In-camera manual flash metering

jonby · 03-28-2015, 12:05 PM

Does anyone know if there's a reason why manual metering of flash in-camera has never been implemented (as far as I know)?

To illustrate what I mean:
Set shutter speed, aperture, ISO as normal
Put the camera into 'flash metering' mode
Half-press the shutter to prompt the meter to wait for a flash
Fire the flash (on a manual power setting)
The flash output reflected back through the lens is measured and exposure calculated with reference to the current settings
Exposure is indicated in the viewfinder, in terms of divergence in stops from an 'normal' exposure.

So in short, this would do the same job as a hand-held flash meter in reflective mode, but be quicker to use and more accurate because it's TTL.

I can't see any technical barriers to implementing this. I would have thought it would be preferable to trial and error test-shots because you could easily see how many stops to adjust for. Or am I missing something?

**Canada_Rockies** · 03-28-2015, 05:52 PM

The LX metered flash with the same sensor as for ambient light. I don't recall seeing anyone else's camera with the metering abilities of the LX (in its day - new matrix metering is something else entirely). The LX metered off the film surface. I don't think that would work too well with a sensor.

jonby · 03-28-2015, 07:01 PM

Originally posted by Canada_Rockies

The LX metered off the film surface. I don't think that would work too well with a sensor.

No it wouldn't work as you say - that's why digital TTL has to use pre-flash metered in the prism. This is why it should be possible for the sensor in the prism to act as a manual flash meter. Probably the bigger question is whether anyone would find this useful. I think I would.

Class A · 03-30-2015, 04:30 PM

Originally posted by jonby

I can't see any technical barriers to implementing this.

An automated version of what you describe happens when P-TTL is used. The P-TTL pre-flash is evaluated by the camera's meter and flash power is adjusted accordingly.

It would be nice to have a system similar to what you describe in order to get some flash power and/or camera setting support for non-P-TTL flashes, but I don't think it will ever happen because manufacturers want to sell their expensive dedicated flashes as opposed to supporting budget solutions.

jonby · 03-30-2015, 05:02 PM

Originally posted by Class A

An automated version of what you describe happens when P-TTL is used. The P-TTL pre-flash is evaluated by the camera's meter and flash power is adjusted accordingly.

Yes exactly.

Originally posted by Class A

It would be nice to have a system similar to what you describe in order to get some flash power and/or camera setting support for non-P-TTL flashes, but I don't think it will ever happen because manufacturers want to sell their expensive dedicated flashes as opposed to supporting budget solutions.

You could be right of course, but this would be a very cynical reason not to do it and I hope it's not the reason. For starters, this would never be a replacement for TTL automation because it would entail a much slower process of firing a test flash, adjusting exposure and then taking the shot. I could see it being quite useful for studio photographers when using a handheld meter is too slow or not right for the job. It would offer a good way to quantify the relationship of each light, work out ratios etc, for photographers who like to work that way. Given that Pentax are considered a bit behind the game with their flash system I would have thought this would be a good little bonus point for them. Just seems odd that given how easy this should be to implement, not a single manufacturer has done it.

Class A · 03-30-2015, 06:23 PM

I don't think that there is anything "cynical" about a manufacturer that watches there bottom line. It would be much more customer friendly if budget solutions were supported, but businesses have to strike a balance between serving customers and generating income.

Your system would not be a replacement for P-TTL, but it could be used in some scenarios were people are currently forced to use P-TTL (if they don't want to "tweak" or use light meters) and hence must be regarded as partial competition to P-TTL.

I like your idea and it would work very well with a system that supports remote power level control of flashes like the Cactus V6, but I just can't see Ricoh doing anything like this. I'd be more than happy to be proven wrong on this one.

