Looking for ISO to be explained a little better... And Star Trails questions

[ceejtank]

First off, I did use the search button to look for this, after scanning the first 4 pages for the search ISO, and ISO explaination, I realized it was frivelous, because many people with list what ISO they shot the image with when looking for critiques.

Anyways. I've done some research and determined that I need a little bit more explanation than what I found on here/ in some other places. (What Is... ISO - Digital Photography Tutorial - Photoxels) and some similar sites. Pretty much what I've determined from research is use as low a ISO as possible to get the least grainy, properly exposed picture.

Now my question is this, for night shots, or star trails, should I set the ISO low? In the manual I have for my camera (Canon EOS rebel, which is the EOS 1000D) it says use 1600 for night settings. But I am also assuming they are talking about if you are taking "normal" (i.e. no star trails) shot. Just a snapshot in a manner of speaking.

I am interested in taking a star trail shot, however I am not sure how long I can keep the lens open without everything becoming a "white out". If it is a dark night, I don't think it would be an issue. But are most star trail shots (especially ones that make more of a "full revolution" - note, this is not my picture, but was from google image search) composites of bursts of 10 minutes or so merged onto one picture to obtain that result?

Any advice on settings from people who have taken star trail shots?

Thanks!

 

[KmH]

http://www.thephotoforum.com/forum/search.php?searchid=656174

How to photograph star trails - Bing

Google

Ask.com - What's Your Question?

 

[ceejtank]

http://www.thephotoforum.com/forum/search.php?searchid=656174

How to photograph star trails - Bing

Google

Ask.com - What's Your Question?

Your link to the photoforum says "Sorry - no matches. Please try some different terms.
"

Thank you for your links.

 

[HomelessBoy]

Yes, I haven't done star trail shots but it's the same for all long exposure shots. Keep the ISO to the lowest. Take a few test shots before starting to shoot.

To get the star looking like they are flying in circles, you will have to keep the shutter open at least for over 1 hour. (According to what I know) It is recommended that you bring a tripod and a shutter remote control so you don't have to press the shutter for all that time and more importantly, there will be no handshake ruining the picture.

 

[analog.universe]

Star trails that show really long arcs are usually a bunch of images stacked together. The stars rotate at 15 degrees per hour, so you can see how often hours of exposure are necessary. These hours are usually the sum of many shorter exposures as you may've guessed.

And ISO is boosted when your desired shutter speed and aperture are not getting you enough light. I haven't tried it myself, but I would think that base ISO at a reasonable aperture will be fine for trails, since the shutter is open for so long. If you find your stars aren't bright enough, then up the ISO. I'd avoid boosting the ISO if possible however, go as far as you can with aperture. High ISO noise is especially prevalent in long exposures with dark backgrounds.

 

[889Media]

Another tip is that when taking test shots to set your composition, boost your ISO way up high. Noise is not something you need to worry about, as you will not use these test shots for anything else than to see how your composition looks. This will let you use faster shutter speeds, and save you a lot of time. Also - turn of the in camera noise reduction and use software to get rid of noise in your final shot. If you leave it on, your camera will use 10 minutes to work on your picture after a 10 minute exposure. Is you are to take more than one shot to merge later, this time will have you miss important minutes between your shots

 

[KmH]

http://www.thephotoforum.com/forum/search.php?searchid=656174

How to photograph star trails - Bing

Google

Ask.com - What's Your Question?

Your link to the photoforum says "Sorry - no matches. Please try some different terms.
"

I was asking for people here's input.

It's ok if you don't want to answer. I guess we should point all users to google when any question is asked. Thanks for your incredibly valuable input to the beginners forum KmH, I don't think I could have gotten a better answer anywhere else. :thumbup:

It doesn't do that when I click on it. At any rate I searched TPF 'thread titles only', and used the search term 'How to photograph star trails.'

 

[ceejtank]

http://www.thephotoforum.com/forum/search.php?searchid=656174

How to photograph star trails - Bing

Google

Ask.com - What's Your Question?

Your link to the photoforum says "Sorry - no matches. Please try some different terms.
"

I was asking for people here's input.

It's ok if you don't want to answer. I guess we should point all users to google when any question is asked. Thanks for your incredibly valuable input to the beginners forum KmH, I don't think I could have gotten a better answer anywhere else. :thumbup:

It doesn't do that when I click on it. At any rate i search TPF thread titles only, and used the search term 'How to photograph star trails.

I did the searches for you. All you have to do is click on any of the links that look attractive to you.

Those links I provided will give you exactly what you want, other peoples input.

I have tried to help you learn how to use a search engine, and how to be more proactive.

I'm truely regret my efforts were to no avail.

Hey, I think you're mis-reading my statement. I thanked you and even clicked the "like" button on your reply. I will re-word it.

 

[KmH]

I am so sorry, I apologise, and I have deleted that portion of my response.
I mistakenly took your response as sarcasm.

 

[ceejtank]

I am so sorry, I apologise, and I have deleted my response.
I mistakenly took your response as sarcasm.

I re-read it.. it did sound sarcastic. Wasn't my intent. I erased it and just put thanks. It was my bad too.

 

[Derrel]

ISO...means "in search of". For example, let's say there's a personal ad that reads: "SWMN ISO compatible SWFN with large lens collection, extra SB's a plus. Must be digital, capable of hosting photos."

So, translated that means Single White Male Nikon-shooter 'In Search Of compatible Single White Female Nikon-shooter with a large "lens collection" [colloquialism for big bustline], extra SB flash units a plus, and must have one's own web hosting area, and not be some digital newbie who has no idea how to upload pics or to transfer via FTP...

So, that's what ISO means....oh, wait.wait a second, nevermind. Sorry.