How to stop starburst when shooting at night...

GadgetRick

Ok, sometimes a starburst looks cool when shooting buildings/bridges/etc at night, however, I'd like to figure out how to shoot at night and not get starbursts.

Here's a shot I took recently. This is not HDR, just one shot. Shot with my Canon 50D and 28-70mm f2.8L. Notice the lights:



As you can see, I'm getting starbursts there.

Now, I've been playing with HDR and shot a few shots last week. Combined the images and this is what I got for one of the shots:



VERY pronounced starbursts here (not happy with my HDR attempts as it seems the images aren't combining cleanly and I'm getting a bit of blur--look at the moon and the buildings in the background--but that's for another discussion). These are too much for my liking but I don't know how to get rid of them.

Any ideas?

Qarik

I don't know for sure but try opening up the aperture. The burst I think is due to the aperture blades. The less they are "in the way" the less pronounced the bursting should be.

pathfinder

Stars are not a defect, but a "feature"

Shooting with a larger aperture may help.

Are you shooting with a filter over the lens?

zoomer

Something that far away you could shoot at F5.6ish. If you are shooting it at f18ish that will give you starbursts.....as already mentioned.

divmedic4

Without hijacking the thread, I am just curious if the second shot is of the Clemente Bridge in Pittsburgh?

GadgetRick

Ah, been shooting at smaller apertures, guess that's it.

I don't use filters, that wouldn't have an affect on the starbursts from what I can tell.

And yes, that's the Clemente bridge.

Thanks a bunch guys!

Art Scott

by reading the exif on the blue bridge it was shot at f7.1 .... that is kinda large for the bursts to be happening isn't it?? the second shot was shot at f16 and that sure account for the starbursts........but the Blue Bridge really shouldn't be bursting at f7.1 .........Are these the correct apertures for these images?? I am hoping my Friedl plug in is not giving junk info.

pathfinder

Art I generally think of starburst occurring with f11-13 or smaller also.

But I also find that after dark, bright specular lights tend to star at times, and I think it is more common with lesser lenses. The Canon 24-70 L is a very good lens, though, so I am not sure why f7.1 should be doing this either. That was why I was asking about a filter.

I read the exif data in image #1 in CS4 at f7.1 also, so I think your software is working Art.

GadgetRick

Yes, the blue bridge was shot at f7.1. Hmm, I had thought I shot it at a smaller aperture. Now I'm really confused as to why I'm getting them (at least on that shot--got it on others from the same evening at the same aperture, btw).

GadgetRick

Anyone else have ideas on this one?

GadgetRick

Beuhler....

GadgetRick

Anyone?

Qarik

perhaps 7.1 wasn't open enough. try some test shot sof any light source at 2.8, 4, 5.6, etc and watch the evolution

David_S85

Agree with the others to set the lens at a more open aperture.

Some lenses do the burst thing at even lower settings. Bursts are more a property of the type of aperture design, and other design qualities of a model of lens. For example, I, for the life of me, can't get my 70-200 L IS f/4 to do quality bursts at any aperture setting under most any lighting situation. But some of my other lenses seem to do bursts at a wide range of settings. YBMV (your bursts may vary). The older 14-24 Nikon G seems to be one of the better producers of bursts, from what I've seen (I don't own one - sure wish I did).

Later lens design schemes focus on more iris petals with rounded edges to curb the busting. I, for one, prefer star busts in my shots.

pathfinder

I said starbursts are not a defect, but a feature!:D

I shot Cinncinnatti in 2005 with a 24-70 f2.8 L, the same lens you are using. I think the humid river air may be a contributing factor also.

Here is the river front in Cinncinnatti shot at f10 - note the starbursts on the bridge with a 24-70 L.



Here is another shot with the same lens that weekend at f9, without nearly the same starburst. But the lights are much closer and larger than the lights in the first image. I think distance and brightness is another factor.



Here is an image shot at f5.6 with a Canon 24mm T&S - lots of stars, but no starbursts. Note also the air in the desert was much, much less humid.



But here is a Canon 15 mm fisheye at f16 in the desert, that does not starburst stars, but definitely does the moon

GadgetRick

Going to have to play around some more. Starbursts are cool but I don't want them all of the time. I'm hesitant to go larger than f7.1 but I guess I don't have a choice.

Many people comment they like them (starbursts) but I just don't want them in EVERY shot.

Thanks for the suggestions. Have to get out and play once this storm passes...

ThatCanonGuy

The lens he's using is the 28-70L. It's the precursor of the 24-70L, and the successor to the 28-80 2.8-4L. This may have something to do with it.

Pop1

In theory...
Just a thought: try a polarizing filter on your lens. It should reduce, if not eliminate, the starburst (in theory).

GadgetRick

Pop1 wrote: »

Just a thought: try a polarizing filter on your lens. It should reduce, if not eliminate, the starburst (in theory).

Unfortunately, a polarizing filter won't help this due to what causes it--the size of the aperture and the number of blades the lens has. I had thought about that and looked into it.

ziggy53

A tilt-shift lens might allow a wide-open aperture while retaining more of the scene in sharp focus.

Curved-blade diaphragms will exhibit shorter "stars" than straight-bladed diaphragms. (I see David already mentioned it so I'm just reiterating.)

Even numbered diaphragm blades will exhibit the same number of star points as blades. Odd numbered diaphragm blades will have twice the number star points as blades. Even numbered diaphragm blades star points may be more pronounced than odd numbered diaphragm blades star points.

You could also switch to a view-camera and use lenses with Waterhouse stops. (Waterhouse stops are simply circular diaphragms which are changed out in order to change effective apertures. Since they are circular at all available apertures they should not induce star patterns for specular highlights.) The view camera will also have full tilts and swings available for both perspective and additional DOF controls.