Pentax K-7 Flash Problems


helios

Link Posted 23/03/2010 - 20:37
I have found the K-7 works pretty well with flash. I usually use aperture priority and set the iso manually to 200. The built-in flash is rather weak so if possible I use my AF360FGZ either on camera but bouncing off the ceiling or or off camera using the built in flash as master or controller. The flash is set to PTTL.

The presence of highly reflective surfaces can cause problems but most normal indoor picures are well exposed.

Archie
Archie

MattMatic

Link Posted 23/03/2010 - 20:43
Anne,
I've just upgraded to the K-7... so I'll check it out with the AF360 & AF540 and see if I can advise in the next few days
Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)

pentaxanne

Link Posted 23/03/2010 - 21:02
archie what im saying is that the camera is not usable using out iso.
try using in apature priorty mode, say f8 using flash i expect it will use 160/sec set the iso to auto 100 to 1600, with mine it will just be way over exposed.
as far as im concerned the flash should be usable in any mode when using auto iso and it should select the right iso,
i had no problems with the k20d and k200d i had in the same modes.

thanks matt, i would be interested on your view on the built in flash to in diferent modes,
Last Edited by pentaxanne on 23/03/2010 - 21:05

helios

Link Posted 23/03/2010 - 21:54
pentaxanne wrote:
archie what im saying is that the camera is not usable using out iso.
try using in apature priorty mode, say f8 using flash i expect it will use 160/sec set the iso to auto 100 to 1600, with mine it will just be way over exposed.
as far as im concerned the flash should be usable in any mode when using auto iso and it should select the right iso,
i had no problems with the k20d and k200d i had in the same modes.

thanks matt, i would be interested on your view on the built in flash to in diferent modes,

Your problem seems to be with auto iso. If restricting it to a smaller range e.g. 100 - 400 does not help then maybe there is a fault in your camera. Does it expose correctly if you set the iso manually - say to 200?

I tried setting my K-7 to auto iso 100 - 1600, aperture priority set to f8 and using the built in flash I took a photo of my study and got a perfectly exposed picture. The camera chose 1/60th at iso 400.

I think your camera might need to go back to Pentax to be checked.

Archie
Archie

pentaxanne

Link Posted 23/03/2010 - 21:58
it works fine i i set it manualy,, try taking a pic of someone close up,
also try tav mode select a shutter speed of 160.sec and f8 auto iso.

helios

Link Posted 23/03/2010 - 22:34
pentaxanne wrote:
it works fine i i set it manualy,, try taking a pic of someone close up,
also try tav mode select a shutter speed of 160.sec and f8 auto iso.

I tried in TAV mode with auto iso set to 100-1600 and shutter to 1/160 and you are quite right the camera chose 1600 though the picture was only slightly overexposed. Presumably the camera adjusts to the ambient light and this is why it uses the highest iso in the auto range. iso 1600 is not really appropriate for flash when photographing a subject who is close as it cannot reduce the flash output sufficiently.

I think I will stick to aperture priority and iso 100-400. It works well for me.

Archie
Archie

pentaxanne

Link Posted 23/03/2010 - 23:52
helios wrote:
pentaxanne wrote:
it works fine i i set it manualy,, try taking a pic of someone close up,
also try tav mode select a shutter speed of 160.sec and f8 auto iso.

I tried in TAV mode with auto iso set to 100-1600 and shutter to 1/160 and you are quite right the camera chose 1600 though the picture was only slightly overexposed. Presumably the camera adjusts to the ambient light and this is why it uses the highest iso in the auto range. iso 1600 is not really appropriate for flash when photographing a subject who is close as it cannot reduce the flash output sufficiently.

I think I will stick to aperture priority and iso 100-400. It works well for me.

Archie

this is my point in most cases when it has done this i have checked it manualy and it could use iso 100 with no problems.
my daughters cheap £50 camera does this bumps the iso up.
i dont expect it of a dslr of nearlly £1000,

i have no problems using it in full manual, but my point is my partner uses it and he doesnt understand and doesnt want to learn how to set it up manualy and i cant blame him ,
the camera should be cleaver enough to set the iso right and in this situation in tav mode set to 160/sec f 8 iso 100 to iso 1600 is a big difference.

pentaxanne

Link Posted 24/03/2010 - 00:18
all at the same distance about 5ft away and 200mm.
tav mode i selected f8 and 180/sec shutter speed and the camera selected iso 1600(auto 100-1600)slow iso adjustment set.



tav mode i selected f32 and 180/sec shutter speed and the camera selected iso 1600(auto 100-1600)slow iso adjustment set.



full manual i selected f8 180/sec iso 100.



must say the iso 1600 looks very clean.
Last Edited by pentaxanne on 24/03/2010 - 00:27

helios

Link Posted 24/03/2010 - 12:46
I take your point, but the K-7 is not a point and shoot. If you want to use it without worrying about settings the use of the green mode allows easy use by anyone and when used with flash gives nicely exposed photos.

