Flash Exposure Compensation

[pnodrog]

Emphatically Yes and Yes.
If Robin were still with us, I am sure that he would agree too.

WW

And here I was rolling up my sleeves getting ready for an argument....

Yes "meaningless" is fair enough.

[Digital]

Grahame, and Paul, forgive my ignorance, but where exactly is the FEC on the camera body of the D300?

Grahame, dumb me did not notice the +/- buttons on the SB 600. Duh!!!!

I believe there is a FEC button for the pop up flash, but I have been talking about a speedlight that is connected, one way or another, to the camera's hotshoe.

Bruce

[Stagecoach]

Grahame, and Paul, forgive my ignorance, but where exactly is the FEC on the camera body of the D300?

Grahame, dumb me did not notice the +/- buttons on the SB 600. Duh!!!!

I believe there is a FEC button for the pop up flash, but I have been talking about a speedlight that is connected, one way or another, to the camera's hotshoe.

Bruce

Hi Bruce,

On the D300 it is the button with the "lightning" strike on it just below the one that 'releases' the pop up flash.

You press it in and then rotate the 'front' control wheel to adjust the FEC which will show in the viewfinder with the +/- value selected. This changes FEC for the pop up OR an attached flash.

BEWARE : If you press this FEC button and rotate the rear thumb-wheel mistakenly that sets the flash mode and you can easily set red-eye, rear sync without realising it.

[Digital]

Hi Bruce,

On the D300 it is the button with the "lightning" strike on it just below the one that 'releases' the pop up flash.

You press it in and then rotate the 'front' control wheel to adjust the FEC which will show in the viewfinder with the +/- value selected. This changes FEC for the pop up OR an attached flash.





BEWARE : If you press this FEC button and rotate the rear thumb-wheel that sets the flash mode and you can easily set red-eye, rear sync without realising it.

Thanks so much Grahame for the information.

Bruce

[Stagecoach]

Thanks so much Grahame for the information.

Bruce

You are welcome Bruce.

And now you have found this you will be able to see that what you described below when it is in respect to the camera being used in Manual .................

I have an idea that using the EC on the camera with the flash in TTL mode has the effect of increasing or decreasing the flash output depending on the EC you have dialed in.
Bruce

Gives the same exposures when the same amount of FEC is entered (on the camera or flash or both combined) rather than any EC.

[george013]

Graham,

It looks as you posted something but I can't see it.

George

[Stagecoach]

Graham,

It looks as you posted something but I can't see it.

George

Yes George, I deleted the post.

It was with respect to a statement in an article I read a few months back specific to the SB-600 that said that model does not use the preflashes in its calculations in any position other than when pointing forward. As Bruce mentions this model, I thought it worthwhile raising.

I had always assumed the calculation process for iTTL (preflash) was exactly as you describe at whatever head angle and had given things no further thought.

Having posted it I investigated further to find that this limitation is only applicable when used on older non CLS camera models.

[george013]

Yes George, I deleted the post.

It was with respect to a statement in an article I read a few months back specific to the SB-600 that said that model does not use the preflashes in its calculations in any position other than when pointing forward. As Bruce mentions this model, I thought it worthwhile raising.

I had always assumed the calculation process for iTTL (preflash) was exactly as you describe at whatever head angle and had given things no further thought.

Having posted it I investigated further to find that this limitation is only applicable when used on older non CLS camera models.

That's about TTL-BL. BL makes use of the distance info from the lens. That's why the flash head should be pointing forward. And the lens should be able to give info about the distance, D-and G-lenses(?).
Nikon changed it. On my SB700 it's always TTL-BL, unless you use point metering. BL is now more back light oriented and makes use of the matrix metering. I don't think it's camera related, but flash related. Not sure about that.
My info .

George

[Stagecoach]

That's about TTL-BL. BL makes use of the distance info from the lens. That's why the flash head should be pointing forward. And the lens should be able to give info about the distance, D-and G-lenses(?).
Nikon changed it. On my SB700 it's always TTL-BL, unless you use point metering. BL is now more back light oriented and makes use of the matrix metering. I don't think it's camera related, but flash related. Not sure about that.
My info .

George

I'm pretty sure the article was not referring to TTL-BL mode which I was aware of at the time of reading. The SB-600 manual makes reference to the preflashes in the small print here ...................

"For cameras in Group I, however, Monitor Preflashes are not fired when the
SB-600's flash head is adjusted to other than the horizontal/front position or the
camera's flash sync mode is set to rear-curtain sync, even when Happears on the
LCD panel."

