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08-28-2012, 03:36 PM - 1 Like   #46
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QuoteOriginally posted by jaytee Quote
I don't use flash much so i don't know and I am just asking, but wouldn't fine tuning with the f/stop do the same thing. With flash you still work at the lowest ISO (for IQ) and set the shutter no lower than what coordinates with the flash. The flash works as a very fast shutter speed and you control ambient light with the f/stop ?
Using a p-ttl flash in manual exposure mode is a different story: You control the proportion of flash to ambient light underexposing to a certain amount.

If you underexpose half a stop, the flash will complete the rest. In this case, you have mostly ambient light.
If you underexpose one stop, you will have about a 50% of ambient light, the rest the flash.
If you underexpose two stops, ambient light will be only about a 25%, 75% of flash light.
... and so on.

With cameras that allow exposure compensation in manual exposure mode, you have the possibility to change the sum of ambient and flash light that is used for exposure. This way, you have control not only over the proportion of flash/ambient light (by underexposing), but also to control total exposure level (with exposure compensation). With the K10 I could influence changing the flash compensation, but this had a smaller effect.

Cheers - Klaus

08-28-2012, 05:39 PM   #47
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Klause, that is interesting, so if I follow correctly you are useing the EV dial to control the output of the flash. Similar to dialing in an adjustment for the built in flash.

Last edited by jaytee; 08-28-2012 at 06:00 PM. Reason: typo
08-29-2012, 03:32 AM   #48
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QuoteOriginally posted by jaytee Quote
Klause, that is interesting, so if I follow correctly you are useing the EV dial to control the output of the flash. Similar to dialing in an adjustment for the built in flash.
In this technique, there are two levels of control:
  • You control the proportion between ambient light and flash adjusting aperture, time and ISO to a level that gives you an underexposure, between a third of a stop, and 3 or more stops (in the last case, you will have only flash exposure, with very little ambient light; I mostly use between a third of a stop, that is about 80% of ambient light, up to 2 stops, that is 25% of ambient light).
  • The exposure compensation allows to vary exposure level: that is the sum of ambient light and flash that is used for exposure.

Cheers - Klaus
08-30-2012, 12:48 PM   #49
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@Klaus:- Many thanks for your info... it really has solved an issue for me. I was trying to figure out whether to shoot my off camera Metz 50 AF1 from my K5 in Servo (dumb) mode of in SLave using Pttl (using the K5 internal flash in commander mode). The only problem that I had with Pttl in wireless slave mode was that every time I adjusted the manual exposure on my camera, the flash (using Pttl) would take that as the NEW exposure rather than a mere correction that I was wanting to make to the actual flash intensity. Using your 'very quick' method of EC on the K5, I have tested it with great results and I can easily adjust the flash (on camera) up to +/- 5 stops!!!. This is much better than manually adjusting the EV on each flash that I use!

Could I also ask another point as you may well be able to advise... I am keen on getting an extra AF58 2 so as to do portraits (key and fill etc) but was unsure if this method of flash control would work on two external flashes? I would really want the key light to be firing at a higher intensity than the fill but would that just be a case of simply manually adjusting the EV compensation on each flash before I start in order to try to get the ratio correct? (I am after a 3:1 ratio with an occasional 2:1 for studio)

Just for those in a similar position, I have found that in SERVO mode (dumb slave mode) the Metz 50 and 58 will not fire correctly on full (1/1) or half (1/2) power using the K5 flash as a commander mode only due to the pre flash of Pttl. You need to use 1/4 power or less then it works fine, took me time to research that one, which is why I have opted for Pttl slave with the onboard flash used only as a trigger in commander mode.

08-31-2012, 01:16 AM   #50
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QuoteOriginally posted by Adventura Quote
@Klaus:-
Could I also ask another point as you may well be able to advise... I am keen on getting an extra AF58 2 so as to do portraits (key and fill etc) but was unsure if this method of flash control would work on two external flashes? I would really want the key light to be firing at a higher intensity than the fill but would that just be a case of simply manually adjusting the EV compensation on each flash before I start in order to try to get the ratio correct? (I am after a 3:1 ratio with an occasional 2:1 for studio)
I havn't tried multiple flash setups with the K5, yet. With the K10 total exposure was correct setting different compensations on the flashes, but there was no global exposure compensation in manual mode (the only way to modify a bit was setting the flash compensation in the camera). I think it should work with the K5 even when using exposure compensation in manual mode to control total exposure, but you will have to try it out (of find somebody who did).

Cheers - Klaus
09-01-2012, 09:32 AM   #51
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Klaus,

This is interesting ; however, i get a somewhat different effect in my set up with the metz 58 af2. If i underexpose, the power of the flash is reduced, but interestingly the the flash to subject distance increases but the image is certainly under exposed.

Adding 1stop of exposure reduces the flash to subject distance but looking at the image it is clear that the flash output was increased.

I maintained a 1/180 ss to ensure ambient light impact was minimum.

Is this a metz thing? I use the exposure compensation to manage the flash output with some predictability in p-ttl. It serves me well
09-03-2012, 04:41 AM - 1 Like   #52
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QuoteOriginally posted by nu12ul Quote
This is interesting ; however, i get a somewhat different effect in my set up with the metz 58 af2. If i underexpose, the power of the flash is reduced, but interestingly the the flash to subject distance increases but the image is certainly under exposed.

Adding 1stop of exposure reduces the flash to subject distance but looking at the image it is clear that the flash output was increased.

I maintained a 1/180 ss to ensure ambient light impact was minimum.
Hi

I don't understand your experiment very well. The method that I propose is designed for mixed light, and the idea is to control the proportion of flash to ambient light. If you ensure that there is minimum impact of ambient light you are just using flash illumination, and your underexposure metering in M-Mode should be very big. If you just want flash illumination, this method is not especially useful. I prefer mixed illumination, to avoid dark backgrounds and harsh shadows.

Cheers - Klaus
09-03-2012, 11:54 PM   #53
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Klaus I did found ur writings here so very usuful and easy to understand for me...anyway this is not so difficult topic but it is needed someone to explain who really do understand this balancing clearly...like u. Very Big tnx

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