Please help with spot meter (warning: long post)

Discussion in 'Exposure Discussion' started by Blake Sims, Jan 21, 2007.

  1. Blake Sims

    Blake Sims Member

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    Hello all,

    I need help with a particular portait situation...

    Setup: Pregnancy nude, using a crushed black velvet backdrop (don't need any texture here). Key light is back/side, so belly and covered breast are lit, but butt is not. Using strobes.

    I used the digital p/s (make up your own acronym :smile: ) for the test shot to show the model, but the real thing is going to be 8x10 b/w. I'm very happy with the test shot, but ran into metering problems as I set up the 8x10. I want to use my flash/spot meter for the final version and anyway, I don't trust the exposure on the digital camera enough to use it or the histogram as a guide.

    So here's the deal. I have my trusty Sekonic L-358 and just bought the 1 deg. spot attachment. The thing is, most of the time I'm getting an E.u. reading, meaning too little light to read. I put the spot on the brightest spot in the scene and about 1 in 4 times I'll get a reading, but the others will say E.u. Of course I never get a reading in the shadows. Picture a nice, round belly with very directional lighting. There is a really nice falloff from right to left, and I just assumed I would be able to read the differences all the way across. It seems like it's all or nothing.

    Does this attachment just stink? If I can only take readings of brightly lit subjects, what's the point? Do I need to fleabay this thing and get a used pentax digital spot? I really wanted to be able to spot meter using both available and flash.

    I'm going to try again tomorrow to make this picture, what other techniques should I try? I was really excited about reading the shadows, then placing the highlights and developing accordingly, I've never tried to be quite this precise and now I feel like I'm head-butting a brick wall.

    Should I just use the incident flash meter like I've always done? I took a reading (with the dome towards the lens) in the most brightly lit portion, and then the darkest shadow area I'd like to not be totally black, and it seems that there was only 2 1/3-2 1/2 stops difference. Can I just adjust my exposure and processing times based on the relative distances of these incident readings from zone 5?

    I really don't want to burn alot of film and chemistry fumbling around for the right exposure. I wanted to control the situation and now I'm getting furstrated.

    Sorry this has been so long, but any insights on the situation, the new spot meter attachment or solutions to my lighting situation would be greatly appreciated.

    Blake
     
  2. David H. Bebbington

    David H. Bebbington Inactive

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    Don't know this meter, but if it is "trusty" (i.e. works consistently well for normal and reflected light readings) but most times fails to read with the spot meter attachment, there must be something wrong with this attachment or the way you have fitted this to the meter. Is there any kind of switchover you need to make on the meter when you fit the attachment? Does the attachment have a switchable angle, or is there anything else which could be misbehaving and cutting off light? Did you buy the attachment new? For the subject you are photographing, I would in any case not use a spot meter, an incident reading would be simpler and should place your (lit) skin tone on zone VII without any trouble. My only experience with this kind of attachment was with a Lunasix 3S that I don't have now, operation with the attachment in place was just the same as without it.

    Hope some of this helps!

    Regards,

    David
     
  3. Ray Heath

    Ray Heath Member

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    hey Blake, keep it simple and think about what your doing

    spot metering is not for flash/strobe lit scenes, you need to measure the light falling onto the subject when the flash fires

    take many readings with a flash meter in incident mode and think about how each area of the image will record in regards to the aperture that will be used

    i.e. if the light falling onto the main area is say f8, and the camera lens is set to f8, and the light falling onto another area is f5.6 than this area will be recorded darker

    also consider that if you want it to be seen, put light on it

    no meter, system or technique will be 'foolproof', you need to get control to present your subject as you want it to be presented

    there is no 'right' or 'wrong' just creative control
     
  4. David H. Bebbington

    David H. Bebbington Inactive

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    Re previous post - according to this
    http://www.sekonic.com/images/files/SekonicL-358_L-558RBrochure.pdf
    the L-358 spot attachment is supposed to work with flash. At a wild guess, fitting the spot attachment is meant to boost the reading level (to compensate for the fact that less light is falling on the meter cell), with your meter, it somehow isn't happening. Does the spot attachment work with continuous light (not flash)?
     
  5. noseoil

    noseoil Member

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    Is it possible to use your setup and a roll film to check development? If you are able to use a smaller format with the same film, you could get the development down first with a snip test, then use this information to get what you need in development with the sheet film. Don't know if this is possible with your film choice, but might be worth a try as 8x10 can be a bit spendy. If the distance to your subject is the same, a 120 film might be the way to go until you have worked out your lighting ratio with the strobes. tim
     
  6. wilsonneal

    wilsonneal Member

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    Hi Blake
    I have the 328 with the spot attachment, but have never used it for strobe, as I never saw a need to. For all strobe situations, I've just used the incident sphere and was happy with the results. I'd try this.
    Neal
     
  7. Roger Hicks

    Roger Hicks Member

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    Dear Blake,

    Spot metering flash is a bit like (unnecessarily) hard work, and I'm not surprised that a meter-plus-attachments isn't up for it; I'm not sure that a built-from-scratch continuous-and-flash meter (like my Gossen Spotmaster 2) would be a lot better.