03-28-2015, 12:05 PM	#1
jonby Senior Member Join Date: Nov 2013 Posts: 161	In-camera manual flash metering Does anyone know if there's a reason why manual metering of flash in-camera has never been implemented (as far as I know)? To illustrate what I mean: Set shutter speed, aperture, ISO as normal Put the camera into 'flash metering' mode Half-press the shutter to prompt the meter to wait for a flash Fire the flash (on a manual power setting) The flash output reflected back through the lens is measured and exposure calculated with reference to the current settings Exposure is indicated in the viewfinder, in terms of divergence in stops from an 'normal' exposure. So in short, this would do the same job as a hand-held flash meter in reflective mode, but be quicker to use and more accurate because it's TTL. I can't see any technical barriers to implementing this. I would have thought it would be preferable to trial and error test-shots because you could easily see how many stops to adjust for. Or am I missing something?

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03-28-2015, 05:52 PM	#2
Canada_Rockies Loyal Site Supporter Join Date: Nov 2007 Location: Sparwood, BC, Canada Photos: Gallery \| Albums Posts: 12,385	The LX metered flash with the same sensor as for ambient light. I don't recall seeing anyone else's camera with the metering abilities of the LX (in its day - new matrix metering is something else entirely). The LX metered off the film surface. I don't think that would work too well with a sensor.

03-28-2015, 07:01 PM	#3
jonby Senior Member Join Date: Nov 2013 Posts: 161 Original Poster	Originally posted by Canada_Rockies The LX metered off the film surface. I don't think that would work too well with a sensor. No it wouldn't work as you say - that's why digital TTL has to use pre-flash metered in the prism. This is why it should be possible for the sensor in the prism to act as a manual flash meter. Probably the bigger question is whether anyone would find this useful. I think I would.

03-30-2015, 04:30 PM	#4
Class A Pentaxian Join Date: Aug 2008 Location: Wellington, New Zealand Posts: 11,251	Originally posted by jonby I can't see any technical barriers to implementing this. An automated version of what you describe happens when P-TTL is used. The P-TTL pre-flash is evaluated by the camera's meter and flash power is adjusted accordingly. It would be nice to have a system similar to what you describe in order to get some flash power and/or camera setting support for non-P-TTL flashes, but I don't think it will ever happen because manufacturers want to sell their expensive dedicated flashes as opposed to supporting budget solutions.

03-30-2015, 05:02 PM	#5
jonby Senior Member Join Date: Nov 2013 Posts: 161 Original Poster	Originally posted by Class A An automated version of what you describe happens when P-TTL is used. The P-TTL pre-flash is evaluated by the camera's meter and flash power is adjusted accordingly. Yes exactly. Originally posted by Class A It would be nice to have a system similar to what you describe in order to get some flash power and/or camera setting support for non-P-TTL flashes, but I don't think it will ever happen because manufacturers want to sell their expensive dedicated flashes as opposed to supporting budget solutions. You could be right of course, but this would be a very cynical reason not to do it and I hope it's not the reason. For starters, this would never be a replacement for TTL automation because it would entail a much slower process of firing a test flash, adjusting exposure and then taking the shot. I could see it being quite useful for studio photographers when using a handheld meter is too slow or not right for the job. It would offer a good way to quantify the relationship of each light, work out ratios etc, for photographers who like to work that way. Given that Pentax are considered a bit behind the game with their flash system I would have thought this would be a good little bonus point for them. Just seems odd that given how easy this should be to implement, not a single manufacturer has done it.

03-30-2015, 06:23 PM	#6
Class A Pentaxian Join Date: Aug 2008 Location: Wellington, New Zealand Posts: 11,251	I don't think that there is anything "cynical" about a manufacturer that watches there bottom line. It would be much more customer friendly if budget solutions were supported, but businesses have to strike a balance between serving customers and generating income. Your system would not be a replacement for P-TTL, but it could be used in some scenarios were people are currently forced to use P-TTL (if they don't want to "tweak" or use light meters) and hence must be regarded as partial competition to P-TTL. I like your idea and it would work very well with a system that supports remote power level control of flashes like the Cactus V6, but I just can't see Ricoh doing anything like this. I'd be more than happy to be proven wrong on this one.