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  1. #21
    Holly's Avatar
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    Quote Originally Posted by polyglot View Post
    I always bring the horrible mathematical!
    You really do, what are you, a physics teacher lol

    Shooting at 1/60 could well be a problem as the lighting from the fluorescents might show up. Unlikely at ISO50 f/16, but possible. I guess you'll know when you get the 1/400 test back.
    Indeed.

    To reduce power but maintain exposure & DOF, you can move the light closer to the subject (can cause issues with uneven light but twice as close gives you about +2 stops) and/or use a faster film. I'd suggest (separately from your love-affair-with-Velvia question) trying some Portra 400. Especially if you're doing a hybrid (scanned) process, you can add in plenty of saturation later. It's not as fine as RVP but it's still very good in 6x7. You can also try Provia 400X - a bit pricey but it has the saturated contrasty chrome look.
    I'll check it out on my next B&H run. The thing with moving in closer with the lights is just space - if you picture a 1930s dormitory room/cell, you're
    pretty much seeing the size of my studio. But I can at least try the lower output/closer in theory on a small scale to see if it does totally
    stop motion.

  2. #22
    Steve Smith's Avatar
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    Quote Originally Posted by MattKing View Post
    Is there any chance they aren't synching together - i.e. there is a slight lag between them?
    That's a good point. Something else to consider is the method of triggering the second flash. If it's using an optical slave, it should be o.k. but if you are using radio receivers the delay involved might differ between the two.


    Steve.

  3. #23
    Holly's Avatar
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    Quote Originally Posted by MattKing View Post
    I see you are using two strobes.

    Is there any chance they aren't synching together - i.e. there is a slight lag between them?

    Try an experiment with just a single strobe to see if the blur disappears.
    Don't know, I'm pretty certain they go off together fine? I may have to dig through my files of previous shots where this
    blur thing is happening to show a visual for people, it might help to show the exact problem. Hmm. But in a different
    studio the same thing was happening, and that was using just the optical slave on the flash head with possibly a Skyport
    if I recall correctly. So for it to be happening to me again in a totally different studio, it must be something else.
    I'll certainly try the one strobe on its own though. It just puzzles me because I can freeze a piece of fabric thrown
    in the air with my little Canon digital point and shoot, but my lovely proper camera and lights can't handle it.

    Or rather, it handles it, but with edges of fuzziness on the very edges of objects that are moving.
    Last edited by Holly; 05-17-2012 at 02:19 AM. Click to view previous post history. Reason: Forgot something

  4. #24
    polyglot's Avatar
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    Quote Originally Posted by Holly
    You really do, what are you, a physics teacher lol
    worse, an engineer with PhD...

    Quote Originally Posted by Holly
    I'll check it out on my next B&H run. The thing with moving in closer with the lights is just space - if you picture a 1930s dormitory room/cell, you're
    pretty much seeing the size of my studio. But I can at least try the lower output/closer in theory on a small scale to see if it does totally
    stop motion.
    To be clear, bringing things closer won't shorten the exposure; it's merely a way of making up for the loss of brightness caused by reducing the flash power. Another similar option (if it's compatible with the photo you're trying to achieve) is to reduce/remove anything that soaks up light, like softboxes or flags/gobos. Direct flash can look nasty, but it is very power-efficient and I bet you could run at minimum power and some decent DOF that way - if testing at min power gives you the short exposures you need.

    Quote Originally Posted by Steve Smith View Post
    That's a good point. Something else to consider is the method of triggering the second flash. If it's using an optical slave, it should be o.k. but if you are using radio receivers the delay involved might differ between the two.

    Steve.
    I would have thought the opposite. If one is slaved from the other, there must by definition be lag between them of the same order as the exposure duration because the photocell in the second won't trigger until it sees the rising edge of the first, by which time the first is kind of half-over. With a pair of quality radio remotes from a SINGLE transmitter on camera (no craziness like hanging an RF transmitter off a Wein cell), the timing difference due to radio should be in the order of 10 microseconds. I would expect the total exposure duration to be approximately halved if you can avoid using an optical slave on the second flash.

    Doing a one-light test is a good thing to try, especially if (as you say) you have a digital back to play with such tests. In fact, such a thing makes all this testing much faster/easier.

    Quote Originally Posted by Holly
    Don't know, I'm pretty certain they go off together fine? I may have to dig through my files of previous shots where this
    blur thing is happening to show a visual for people, it might help to show the exact problem. Hmm. But in a different
    studio the same thing was happening, and that was using just the optical slave on the flash head with possibly a Skyport
    if I recall correctly. So for it to be happening to me again in a totally different studio, it must be something else.
    I'll certainly try the one strobe on its own though. It just puzzles me because I can freeze a piece of fabric thrown
    in the air with my little Canon digital point and shoot, but my lovely proper camera and lights can't handle it.

    Or rather, it handles it, but with edges of fuzziness on the very edges of objects that are moving.
    Shutter and exposure in a P&S is quite different. The P&S may be running with very short shutter times to exclude ambient or (more likely) has a much-shorter flash duration because it needs a lot less light. The P&S probably shoots with flash at ISO800, f/4 or so but you're trying to get ISO50, f/16, which is 8 stops or 256x as much light, so it's not really surprising that the flash duration from the P&S is shorter.