I suspect someone had read this and not referred to what cameras were in Group 1

[Manfred M]

That's about TTL-BL. BL makes use of the distance info from the lens. That's why the flash head should be pointing forward. And the lens should be able to give info about the distance, D-and G-lenses(?).
Nikon changed it. On my SB700 it's always TTL-BL, unless you use point metering. BL is now more back light oriented and makes use of the matrix metering. I don't think it's camera related, but flash related. Not sure about that.
My info .

George

I'm not sure if that is 100% correct George. The iTTL-BL mode (the BL stands for "Balanced Light") means that the camera calculates exposure based on a measurement of the amount of ambient light in the scene via that camera's light meter. The pre-flash measurement still takes place, but the ambient light conditions are calculated in to determine the exposure. This really means that we are getting more of a fill-light type of exposure, rather one where the flash provides the light and this generally results in a more "natural" looking shot. I've tested it with bounced flash and with a light modifier (umbrella) and it works with these (i.e. the light is not aimed at the subject).

The problem with generalizations with flash is that Nikon's approach has varied over time and older generations of cameras that do not support Nikon CLS work differently. I know that backward compatibility with older camera models is dependent on the flash model. My SB-600 seems to be backwards compatible, but my SB-900 is not.

[george013]

I'm pretty sure the article was not referring to TTL-BL mode which I was aware of at the time of reading. The SB-600 manual makes reference to the preflashes in the small print here ...................

"For cameras in Group I, however, Monitor Preflashes are not fired when the
SB-600's flash head is adjusted to other than the horizontal/front position or the
camera's flash sync mode is set to rear-curtain sync, even when Happears on the
LCD panel."

I suspect someone had read this and not referred to what cameras were in Group 1

I had the SB600 and a D80. There it worked like that. Only BL with the head to the front. It might be on the D300 and SB600 combi too. Bruce can tell us, he owns that combi.
In BL mode the flash makes use of the distance info given by a D or G lens. That distance is the distance between camera and subject. It doesn't make sense to enlarge the way the light has to travel or pointing to something else with that info.

Manfred,
I discovered too that Nikon changed his approach about BL. On my combi D700 and SB700 the default is TTL BL. I only can get TTL sec when in spot metering mode. With matrix and centre weight itś alway TTL BL. The link I gave http://nikonclspracticalguide.blogsp...-bl-flash.html is a really good explanation of Nikons CLS system. But it was written in 2008, the time of the SB 600. The manual of the SB 600 does make reference to the D70 as the newest camera.

George

[Manfred M]

Manfred,
I discovered too that Nikon changed his approach about BL. On my combi D700 and SB700 the default is TTL BL. I only can get TTL sec when in spot metering mode. With matrix and centre weight itś alway TTL BL. The link I gave http://nikonclspracticalguide.blogsp...-bl-flash.html is a really good explanation of Nikons CLS system. But it was written in 2008, the time of the SB 600. The manual of the SB 600 does make reference to the D70 as the newest camera.

George

I think that the important point you make is that specific cameras and specific speedlights may not work the same way as other combinations of camera / speedlight because Nikon has changed their approach over time. I seem to remember using an SB-400 at one time and it had very strange behavior versus what I was used to.

[george013]

But the basics are still the same. By example the flash can calculate its needed power only with a pre flash. It measures the reflected light.
I'm looking for some info I had long time ago about the development how flash power was measured and calculated. Only 1 page, I printed it. When I found it I'll show it here.

George

[Stagecoach]

I had the SB600 and a D80. There it worked like that. Only BL with the head to the front. It might be on the D300 and SB600 combi too. Bruce can tell us, he owns that combi.
In BL mode the flash makes use of the distance info given by a D or G lens. That distance is the distance between camera and subject. It doesn't make sense to enlarge the way the light has to travel or pointing to something else with that info.
George

George,

I think this is a good example of differences between specific gear and the need to know exactly how your own kit works, which can so easily be done with flash (apart from determining if preflashes have gone off)

It seems that the "preflash" aspect has now moved on to BL, but ......................

For info, I have just placed an SB-600 on a D300 and set the flash to TTL-BL. The BL indicator on the flash LCD readout shows BL whether the flash is pointing forward or at any other angle. This suggests to me that for this combo BL mode is not just available when the head is to the front. The fact that the BL indicator on the flash also goes off when I change to spot metering suggests that Nikon is using this indicator to tell me when BL is or is not available.

I also can't see a logical reason why BL mode would not 'technically' work at any head angle and would be "restricted" to just front facing flash. BL is simply taking and using measurements, a) distance, b) ambient light and c) preflash return.

If we consider the preflash in TTL-BL (and in TTL non BL) what the camera see's (measures) will vary also with such things as diffusers fitted over the head which could be more significant than bouncing off a low ceiling with no diffuser.

