Lighting -- What am I doing wrong?

[Jennifer Waak]

I've just ventured into the land of strobe photography with a 4x5 and am having problems with underexposure. Right now I'm using a Canon Speedlight 550EX as my strobe, which I realize isn't ideal, but I was hoping with multiple pops I could get away with it for a while so I can choose a studio strobe system. I'm taking a simple tabletop photo of glass of wine and wine bottle. I'm using Polaroid Po lacolor Pro 100. I have a Sekonic L-608 light meter.

If I point the flash directly at the subject and take the flash reading my expos ure basically turns out right -- I just have really bad shadows. So, I decided t o try a bounce flash -- I have 9-ft. white ceilings. I set the light meter for m utiple flashes and I did 3 pops to get an aperture of f22 (light meter sitting i n the middle of my composition). So, I set the camera for f22 and took the photo -- because of the slow recycling times on the flash the total exposure ends up being a little over 1 minute. The photo came out seriously underexposed (I tried 3 or 4 photos, just to make sure it wasn't me doing something monumentally stup id), so I tried 4 flashes and the light meter told me f32 (but I left the camera set at f22 to minimize variables) -- the photos between 3 and 4 flashes look vi rtually identical.

I'm at a complete loss as to what I'm doing wrong. Any ideas are greatly appreci ated -- I've been beating my head against the wall on this.

Thanks!

[Ellis Vener]

If your meter is telling you that 3 pops = f/22 and 4 pops = f/32. Something is definitely wrong with either your meter or your technique. Sekonic meters are not known for their low light responsiveness. and this is a low light situation.What does it indicate your f-stop should be for just one pop of the flash?

Let's say that your meter , when you measure just one pop, tells you that your camera should be set at f/5.6 for ISO 100 material. To get f/8 you'll need 2 pops. To get f/11 you'll need 4 pops. To get f/16 you'll need 8 pops. To get to f/22 you'll need 16 pops. Now wait! it gets worse! I have found over the years that if the meter is telling me I need 4 pops of the strobes to get a certain f-stop, I have to add an addition pop for each 4 the meter is indicating a need for. So if my calculations tell me I need 16 pops, I'll start with 20 pops, and yes I do see a difference with just that extra 1/4 stop of light.

So try reading a single pop and then extrapolating from there, doubling the number of pops from the previous f-stop

[Scott Walton]

Jen, The harsh shadows are created by the point light source. This is why we use softboxes of all sizes. The larger the lightsource, the softer the light when shooting close. You don't have to go out and buy a softbox right now ... for starters, 9' ceilings, your wasting valuable light and spreading it way to far! Get yourself a large (20x24 or larger) piece of foamcor e and suspend it horizontally just out of camera range above your set. Bounce your flash off of that. If you "feather" (tilt the foamcore towards the camera maybe 45 degrees from the horizon) you will get a darker, graduated background. The other alternative is to make a shoot through p anel out of PVC tubing and a transparent white material you can get from the fabric store. Make it 3' square or larger. These can be bought commercially also but it is cheaper to make your own. As far as your multiple pops, your getting into the realm of reciprocity failure. You'll e ither have to open up a few stops or pop a few more times.... that is if your pictures are nicely exposed with the straight flash and one other thing, st op with the head against the wall... it puts dents/holes in the walls and will cause dane bramage! Cheers

[Glenn Kroeger]

Jennifer:

One f-stop is doubling or halving the amount of light. So if 3 pops is f/22, then 6 stops MUST be required for f/32. The difference between 3 and 4 pops is about 1/3 f-stop which is right at the limits of detectability.

[Jennifer Waak]

Thanks for all of the great responses so quickly!

Yes, it is a low-light situation. I turned off the light in that room to avoid all of the reflections of the light bulbs.

Last night one pop gave me f11, 2 was f16, 3 was f22, 4 was f32. I had remembered an old post of Ellis' stating that you basically double the number of pops to open up a stop, so this didn't make sense to me (hence the experiment last night).

I just went and re-tried testing my exposure. With good room light the fstops went as follows: 45, 64, 90, 90, 128. When I turned off the room lights (but I now I have a lot more ambient light because I have windows) I got 32, 45, 45, 64, 64, 64, 64, 90.

Armin, BTW, you were right. I did have my light meter pointed towards the ceiling -- when I re-ran my tests I found it made no difference but it's still a good habit to get into.

I just ran a new set of Polaroids with the room lights off (so, the 32, 45, 45, 64, ... sequence). With 4 pops my photo was so dark it was almost as if I left the lens cap on (I could just see shadows of the subject). So, I took Ellis' advice and added 4 pops, for a total of 8. Again, everything was really dark. I reshot once again with the flash pointed directly at the subject, which got me back to the problem of having too direct of a light source, but at least the photo was well-exposed -- verifying that the light meter and I seem to work correctly for a single flash.

I'm going to try Scott's advice and play with some sort of diffusion; I knew that was an option, I just wanted to see how well my Speedlight was going to hold up for this sort of work and I think my conclusion is "not well".

This leads me to a follow-up question. I've been reading everything I can about studio lighting and have basically decided on a head and pack kit (because I want to have an overhead light and that seems precarious with a monolight). I think something around 1000 w/s to start and a couple of heads. I was leaning towards Dyna-Lite because of the weight -- right now I have no plans to travel with it, but less than a year ago I said I'd never shoot anything other than 35mm and bought a 35mm darkroom so I don't want to make that mistake again. But, Speedotron Black Line seems to have an advantage because of the interchangable reflectors. I can't find much on Elinchrome or Balcar, other than Ellis is currently using Balcar and loves it. I can rent everything except Balcar to try, but never having used studio lights I'm not sure of the value in that -- it took me a long time after moving from point-and-shoot to SLR to figure out what I liked and didn't like about my SLR and am sure it would be the same way with studio lighting. Right now I'll only be using the lights for table-top still life photography in my home; I'd also like to start doing architectural photography (where I guess monolights would win out). I have no intention of doing portraits, or at least not in any sort of volume. While this is just a hobby now, I would like to develop the skills and equipment to be doing this professionally (at least part time) down the road. Can anyone help me sort through the differences between the brands I listed above?

Thanks again!!!

[Bill Smith]

You say you are shooting 4x5.

Your meter is probably correct, but I wonder if you have made an adjustment for the bellows factor, or if you are filtering have you included a filter factor.

I think that a close up tabletop with bellows extension would require at least one more stop of exposure. Once you calculate the bellows loss you can adjust your meter to compensate if you wish.

Just one suggestion.

Bill

[adam friedberg]

i always look for the simplest answer first. is your shutter set on "t" or something else? just a thought.

[Jennifer Waak]

I completely forgot about the bellows factor! What I would give for TTL metering right now. :-) That's probably part of the problem, but not all of it since my single-flash, direct light source photos are coming out more or less OK (minus the terrible shadows). I'm not using any filters.

I do have my camera set to "T" -- I click it once to open the shutter and a second time to close it (between time I'm sitting there and repeatedly firing my strobe).

I'll try a new set of exposures with the bellows factor accounted for later today.

Thanks for all the new ideas!

[David Grandy]

"Last night one pop gave me f11, 2 was f16, 3 was f22, 4 was f32. I had remembered an old post of Ellis' stating that you basically double the number of pops to open up a stop, so this didn't make sense to me (hence the experiment last night)."

If one pop is f11, two pops should be f16, but it'll take FOUR pops to get to f22, 8 pops to f32, 16 pops to f45.

[Ellis Vener]

An experiment. If the meter read f/11, did you try to make an exposure at f/11?