    Here's a suggestion for a work-around. Check the brightness range of the sibject using the modelling lights and the meter in continuous mode. As long as it's below about 5 stops, use a spot highlight reading or (better still) an incident flash reading as a basis for your exposure. If you're determined to use the spot meter, take a flash spot reading off white paper, at whatever Zone turns you on and where the meter gives you a reading.

    The point is, under controlled lighting, YOU set the brightness range, and as long as its modest, you don't need spot shadow readings.

    Cheers,

    R.
     
  8. Helen B

    Helen B Member

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    I've used spot metering for flash, but only out of curiosity - like everyone else I'd suggest sticking to incident metering for flash.

    The Sekonic L-358 loses six stops of sensitivity when the 1° attachment is used. The limit becomes f/8 at ISO 100.

    Best,
    Helen
     
  9. Blake Sims

    Blake Sims Member

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    WOW

    Wow, you guys are quick and good!

    I was getting a bit panicked last night, I'll admit. After carefully reading my own post and sleeping on it, I have reached largely the same conclusions as the good people here.

    When I put it to paper, I had a reading of f/5.6 in the area that I want to barely see anything at all, a reading of f/13-16 in the area I want "properly" recorded and nice falloff in between. Seems like exposing at f/16 would place the shadow area at zone 2, and place the well lit side right about at zone 5. Seems like I should just experiment with my processing at N to +1 to +2 to get the skin tones where I want.

    Of course, with 8x10 I need more depth of field than f/16 so I'm going to try to reconfigure my setup for more total light, but that's another post for another day!

    I guess I was just at brainlock last night, because it all makes perfect sense to me in the light of day! :smile:

    So the L-358 attachment is only good at f/8 ISO 100? Of course I didn't just buy it for studio stuff, also for landscape work. That sensitivity range doesn't sound like it would be good for all that much? Any comments?

    Thanks to all for the help, any more comments will be greatly appreciated and I'll do my best to get back with results!

    Blake
     
  10. Helen B

    Helen B Member

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    Blake,

    f/8 at ISO 100 is the sensitivity for flash. The sensitivity for continuous metering is EV 5 at ISO 100 with the 1° attachment, according to Sekonic. That should be OK for most daylight landscape work, I think.

    Best,
    Helen
     
  11. Blake Sims

    Blake Sims Member

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    Quick follow up

    Helen, a quick followup:

    I could probably search for this, but if you'll indulge me...

    What's the difference between f/8 @ 100 (flash) and EV 5 @100. I've never used EV and have never really tried to understand. I do know that when I was fooling around with the new spot attachment in my living room after it arrived, I was unable to read dark spots in the room under normal (dim) incandescent light.

    I guess I'm wondering if it'll be worth it to keep this thing or get something more purpose-built. I guess the only way to know is to take it out into the wild and try it!

    Thanks again for all your help,
    Blake
     
  12. Helen B

    Helen B Member

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    Blake,

    EV 0 is 1 second at f/1, and any other combination giving the same exposure (2 seconds at f/1.4, 4 seconds at f/2 etc). EV 5 is 1 second at f/5.6 or 2 seconds at f/8 or 4 seconds at f/11 etc. When used with a film speed (usually ISO 100) it's a convenient way of describing the sensitivity of a hand-held meter. In this case the meter will tell you the correct shutter speed for ISO 100 film and f/5.6, f/8, f/11 etc at the meter's lowest sensitivity limit. (This isn't quite the same with TTL meters, but that's a different subject)

    For flash measurement the shutter speed is irrelevant, so the sensitivity of the meter is best described with just an aperture and a film speed. The meter, if it performs according to Sekonic's specifications, will not show f/5.6 for ISO 100 film when used in the flash mode because the meter is not sensitive enough. It will only show f/8, f/11 etc, depending on how much light energy there is in the flash pulse.

    I'm not convinced that I've answered your question, but it's a start.

    Best,
    Helen
     
    Last edited by a moderator: Jan 21, 2007
  13. Blake Sims

    Blake Sims Member

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    Meter

    So do you use this meter/attachment combo, or do you find a more traditional meter like the pentax digital spot more usefull to you? I'll probably keep it until I know it won't suit my needs.

    I've been a photographer for a long time, and understand exposure etc., I'm just trying to expand my horizons into b/w, something I've not done with any seriousness before. Asking those who know is the best way to learn, so thanks.

    By the way, I'll probably be asking for pt/pd printing help in a few weeks! :smile:

    Blake
     
  14. DrPablo

    DrPablo Member

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    I have the exact same problem with the 1 degree spot attachment for the L-358. For scenes that are otherwise easily metered I very frequently get an E.u. reading.