540 help

hi all... i would like to ask a few question regarding the 540 flash...

firstly i had a group shot with few other brands last month but mine are mostly underexposed. i am pretty sure that my flash fired according to the pentax software... standing distance are the same about 2~3 metres...

secondly i notice that the maximum shutter speed is fixed at 1/180 while other brands can go till 1/4000...

lastly when i use prime lens my flash cannot fire no matter what mode i use on the camera as well as the flash...

any ideas what the main cause beside user problem? real appreciate all the help i can get here... tks

The Pentax flash system does tend to underexpose, especially if the subject itself is bright or reflective. Add a bit of compensation on the flash, or exposure compensation on the camera.

To use a shutter speed higher than 1/180th, you'll need to use high speed synch. You too can use a shutter speed of 1/4000th if you want to.

If you mean your shutter doesn't fire when you use a manual lens, you need to change the custom menu setting to permit use of aperture ring.

Hope that helps.

Hi,
I'm interested in this, because I haven't got a new flash yet.

Which camera are you refering to when you say that your shots are under exposed?
Peter

well i have tried with my subject indoor but with outdoor background... results are totally underexpose... havent tried to increase the compensation on both the flash and camera... will it helps?

i can shoot with my manual lens so i supposed my aperture ring is permitted already but yet i cannot fire my flash still... anymore setting that i should take note of?

anyway tks for the inputs...

Hi,
I'm interested in this, because I haven't got a new flash yet.

Which camera are you refering to when you say that your shots are under exposed?
Peter[/quote]hi i am referring to my pentax 540 flash and k20d...

In order for your flash to work in P-TTL mode it requires information from the lens as well as the camera, if you're using an older (manual) lens then P-TTL is unable to work; hence you need to set your flash to either manual or auto mode.

In order for your flash to work in P-TTL mode it requires information from the lens as well as the camera, if you're using an older (manual) lens then P-TTL is unable to work; hence you need to set your flash to either manual or auto mode.[/quote]i am using the smc pentax-m 1:1.7 lens so i guess p-ttl wont work right? bur then again i have tried all mode on the flash as well as the camera but still no flash fire...

anyone got this problem as well?

No, no problem at all besides what has been said and P-TTL doesn't work with that lens.
I know I'm very helpfull now...

but i still cannot get my manual lens to work with my flash no matter what mode the falsh is in...

Went into the magic latern book since i don't have an old lens by the hand and it said nothing with KA lenses but with K or M42 it says: "The built-in flash will always fire at full power and will rarely provide correct flash exposure, and the FGZ series flash units wil not provide the high-tech P-TTL controll." this from the K10D book but the camera's are almost the same.

It might be a problem in what camera mode you're shooting but if you set everything on munual it will certainly need to work no matter what lens you're using, if it doesn't it must be a fault somewhere so simply go back to the shop we can't do much without holding your camera in our hands.

edit: typos

I have K20D, AF540FGZ, but I don't have a SMCP-M 50mm 1:1.7 lens.

The nearest I have is a SMCP-M 400mm 1:5.6 lens.

Settings: ISO 100, f16, 1/125th

My findings:-

P-TTL mode on flash - flash fires and discharges 100%. Note that when the shutter button is pressed halfway, the flash switches to TTL mode, which is not supported on the K20D, hence the flash fully discharges.
A mode on flash - flash fires and exposure is as expected, slightly underexposed.
M mode on flash - flash fires and exposure is as expected, slightly underexposed.

My subject is a white eagle statue on a pine backed shelf.

Result: Everything works as expected.

Try firing the flash with no lens on the camera and tell us what happens.