Flash meter reading compared with ambient reading

<p>Hello, I've been searching around the forums/google but haven't seem to have come across the issue I'm experiencing. I hope the question is clear, because I'm not 100 percent sure what or if there's a problem though. Basically, I'm taking an interior shot and trying to balance a flash exposure with an outside, background ambient exposure coming through a window.<br /> I've included pics, but first, here are the details of the setup. D80 in manual mode, ISO 200. SB-600 on manual, full power. Minolta Flash Meter III, set for ISO 200 and shutter speed of 125 (highest shutter speed available on meter that won't go over my camera's sync speed.)<br /> For the background, f/16 at 125 (from a reflective reading off the building stucco using a spot meter) gives an exposure that leaves the building a little underexposed, retaining detail in the stucco. For the interior, when I take a flash reading, at full power, with the Minolta set to cordless and placed in front of the guitar, the reading comes back at f/8. I would expect this setting to overexpose the background, but it also makes the interior look overexposed. Now, I'm not sure if the white walls are overexposed purely because they're white and are reflecting back a lot of the flash or if the reading of f/8 is inaccurate--the guitar itself looks properly exposed.<br /> The other issue I'm not sure I understand is, if my flash is already at full power and the reading comes back as f/8, is it not powerful enough to match the brightness of the outdoor background?<br /> Hope that's clear. Please let me know if anything needs to be explained more or if someone knows of a resource I may have overlooked in my searching.<br /> Thanks!</p>

<p>f/16 @ 125</p><div></div>

<p>f/8 @ 125</p><div></div>

<p>Interiors look a little "staged" when the light is brighter than the background exterior (windows to the outside). In assuming you are not lighting the exterior with separate flash, you have to work with available light to match your flash. Therefor you have to work first with your shutter speed, then your aperture. I don't see an image attached to your inquiry, but i would guess your SB isn't powerful enough to get anywhere near intensity of the outside light. I would step outside, get your reading that is falling on your stucco walls with the ambient bubble on your meter, toward your camera. Place that at one and then two stops over your "exposure." Say, if reading is f16 @ 125, then let your "exposure" be f8 @ 125. Go inside, get your flash to read at f8 at 125, ambiently, directing your bubble toward the camera. Don't bother fooling around with both reflected and ambient readings. You may have to wait till the light settles down, or work on a cloudy day to get your SB to get in the ballpark of your exterior readings. IMHO, let the available light do most of the work for you, then fill shadow or add accent to areas within your shoot.</p>

<p>I would try f11@ 60 and broadcast your flash from your left side, off the ceiling. And exposure on the stucco doesn't look like 2 stops, more like 4.</p>

<p>Thanks Chris, as far as the interior f/8 reading, disregarding the background, have the white walls overexposed simply because they're white and reflect back more of the flash than, say, the wood of the guitar? Though not flattering at all, the guitar itself looks properly exposed, so I'm wondering if the flash reading is correct.</p>

<p>I took a reading outside and it came back as f/16, 7/10 @ 125. On the camera, I set this as f/16 @ 200 taking the extra 7/10 into consideration. When I was originally shooting, the outdoor light could have easily been closer to f/22, even f/32 maybe @ 125. So I think this answers my question in that my SB just doesn't have the output to match daylight that strong. But now I'm wondering about the flash reading of f/8. Judging from the shot at f/8 @ 125 does it look like this reading is incorrect or is the overexposure just the nature of the white walls in close proximity to the flash?</p><div></div>

<p>Again, Chris, thanks for your replies. Aesthetically, bouncing the flash into the camera-left corner at f/8 (from flash reading) @ 125 (from exterior reading and opened a little to keep the interior from looking brighter) looked very well-balanced. Also, as far as the white walls looking overexposed, I shot a scene where the only white was the cover of a book. When set to the meter reading for flash, everything looked fine when the book wasn't in the frame. Once the book was added, at those same "correct" settings, its white cover completely blew. I believe that's the same thing happening here with the white walls if I'm correct.</p><div></div>

<p>A little better, maybe 1.5 more stops more power on the SB, if possible. That would help match the light of the outside stucco. It gives more of a feeling of light coming through the ceiling of course. Again, I found that working with ambient settings on your minolta, pointed toward your camera, is far easier to follow than trying to track reflected meterings.</p>

<p>Thanks Chris. Yeah, opening up a little bit more definitely helped. As far as the direct flash is concerned (f/8 @ 125 No.2), light quality aside, am I correct in that the overexposure is caused by the reflective qualities of the white walls? Or could the meter be inaccurate?<br>

Thanks</p>

<p>could you try a f16, 1/200 shot? move your full power flash closer to guitar, obtain a flash metering of f16, that shoot at f16, 1/200.</p>

Not sure why you are going through all these complications. Take an ambient reading of the outside then use your flash as fill. Adjust accordingly using FEC.

<p>Just like Harry said<br>

There are two exposures here, background and subject.<br>

Set your exposure for the background.<br>

Set your flash at 1/2 power, fire a test shot, chimp and increase or decrease flash to taste!<br>

Lot of info at the strobist site, check out the indexed archieves<br>

<a href="http://strobist.blogspot.com/2006/03/lighting-101-balancing-flash-and.html">http://strobist.blogspot.com/2006/03/lighting-101-balancing-flash-and.html</a></p>

 

<p>I have been writing about this issue for many years. You can find some of my notes in my blog: http://laestrategiadelaluz.blogspot.com in the notes CX, CXI, CXII, CXIII, CXIV and CXV.<br>

In spanish. Sorry, not all the good information should be available in english.</p>

<p> </p>

<p>Regarding spot meters...</p>

<p><strong>ALL</strong> exposure meters tell you what exposure will render the target subject as a medium gray (18% reflectance). So if you measure a white wall and shoot at the prescribed exposure, you get a gray wall.</p>

<p>You must adjust the exposure to compensate for the brightness of the target if it's not mid-gray. For a white wall you would increase the exposure by two to three stops, depending on the actual tone and the imaging media that you're using. </p>

<p>Increase means slower shutter or larger aperture (smaller f number). For example, if the spot meter says 1/125 @ f/8, a two stop increase would be 1/30 @ f/8 or 1/125 @ f/4.</p>

<p>- Leigh</p>

 

<p>#1 The flash you are using cannot provide enough output @ f/16 to keep in step with the outside ambient light. I presume that you have the flash in Manual 1/1 power since you say it is at full power. There are two ways to handle this type of a shot. First would be to get you flash exposure to the correct level of exposure. F/8 appears to let in too much light, try an exposure at f/11. That should give you better exposure on the flash. When you get that, your outside exposure will be a little darker also. If you want to make the outside darker still, you can go up to 1/200th of a second with normal sync speed.<br>

#2 You would need to get a flash with more power output, such as the SB900.</p>