Lights or highlights in photos as stars?

Discussion in 'Beginner Questions' started by Ricochetrider, Nov 3, 2020.

  1. Hi folks,

    Wondering if there is a hard & fast rule for having lights or highlights in photos come out as mini starbursts, such as seen in the following 2 photos. Any combination of settings, settings + hardware (lens?) or is this purely random? Clearly it is possible in daylight and night light.

    I recently shot a pile of film and on at least one shot there were sunspots that IMO were super unsightly & more than a little annoying (see final image).

    As often as not, I'm shooting out doors so I have to make do with whatever light is happening. If there is a way to consistently turn these photo killing "light blob" highlights into happy little mini starbursts, I'd sure like to know.

    Thanks in advance & have a lovely day.

    [​IMG]

    [​IMG]

    [​IMG]
     
    mikemorrell and rosecook like this.
  2. Tony Parsons

    Tony Parsons Norfolk and Good

    Is a 'Starburst filter' what you seek ?
     
  3. SCL

    SCL

    "Stars", a version of flare, come about by the diaphragm blade shape influence distorting light passing thru the lens. Rounded blades typically produce round "blobs" and as they approach straight lines the "blobs" take on a shape mirroring the number of blades...similar for the arms of the stars. The more you close down the diaphragm, generally the greater propensity for "stars". My understanding is that higher end lens manufacturers try to reduce this effect by reducing the number of lens surfaces which contribute to flare or by using more effective coatings to improve light transmission, or even by using a lens shade and not shooting directly into a strong light source.,
     
  4.  
  5. Lenses with an even number of blades produce stars with the same number of rays as the number of aperture blades; for lenses with an odd number of aperture blades, the number of rays in the star is double the number of aperture blades. The starburst become more pronounced as you stop the lens down - and, as already has been pointed out, straight aperture blades give more pronounced stars than rounded ones.
     
    William Michael likes this.
  6. I've never counted, but that seems very odd to me. (Sorry)

    So a 3 bladed iris would produce a 6 pointed star, and a hexagonal iris would also produce a 6 pointed star?? Very strange.

    I thought you got one star-arm per iris 'corner' regardless.

    Small apertures (big f-numbers) and small and very bright light sources are the formula. Wide-angle lenses help, by reducing the image size of the light source and the physical size of the aperture.

    Incidentally, the lens has to be very clean, contrasty and smear-free to produce good stars. Totally the opposite from what usually produces flare.


    FWIW. Process lenses for half-tone screening used to have a rotating aperture holder. A square 'Waterhouse' stop could be fitted, which would create square(r) dots, when the aperture mask was rotated to align with the screen orientation.
     
    Last edited: Nov 3, 2020
  7. I like all three photos w.r.t subjects, lighting, color and composition. But I personally dislike 'starburst lighting'. I fully realize that this may well just be my personal aversion but to me it loudly screams' starburst effect"!. This applies esp. to photo 1 in which the 'starbursts' are 'in your face ' Much Less so in photo 2. I can't see any 'starburst' in photo 3.One tip w.r.t. photo 3 is to darken the background.

    Mike

    I recently shot a pile of film and on at least one shot there were sunspots that IMO were super unsightly & more than a little annoying (see final image).

    As often as not, I'm shooting out doors so I have to make do with whatever light is happening. If there is a way to consistently turn these photo killing "light blob" highlights into happy little mini starbursts, I'd sure like to know.

    Thanks in advance & have a lovely day.

    [​IMG]

    [​IMG]

    [​IMG][/QUOTE]
     
  8. @mikemorrell Thanks, that 3rd shot was to illustrate how I DON'T want my photos to look. I'd much prefer a "star" vs a massive blob, such as appear on the front forks of this chopper.
     
    mikemorrell likes this.
  9. Might seem odd but nonetheless is true :cool:
    Best lenses for Sunstars - phillipreeve.net
    The number of rays is always double the number of aperture blades - just for an even number of blades, the two rays for each corner coincide (for symmetry reasons): https://cdn.photographylife.com/wp-...with-even-and-odd-aperture-blades-960x619.jpg. The stars are caused by diffraction and the Huygens principle can be used to explain the number of rays that are seen.
     
    William Michael likes this.
  10. William Michael

    William Michael Moderator Staff Member

    Correct in all aspects of the four statements.

    Additionally, in most cases, Prime Lenses render crisper Star Bursts than similar Focal Lengths set on (most) Zoom Lenses.

    I have (had) a particular interests in Star Bursts when in Tech College, subsequently, where possible selection of my Prime Lenses always considered the number of aperture blades (preferring six or eight i.e. even) and the style (straight or round, preferring straight).

    WW
     
  11. William Michael

    William Michael Moderator Staff Member

    Thanks! I was trying to remember, and couldn't, to put that into my response.
     
  12. One way is to use special filters

    Untitled.jpeg
    from "Be Gone Dull Filters" 1977-10 Modern Photography
     
  13. Thanks to everyone for your knowledge and for taking the time top respond. I did find what seems like a decent article on this at B&H:

    6 Tips to Create Compelling Star Effects, Sun Stars, Starbursts, Sun Flares, or Diffraction Spikes in Your Photographs


    Just looking around a bit at related things (Cal Tech paper on Diffraction, for instance) on the web, there's a lot here that is far above my head. That said, it does seem as though one might somewhat dependably create a star effect by stopping down in situations where reflected light might otherwise cause an unbearable, or undesirable aberration or flare (as seen in my shot of the bike above). Seems too like one might not need to get too over the top with it, like f8, f11, or f16 would (or might) be plenty?

    Now all I need is a sunny day with some shiny stuff - or some lit-up night scenes, to shoot.

    PS, @mikemorrell & thanks also to @JDMvW for bringing it up, I see from doing some reading that folks do in fact use special "star filters" to artificially create this effect. That's something I wouldn't do personally, my intention in this is to simply keep photos from being marred by (as I called them) blobs of bight sun glinting off metal car or bike parts.
     
  14. William Michael

    William Michael Moderator Staff Member

    Typically, I use around F/11 on a lens with a minimum aperture of F/22.

    The key ingredient is an hard point source of light on a relatively darker background palette: for example, in the two images you posted, the street lights are point sources of strong light on a dark sky; the specular reflections from the chrome are point source and intense, compared to their immediate surroundings.

    A Ghost Image is one element which maybe that you will want to avoid when shooting scene which, overall, is dark; such as a night street scene or indoors low light. A Ghost Image will appear inverted. One measure to help avoid, is to remove any lens filters.

    WW
     
    Ricochetrider likes this.
  15. Not just filters on the lens. There are post processing virtual filters that achieve the same effect.
    Not tried them myself, but I suspect they're very convincing and effective.
     
    Ricochetrider likes this.
  16. Yes it is diffraction off the edges of the aperture blades.

    Straight edge blades will make sharper lines, the shape being the
    Fourier transform of the aperture shape. Otherwise, there is a line
    perpendicular to each edge, and so yes they will be twice the number
    of odd blade counts. I suppose if even number of blades weren't quite
    parallel on opposite sides, you could see separate lines.

    Some have curved edges, though not quite a circle, which should give
    less sharp lines, and more like the blob shape.
     

Share This Page