wayne_f1

<p>You can buy something ready made.... For example, for about $300, the Cognisys Stopshot timer will do it. It does very many much more complicated things too, three programmable timers which can be sync'd. I use it to operate a solenoid valve to time the pulse duration and timing frequency of multiple water drops, to photograph drop collision splashes. The first drop trips a input sensor gate, which delays for the fall time (timer 2). Then it triggers the camera shutter, and waits for the shutter lag time to trigger the flash to capture it (timer 3). <br>

See for example, http://www.scantips.com/drops/shako/</p>

<p>It is not clear to me at first glance how to program the above to do your job, but seems likely possible, it is very versatile. Contacting the company can probably tell you if and how it can do it.<br>

But I can see that it also has another simple mode called Time Lapse. You can set it to trigger an output (a flash) repeatedly, from every one second (in tenth seconds) to every 24 hours. The flash trigger pulse duration is programmable (default 500 ms). This mode has no overall limiting duration until shutoff, but it will count up to 9999 of these triggers.</p>

<p>StopShot manual is here http://www.cognisys-inc.com/TechnicalSpecs/stopshot_technical_specs.php?osCsid=c6999728c0571f0f29dbafb2586a3ebe<br>

Time Lapse option, para 3.7 on page 30.</p>

<p>And there are other brands of similar timers.</p>

<p> </p>

<p>Yes, FP HSS Mode starts the continuous light from just before the shutter opens, and keeps it on continuously until the shutter closes. The goal is to mimic a continuous light. The only useful word is "continuous". Any exposure properties are exactly the same as other continuous sources, sunlight, tungsten bulbs, fluorescent bulbs, flashlights, campfires, etc.. </p>

<p>Speaking of X or M sync, FP flash is like the old FP sync bulbs, which were longer burning flashbulbs expressly for focal plane shutters, exactly the same thing for exactly the same purpose. Continuous duration while the shutter is working.</p>

<p>FP flash does appear to "flash" to humans, seen as a brief pulse, but interaction with shutter speed is very different than like shorter flash. Its duration is longer, lasting perhaps a 1/4 second duration, being "on" continuously all the time the FP shutter is in the process of being open in any way. So all of its properties regarding shutter speed are same as any continuous light, and not at all like flash.</p>

<p> </p>

<p>>It appears from your statement that HSF breaks the rule that the shutter controls the ambient light and the aperture the flash ... when the focal plane shutter gets faster it also affects the flash strength ... complicated :-)</p>

<p>Yes. FP flash mode is extremely different than regular flash. Simply said, no FP shutter can sync flash faster than maximum shutter sync speed. Period. That is what maximum shutter sync speed is. So FP mode changes the flash instead, to become a continuous light (rapidly repeating flash pulses to mimic continuous, for the FP shutter travel time, but at much reduced power level in order to be continuous). Continuous light has no sync requirements (same as sunlight). Note that continuous light has no motion stopping ability like flash, so the FP mode is NO LONGER a Speedlite. FP mode is continuous.</p>

<p>Realize the difference - there is continuous light (sun, incandescent, fluorescent, etc) - always on with respect to period the shutter is open. And there is instantaneous light (regular flash), extremely brief, hopefully sync'd to happen sometime while the shutter is open.</p>

<p>Regular flash duration is near instantaneous, at least shorter (faster) than any sync-able shutter speed, therefore shutter speed does not affect regular flash exposure. It does not matter how long the shutter might stay open afterwards, the flash finishes nearly instantaneously, and nothing more can happen, exposure-wise. As you say, this difference with regular flash allows us to use shutter speed to control ambient background, while exposing flash properly with aperture (and flash power).</p>

<p>But FP flash mode is NOT regular flash, not even close. FP flash (HSS, faster shutter than a FP shutter speed can sync) is continuous light (for the brief duration of the focal plane shutter travel). It is no longer Flash at all, it is Continuous light. Continuous light has no sync requirement. Works same as a desk lamp, or a flashlght, or the sun, or other continuous lights. It is on both before and after the shutter duration activates.</p>

<p>Continuous means, if you double the shutter speed, the light sampled in that shorter duration is reduced to half. Exactly like sunlight.... continuous. So yes, unlike flash, shutter speed definitely affects continuous, including FP flash. However, in practice, like sunlight, we simply open the aperture correspondingly to produce an equal "equivalent exposure", so in that sense, it does not. Same as sunlight.</p>

