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Niko D7000 with SB 800 Flash


linda_roina

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<p>Putting WB to Auto with hot shoe flash drastically changes what Auto WB does. Auto WB is no longer just guessing. Then it is instead Nikons Flash Color Temperature Communication, page 5 of the SB-600 or SB-800 manual. <br>

Flash color temperature (WB) changes with power level. On speedlights, high power is reddish, low power is bluish. Your shooting situation is using more power level. Maybe because D7000 is ISO 100?<br>

But the flash knows what power level it used, and it is designed to know about what color temperature that is. If on the hot shoe, it can report this temperature to the camera. If WB is Auto, the camera can use it for WB. You will like it. (Flash WB is "close", but is a constant regardless of power level.)</p>

 

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<p>Perhaps flash color temperature does not change more than some 5% with flash duration change (or energy/power change). This is the nature of the technology, and not deficiency of Nikon flashes.

<p>It your flash color does change, it is due for Nikon service or at least for checkup, like in the statement:</p>

 

<br>

<em><strong><strong>

<p>Have Nikon spot-check your Speedlight regularly</p>

</strong></strong></em>

 

<br>

By sending flash temperature information to the camera, that is a constant value regardless what power output is needed, Nikon just makes sure that other pre-set temperatures are not used in auto while balance mode with flash used.<br>

 

<p> </p>

<br>

 

<p>Nikon recommends that you have your Speedlight serviced by an authorized dealer<br>

or service center<strong> at least once every two years</strong>.</p>

</p>

<p> </p>

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<p>No, the results may be more constant, but the Flash Color Temperature Communication is NOT a report of a constant number. What would be the point of that? Camera flash WB is the constant. We already have that constant, which is ballpark, but which is the problem when power level varies.<br>

<br />All flashes do this, that is correct, and right, it is not at all specific to Nikon flashes.<br>

<br />Nikon is not going to say much about all flashes varying though, but they do word it this way:<br>

<a href="http://www.nikonusa.com/Learn-And-Explore/Nikon-Camera-Technology/ftlzi4zw/1/Flash-Color-Information-Communications.html">http://www.nikonusa.com/Learn-And-Explore/Nikon-Camera-Technology/ftlzi4zw/1/Flash-Color-Information-Communications.html</a></p>

<p>Says "transmits information to the camera about the color temperature of the light that it is emitting."<br>

The flash manuals describe Flash Color Temperature Communication as<br /><br />"Flash Color Information Communication<br />When the SB-600 is used with compatible digital SLRs, color temperature<br />information is automatically transmitted to the camera. In this way, the<br />camera?s white balance is automatically adjusted to give you the correct<br />color temperature when taking photographs with the SB-600."<br /><br />(on Page 5 of SB-600/SB-800 manual, and page B-3 of SB-900)<br /><br />But it requires a hot shoe flash and Auto WB to get and use this communicated value.<br /><br />All flash tubes change color with power level. This is very normal of course, and a necessary fact of life, and Wikipedia describes it here:<br /><a href="http://en.wikipedia.org/wiki/Flashtube#Output_spectrum">http://en.wikipedia.org/wiki/Flashtube#Output_spectrum</a></p>

<p>Flash tubes cannot "not vary", and here is a report of measured values for some studio monolights at different power levels (some are sort of high dollar):<br /><a href="http://forums.dpreview.com/forums/read.asp?forum=1025&message=7891229">http://forums.dpreview.com/forums/read.asp?forum=1025&message=7891229</a></p>

<p>Speedlights vary too of course, and they have more range, and the mechanism is different (opposite in some ways - at low power, monolights become slow and red, but speedlights become fast and blue). But their color temperature still necessarily varies with power level, and this is pretty basic. You can see it shown in the last combo picture near the bottom of the page here<br /><a href="http://www.scantips.com/lights/flashbasics3c.html">http://www.scantips.com/lights/flashbasics3c.html</a><br>

(some are pink, some are blue, depending on speedlight power level)<br /><br />Just how it is.<br /><br /><br /><br /><br /></p>

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<p>"<strong>Interestingly my D3 also has a very warm tone when used with SB-800"</strong><br>

Settings for D3 + SB800 :</p>

<p>OUTSIDE (sunny day) - Picture control = "Neutral" ; WB = sunny</p>

<p>INSIDE - Picture control = "N" ; WB = auto</p>

<p>NO MORE WARM TONE</p>

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<p>Another Nikon's blunder in this statement:</p>

<p><em>"In Auto White Balance mode, the master Speedlight—the unit attached to the Nikon D-SLR, transmits information to the camera about the color temperature of the light that it is emitting."</em><br>

<em> </em><br>

Nikon flashes do not have capability to vary color temperature of the light they produce<em>. </em> At any of the flash power ratio setting, or at any automated light output, the flash light produced has a constant temperature.</p>

<p>Possibly, Nikon uses a different white balanced algorithm applied to the picture data for different levels of flash power output in AutoWB, but has no abiity to chage color temperature of the light prodiuced by the flash.</p>

<p>This is anotheer example where Nikon cannot get too technical, and explains this the way that could possibly make sense, even if it is not exactly true.<br>

You could add this statement to collection of other misgivings, omisions, misrepresentations, or plain errors, produced by Nikon or their vendors.</p>

 

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<p>Some large studio lights, perhaps Elichron ?, or monolight, they do vary color temperature when the power output is controlled by applying varying voltage level of the capacitor, and do not use a thyristor for output control. This is not the case with most thyristor controlled small auto shoe mount flashes, including all Nikon flashes.</p>

<p>If a flash duration is listed as longer when a smaller power ratio is selected, then most likely this is a flash where temperature of light produce will change, due to different discharge voltage applied to the flash tube.</p>

<p>Thyristor controlled flashes use constant high voltage capacitors, and do not vary their operation voltage, and produce the same light color temperature at full power or at fractional power. Only duration of the light changes,but not the output color temperature, since the lamp voltage discharge level is constant.</p>

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<p>>>Nikon flashes do not have capability to vary color temperature of the light they produce<em>. </em> At any of the flash power ratio setting, or at any automated light output, the flash light produced has a constant temperature.</p>

<p>LOL Obviously not true. I wonder what planet... :) Because - Any flash pulse quickly peaks to maximum output (blue hot), and then slowly decays into the red cooler tail, becomes redder and redder. Full power averages color over this duration, supposedly to Daylight white for Xenon. </p>

<p>The Speedlight lower power durations largely truncate the trailing red tail. Removing red, leaving blue initial hot initial pulse. Picture becomes more blue. Color definitely varies with power level, in this way. Plus of course, in the first place, the Xenon flash tube spectrum varies with energy too.</p>

<p>Monolights typically have no thyristor-type truncation (I know two exceptions). Their low power just turns flashtube voltage down... cooler and cooler, redder and redder (and slower and slower instead of like the fast truncations). True no matter what price you pay (all the rest is just wishful thinking).</p>

<p>Exceptions: High dollar studio packs can be more elaborate, and the new Paul Buff Einsteins also are elaborate.</p>

<p>So no, it can only be correctly worded that "flashes do not have capability to CORRECT the color temperature of the light they produce". This color temperature definitely varies with power level, in any flash tube. See the previous Wikipedia link. It just does, fact of life. We can leave out the word Nikon, since this is not about Nikon, it is about flashes. But Nikon is no different. This is true of any flash tube in any flash - Xenon color spectrum simply varies with power level. Just how life is.</p>

<p>What <strong> Nikon Flash Color Temperature Communication</strong> does is to "report" the approximate color temperature represented by the current power level (it does know power level, and the firmware contains a chart). Then Auto WB can take corrective steps (but is only approximate steps). Surely you do not claim Nikon does not know how their flash works? Hot shoe flash is a very different mode of Auto WB than otherwise.... different animal with hot shoe flash.</p>

<p>I agree the WB info appears to report a constant 5400K with Auto WB, but that is only a superficial part of this story. It is not like you must have interpreted it. We can set Incandescent WB and then see report of a constant lower number (no matter what light we aim the camera at), but it is just a number. That number is NOT about the actual color of the scene. It is a correction to be applied. Hopefully, we do try to make WB match the actual color, but of course, it may not match, which is the WB problem.</p>

<p>You can easily see this Nikon correction in action if you have RAW. Just position the hot shoe flash at sufficient close distance so that f/22 is just barely enough power to avoild the blinking error. Then use TTL BL to take same picture at each stop, f/22, f/16, f/11, f/8, f/5.6, f/4, f/2.8... so that the power requirement keeps decreasing. Repeat series in Flash WB and again in Auto WB.</p>

<p><strong>THIS MUST BE IN TTL BL mode to work</strong>. Other flash modes do NOT do this, not TTL, not Manual, etc. Just TTL BL. Real pity.</p>

<p>Do include a White Card in the scene, and then correct color in Raw, for all pictures, Flash WB and also Auto WB. Examine numerical results. Examine the range of the corrections.</p>

<p>I cannot show you, and the pictures would look all alike, and you will need to see this yourself anyway. It is trivially simple. Here are my results:</p>

<p><strong>MUST BE TTL BL</strong>. Mine was hot shoe SB-800, direct flash. D300 105mm, 1/200 second. +1EV Flash Compensation to ballpark it. ISO 200. Distance about 9 feet, adjusted to maximum distance so that f/22 rarely blinked the 0 EV error warning.</p>

<p>Indoors, without the flash, it is an extremely black frame (no ambient confusion). There are always minor inconsistencies, but waiting a few more seconds after Ready LED comes on can affect these numbers somewhat. I triggered the next when the rear LCD timed out.<br>

Numbers reported in Adobe ACR are:</p>

<p>Original w/Flash WB near 5900K (blue)<br />Original w/Auto WB near 5400K (more red)</p>

<p>You are merely saying the number is always 5400K, but which means nothing about the flash.</p>

<p>No matter what, we always need to pay attention to correcting White Balance. So, then do necessary correction using White Card included in test scene (Adobe ACR). All pictures below were color corrected, and the resulting number examined.</p>

<p>Flash WB, correction result reported:<br /><br />f/22 6350K<br />f/16 6550K<br />f/11 6600K<br />f/8 6700K<br />f/5.6 6850K<br />f/4 6800K<br />f/2.8 6850K<br>

500K range.</p>

<p>Auto WB, correction result (this only works in TTL BL mode)<br /><br />f/22 6450K<br />f/16 6450K<br />f/11 6600K<br />f/8 6650K<br />f/5.6 6700K<br />f/4 6750K<br />f/2.8 6600K<br /><br />300K range. This is more in the range of what monolights do (but speedlights do all that truncation too).<br>

<br />Results: Flash WB 500K power range vs Auto WB 300K power range - which needs less correction - roughly half as much. Not precise, but which is improvement.</p>

 

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