    In that vein, you should still try to borrow a speedlight (hotshoe flash) and test with that because they often have shorter durations than studio strobes. And definitely test with the strobes at lower powers.
    Last edited by polyglot; 05-17-2012 at 02:50 AM. Click to view previous post history.

  5. #25
    David A. Goldfarb's Avatar
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    Lois Greenfield has been photographing dancers like this for 30-odd years, so it ain't the digital back, but the digital back might be letting her use a higher ISO, and thus less light. She may also be using dual-tube heads, which let you shoot at half the duration at the same power as a single-tube head.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  6. #26
    markbarendt's Avatar
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    Quote Originally Posted by Holly View Post
    I should clarify: I'm not after frozen bullets through water balloons (although that would be fun) but just
    have a model simply moving from position to position on the spot, and she's mostly motionless as I'm shooting
    but on the occasions when she's still turning around or what have you, there's blur in the hands and arms.
    So it's not as if I'm trying to capture insane micro miliseconds of action but more trying to solve the reason
    why a really slow moving model still has blur.
    The only reasons I can see for motion blur are that the part that blurred moved a significant distance and was lit long enough to blur or the camera moved and the subject was lit long enough to blur.

    It is truly rare, in my experience for any flash setting to last long enough to provide a blur for most non-racing human movement.

    I used to do baby photography with strobes and would have the kids crawl from the back ground to mom who was beside me at the camera. Some of these babes were really quick and active and it worked great.

    The trick, if you will, was making the ambient light irrelavant. When the strobes didn't fire the frame was essentially black and the background was a white backdrop and floor.

    Using zone system language, ambient white was placed about zone 1 or 0.
    Last edited by markbarendt; 05-17-2012 at 09:21 AM. Click to view previous post history. Reason: Clarity
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  7. #27
    DesertNate's Avatar
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    Why are you trying to use ISO 50 for fast movement? As modern films go, 50 is a rather low speed. If you're shooting slide film, you could always switch to Provia 400x and keep much of the same look while allowing for much lower power out of your strobes.
    I am assuming here that you're using monolights. If so, shut off the modeling lamps and set your shutter to its max speed as the RZ is a leaf-shutter camera and syncs at all speeds.
    I hope you sprung for the high power monolights, as that's what is going to provide the shortest duration. Since it's a woman's arm that's blurring, and not a bullet, you should be able to get away with ordinary equipment and still stop the movement.
    Posting a photo is more valuable to a forum than 1000 words.

  8. #28
    Holly's Avatar
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    Quote Originally Posted by DesertNate View Post
    Why are you trying to use ISO 50 for fast movement? As modern films go, 50 is a rather low speed. If you're shooting slide film, you could always switch to Provia 400x and keep much of the same look while allowing for much lower power out of your strobes.
    I am assuming here that you're using monolights. If so, shut off the modeling lamps and set your shutter to its max speed as the RZ is a leaf-shutter camera and syncs at all speeds.
    I hope you sprung for the high power monolights, as that's what is going to provide the shortest duration. Since it's a woman's arm that's blurring, and not a bullet, you should be able to get away with ordinary equipment and still stop the movement.
    Posting a photo is more valuable to a forum than 1000 words.
    I'm not using ISO 50 for fast movement:
    I should clarify: I'm not after frozen bullets through water balloons (although that would be fun) but just
    have a model simply moving from position to position on the spot, and she's mostly motionless as I'm shooting
    but on the occasions when she's still turning around or what have you, there's blur in the hands and arms.
    So it's not as if I'm trying to capture insane micro miliseconds of action but more trying to solve the reason
    why a really slow moving model still has blur.

    I'm using it for rich colour and fine grain. I get how ISO works.

  9. #29
    Holly's Avatar
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    Quote Originally Posted by polyglot View Post
    worse, an engineer with PhD...
    Ah that would explain it

    Another similar option (if it's compatible with the photo you're trying to achieve) is to reduce/remove anything that soaks up light, like softboxes or flags/gobos. Direct flash can look nasty, but it is very power-efficient and I bet you could run at minimum power and some decent DOF that way - if testing at min power gives you the short exposures you need.
    I'm afraid it's really all about softboxes and brollies at the moment. I did have the fuzzy hands thing when using bare flash with snoot
    in previous shoots though.

    Doing a one-light test is a good thing to try, especially if (as you say) you have a digital back to play with such tests. In fact, such a thing makes all this testing much faster/easier.
    I wish I had a digital back, my god! The frustration it would remove! But I will add the one-light test to the list of things to rule out.

    In that vein, you should still try to borrow a speedlight (hotshoe flash) and test with that because they often have shorter durations than studio strobes. And definitely test with the strobes at lower powers.
    Actually inherited a daggy Hanimex CX330 flash from my grandfather's collection, it's crap but oddly endearing. Will test out some
    on-camera flashes as well. Hope I will be reporting back with very sharp frozen pictures soon!

  10. #30
    Mainecoonmaniac's Avatar
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    Sometimes the shutter speed doesn't matter if the scene is in total darkness. What matters is the duration of the strobe. Generally, the lower the strobe setting, the shorter the flash duration. Am I wrong?

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