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K1 and flash - help please

Cayman
Posted 30/05/2017 - 20:53 Link
OK - so i have a problem using the K1 with my AF360FGZ: the aperture I am selecting in P mode is not the aperture used for taking the picture.

I have been in P mode with P-TTL but although the viewfinder displays an aperture of say f8 or f11 the picture is actually taken at f2.8. The flash is connected to the hot shoe and is in the bounced position.

I get this problem with the DFA 24-70/2.8 and with the Tamron 28-75/2.8. If i set the camera to M mode then all is fine - I get the aperture i have selected.

Any ideas? I am sure i am doing something silly but I don't recall having this issue with other Pentax DSLRs.
McGregNi
Posted 30/05/2017 - 21:12 Link
Just a quick question first .... Are you half pressing the shutter button with the flash turned on before then taking the picture? The displayed aperture should be the correct one after the half press. The flash will impact the possible apertures the program mode can choose, because it will limit the shutter speed to 1/180th.

The discrepancy might be because when you're setting the aperture the metering circuit has gone to sleep, therefore it doesn't factor in the flash.

Are you using a long focal length? This might he forcing the aperture open to keep shutter speed fast for steadiness. Also check your Program Line setting. ..... The MTF setting might be more suited to your flash images.

Personally I recommend Av or M modes for the needed control over flash photography.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
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
Edited by McGregNi: 30/05/2017 - 21:17
Cayman
Posted 31/05/2017 - 17:46 Link
Thanks for that - whatever the issue was i don't seem to be able to reproduce it, so i don't think it's a hardware issue. I suspect it may have been the metering circuit going to sleep or the flash pins not being perfectly located in the hot shoe.

And yes - i generally use M mode with flash and use a Metz 45 CL4 which always seems to give me the correct exposure first time

Cheers for the advice!
RobL
Posted 31/05/2017 - 18:12 Link
Minor correction McGregNI, max flash speed with the K1 is 1/200
McGregNi
Posted 31/05/2017 - 22:19 Link
Yes thanks Rob, now we have to remember that difference between camera models, a fairly new thing!

Cayman, I'm glad to hear the issue is not persisting. Sometimes full automation is handy, but I rarely find it works well for flash ..... We get the results by taking firm control of at least 2 or 3 of the key exposure settings.

I hope your flash work with the K1 keeps going well ....I certainly envy you with that dynamic range and ISO performance!
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
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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