<p>If your camera is set to an automatic metering mode (aperture or shutter priority), then in sunlight, we twist the dials with wild abandon, and as we change one of them (shutter or aperture), the other is automatically compensated, to be same equivalent exposure. FP flash works exactly the same, same continuous light. Regular flash does not, not continuous. Very different animals.</p>

<p>So in regard to seeking to meter 1/4000 with a 1/1000 meter, it really does not much matter. Just meter for 1/1000, then open aperture two stops for 1/4000 (equivalent exposure, FP flash is exactly like sunlight).</p>

<p>This is surely fill flash, where you must balance the ambient too. Because FP mode would seem a dumb choice if it were the only light (indoors for example). Because regular flash mode is at least 4x stronger, and the flash is also vastly faster to stop motion. The only possible advantage of FP flash mode would be to use fill flash with a wide aperture in bright sunshine.</p>

<p>FP flash is different than sun in one way... sun is many millions of miles distance and inverse square law does not affect it here on Earth. But the flash distance is only a few feet, so small distance changes will decimate the flash however.</p>

<p> </p>

<p>>> What if I were to shoot directly into the sun, do shutter speeds above 1/1000 still have no effect on the scene?</p>

<p>Result is correct, but the reason why is not precise.</p>

<p>Definition: FP flash mode is a series of rapid sequential flashes, for the purpose to mimic continuous light, like the sun or a desk lamp is continuous. FP flash mode no longer acts like "flash", instead it acts like continuous light, like sunlight (continuous for the duration of the focal plane shutter travel).</p>

<p>So... we know continuous light (like sun light) has "equivalent" exposures.</p>

<p>1/500 at f/11<br>

1/1000 at f/8<br>

1/2000 at f/5.6<br>

1/4000 at f/4</p>

<p>These are equivalent exposures. True of continuous light - so true of sun light, and true of FP flash mode.</p>

<p>Your SB-900 shows maximum flash range distance reported on its LCD (with level flash head). In FP mode, you will see that that maximum range distance is all the same, for any FP shutter speed (FP - faster than 1/250 second) - when and if the aperture is adjusted accordingly, to be equivalent exposures.</p>

<p> </p>

<p>Search for Aperture. For example<br>

http://en.wikipedia.org/wiki/Aperture<br>

The fstop number is (focal length / aperture diameter), and is a magic number so that at the same aperture, say at f/4, your 200 mm lens and your 35 mm lens will see the same exposure.</p>

<p>The Sekonic L-308S is great for flash indoors, easy to use. But it only does shutter preferred exposures. Which is required for flash, so that's great, but we might want aperture preferred outdoors.</p>

<p>"You can use cords to connect two SB-400 together and get them to flash simultaneously"</p>

<p>I would doubt you can even do that. I think the AS-10/SC-26 is doomed too. These were called TTL cables, meaning old film TTL mode, which was named TTL. Obsolete now, they are not iTTL cables. There is no such thing as a iTTL cable, because multiple iTTL flash uses the commander wireless system. Nothing else is defined. </p>

<p>Two SC-28 might be cool, but that is not how the system is designed. One iTTL works in the hot shoe. Multiples work wirelessly. Two might possibly work that way anyway somehow (no clue), but the hot shoe iTTL system is not designed to share among multiple flashes. It seems the hardest possible try. Not your fathers flash system. :)</p>

<p>The SB-400 is not quite a complete flash. It's menu is in the camera menu. It requires the camera and hot shoe to work at all (which includes the SC-28 hot shoe extension cord). No way it will work off camera with an optical trigger or radio trigger - it has no Manual mode without the camera menu. It will never work standalone not connected to the hot shoe. It is not a "whole" flash. It needs the camera hot shoe to work.</p>

<p>The SB-400 was only designed to operate in the camera hot shoe. If you want two remote flashes, you will need two of a different flash model, used either wirelessly, or with a real Manual trigger system. <br>

SB-600 to SB-900, or SB-R200 in its way. Just how life is.</p>

<p> </p>

<p>>>Commanding is a two directional communication, where the other way goes through the lens.</p>

<p>? This is confusing things. Commander has no receiver, no provision to receive anything. Remotes have no IR transmitter, no output except regular flash. Commands are one way.</p>

