High Speed Sync Query
Good luck with your latest project.
Al
Will test when I get half a mo'!
Matt
(For gallery, tips and links)
What I'm interested in confirming really, is the apparent good performance of HSS using P-TTL mode with 'a' series lenses. In theory (I thought) any P-TTL operation should not work with 'a' lenses ?? And it certainly doesn't, not consistently, in normal mode (ie not HSS) - but for some mysterious reason, exposures and compensation adjustments in HSS mode seems to work perfectly with 'a' lenses! Great I say It will make for some great wide aperture outdoor portraits
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
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5986 posts
12 years
Surrey,
England
Now, we're lucky of course to have a gun that offers P-TTL, TTL, Auto & manual flash modes - wow, we can really have it all ... but I've noticed an interesting thing ... tell me what you think ...
In theory, P-TTL is not compatable as a flash mode for anything other than autofocus lenses - and mostly thats going to be the later DA type, or third party AF equivelants. (It says so in the manual). So, for A-series lenses, if we want auto-flash on a digital SLR then we should use Auto Flash mode ('A' on the LCD display). Here we tell the gun the ISO & aperture. It needs to be told that because the lens / camera does not send the info through the contacts, nor does the flash get distance and focus info - sound right so far?
Now P-TTL just doesn't work with 'a' lenses - in practice I have found that some lenses will activate P-TTL and you can get a decent exposure, but there's very little consistency - try any bounce and you'll soon see!
BUT - and this is the question really ... my tests have shown very consistent and repeatable performance with HSS , in P-TTL mode with 'a' series lenses ... in manual exposure mode with HSS set on the flashgun you set a speed higher than 180th (this then controls the 'background' lighting) and let the flash provide the 'foreground' lighting using HSS. You get the normal P-TTL flash exposure compensation adjustment (+1 / -3 stops), and this seems to work perfectly! I didn't think it should??? But I've had 100% perfect performance and exposures using HSS in P-TTL with 'a' series lenses ....
Is this how it should be , ie designed to be (because the manual doesn't suggest that), or is it a fortunate and explainable freak of the technology that just gives us lucky Pentax people another great choice for flash shooting?
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver