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over exposure using fill in flash

Trubshore
Posted 26/08/2013 - 14:41 Link
Using a Pentax K5 with a 50-135 DA* and AF-360 FGZ flash on a offset bracket i am having mixed results with some of my images comming out over exposed especially in sunny conditions.
I have the camera set to AV with the flash output on the camera set to -0.7 with a diffuser on the flash unit which is set to -1.0
I have also tried the camera set to P mode but makes no difference.
I want the fill in flash to reduce facial shadows especially under hats etc.
I would be most grateful for any advice on set up settings etc as i am not that conversant with using flash
Many thanks Peter
dpm
Posted 26/08/2013 - 15:08 Link
what metering mode?
SteveEveritt
Posted 26/08/2013 - 15:16 Link
Is this in burst mode? I have the same thing happening when shooting karts in burst mode, for no reason one or more of the burst will be massively over exposed.
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Trubshore
Posted 26/08/2013 - 15:19 Link
The metering mode of the flash is TTL. ISO 200
This is in burst mode but also happens when taking a single shot
McGregNi
Posted 26/08/2013 - 15:24 Link
My advice would be to set M mode - to control both flash and ambiant light exposures manually.

I would forget about trying to cut the flash output using the on-camera Flash Exposure setting, as this is still subject to the quirks of the cameras TTL metering system and the varying relfectivity of light bouncing back. Also it just adds an extra step to the process.

firstly use Av mode to get the aperture and shutter speed you want for good ambiant exposure - set these values in M mode. Take test shots with the flash. If the flash is overexposed, you have only 3 options really :

1) Set a smaller aperture (ambiant exposure will not be affected)
2) Set a lower ISO (you will have to adjust shutter speed to equalise the ambiant exposure)
3) Move the flash gun further away (ambiant exposure will not be affected)

The best of these is usually to change the aperture. This might affect the depth of field depending on the focal length and distance away you are, so a readjustment of these might be needed if the DOF was really important.

Let us know if this approach helps
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: 26/08/2013 - 15:25
davidstorm
Posted 26/08/2013 - 15:31 Link
Buy a cheap, good quality manual flash like the Youngnuo or similar, you can get decent ones for £30 upwards. It's much easier to dial in the power you need to get just the right amount of fill-in flash.

I have a TTL Metz and it never gets used because I can't balance the flash output satisfactorily. Also it's not as powerful as my manual ones (Neewer TTL560, Amazon £26 each). The cheap manual ones produce far better results for me.

Regards
David
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Nicola's Apartments, Kassiopi, Corfu

Some cameras, some lenses, some bits 'n' bobs
McGregNi
Posted 26/08/2013 - 16:36 Link
But the basic exposure rules for flash remain the same whether of not you have a new / old / manual / TTL unit. Flash exposure is always controlled by aperture and flash distance to subject, and / or power output (the same thing really as distance).

I agree its better to remove the TTL aspect, as this is affected by the meters response to the subject 'reflectivity', and can vary unpredicably. Keep any flash gun on manual and control the shot from the camera - aperture for flash exposure, shutter speed for ambiant exposure.

You should only need to try and cut the flash power if you can't get the flashgun far enough away from the subject and you're already at your acceptable aperture limit.
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
Posted 26/08/2013 - 16:55 Link
all this shoot in M with manual flash is well and good . . .

BUT, how come the OP is having this problem? And how come the camera cant deal with this?

Even my lovely old AF280T gets it right pretty much every time on Auto - and that's on a K10D with no TTL, the flash is figuring this out all by itself using 30 year old technology . . .
davidstorm
Posted 26/08/2013 - 17:24 Link
LittleSkink wrote:
all this shoot in M with manual flash is well and good . . .

BUT, how come the OP is having this problem? And how come the camera cant deal with this?

I honestly have no idea! I was only offering some advice based on what works for me, I like to use manual flashes because they offer so much control. I can't see the point in spending hundreds of pounds when a manual flash will give better results.

I'm speaking of course from the point of view of using flash occasionally for amateur purposes, I'm not trying to imply that cheap manual flashes will produce better results than a proper studio setup.

Regards
David
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Nicola's Apartments, Kassiopi, Corfu

Some cameras, some lenses, some bits 'n' bobs
sterretje
Posted 26/08/2013 - 17:40 Link
Possible explanation

With flash, the camera is limited to 1/180s as the shortest shutter speed. In bright conditions you might actually need e.g. 1/500 for the chosen aperture. And hence the overexposure. Closing the aperture more helps but that affects the reach of the flash (as does changing ISO to 100).

The only way to use 1/500 (as in the example) is to use HSS.
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)
McGregNi
Posted 26/08/2013 - 19:37 Link
I assumed it was the flash that was 'overexposed'. In this case increasing the shutter speed to 1/500 will have no effect on the flash exposure whatsoever. The OP said be was shooting in Av & P modes, so the camera would close down the aperture automatically for ambiant exposure - Only 4 things will reduce the flash exposure -

1) smaller aperture
2) more distance flash to subject
3) lower ISO
4) reduced flash power

The easiest and most effective of these to manage I believe is aperture and flash to subject distance.
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: 26/08/2013 - 19:38
sterretje
Posted 26/08/2013 - 20:52 Link
Trubshore also stated that the problems especially happen under sunny conditions Which made me think it's an ambient light problem and not a flash issue. And in which case faster shutter speeds do help
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)
McGregNi
Posted 26/08/2013 - 21:43 Link
Trubshore, help us out here! I see what you're saying sterretje - but if he's in Av or P, OK, the maximum speed will be 180th, but won't the aperture stop down to produce an acceptable exposure. Another poster mentioned metering mode above - I suppose if it was spot mode on a dark face the meter might be way off? So Trubshore - is it just an overexposed background, very bright highlights behind that is the problem - or is it an overexposed subject?
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
sterretje
Posted 27/08/2013 - 06:34 Link
McGregNi wrote:
... but if he's in Av or P, OK, the maximum speed will be 180th, but won't the aperture stop down to produce an acceptable exposure.

Not in Av. Photographer chooses the aperture so camera does not have a choice there. ISO is fixed so camera does not have a choice either. So only variable that can be changed by the camera is the shutter speed but that is limited to 1/180s as the fastest.

In P yes, but will it be able to stop down the aperture enough? Once it reaches narrowest aperture (f/32?), fastest shutter speed (1/180s) and possibly lowest ISO, the camera has no longer any choices.

Let's see what Trubshore's input is (maybe some samples).
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)
gartmore
Posted 27/08/2013 - 07:30 Link
My technique is to set the flash to underexpose by 1 stop, the 'correct' setting always looks too bright. What are you using to connect the flash to the camera?
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 -

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