SB-600 + STO-FEN exposure problem with D90

[bikealps]

<p>I got a SB-600 about a year ago. I also picked up a STO-FEN diffuser so I could get less harsh lighting.<br>

I took a lot of shots with the SB-600 + STO-FEN combo but found many, if not all of them, were grossly overexposed. I didn't understand why, but decided to put the STO-FEN on the shelf and everything was ok.<br>

More recently, I was using the SB-600 for some people photos without the STO-FEN. To soften the lighting, I used 45, 60, and 75-degree angles to bounce the flash off the roof. In a room with an 8-10" white ceiling, I had no problems. In another room (in my house) with taller arched, darker ceilings, I got consistently underexposed photos.<br>

So, I figured, instead of bouncing it, why not use the STO-FEN. I thought back to the overexposed shots with the STO-FEN (most were outdoors with fill flash) and wondered what the problem is.<br>

The STO-FEN site, in their FAQs, claims you must use a 45-degree angle to avoid overexposure. <a href="http://www.stofen.com/FAQ/index.htm">http://www.stofen.com/FAQ/index.htm</a><br>

OK, so if this is the issue, I should be able to do 4 test shots:</p>

<ol>

<li>straight on</li>

<li>45-degree angle</li>

<li>straight on with STO-FEN</li>

<li>45-degree angle with STO-FEN</li>

</ol>

<p>and all should be properly exposed except #3, and #2 and #4 should have nice, soft lighting.<br>

So I took this series of photos of my wife in the kitchen and got correct exposures for all 4.<br>

Anybody have ideas about what is going on here? The STO-FEN ruined a bunch of good shots last summer. They were outdoor, fill-flash portraits. What do I need to know to use it correctly?<br>

A good rule would be to always use it at a 45-degree angle indoors. Outdoors, you only need fill flash, so you don't care about soft lighting, so don't use the STO-FEN and just shoot the SB-600 straight on.<br>

That sounds like a reasonable lesson, but what am I missing? Why were my previous STO-FEN shots overexposed when my test shots tonight were just fine?</p>

[george_peng1]

<p>It's nothing to do with the Sto-fen. By the way, the Sto-fen isn't going to do a lot to soften your pictures, especially straight-on, because you're not increasing the light source at all. What's happening is that the sides of the Sto-Fen are sending some light in every direction, which eventually bounce back to the subject and soften the look slightly. Bouncing without a Sto-fen, if possible, is more effective. Personally, I've found that Sto-fen tends to flatten the light a little too much for my taste so that it often lacks any directionality.</p>

<p>But with respect ot your problem, it depends on what your camera settings were. If you were shooting outside, depending on your settings, there's a pretty good chance that any flash shot would have been overexposed, especially if the ambient light was strong and the exposure setting were pretty close to where ambient would be. Put another way, the flash might have put it over the top. That's why you have these discussions about max sync speed, the higher of which allows you to take a bit of ambient out of the equation. You can do the same with stopping down the aperture, but you end up taxing the flash a bit in the process.</p>

<p>That would be my guess.</p>

[elliot1]

<p><em>"taller arched, darker ceilings, I got consistently underexposed photos</em>" Less light is being reflected because of these conditions. User intervention is sometimes needed. </p>

<p><em>"The STO-FEN ruined a bunch of good shots last summer"</em> Actually, it was your camera's settings. Again, user intervention is sometimes needed.</p>

 

While the SB-900 and SB-800 have a sensor built into the flash so it knows when the supplied diffuser is being used, the SB-600 does not include a diffuser (from Nikon) and has no built-in sensor. You will have to, on occasion, adjust the camera's or flash's settings to insure correct exposure. (FWIW, the SB-800/900 do not always get it right when the diffuser is being used.)

 

 

I don't believe there is any camera that gets the exposure right 100% of the time. As a general guide to help you improve your exposure, take the shot, preview the shot on your monitor, correct your settings either on the camera or flash as needed if the exposure is too light or too dark and reshoot.

[Peter_in_PA]

<p>George says [bouncing without a Sto-fen, if possible, is more effective.]</p>

<p>I've been using this device for almost 4 years, and my experience is very different. I use my SB600 almost exclusively with the Sto-Fen on, and almost always bounced at the sweet spot, 45 degrees. But I find unbounced flash mostly worthless anyway, so consider that.</p>

[Peter_in_PA]

<p>Oh, I forgot, I do often take it off for fill-flash outdoors in bright light.</p>

[douglas lee]

<p>The sto-fen should not be the problem. If anything, it would cause underexposure, depending on the flash being and flash mode. Can you post examples which include the EXIF data? BTW, use of a sto-fen outdoors is not necessary in most cases and it wastes light.</p>

[bryan_davis3]

<p>Allan,<br>

Just to add to what George said, if your outdoor shots were in bright light and you shot in aperture priority or program mode, the camera would have picked a slowish shutter speed (like 1/60 second) when it detected the flash. At that shutter speed in bright light, you'd have to close down the aperture to keep from over-exposing, so perhaps the aperture was too wide-open to get the proper exposure. <br>

This would be true with or without the diffuser attached, so if it's bright out today you could take a picture with the flash attached, note the ISO, aperture and shutter speed, then remove the flash and take the same picture (but you'll have to manually set the ISO, aperture and shutter to the same settings). If both images are over-exposed, it isn't the fault of the flash or the diffuser but simply the default settings of the camera. Next time you want to use fill-flash in bright light, you'd need to close down the aperture 'till the image isn't over-exposed, or set the exposure yourself manually.<br>

Of course, if you're already doing it manually, you can safely ignore my whole post. Good luck!</p>

 

[bikealps]

<p>Hi George, Elliot, Peter, Douglas, Bryan,<br>

Thanks a bunch!<br>

Sounds like it is not an equipment problem but pilot error. I can fix that without spending money!<br>

So, lessons learned:</p>

<ul>

<li>for outdoors fill flash, don't use aperture priority -- that's why my photos were overexposed -- STO-FEN is not at fault</li>

<li>STO-FEN doesn't help if you are shooting the flash straight on. The whole point is to soften the light. Softer light comes from a larger source. STO-FEN should never be used straight-on, only at 45' angle or so.</li>

<li>for indoors photos, STO-FEN may fix the exposure problem. if I am blouncing off the roof and the roof is dark and far away, STO-FEN can divert some of the light straight at the subject.</li>

<li>STO-FEN should only be used when the flash is set an an angle, for example 45'. do not use STO-FEN at 0'. 60' and 75' are ok, too.</li>

</ul>

<p>I'll try obesriving these lessons learned and see how it works.<br>

Thanks so much!<br>

Allan</p>

[mark_drutz]

<p>The SB-600 does have a built-in diffuser (at least mine does). If you want to soften the flash indoors w/o the StoFen, use the built-in diffuser. I use the built-in diffuser for all direct flash shots except at long range. I've also used the StoFen for direct flash with no problem. It's not a dramatic difference, but there is a subtle difference.</p>

[bryan_davis3]

<p>Allan,<br>

To edit your first lesson learned, I'd say that using aperture priority might be ok as long as you make sure you've got a small aperture (large number) selected. <br>

I think aperture priority is a convenient mode when I don't want to think about every exposure, but still want to guarantee myself a particular depth-of-field, so I'd take a test shot with the flash on and the aperture I planned to use and see if it is overexposed. If not, great! If yes, then I'd consider switching to manual and/or closing down the aperture enough to tame the exposure.</p>