A K20D anomaly when using flash?


salixarbour

Link Posted 20/03/2009 - 14:58
Hello, all.

As a newbie to photography I sincerely hope that Im not about to make a fool of myself here! Wouldnt be the first time, and certainly wont be the last I guess!!

I have an anomaly/query regarding the shutter speed whilst using the in-built flash.

Whilst experimenting with the K20D & Pentax 16-45 lens, and whilst using the in-built flash in P Program Mode, I noticed that I could reduce the shutter speed (using the front speed-dial), but then having reduced it, could never then re-increase the shutter speed back to any previous stop. Control over the aperture was however still possible.

In more detail:
Please note: through the function button options, the flash was simply set to the first option on the left Flash On.

Green Mode:
Auto Flash is activated, (A+ Flash Symbol) displays in top panel.
ISO fixed on 400.
Camera chooses:
1/60th Sec exposure.
f4.0
Picture quality good.

If I then move to P on the Control Dial;
All settings remain as in the Green Mode test above, except A+Flash Symbol changes to just the Flash Symbol, as would be expected.
Picture quality good.

However, if I then reduce the shutter speed using the front speed dial to:
1/45th or 1/30th Sec exposure etc., for example, the camera then refuses to allow me to return to 1/45th or 1/60th should I choose to, or any faster shutter speed. It will only allow me to reduce the shutter speed, and never increase it. Control over the aperture is however still possible.

Could I ask please: Is this a fault in the K20D/firmware? Im still on V1.0.

(Im keeping my head down behind the parapet for the moment) !!

Many thanks.

Alan Lowe-Jones.
Camera: K20D.
Lenses: Pentax DA* 55mm f1.4 SDM, Pentax DA* 16-50 SDM, Pentax 18-250 SMC DA, Pentax-M 50mm f1.7, Sigma 70-300 F4-5.6 DG macro.
Flash: Pentax AF360.

MattMatic

Link Posted 20/03/2009 - 16:22
Hi Alan,
It is confusing isn't it!

Normally when using flash you should be mostly interested in the aperture - because it's the aperture that controls the amount of flash lighting applied (the shutter speed is more or less irrelevant).

If you use P mode on the camera and adjust the Av setting then everything is logical.

If you want to adjust Tv then the Tv mode makes perfect sense - and that works logically too.

Try this: Put down the flash, use P mode, point to a bright object and manually override the shutter speed to a high value. Now point to a dark object and adjust the Tv again. You'll find that it's limited in the way you describe.

However, the difference is that without flash the camera blinks the aperture value (i.e. "I can't open the lens any wider than f/4!!"), but when you engage the flash the camera turns off this flashing warning

(There is a similar issue with bright objects too - when using flash there are situations where you'd expect the meter to blink to indicate out-of-range, but because flash is enabled this blink operation seems to be disabled.)

In general I'd suggest Av mode or M for flash
Hope that helps explain!
Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)

salixarbour

Link Posted 20/03/2009 - 16:32
Thanks, Matt.

I'm just logging-off at work (got to rush before they lock me in for the weekend), and will read your post later this evening.

There seems to be a learning curve involved here, which I'll have to get my head round later this evening.

I will reply later, but for the moment very many thanks for your detailed response.

Kind regards.
Alan.
Camera: K20D.
Lenses: Pentax DA* 55mm f1.4 SDM, Pentax DA* 16-50 SDM, Pentax 18-250 SMC DA, Pentax-M 50mm f1.7, Sigma 70-300 F4-5.6 DG macro.
Flash: Pentax AF360.

salixarbour

Link Posted 22/03/2009 - 00:55
Hi, Matt.
It certainly is a bit confusing! I've had several more periods of experimenting with the K20D and from what I've learned, I guess it's just a case of becoming familier with how it behaves under various setups and conditions. Although, it still seems odd that you can't take the shutter speed back up the numbers (faster) having first been able to reduce the shutter speed in P mode (with flash raised).

I tried doing a similar experiment with my wife's Sony A100...yuk! This made me realise just how much more control you do actually have over the K20D, and how easy it is to use.

Thanks again for your help, Matt.

Alan.
Camera: K20D.
Lenses: Pentax DA* 55mm f1.4 SDM, Pentax DA* 16-50 SDM, Pentax 18-250 SMC DA, Pentax-M 50mm f1.7, Sigma 70-300 F4-5.6 DG macro.
Flash: Pentax AF360.

pentaxian450

Link Posted 22/03/2009 - 01:25
salixarbour wrote:

my wife's Sony A100...
Alan.

Some people do swear a lot.
Yves (another one of those crazy Canucks)
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