PocketWizards, Auto FP, and Loss of power

<p>Ok, so I'm a little new to the whole PocketWizard and Auto FP options. I'm used to hard lights where the worst that will happen is if you go to a high shutter you could see the flicker in a HMI unit. So I've got a PocketWizard TT 1\5 setup, with an SB-800. Camera is D7000. When I set the flash sync shutter to Auto FP 1/250 sec, then nothing changes when I move my shutter, i.e. if I shoot in manual mode with the flash on manual and I change my shutter from 1/125th to 1/250th, then the picture doesn't change, if I then change to 1/60th from 1/250, and the picture looks exactly the same, even though I checked it in my camera and it shows the change in shutter with no other exposure changes. But the trouble comes when I go over the Auto FP number, then my exposure drastically (meaning 2 or 3 stops), gets darker!</p>

<p>So my question is, do I have something set wrong, is this just the nature of the system, that I have no shutter control under the Auto FP and over the Auto FP I'm going to loose 2 or 3 stops of exposure even though I may have barely crossed the Auto FP mark by less than half a stop?<br>

If this has already been posted, could someone please point it out? I searched but could not find anything similar.<br>

Thanks in advance for your help!</p>

<p>Auto FP causes a HUGE drain on the flash by requiring a ton of power, such that your flash's distance capability decreases exponentially when raising the shutter speed. It is mentioned in your Nikon manual, along with pretty much anywhere that discusses Auto FP. Basically, you're trying to take pictures of subjects too far away from your flash. Read these links, along with a few creative google searches, and everything will become clear.</p>

<p>http://www.nikonusa.com/Learn-And-Explore/Nikon-Camera-Technology/ftlzi4zp/1/Auto-FP-High-speed-Sync.html<br>

http://nikonclspracticalguide.blogspot.com/2008/03/10-auto-fp-high-speed-sync-explained.html</p>

<p>If you get 2 or 3 stops darker pictures, so obviously the Auto FP is not longer auto, due to insufficient power for your ISO and aperture settings, or for the distance to long, or something else set wrongly.</p>

<p>Boost the ISO, and you will get longer distance for the Auto FP, possibly up to the max CLS/iTTL range of 20 meters, or 66 ft, depending also on your aperture value used. Open up the lens aperture, if you can afford some DOF loss.</p>

<p>Your SB800 flash is your friend, so try to learn how it works and and see what it tells you. If in FP mode, or any mode, it will tell you maximum range for proper exposure, right on the back of your flash LCD screen. You just need to pay attention and understand what the flash is telling you. The max range does not display if the flash head is tilted, rotated, or any flash light altering attachment is used, then all bets are off.</p>

<p>Pay attention to any flash light compensation possibly set on your flash or on your camera.</p>

<p>If your shutter speed is 1/250 sec or slower, the flash will not operate in the FP mode, and will default to normal single flash blast mode, so you see no difference, except the possible influence from ambient lighting. This is because your camera X_sync speed is 1/250. At any faster shutter called for by the exposure automation, when the shutter is set at "1/250 FP", or on some cameras also to "1/320 FP", you will get flash FP operation when the shutter speed will get faster than the X-SYnc 1/250. This could happen in Aperture priority mode, or your setting in Manual camera mode.</p>

<p>I am not sure about the "scene" modes for amateurs on D7000, since they can have own rules for each of the easy shooting scene mode. You try and observe the flash LCD, and see how that works.</p>

<p>Pocket Wizard just switches to Nikon FP, possibly (hopefully ?) doing it at more apropriate time and conservative light duration, utilizing the Hyper Sync method heralded by PW, if it really works as claimed.</p>

<p>If you're shooting under circumstances where the ambient light is neglible, changing the shutterspeed will exposurewise not influence the picture.The (proper) exposure is determined by the settings on your camera i.e. the aperture and ISO, and the metering that is done accordingly by your camera based on the exposure as read by your camera in combination with the SB800.</p>

<p>So if you shoot in a dark space where there is no light with the aperture on the camera at e.g. f8 (which the SB800 uses to make the flash give enough light for a properly exposed picture), changing the speed from 1/10th to 1/250th will have no influence.</p>

<p>If you shoot in a space with a lot of light, or outside, where the ambient light will by itself give an exposure of e.g. f8 by 1/100th of a second, the flash exposure will still be determined by the flash. But in the shot itself, the ambient light will be less or more present if you set the speed faster (gives an picture with the main subject properly, and the background/surrundings under exposed) or slower (gives an over exposed picture).</p>

<p>The underexposure with a faster speed then indicated by the metered exposure for the ambient light can e.g. be used to compensate from a heavily overexposed background, or to create a dramatic dark background like gark clouds, looming shadows or silhouettes etc.</p>

<p>Normally if you use a speed faster then the X-synch speed, the picture will not get properly exposed (varying from dark banding to totally underexposed). The FP setting helps avoid this by rather then emitting just one big flash, giving a series of smaller pulses that in total give a proper exposure of the full picture/sensor. That comes at a cost though, as the smaller pulses will give less intense light, and effectively mean a lower GN for your flash. If your flash is too far away, or is bounced, the flash is simply too underpowered to give strong enough small pulses for a properly exposed picture.</p>

<p>If you want to keep shooting with a higher then X-synch speed in FP mode, the solution is setting your flash closer, or opening your aperture and/or ISO or using more flash units synched together.</p>

<p>The TT1/TT5 offer the socalled Hypersynch option<br>

http://www.pocketwizard.com/inspirations/technology/hypersync_fpsync/<br>

where by changing some settings in the TT1/TT5 units it's possible to use your flash unit in a normal (i.e. one big flash) way at higher speeds (to a point). Pesonally I have not chosen to go for that option, I prefer shooting in FP/Auto mode and simply adding a few more flash units in my light source ( I have a number of SB800's and SB600's in my gear), so I can't comment if and to what extent the Hypersynch stuff works.</p>

<p> </p>

<p>Yes, there is a severe loss of recorded flash output when employing HSS/FP at shutter speeds above X-sync (e.g., >1/250th). Here's a re-posted excerpt of some older tests (pre-v3.0 firmware) I performed using TT1/TT5 PocketWizard remotes a few months ago:</p>

<p><em>Body: Nikon D3s</em><br /><em>Strobe: Dynalite Uni400JR, full-power; t.5 = 1/675th</em><br /><em>HSS/FP = enabled; HSS/FP begins at = 1/500th</em></p>

<p><img src="http://studio460.com/images/FP-ON-1400-250.jpg" alt="" width="600" height="399" /></p>

<p><img src="http://studio460.com/images/FP-ON-1400-500.jpg" alt="" width="600" height="399" /></p>

<p>In contrast, employing PocketWizards' HyperSync mode (shown below) fares a bit better, up to a point. However, using HyperSync results in an uneven, vertically graduated exposure. Note also that the efficacy achieved with HyperSync is both body-specific (i.e., different bodies will have different results), and flash-dependent (longer-duration flashes will have better results):</p>

<p><em>Body: Nikon D3s</em><br /><em>Strobe: Dynalite Uni400JR, full-power; t.5 = 1/675th</em><br /><em>HSS/FP = disabled; HyperSync offset = -2,300</em><br /><em></em><br /><img src="http://studio460.com/images/FP-OFF-2300-250.jpg" alt="" width="600" height="399" /></p>

<p><img src="http://studio460.com/images/FP-OFF-2300-500.jpg" alt="" width="600" height="399" /></p>