Archie
Archie

gartmore

Link Posted 24/03/2010 - 12:56
Pentaxanne, it would be of enormous help if you left the EXIF data intact before posting. We would get a much better idea of what was going on. Perhaps you are 'saving for the web', if so it would be better to just resize to 800 pixels and a resolution of 72 and just 'save as'. Could you repost those pictures that way?
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

MattMatic

Link Posted 24/03/2010 - 13:21
Just a few thoughts before a full info (although excuse this very long reply! ) :

* The K-7 isn't a point-n-shoot
* Flash isn't a "magic bullet" - it can't cover all lighting situations automatically. A lot is left to the photographer (but it isn't hard once you know how!!)
* I suspect there is a discrepancy between what you are expecting to happen and what you have actually programmed

For example - this information may help enormously. Flash has limits. First, it has a limit to its full power. If you set ISO100, f/32 and try and light something a few meters away it will be underexposed - especially with the pop-up. It just doesn't have infinite lighting power.

Secondly, flash has a limit to its minimum power! This is probably what's happening in your case (but I will check later). You have made an incorrect assumption about which Auto ISO setting to use - you said you set it to "fast" because you want to freeze the action. It's definitely NOT what you want to do! The reason is this: the camera makes a decision about ISO setting largely before using the flash - based on the ambient light. As you asked for "fast" the camera will veer towards the higher ISO sensitivities. Because the flash has a minimum power, and probably because the subject is close, the flash will not be able to 'cut off' early enough. (That's why when you reduce the aperture - to f/32 - less light is let through and your exposure is then correct.)

Flash works within a certain range of distances for any given ISO sensitivity. This range is shown on the AF360/AF540, but unfortunately not on the popup (though there is information in the manual... but that may be intimidating at first).

I quickly tested the K-7 with the pop-up last night. The results are, actually, very impressive! But, I had the ISO set to "slow" In general, I want the lowest ISO (because it has the lowest noise). The flash will do the "freezing" of motion for me My exposures were pretty much bang-on every time (but then I have a feel for the max & min distances of flash anyway.)


Some of the skill that is left up to the photographer is how to balance the ambient light with the flash lighting. I've covered much of that in my flash e-book - and it's a fairly big subject to discuss here.


I'll double check the flash behaviour of the K-7 further (to see how it differs from the *ist-D, K10D, and K20D that I've had) and report back...

Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)
Last Edited by MattMatic on 24/03/2010 - 13:23

pentaxanne

Link Posted 24/03/2010 - 13:36
ken i guess flicker has removed the exif data will try find somewhere that doesnt. arche and matt i know its not a point and shot and nor is my d300 and my partner can pick that up and use that with built in flash with no problems with shutter speeds of 360.sec f8 with the iso adjusting its self and it doesnt just select a high iso its selecup the right iso to give the right exposure. I never had the problem with the k20 or k200.0also matt i selected slow iso adjustment. Sorry using my phone at the moment its abit hard.

MattMatic

Link Posted 24/03/2010 - 13:44
Ooh - nearly forgot! Check that you have the latest firmware for the K-7 (which is 1.03 I believe). Just hold down the MENU button while powering up the camera and it will show you.

If you're not on the latest, then I'd suggest updating that before proceeding further

Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)

pentaxanne

Link Posted 24/03/2010 - 13:47
hi matt yes on the later version 1.3 first thing i done. Anne

MattMatic

Link Posted 24/03/2010 - 13:51
That's definitely odd - because I've just tried everything I can think of to make it go wrong.... and every flash exposure comes out wonderfully! (Much better exposure compared to the K20D and prior).

I picked P mode, Auto ISO 100-2500 (Fast) and tried all kinds - both near and far - and I just cannot make it go wrong. (Generally it was picking ISO1600). Tried in Slow auto ISO as well - same great results.

I'm going to re-read your posts to make sure there's nothing I've missed.

Edit: Just tried in TAv mode - same thing. Perfect.



I take it you have the original focus screen?

Edit: Other questions:
* What lens are you using?
* Have you double checked your flash settings on the camera?
* Are you set to Matrix metering?

Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)
Last Edited by MattMatic on 24/03/2010 - 13:55
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