Note : my observations are in no way suggesting that any TTL mode should be, or is best, for any specific situation.

[george013]

George,

I think this is a good example of differences between specific gear and the need to know exactly how your own kit works, which can so easily be done with flash (apart from determining if preflashes have gone off)

It seems that the "preflash" aspect has now moved on to BL, but ......................

For info, I have just placed an SB-600 on a D300 and set the flash to TTL-BL. The BL indicator on the flash LCD readout shows BL whether the flash is pointing forward or at any other angle. This suggests to me that for this combo BL mode is not just available when the head is to the front. The fact that the BL indicator on the flash also goes off when I change to spot metering suggests that Nikon is using this indicator to tell me when BL is or is not available.

I also can't see a logical reason why BL mode would not 'technically' work at any head angle and would be "restricted" to just front facing flash. BL is simply taking and using measurements, a) distance, b) ambient light and c) preflash return.

If we consider the preflash in TTL-BL (and in TTL non BL) what the camera see's (measures) will vary also with such things as diffusers fitted over the head which could be more significant than bouncing off a low ceiling with no diffuser.

Note : my observations are in no way suggesting that any TTL mode should be, or is best, for any specific situation.

The Nikon CLS system uses pre-flashes in TTL. Always.

The BL addition originial is taking in account the distance to the subject to calculate the flash power. The distance is from camera to subject. If the head is not pointed to the subject, then the distance the light has to travel to hit the subject, if it hits so, is longer and the illuminance is less. But Nikon seems to have changed that.

George

[pnodrog]

I use my flash so little nowadays that I don't really care how it works so long as it will HSS when required. If it is half a stop or even a stop out with RAW I can massage it in PP.... I would not buy shares in a flash manufacturer. The ISO capabilities of the newer cameras must be making a huge impact on sales. I always prefer working with available light as much as possible.

[Stagecoach]

The Nikon CLS system uses pre-flashes in TTL. Always.

Agreed, disregarding certain older models where Nikon states it does not in certain conditions.

The BL addition originial is taking in account the distance to the subject to calculate the flash power. The distance is from camera to subject. If the head is not pointed to the subject, then the distance the light has to travel to hit the subject, if it hits so, is longer and the illuminance is less. But Nikon seems to have changed that.

George

I'm not familiar with any changes that have been made to the Nikon TTL-BL mode since introduction and there are many articles on the web describing how people think it works, a pity Nikon does not reveal the full details.

But whatever, in any calculation it's doing to work so well it has to be assumed that it take's account also of light loss due to bounce or a diffuser fitting and not just flash/camera distance only determining the flash power.

[george013]

Agreed, disregarding certain older models where Nikon states it does not in certain conditions.



I'm not familiar with any changes that have been made to the Nikon TTL-BL mode since introduction and there are many articles on the web describing how people think it works, a pity Nikon does not reveal the full details.

But whatever, in any calculation it's doing to work so well it has to be assumed that it take's account also of light loss due to bounce or a diffuser fitting and not just flash/camera distance only determining the flash power.

For me it makes understanding easier when I know how it developed. Here's a link https://www.scantips.com/lights/ttl.html. It contains what I was looking for. See the development from TTL, D-TTL to i-TTL.

George

[Stagecoach]

For me it makes understanding easier when I know how it developed. Here's a link https://www.scantips.com/lights/ttl.html. It contains what I was looking for. See the development from TTL, D-TTL to i-TTL.

George

I have seen that one before George, useful for a basic understanding of the flash development and terminology but lacking in any really useful technical details.

What was it you were looking for?

[Manfred M]

I use my flash so little nowadays that I don't really care how it works so long as it will HSS when required. If it is half a stop or even a stop out with RAW I can massage it in PP.... I would not buy shares in a flash manufacturer. The ISO capabilities of the newer cameras must be making a huge impact on sales. I always prefer working with available light as much as possible.

It really depends on the look you are after.

For existing light photography, I would tend to agree, so long as I can get the shot parameters I want. By this I mean the look, the appropriate dynamic range and colour depth. This works for relatively static objects. Here, with a heavy duty tripod, I can shoot a low ISO and use long exposure to overcome some of the limitations of higher ISO shots. Sometimes blending multiple shots is another solution.

For others, especially when shooting people, where I want control of the lighting, I will use flash; either small flash if I am shooting where I need a portable lighting solution or studio lights where I can get away with something more stationary. I have an intermediate solution as well; my Godox Witstro 360 gives me some of the advantages (high power) of a studio flash solution with a slightly less portable approach than a small flash, but still more portable than the studio lights with a battery pack.