how your auto iso and flash works ?

alaios

Senior Member
Hi there,
I have a question about my d750 camera and the tiny nikon sb-500 flash.

When my LCD Shows

AUTO ISO
100


my shot would be exposed with flash at iso 100


when my LCD shows

AUTO ISO
3200

my shot would be exposed with flash at iso 3200

is this how auto iso with flash is supposed to work with?

My major problem is that I am trying to walk at venues and tell camera "Look, give me an EC of -1 and then a FEC of 0." or
"give me a FEC of -2 and an EC of 0"

For that I need auto iso to do it.
What is your workflow?
Regards
Alex
 

singlerosa_RIP

Senior Member
I agree with you when you state that you want to tell the camera what to do. When you use Auto-anything, you give up control and let the camera decide what's best. I've played with Auto-ISO over the years and it's hurt me more than helped. And I've never used it with flash. You can remap the video button on the top right of your 750 to control ISO. By doing that, you have control over the exposure triangle with one hand.
 

WayneF

Senior Member
Auto ISO is a mixed bag for flash. Bringing ambient up with high ISO means incandescent lighting is seen, and is orange, actually needing incandescent White Balance, which is incompatible with flash. Keeping ISO low shuts it and the orange out, and uses flash instead.

With a regular hot shoe flash (with its own menus), the D750 should never allow Auto ISO to advance more than 2 stops above Minimum ISO (like to ISO 400 from 100) if a flash is detected present. Because 1) you're using flash, and don't need ISO to bring the ambient up full bright, and 2) ISO 400 is about right for bounce flash.

But the internal flash is tiny and different, and for it, the camera will bring ISO up to maximum for the low ambient, regardless if internal flash is being used or not.

I think the D500 has no LCD and uses the cameras internal flash menu like the SB-300 and SB-400 do ?

So it sounds like it is letting ISO go to maximum, regardless of flash. Certainly the SB-300 and SB-400 do, and your description says the same.

You can always turn Auto ISO Off with flash (not in Auto mode, but in A, S, P, or M modes).

On Nikon, Exposure Compensation adds to Flash Compensation. EC -1 and FC 0 reduces both ambient and flash exposures by -1 EV.

The D750 has menu E4 to change that, to keep that default, or to make them separate (as per Canon). What the E4 menu calls Background means "ambient".
 
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alaios

Senior Member
Auto ISO is a mixed bag for flash. Bringing ambient up with high ISO means incandescent lighting is seen, and is orange, actually needing incandescent White Balance, which is incompatible with flash. Keeping ISO low shuts it and the orange out, and uses flash instead.

With a regular hot shoe flash (with its own menus), the D750 should never allow Auto ISO to advance more than 2 stops above Minimum ISO (like to ISO 400 from 100) if a flash is detected present. Because 1) you're using flash, and don't need ISO to bring the ambient up full bright, and 2) ISO 400 is about right for bounce flash.

But the internal flash is tiny and different, and for it, the camera will bring ISO up to maximum for the low ambient, regardless if internal flash is being used or not.

I think the D500 has no LCD and uses the cameras internal flash menu like the SB-300 and SB-400 do ?

So it sounds like it is letting ISO go to maximum, regardless of flash. Certainly the SB-300 and SB-400 do, and your description says the same.

You can always turn Auto ISO Off with flash (not in Auto mode, but in A, S, P, or M modes).

On Nikon, Exposure Compensation adds to Flash Compensation. EC -1 and FC 0 reduces both ambient and flash exposures by -1 EV.

The D750 has menu E4 to change that, to keep that default, or to make them separate (as per Canon). What the E4 menu calls Background means "ambient".

that might be the case that the SB-500 takes the cameras iso. It is weird though why it was using my iso setting (see my example above) even though that was making my shots really over exposed.
I also ordered a SB-700 and I will let you know.
What I want to do is to have a minimum of shutter speed 1/200 control my aperture with the dial and then being able to havee my flash do some fills (Lets say a -2).
Which is the right ISO setting I need to set though since I am moving, framing that fast and still keep shooting? How much plus or minus I need to be in my EV scale?
Alex
 

WayneF

Senior Member
that might be the case that the SB-500 takes the cameras iso. It is weird though why it was using my iso setting (see my example above) even though that was making my shots really over exposed.
I also ordered a SB-700 and I will let you know.
What I want to do is to have a minimum of shutter speed 1/200 control my aperture with the dial and then being able to havee my flash do some fills (Lets say a -2).
Which is the right ISO setting I need to set though since I am moving, framing that fast and still keep shooting? How much plus or minus I need to be in my EV scale?
Alex

How much EV is "whatever is seen necessary to get the results you want". Sorry, that is too general to be able to answer. It depends. There are so many variables... flash mode iTTL or Manual? Camera mode, A, S, P, M? Bright or dim ambient? Indoors or outdoors?

