SB-800 exp comp doesn't work when bouncing?

<p>I'm a Canon user and I have a friend who is Nikon user and she is having a problem with her sb-800 on a Nikon D300. When shooting with the flash pointed straight ahead, eu compensation on the flash works like a charm. Tilt the flash head and it doesn't.</p>

<p>To be specific, two pictures with tilted head, one at 0 and the other at +3 on the flash, produce the same image. The same two pictures taken with the flash pointed straight ahead produce what you would expect: one good picture and one blown out.</p>

<p>Flash is set to TTL/FP</p>

<p>Any help appreciated!</p>

<p> </p>

<p>Need distance / f-stop / ceiling height.</p>

<p>I suspect that you're driving close to full power on the bounce at "0", and at "+3", there's nothing left to give.</p>

 

<h2>"I can't do it, Captain. I can't defy the laws of physics!"</h2>

<p>After flashing, does the exposure compensation indicator on the back blink for 2-3 seconds? If so, it's flashing at full power, and so setting it to +3 would make no difference.</p>

<p>It works but it's inconsistent. Probably the only real complaint I have about the SB-800 (I use it with a D2H). Flash exposure compensation is very consistent with the head aimed straight ahead, but some guesswork is involved with bounce. However I see an unmistakable difference in bounce flash exposures between flash EV neutral and EV -3 indoors. As other folks have noted, when the flash is already at full output at EV neutral, there ain't no more to give so +EV won't accomplish anything.</p>

<p>Generally speaking I avoid the FP setting. Outdoors I use TTL-BL. Indoors I use TTL only. The BL option doesn't work well in anything less than fairly bright daylight or unusually bright indoor lighting. Since even the brightest indoor lighting scenario seldom exceeds EV 8, I've never encountered a situation where TTL-BL can be used reliably.</p>

<p>I've run some tests indoors before but can't find the notes to accompany that series of photos. I'll reshoot a few and post the results later. <em>(Note to self: remember to keep notes to self.)</em></p>

<p>Test shots were done in a very bright room, f7.0 at 60 100iso. Ceiling height 20 feet. After I take the shot, for a brief moment the flash will show "-2 2/3 eu". Like the flash is turning down my manual exp. comp.</p>

<p>Mark, you are saying that when I bounce, the flash is already jumping to +3 and so has no power left for exp comp? That seems like a lot of light loss from a ceiling bounce and large bounce card. With my Canon 580EXII I blow out the room at +3. Is it possible my flash is that much more powerful?</p>

<p> </p>

<p>Right, it's saying that it fired at full power, and underexposed by 2 2/3 stops. You need to raise the ISO or open up the aperture by at least that amount to compensate.</p>

<p>Is your shutter speed at or below the max sync speed? (Is that what your "60" means above?) You may be getting into high-speed sync, which would explain the relative lack of power to the Canon, which is approximately equivalent in power.</p>

<p>Shutter speed is well below sync because I was attempting to teach my friend how to lower the ambient by raising the shutter speed.</p>

<p>I just don't understand how the flash can be at full power when the camera is in Manual Mode and the meter is centered. As far as the camera knows, I have a proper exposure with no flash at all, then I turn on the flash at 0 exp comp and it fires at full power in TTL? Even with a 20 foot white ceiling for bounce and a demb bounce card pointed straight ahead, that seems like a lot of power for what the camera sees as essentially fill flash.</p>

<blockquote>

<p>"f7.0 at 60 100iso. Ceiling height 20 feet."</p>

</blockquote>

<p>You've described a perfect scenario for exceeding the limits of most hotshoe flash units in bounce mode. In that situation I'd expect to use an aperture of f/4 or faster.</p>

<p>When you say "very bright room", what was the actual EV of the available light? For example, right now my work area is EV 6-7, depending on where in the room I meter. It's a typical residential room, around 14'x16' with 8 foot ceilings, all painted off-white. A single large window with white blinds shut for filtered sunlight facing west (plenty of daylight). And a 100 watt overhead lamp is on. At ISO 100, I'm looking at f/1.4-f/2 at 1/60th, depending on where I hold the incident meter.</p>

<p>That's about as bright as a typical indoor scenario gets. It's also typical lighting for most school gyms and auditoriums. Occasionally pro venues and a few upper level college gyms will be EV 8 to accommodate TV cameras.</p>

 

<blockquote>

<p>"Is it possible my flash is that much more powerful?"</p>

</blockquote>

<p>It's difficult to compare the two because they don't list technical specifications using identical methodology.</p>

<ul>

<li>Canon 580EXII is listed as: Guide number 190 (at ISO 100, feet) / 58 (meters); flash head at 105mm zoom setting</li>

<li>Nikon SB-800 is listed as: Guide number 38/125 (at 35mm) to 56/184 (at 105mm) (ISO 100, m/ft.)</li>

</ul>

<p>Assuming performance of each is pretty close to the specs, there isn't much difference between GN 190 for the Canon and GN 184 for the Nikon.</p>

<p>If you're seeing radical differences in results, check to be sure the exposure settings and rooms are comparable.</p>

<p>Were you using the Balanced iTTL mode? - you give away some degree of flash contribution control, it may tend to determine the need for flash differently than what you intended, to do the best balancing with the ambient light, that highly depends on the room refectivity and angles and may not be perfectly repeteable, but strives to provide well lit pictures.</p>

<p>Moose Peterson on his old web site used to think that the SB-800 Balanced iTTL lighting "circumnavigates the invers square law of light", so it is that good. </p>

<p>I agree with Mark. Change your aperture, ISO or both. And possibly your synch setting. If you want the shutter speed to go below 1/60, you have to change the flash mode from front curtain to slow synch or rear curtain snych. Make sure the custom settings for flash, especially e1 and e2 are set correctly for your particular shooting situation. Just so you know TTL is true fill flash. Ambient light is producing the main exposure. So you need the right ISO and shutter speed and aperture to get a good exposure. TTL flash is just providing the fill light. If TTL BL is set then the camera and the flash are working together to get the right exposure. An excellent Internet source that explains all of this is by Moose Peterson. Just do a serach for " Nikon TTL flash system Peterson". Joe Smith</p>

<p>Here are the two links for Moose Peterson on TTL flash. The first explains the basics and was done before D TTL. However, basics are still basics. The second was done after the intorduction of digital TTL flashes:</p>

<p ><a href="http://www.moosepeterson.com/techtips/flash.html">http://www.moosepeterson.com/techtips/flash.html</a></p>

<p > </p>

<p > </p>

<p ><a href="http://www.moosepeterson.com/D3/flash.html">http://www.moosepeterson.com/D3/flash.html</a></p>

<p > </p>

<p >I use a SB 800 on my D 300. I rarely use the Manual setting on my SB-800. When using my flash, I shoot mainly in aperture priority mode, and use rear curtain synch. I set my ISO and f stop according to light present and shutter speed needed to stop action. I use rear curtain synch because I want ambient light to be as dominat as possible and I am often using slow shutter speeds. Auto FP is set 99.9% of the time too.</p>

<p > </p>

<p >This is just me. Others do it differently. Joe smith</p>

<p > </p>

<p > <br>

 

<p> </p>

</p>

<p>Thanks everyone, I'll pass this info along to my friend.</p>

<p>Lex - Just so you know what I was talking about.... the very bright room is my living room in Florida with 20 foot windows on two sides at 3 PM. I don't know what the exact ev setting is but it almost daylight. :)</p>

<p>I think I understand where I went wrong. </p>