Photographing lights - eliminate stars

Started Aug 6, 2011 | Discussions
Martin Kristiansen
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Photographing lights - eliminate stars
Aug 6, 2011

How do I avoid the star effect on the lights in my images? (see 2 examples below)

One of my clients (a lighting architect company) are obviously not interested in showing their light work with stars. When I take night images I always seem to get this effect which takes a LONG time in post processing.

Any suggestions to how I can eliminate this effect?

I shoot with the Canon 5D MKII using various lenses from Canon
50mm 1.2
24-70mm L
16-35mm L

I have tried to remove the UV filter I have on the lenses, but i does not make a difference.

I hope someone have a good suggestion to avoid this effect, also if you have a good suggestion to remove the effect easily it will be highly appreciated

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Joergen Geerds
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Re: Photographing lights - eliminate stars
In reply to Martin Kristiansen, Aug 6, 2011

Martin Kristiansen wrote:

How do I avoid the star effect on the lights in my images? (see 2 examples below)

One of my clients (a lighting architect company) are obviously not interested in showing their light work with stars. When I take night images I always seem to get this effect which takes a LONG time in post processing.

The star rendering is specific to each lens, and as far as I know depends on the number of blades in the diaphragm, and the shape of the blades.

It is pretty much a trial and error, since the effect also depends on the f-stop, or in other words how much of the blades are in the light path.
Have a look at my lens flare comparison I did a while ago:
http://newyorkpanorama.com/2009/12/24/lens-flare-comparison-canon-zeiss-olympus/

The wider open the lens, the less stars you get (on average)... the most extreme example is the tamron in this test (I've abandoned the lens years ago). the worst stars I've ever seen was with the sigma 100-300 f4: everything at night looked like Christmas, everything had large 18 point large stars... awful, great lens during the day, absolutely unusable at night.

Any suggestions to how I can eliminate this effect?

do a composite shot. the first with your working f-stop and careful attention to the focus plane and dof), then another one wide open (focus plane exactly on the light source and compensating the exposure time), layer them in photoshop (align if necessary, especially when you changed focus between the two or more shots) and mask or auto blend.

alternatively, it may also help to treat the photo like a partial panorama, and stitch multiple images rotated around the no-parallax point together, since the stars also turn depending on the entry angle.

let us know how it went.

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ScottyNV
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the CORRECT answer: shoot with the aperture wide open.
In reply to Martin Kristiansen, Aug 7, 2011

ALL lenses will create the stars when stopped down, and the smaller the aperture, the more defined the stars.

the number of rays depends on the number of blades in the aperture of the lens.

unfortunately, there is no easy way to eliminate them, save shooting wide open, but then you may not get the depth of field you want.

S.
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Martin Kristiansen
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Re: Photographing lights - eliminate stars
In reply to Martin Kristiansen, Aug 7, 2011

Thanks guys for the answers - I will shoot multiple images from low to high aperture and merge in Photoshop - I assume that this way should get both the depth of field and eliminate the stars.

Thanks again
Martin

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geoffire
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Re: Photographing lights - eliminate stars
In reply to Martin Kristiansen, Aug 7, 2011

Stars move quicker than it seems. If you take at least three images a few minutes apart and do a median stack in Photoshop you'll get a cleaner image and remove those unwanted stars. Note, pointing towards the poles will need more time between shots, and the north star (Polaris) never moves. Six images works pretty well for noise reduction and effective moving object removal.

http://help.adobe.com/en_US/Photoshop/11.0/WSA1E7602F-1D34-4ecf-B2FE-2BB344D6937Ca.html

As for aperture, chose whichever gives you the best effect your looking for on those lights. Smaller apertures give a more 'sunstar' look, and the number of blades in your lens affects how many points the star has.

edit: I thought you were talking about real stars...

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Ron Kruger
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Re: Photographing lights - eliminate stars
In reply to geoffire, Aug 7, 2011

I'm currently testing the Zerene Stacker and find it much easier to use with better results than Photoshop. You'll have to use some long exposures, but I'd try shooting multiple images at f-2.8 and progressive focus points, then stack them all. (Might work best with a prime lens.) You'll actually get much better DOF and better detail with this as well.
You can download a free trial of Zerene to try this.
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John
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Re: Photographing lights - eliminate stars
In reply to Martin Kristiansen, Aug 8, 2011

One question....Why are you shooting at such a small aperature and long shutter speed? I assume these are just test shots you are showing. Try shooting at 4-5.6f

with shorter shutter speed. I doubt there will be much loss in depth of field (if that is even important)
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Martin Kristiansen
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Re: Photographing lights - eliminate stars
In reply to Martin Kristiansen, Aug 11, 2011

Hi all

Thanks for the answers/suggestions, I really look forward to test it. I am fortunate to live in Denmark where it has rained pretty much non stop since I posted this so I have yet to test the methods.

Martin
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John Adler
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Remove the star filter
In reply to Martin Kristiansen, Aug 11, 2011

Thank you, thank you, I'm here all week. Please tip your waiters.

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Roger Krueger
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Shoot wide open.
In reply to Martin Kristiansen, Aug 15, 2011

Shoot wide open. Quality slow primes are good for this, like say the Contax 35/2.8.

Slow zooms will fix the stars, but most are horrid wide open.

Or stack, you don't need an elaborate stack, just one wide-open frame masked "hide all" over a stopped down frame, paint in the mask over the starry bits until they go away.

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Boomanbb
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Eliminate the stars with focus stacking techniques
In reply to Martin Kristiansen, Aug 16, 2011

Shoot wide open and adjust focus from near to infinity. Then use a technique like this. http://www.tawbaware.com/tufusepro.htm

Ben

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mironv
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Re: Eliminate the stars with focus stacking techniques
In reply to Boomanbb, Aug 17, 2011
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To avoid this optical fenomen you need to use lenses with a Nocto in a name Nikon makes one Leica and maybe some other I don't know. What thay have is special optical sferical elemant eliminating coma and they minimaized this start effect. They expencive but only way to do so.
Mironv
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Bill MacBeth
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Re: Photographing lights - eliminate stars
In reply to Martin Kristiansen, Aug 17, 2011

You just can't make all of them happy all of the time.

Last week I had a professional photographer ask me if I knew of a Photoshop plug-in that would add 'stars' around lights.

Regards, Bill

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