Indoors (assuming low and reasonable ISO), ambient will be insignificant and flash is the main light, so flash compensation is only used to adjust desired TTL flash exposure. More to be brighter, less to not be so bright, as seen needed for the result you want.

Outdoors in sun, flash compensation is usually set perhaps near -2 EV to provide a lower fill level, to prevent overexposing the subject with two exposures, flash plus ambient. Some like to underexpose ambient a bit, others don't. It depends...

High ISO is mostly only for low level ambient alone. Or we use flash instead to provide light, but doing both is not a good idea. Bounce flash indoors typically needs maybe ISO 400 in order to have sufficient flash power (but which depends on bounce ceiling). It often needs a bit of +EV to make it bright enough (simply as seen needed). ISO 100 should be enough for direct flash. Distant dark backgrounds can cause direct flash to overexpose a bit. Either way, just do what you see is needed.

If you want only one answer for all situations, then camera P mode and iTTL flash mode (esp good out in bright sun), but there can be better choices. It is full automation, but wedding photographers moving between indoors and outdoors joke and call P mode as "Professional Mode", since its automation can accommodate most flash situations. :) Again, compensate to do what you see is needed.

Shutter speed will depend on what camera mode you are using. Outdoors in sun should be no issue, likely 1/250 second on the D750.

Camera A mode will use 1/60 second with flash indoors. This is Minimum shutter speed with flash (in A and P modes), and you can make this be slower with menu E2 (or Slow or Rear Curtain sync modes), but the only way to make it faster n A or P mode is to go out into brighter ambient light. The camera meters the ambient, and the flash has to work into that result. 1/60 second can pick up some of the ambient, and the orange incandescents can warm it some (might be desirable, might be ojectionable).

So, instead camera M mode works great with flash indoors. M mode is about the ambient, and the ambient will be too low to matter, we're using flash instead. Then you can set any shutter speed you want (up to 1/250 second maximum), and any aperture, and then iTTL or your manual power settings will handle the flash. TTL flash is still automatic flash, even in camera M mode.

A little experience will see several things to help understanding, and then each situation should become mostly obvious.

Bottom line, simply do what you see you need to do.
 
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The situation is this ...in auto iso the flash ISO goes to 4x your base iso I use 200-6400 so I get 800 ISO BUT BUT BUT if its light daylight it sticks to the iso 200 and when its very dark goes up above iso 800. 99% of the time its sticks with 800.
You need to check whats going on in daylight /a lit interior / when its very dark

Don't forget to use FP 1/320 or you will be in for big supprise if you forget to turn the flash off outside ( FP stands for flash programme not focal plane)

I use a SB400 but it does it with all my Yongnou as well....( D710/D800/D810)
 

alaios

Senior Member
I think what I described with my sb-500 is rather different. It looks like that even AUTO ISO is enabled it would pick the iso that was left visible there in the LCD.

I have forgotten turning it off outside and I thought that I could still use it as fill light (at -2). I got some funny exposure as iso 640 and ss of 1/4000.....
How do you use fill flash outside? (settings?)
 

alaios

Senior Member
How much EV is "whatever is seen necessary to get the results you want". Sorry, that is too general to be able to answer. It depends. There are so many variables... flash mode iTTL or Manual? Camera mode, A, S, P, M? Bright or dim ambient? Indoors or outdoors?

Indoors (assuming low and reasonable ISO), ambient will be insignificant and flash is the main light, so flash compensation is only used to adjust desired TTL flash exposure. More to be brighter, less to not be so bright, as seen needed for the result you want.

Outdoors in sun, flash compensation is usually set perhaps near -2 EV to provide a lower fill level, to prevent overexposing the subject with two exposures, flash plus ambient. Some like to underexpose ambient a bit, others don't. It depends...

High ISO is mostly only for low level ambient alone. Or we use flash instead to provide light, but doing both is not a good idea. Bounce flash indoors typically needs maybe ISO 400 in order to have sufficient flash power (but which depends on bounce ceiling). It often needs a bit of +EV to make it bright enough (simply as seen needed). ISO 100 should be enough for direct flash. Distant dark backgrounds can cause direct flash to overexpose a bit. Either way, just do what you see is needed.

