Saturday, May 16, 2009

Strobe or Halogen? (flash or hot lights?)

Dear Kirk,
I am a young photographer who has been shooting architectural work for a short while. I have sent you this email because you are a noted architectural photographer and I figured you could give me a dependable answer. I have very basic knowledge of interior lighting, but wonder which is better using strobes daylight balanced or hot lights with quartz halogens. I have been asked to shoot an interior with a large glass curtain wall on one side and several banks of flourecents on the other and possibly some tungsten accent lights. So for me I am unsure what would work best. I realize that this may not have a simple answer but would appreciate your suggestions.

Yours truly,
Mike

Mike, this is a big question that is hard to answer without seeing the space. But here are some thoughts.

Are you shooting digital? Digital is more forgiving and easier to adjust color temperature in mixed light situations. Your example sounds like a situation where I would use strobe (which is daylight balanced) for fill light, if I was shooting it in the daytime (at night I might choose halogen fill). The warm accents from a few small halogens can look good and natural in a strobe lit daytime interior. The glass in the curtain wall commonly has a slight green cast. This will make daylight coming through the glass more like the color of the fluorescents if they are cool whites. It may be useful to put a light green filter on the strobes to make a color match between the daylight coming through the glass and the cool white fluorescents and then do a custom white balance to neutralize these three main sources. A 1/4 Rosco + green filter is usually good (see B&H)

Final tweaking of the color can be done in Photoshop by many means. An easy one is the plugin Color Mechanic Pro . CMP is good for small adjustments in color. If you try to over do it you will get pronounced noise in the transition areas.

2 comments:

  1. Hi Kirk,

    Funny, I came to your blog today intending to ask you the exact same question: Stobes or hot lights?

    My situation is a little different. I specialize in panoramic photography and have learned to deal with high contrast via HDR techniques (bracketing, exposure fusion, separate exposures for windows, etc). As such I've gotten used to dealing with just about any situation without supplemental lighting. Admittedly, shooting exclusively in available light is not ideal, but for panoramic photography it's really the only practical technique. Lately I've had clients ask me to shoot traditional architectural stills while I'm on site and I've done this using the same HDR techniques, but I'd really like to step up the quality of these architectural stills and that will require supplemental lighting.

    I shoot a lot of vacation properties in Hawaii and a typical scenario can be seen here: http://tinyurl.com/hdr-sample It is a tungsten-lit interior with yellow walls and a big door that opens to a very bright outdoor scene. Maintaining the view out the doors & windows often requires as many as six bracketed exposures (each 2 stops apart). On top of that, the tungsten/yellow interior is in stark contrast to the blue daylight spilling in from the door. The extreme contrast & white balance disparity makes for muddled, inaccurate colors and harsh reflections. I've seen other photographers deal with these situations by blasting a ton of light onto the scene, presumably with powerful daylight-balanced strobes. But to my eye the results are again less than ideal. To my eye a good architectural photograph shows how the existing light fixtures look & work in the space - you can see the glow of lamps and ceiling fixtures, spotlights on paintings, how sconces spill their light onto the walls, etc. I'd like to find a hybrid solution that does a good job of marrying the existing light with supplemental lights and reduces the extreme bracketing that these situations can require when using only available light.

    Obviously every situation an architectural photographer faces is a little different and there is no single answer, but knowing the conditions I commonly face, what would your approach be? What sort of lighting equipment would you recommend? Strobes or hot lights? Or a combination of the two? As far as cameras go, right now my stills are shot with my panoramic outfit: a Canon 350D/Nikon 10.5mm fisheye and defished & straightened with PTLens. I've got a 5D2 on order and plan on using it with my 17-40mm f/4L. Do I need to plunk down $2,200 for the canon 24mm ts-e 2?

    Thanks,

    Dave

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  2. Dave,
    "blasting a ton of light onto the scene" is simply an amateurish way to utilize strobe fill. Properly used strobe is subtle and natural looking, but that takes time and finesse. Depending on budget, client expectations, accessibility etc. we may or may not have the time we need to do jobs like these right. As I have been doing this for 30+ years and have a very experienced lighting assistant of nine years, we are able to work strobe fill rather quickly, and I routinely use strobe fill to balance lighting levels and color with stitched panoramas. I carry both strobe and halogen lighting systems on every job. If I am shooting in daylight, I will probably use strobe and if at night or twilight I will use halogen. Used lighting gear is cheap right now, oftentimes cheaper than getting units repaired. I use old Norman power packs and heads, some of which I bought 30 years ago. I own 6 2000 watt and 3 800 watt power packs and maybe 12 heads. In the days of 4x5 film we needed that much light to photograph big commercial buildings sometimes. These days we rarely use or even carry more than 2 800's, 1 2000 and maybe 5 heads. That is because shooting FF DSLR we have so much depth of field at say f8 or 11 that we simply need allot less light than when we tried to get reasonable DofF at f22 on 4x5 film. For halogens we use Tota and Omni lights from Lowell. I think we have maybe 6 Tota's and two Omni's with a variety of bulb strengths available. I prefer the cheap household bulbs from your local hardware store as the color temperature is closer to commercial and residential halogens and incandescents. They also last allot longer than true 3200K photo bulbs.

    We also have a "kit" of light modifiers to help make the light do what we need it to. I'm not fond of light boxes as they are a pain to set up and hard to hide in a scene. So we use umbrellas and reflectors and gels and allot of gizmo's we have picked up over the years.

    As far as the new Canon 24T/S lens. I have great hopes for it and will probably get one. In general for my kind of shooting I wouldn't shoot without T/S lenses. See: Why Perspective Correction Lenses

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