera's of night stuff. Rocky Raybell