<p>Commanders have Groups, A, B, and some have C. Commander outputs sequential commands to each group not disabled. If TTL mode, the command requests preflash. If there is a flash in that group, it responds and the metering system meters it, then commander can give command for power level to use. If there is no flash in that group, commander shrugs, and continues to next group. Matters not in the least if there is no flash present.</p>

<p>If the commander group mode is Manual, then immediately before shutter opens, the commander merely issues the power level signal from the commander menu (same here as TTL power level). If there is a flash present in that group, it obeys. If not, who cares? Progress goes on. This should not affect use of its red assist light.</p>

<p>>>I doubt if SU800 commander could be used as a focus assist device,</p>

<p>See SU-800 manual, page 91. Range is up to 33 feet. Works same as the speedlights.</p>

<p>Don't know if it would be allowed, but the assist ought to work. Commander is a one way data transmission. It does not know if there is any flash out there or not. If there are flashes, they will receive the signal and do their thing. If not, no matter, no response expected anyway.</p>

<p>I would set all but one Commander group Off, and set that one to MAN, to speed up shutter lag... to not waste time with more signaling.</p>

<p>The aperture and ISO settings on the flash can only be used two ways:</p>

<p>The flash has its own Auto mode (probably not used), where it attempts to use its own light meter sensor (in the flash) to evaluate its flash return (reflection from subject) to try to control the exposure itself, without assistance. That needs to know ISO and aperture that the camera will use, to match it, so exposures match.</p>

<p>If it may also have have maximum range display on the flash, that will need to know ISO and aperture to compute this range - again, to match what the camera is doing.</p>

<p>But none of this has any effect at all on your exposure in the camera. Not matter what the ISO and aperture settings on the Flash are... no matter what - if you tell it to use 1/4 power, it will use 1/4 power. That is all that matters.</p>

<p> </p>

<p>I don't know, I can't think of any use for a hole down in there, except my guess is that it just makes it weigh less, and maybe more importantly, it saves some scrap material they can recycle. Seems to seriously limit its versatility, in that it can only be rotated one way to be able to clamp on it.</p>

<p>You can replace it here: http://www.bhphotovideo.com/c/product/438701-REG/Smith_Victor_661205_Brass_Adapter_1_4.html</p>

<p>You do NOT need the SG-3IR shield at any halfway long distance. Only for close and shiny subjects, for example macro work.</p>

<p>My experience, using D300 internal commander to trigger a SB-800 in Remote mode,<br /> with the flash indoors (aimed out the open door via 50 foot path in the house),<br /> and the camera across the street in bright sun (flash must see that target), then:</p>

<p>the D300 triggered it from 118 to 120 feet.</p>

<p>With the SG-3IR shield on D300, from 77 feet.</p>

<p>A SB-800 commander on the hot shoe triggered it from 88 feet (no IR shield, but same situation). However, long zoom would strengthen it.</p>

<p>The SU-800 has the similar internal IR shield, and I would expect slightly less, 50 to 60 feet, from hearsay.</p>

<p> </p>

<p>The Nikon commander trigger signal can reflect to cause a catchlight in close or shiny things - even the eyeball catchlights in close portraits - and the SG-3IR panel can prevent it (designed for close macro work). But it is not usually a problem, and is usually not necessary in most situations.<br>

You can see examples at http://www.scantips.com/lights/awl.html#panel</p>

<p>If you suspect the flash is triggering as Rear Curtain Sync when it should not, you can verify or disprove this very easily. Just set a 1 second shutter speed, and press the shutter button. The 1 second allows humans to distingish when the flash triggered.</p>

<p>In flash modes other than manual flash, you might see a preflash just before the 1 second shutter starts, which will be indistinguishible from any real front curtain sync which may occur then too. Only if there is a flash near the end of the 1 second can it be rear curtain sync. If no flash near the end of the one second, then it is not doing rear curtain sync.</p>

<p>Geoff, is the flash working well now? The LCD -3 seems a bit puzzling. It says the last flash exposure needed 3 stops more flash power than the flash was capable of delivering (SB-600 page 29 is a good page to memorize). If bracketing was telling it to use less exposure for the second (was it?), I doubt you would get that warning, assuming first was about OK.</p>

<p>After the 5 seconds recycle, it should do all it is ever going to do. But if triggering it before the Ready LED is on, then yes, you will get unpredictable flash - probably at lower power level than expected. If your setting only needs say 1/8 power, another quick flash or two might work OK. But high power has to recycle first.</p>

