High speed sync flash ( FP )

<p>I have K-10 and Sigma EF -500DG SUPER. For high speed sync, the lcd panel on the flash displays FP. As per Sigma manual any mode on the flash with FP indicator can be used for high speed sync. Similarly on the camera, too, any mode can be set. However, I am confused about the camera mode. In AV mode, the shutter is automatically set at 180. In TV mode, though higher shutter can be set there will be no control over aperture. The only way out appears to be manual mode-when shutter/aperture both can be set. But then proper exposure would be trial/error exercise. I would like to know- which mode and settings to use when the flash is in FP mode.</p>

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<p>I have <strong>[Pentax] K-10</strong> and Sigma EF -500DG SUPER. For high speed sync, the lcd panel on the flash displays FP. As per Sigma manual any mode on the flash with FP indicator can be used for high speed sync. <strong>Similarly on the camera, too, any mode can be set.</strong></p>

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<p>I don’t have a Pentax K-10, but your question interested me enough to read various sections of the camera’s Instruction Manual.<br>

Are you sure that the Instruction Manual states: “Similarly on the camera, too, any mode can be set.”<br>

I ask because the text on Page 181 of the Instruction Manual under the heading <strong>"Using High Speed Sync Flash Mode"</strong> describes how to ready the camera for HSS with either of the Pentax Flash Units, AF 540GZ and AF360 GZ: one assumes that your Sigma Unit is comparable.</p>

<p>An extract from those instructions (my bold for emphasis):<br>

“1. . . . Attach the External Flash<br>

2. <strong>turn the mode dial to set the exposure mode to Tv or M</strong><br>

3. . . . etc”</p>

<p>*</p>

 

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<p>I am confused about the camera mode. <strong>In AV mode, the shutter is automatically set at 180.</strong></p>

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<p>I suspect that in Av Mode, once the camera detects a Flash Unit is attached to the Hot-shoe and is active, there is an inbuilt software safety mechanism to restrict the Tv to 1/180 or slower and that might be one reason why the Camera's Instruction Manual requests the Camera Mode be set to either Tv for M Mode to allow HSS to be engaged on the Flash. </p>

<p>*</p>

 

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<p>In TV mode, though higher shutter can be set <strong>there will be no control over aperture.</strong></p>

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<p>I suspect that is incorrect, in Av Mode you have available Exposure Compensation – the manual states: plus and minus 2 Stops in one-third Stop increments; or plus and minus 3 Stops in one-half Stop increments.</p>

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<p>The only way out appears to be manual mode-when shutter/aperture both can be set. </p>

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<p>I use Manual Mode mostly always when balancing a Flash and an Ambient Exposure. I find that the simplest procedure. But it appears that you could also choose Av Mode if you wanted.</p>

<p>*</p>

 

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<p>But then proper exposure would be trial/error exercise. I would like to know- which mode and settings to use when the flash is in FP mode.</p>

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<p>I agree that there is trial and error in a lot of Photography, but this procedure is no more a difficult exercise than using Flash without HSS engaged. One can determine and control the AMBIENT EXPOSURE by setting the Av and the Tv and the ISO in M Mode and then one uses the Flash in the TTL Mode and adjusts the Flash exposure using Flash Exposure Compensation (FEC).</p>

<p>Alternatively, as it appears with your camera, one could use the Camera in Av Mode set the ISO and the Av and employ EC to adjust the Shutter Speed to control the Ambient Exposure and then the Flash Exposure should controlled, as describe above.</p>

<p>I did not check the K-10 Instructions Manual, but I would be surprised if these procedures outlined were not allowed by your camera: it is a common procedure and has been for many years. </p>

<p>WW</p>

<p>I imagine what you're wishing for is that when HSS/FP is enabled, higher shutter speeds will be engaged even in Av or P but it appears that the camera won't do this.</p>

<p>I haven't used this much myself for flash but did you try <strong>TAv</strong> mode? The question is whether the camera will select an ISO that you're happy with. You might want to restrict maximum auto ISO as well if doing this. If not, M would probably be the way to go. </p>

<p>TAv + flash might be described in the K10D manual, it probably is not mentioned in most manuals included with flashes (the AF360FGZ/AF540FGZ manuals that William cites pre-date TAv which was introduced by Pentax with your K10D).</p>

<p>Bear in mind that when using P-TTL flash the flash power is automatically variable as well, and its output can be tweaked with flash exposure comp (on-body and possibly on-flash as well). When used in this manner, even M becomes a somewhat constrained autoexposure mode. </p>

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<p>TYPO / BRAIN ERROR:</p>

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<p>Alternatively, as it appears with your camera, one could use the Camera in<em> Av </em><em>Mode</em> set the ISO and the <em>Av</em> and employ EC to adjust the <em>Shutter Speed</em> to control the Ambient Exposure and then the Flash Exposure should controlled, as describe above.</p>

<p>Should Read:</p>

<p>Alternatively, as it appears with your camera, one could use the Camera in <strong><em>Tv Mode</em></strong> set the ISO and the <em><strong>Tv</strong></em> and employ EC to adjust the <em><strong>Aperture</strong></em> to control the Ambient Exposure and then the Flash Exposure should controlled, as describe above.</p>

<p>Sorry for that.</p>

<p>WW</p>

<p>Thanks, William for your detailed response. As suggested, I shall try Tv mode with EC which seems to work.<br>

Thanks, Andrew. TAv + flash- good suggestion, never occured to me. Surely try it.</p>

<p>Newer cameras like the K-5 and K-3 allow you to use Av with higher shutter speeds. Maybe your K-10d would be able to do it after a firmware upgrade? Something to look into if it's important to you. <br>

The drawback of this which has bitten me a few times is if the flash isn't in FP/HSS mode, the shutter speed will still go over 1/180 and then the flash just doesn't fire. It's not always obvious why when I'm in mid-shoot. </p>

<p>I have a K10d, but I do not have an HSS-capable flash.</p>

<p>The user's manual says that HSS is only supported in Tv or M modes. In all other modes, the shutter speed tops out at 1/180. See page 181.</p>

<p>I don't believe that any of the firmware upgrades (culminating in version 1.31) changed this.</p>

<p>Thanks, Matt.The firmware upgrade doesn't help.<br>

Thanks, Paul.You are right. Tv/M mode works.</p>

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<p>From original Q:<br>

The only way out appears to be manual mode-when shutter/aperture both can be set. But then proper exposure would be trial/error exercise. I would like to know- which mode and settings to use when the flash is in FP mode.</p>

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<p>In M mode on camera, the flash becomes the primary light and proper exposure is automatically adjusted by flash power (assuming xTTL or Auto setting on flash). Just make sure M mode camera settings are set to under expose.</p>

<p>Thanks, Tom. Will try it.</p>