How can I increase shutter speed while using remote flash

HI everyone
Need some help with my settings.
I am trying to set up my K20 so that I can increase my shutter speed to around 250 while using my Sigma flash remotely.
The problem is it only lets me go to 180. The moment I pop open my onboard flash so that it can be used as controller immediately the shutter value goes to 180 and as I turn the wheel if I happen to turn the opposite way it will decrease the shutter value and just remain there. If the shutter value goes lower and if I try to increase it again it won't go.
But my main problem is wanting to increase the shutter value to 250 and it won't let me do it. I have tried M mode and still it just stops there.
Am I missing something here?
Can someone please shed some light into this?
I am trying to do some abstract work with smoke so I need as much light as possible from different angles while bumping the shutter value as high as possible, oh and keeping the iso at 100 as well.

Thank you

Amin

The flash synchronisation speed is 1/180 secod. You can set whatever speed you want in manual mode, but at faster than the synch speed you will get a black bar in the image because the flash is not totally illuminating the frame.

This is a limitation of focal plane shutters.

Do you have a Pentax flash? You can set that for high speed sync, by setting the flash to HS mode. The flash will send a series of short low intensity bursts. This can result in underexposure as it is really intended for fill-in flash to lessen shadow and the like, so it may not work for what you want.
The faster the shutter speed the less light the flash emits.

As John says - that's the way it is. I have links (somewhere) of the technical side (I haven't time today to describe it!)

If you're trying to "freeze" action - the flash itself will do this anyway. The burst of light from the gun can be much, much shorter than any focal plane shutter can achieve
Matt

Thanks for that suggestion.
I have a Sigma EF-530 DG Super and have been knocking my head to try to work it wirelessly and in HSS. And still haven't managed.
Talk about reading the manuals, , and before someone tells me.. yes I have read the manual and been following it through, but still aaaaaaaahhhh can't get it to work.
I might be doing something wrong but not sure what it is. This sigma flash menu system is a total disaster. Its a great flash but whoever wrote this UI really did a lousy job.

I am quite well capable of using the flash wirelessly as slave, have been doing so quite efficiently, also manage to use the onboard flash as controller but just cant get the menu to hold at FP (HSS in sigma flash language).

Anyone please help if you have an idea. Thanks

Amin

The K20D popup flash cannot trigger HS wireless flash
You can only do wireless HS with two flashguns.

Amin - why do you feel you need higher shutter speeds with the flash?

Matt

Thanks Matt.

I was thinking of bumping up slightly more the ss to shoot some smoke images. I
Aparently the other way would be to shoot in a darkened room.

This might be a really daft question so please excuse my total ignorance in this, but from what I read for example the ss for some of the hummingbird images taken is well above 180.

Can you please just help me understand a bit more about this?
thank you in advance


EDITED: My apologies Matt, I just read some details that have now given me the full idea of it . I should be able to get what I want at 180ss, just need to darken my shed a little
its here link

Amin,
Yes, as long as the ambient light is one or two stops under your "correct" exposure it won't matter - the duration of the flash light will freeze any action.

If you want really fast flash then make sure the flash isn't trying too hard. If the flash discharges completely then it's quite a long flash pulse. If you up the ISO and can get away with around 1/32 power then the flash duration is going to be extremely short (around 20ms perhaps) - that's an equivalent shutter speed of 1/50000 (one fifty-thousandth of a second)

Haven't actually measured the Pentax flash duration...
Matt

Hi Matt
Thanks again for this. I see a long day in the shed probably tomorrow trying all these settings.
My problem in order to achieve what I want is that I am limited to the very low ISO. I want very little or preferably none of the noise if possible so would like to shoot at 100 ISO.

Also I want the intensity of the flash output to be as maximum as possible while as you mentioned keeping the duration as low as possible so that I can freeze the subject.

Last time I experimented with this I had to physically position the flash (in wireless mode) to the side of the subject, a few inches away but making sure that the background did not get any light at all from the flashgun. So basically I was literally working with the flash discharging the light partially towards the lens. I seem to be able to put up with that light as long as there is nothing going to the background which then ruins the setup.

Any more ideas or input for me to experiment would really be helpful, if you think of any. I am using the Sigma EF-530DG Super flashgun.