<p>NiMh rechargeable batteries will recycle a bit faster than alkaline or lithiums (page 19 shows full power recycles - but most uses are less than full power and faster).<br>

Sanyo Eneloop batteries are about as good as there is.</p>

<p>Great, bracketing is the best possible answer. :)</p>

<p>Sure, TTL works fine with bounce. Regardless if you use direct flash or bounce or an umbrella or a quart fruit jar over the flash head, some amount of light will reach the subject and reflect back to the camera metering. The metering will give you a flash power level suitable for that received amount of light (to give a good final exposure).</p>

<p>It does not directly measure distance, but it definitely measures the "result" of the longer path up to the ceiling and back down, and also the losses at the reflected bounce. Does not matter where you send the light, TTL measures the light that makes that total trip back to be metered.</p>

<p>Old timers story: In the very old days (flash bulbs and no automation), we used guide numbers. Guide numbers are for direct flash. But for bounce (thinking roughly in our heads), we calculated from the Guide Number by using half again more distance than direct, which approximated the 1.414 square root of 2 for a hypothetical path at 45 degrees up to the ceiling, and back down. Then we opened up one more stop, for the losses at the ceiling reflection. 1.5 is not 1.4, and it usually wasn't 45 degrees anyway, but negative film had much more latitude than does digital (easy to correct in dark room), so this normally worked pretty well.</p>

<p>Today, TTL simply just meters it. And bounce is the good stuff for hot shoe flash. And a **SMALL** bounce card is a good thing too, to add slight frontal fill. But don't overdo it (with too large a bounce card), so as to cover up all your bounce light. You want to see the bounce light.</p>

<p>Also, learn to pay attention to TTL results, and if it needs 1/2 stop more flash (or whatever), simply give it 1/2 stop more. Flash Compensation is how you do that, it makes all the difference.</p>

<p>No, camera Manual mode and flash TTL mode is one of the best choices for indoor flash (as you know). The TTL flash is still automatic, in any camera mode.</p>

<p>Your reported behavior seems pretty strange. Should not do that of course, it should be quite repeatable in same situation. It could be a flash unit defect, but that really sounds unlikely.</p>

<p>All I can think of is to check your camera's Bracketing setting, and make sure Bracketing is turned off. Flash is one form of Bracketing, changing things from shot to shot, which you may have forgotten since last you used it. D90 pages 92-94.</p>

<p> </p>

<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>

<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>

<p>You are asking about D90 menu E1 - Flash Shutter Speed. The default (Minimum Shutter speed with Flash) is 1/60 second. This E1 menu will allow it to go slower (lower minimum). This applies only to camera A or P mode. This is a Minimum shutter speed. If outdoors in bright light, it will always go faster (to whatever is metered).</p>

<p>There are also two other ways to do it. </p>

<p>Slow Sync mode (D90 page 71) will allow camera A or P mode to use the actual metered shutter speed (which may be very slow in a dim setting where you need flash, like maybe 1/2 second). This is the metered value of ambient, it uses whatever is metered in that dim room.</p>

<p>Best way for flash in any dim setting (for example indoors) is to use camera M mode, and simply set any shutter speed you wish. Shutter speed does NOT affect flash.</p>

<p> </p>

<p>First thing to check is to make sure your D90 E2 menu for flash mode on TTL (D90 page 185). It would likely do what you describe if you instead had it at Manual, full power.</p>

<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>

<p>I dropped my Nikon 12-24 on a D300. Camera was OK, but filter threads were messed up good. Nikon repaired it for $179, plus tax and shipping was $207 total.<br>

Replaced: Lens barrel, Filter ring, zooming ring, Roller / Guide Ring<br>

Checked focusing, apeture, zooming, infinity focus, exposure.<br>

General check and clean.<br>

It took awhile awaiting parts. Well worth it, was like new. I had home owners insurance policy covering camera gear, which fully reimbursed it. This repair paid for two years of the insurance on $9500 of gear (recommended).</p>

<p> </p>

<p>The commander menu mode "- -" will turn the internal flash off, but it is still commander, and still must fire commands before the shutter opens.</p>

<p>Then when the shutter opens, there is a weak "Everybody fire Now!" signal to trigger the remotes. Normally it has little effect, but it can cause catchlights in shiny near subjects (perhaps eyeballs)... This can be solved by using the $12 Nikon SG-3IR panel.</p>

<p>See http://www.scantips.com/lights/awl.html#panel to get the idea of what actually happens.</p>