Reading one of the sites that someone experimented shooting the subjects they used a 2000W Bowen studio flash light. Aparently to make this work efficiently a lot of light is required.
Do you think anything close to this can be achieved with my flashgun? and as you say by bringing it to 1/32 and adjusting the exposure?

thanks

Amin

Matt
been doing some experiments and just like you said, I can darken the background by playing out with the aperture settings and keeping the shutter at 180 given to me by the default settings. And also using the exposure settings to regulate it.

One question to then put this to rest and go into the shed next time and waste my K20 battery please, as this manual of the sigma is such a pain, let me see if I got this correct:

The setting on my Sigma flash which allows me to move 1/2, 1/4, 1/8 etc up to 1/64 relates to what please? Is this the time of the flash output? in relation to seconds? And does the intensity remain unaltered? (because I want the highest light output possible but keeping it on fraction of the time)
And if not how do I achieve that?

And the other setting I see the -0.5, -1, 0.0, +0.5 and 1.0 what exactly is this?

I can shuffle and achieve all the settings, its understanding what they stand for that now I am getting to grips with.

Cant stop mentioning how bad this manual of the sigma is. I am sorry if I am getting to someone's nerves with this but just wanted to get it out of my system .

Thanks again for all your help.

Amin

I don't have your flash but I guess that:

1/2, 1/4 etc are the power of the flash compared to full power (regardless of any metering), i.e. half power, quarter power etc.

-0.5, -1.0 etc are probably half a stop under exposure, whole stop under etc. compared to the metered reading.

HTH. Kris.

You need to set the flash on manual mode, then you get 1/4 1/8 etc.

Amin,
The "1/2", "1/4" are power outputs used when the flash is in manual ("M") mode. With a fixed setup you are always best using fully manual anyway. Each power stop is one "stop" lower. So, if you had a good exposure with 1/4 at f/8, then 1/2 at f/11 will give you the same exposure, as will 1/8 at f/5.6, and 1/16 at f/4, etc.

However, be aware that 1/1 (full power) takes time to discharge, and that "1/64" will take far less time to discharge than 1/1.

If you are taking shots of a hummingbird then you may need to be using a flash power of much less than full power - to get the really short flash duration. However, if you are taking shots of smoke then I reckon it's not going to matter at all. Try at 1/2 power first and work from there - too bright, reduce the power; too dark, increase the power to 1/1.

The -1, -0.5, 0.00 etc are exposure compensation values - usually when the flash is in P-TTL "intelligent" mode. However, for a fixed setup (like your smoke scenario) you should be on fully manual

Matt

(PS. Sounds like you might need my flash e-book... plug plug )

Matt,
Thanks for that explanation. Quite clarified now. The part where you mention 1/1 (full power) takes time to discharge, and that "1/64" will take far less time to discharge than 1/1 was what I was confused about but now after you mentioning it I understand . That's what I wanted in fact, the short duration. I see that duration of the flash is directly proportional with the power, laws of physics here again I see . Because ideally I wanted full power but with the shortest duration, and that however I think the normal flashguns might not be possible. That's where I suppose people get around by using multi flash setups, specially when shooting hummingbirds.

The Sigma I have lets me change the Exposure values when I am in manual mode also.

And Matt, by the way, I ordered and got your e-book just a few weeks ago, and have gone through the first pages already, that's how I learnt already how to use the flash adjustments to match the ambient light and make use of it to enhance the images . Also that's what has prompted me to start making more use of the flash, until now I suffered from an authentic phobia of flash .

Thanks so much for your kind patience and help in understanding this.

Amin

Hi Amin,
Perhaps I need to add a "high speed flash" section to the e-book
Glad it's started you experimenting!

As I mentioned, I doubt that even full power 1/1 is going to be a problem The duration of a full flash discharge is going to be short enough to freeze most movement. It's only if you find that 1/1 is giving blurred images will you need to reduce the flash power (and adjust aperture/setup/etc to compensate).

Also bear in mind that the recycle time is longer when you discharge fully. So, at 1/1 you'll have to wait 3 or 4 seconds between shots (or more!). As I mentioned, start with 1/2 power since that will give you shorter flash recycle time and more freedom to shoot. If you can't get what you want, try changing the setup.

For example, adding a Fresnel lens attachment to the flash head should "focus" the light on a smaller area. You could even try making a tube out of household aluminium foil to funnel and direct the light onto your subject You may need a more directed light rather than more brute force power.

Have fun!
Matt