If you want only one answer for all situations, then camera P mode and iTTL flash mode (esp good out in bright sun), but there can be better choices. It is full automation, but wedding photographers moving between indoors and outdoors joke and call P mode as "Professional Mode", since its automation can accommodate most flash situations. :) Again, compensate to do what you see is needed.

Shutter speed will depend on what camera mode you are using. Outdoors in sun should be no issue, likely 1/250 second on the D750.

Camera A mode will use 1/60 second with flash indoors. This is Minimum shutter speed with flash (in A and P modes), and you can make this be slower with menu E2 (or Slow or Rear Curtain sync modes), but the only way to make it faster n A or P mode is to go out into brighter ambient light. The camera meters the ambient, and the flash has to work into that result. 1/60 second can pick up some of the ambient, and the orange incandescents can warm it some (might be desirable, might be ojectionable).

So, instead camera M mode works great with flash indoors. M mode is about the ambient, and the ambient will be too low to matter, we're using flash instead. Then you can set any shutter speed you want (up to 1/250 second maximum), and any aperture, and then iTTL or your manual power settings will handle the flash. TTL flash is still automatic flash, even in camera M mode.

A little experience will see several things to help understanding, and then each situation should become mostly obvious.

Bottom line, simply do what you see you need to do.

You are right. In manual mode I can keep my shutter speed to 1/200 and my aperture to 1.8 and then adjust iso.
It is part of my iso adjustment to match the ambient light I am photographing. If I am not wrong the indicator inside camera would always show what is the ambient measure. I love to underexposure ambient many times a bit to make my flash in my subjects more prominent. Turning my dial (EASY ISO) is the way to go for this

Thanks for that support
Alex
 

WayneF

Senior Member
The situation is this ...in auto iso the flash ISO goes to 4x your base iso I use 200-6400 so I get 800 ISO BUT BUT BUT if its light daylight it sticks to the iso 200 and when its very dark goes up above iso 800. 99% of the time its sticks with 800.
You need to check whats going on in daylight /a lit interior / when its very dark

Nikon iTTL DSR have had three versions of how Auto ISO works with flash.

Early models (D70 up through the D300) never increased Auto ISO above Minimum with flash, it always remained at Minimum ISO with flash (one exception, if a hot shoe flash had insufficient power for the situation, then it would increase ISO for it, but otherwise, Auto ISO never increased with flash. This was sensible, and the best plan, but they abandoned it.

Middle age models, D300S on, would ALWAYS increase Auto ISO for the ambient reading, regardless if flash was present or not. This means indoor flash is always working into high ISO if Auto ISO is on. But if using flash, we don't need or want high ISO. This is when they started adding the filter holders to try to match the ambient light. :) Frankly, this was the pits with flash, but Auto ISO can be turned off.

Then recent models recovered from this, certainly since the D800, and possibly a couple of models earlier) started limiting Auto ISO with flash increase to two stops above Minimum ISO (4x above Minimum), but only for hot shoe flashes. The Commander still never increases Auto ISO, but the internal flash used alone still fully increases Auto ISO based on the ambient (ISO will of course remain low in sunshine outdoors). But at least it became unnecessary to turn Auto ISO off for flash, as two stops was usually workable, and was generally good for bounce flash.

Nikon does not spec or discuss that, but it always depends on which camera we are discussing.
smile.png


And of course, Auto ISO can never increase with a manual flash in any camera model, because manual flash cannot respond to Auto ISO. The manual flash brand does have to be recognized (CLS capable) for Auto ISO not to increase.

Don't forget to use FP 1/320 or you will be in for big supprise if you forget to turn the flash off outside ( FP stands for flash programme not focal plane)

I use a SB400 but it does it with all my Yongnou as well....( D710/D800/D810)


My notion is that 1/320 is where the surprises occur. :)

If in camera A mode, and outdoors with fill flash, we do have to know we must stop down to up near f/11 so the maximum sync shutter speed can work. Otherwise, it just flashes a LO error at us.

P mode is good for fill flash outdoors, it knows to stop down to around this f/11 (to allow maximum sync shutter speed to work in sunshine).

Yes, Auto FP mode will allow fast shutter speed there, but at very reduced flash power (about 20% maximum).

That can work, at least for fill flash if not too far, but the problem is that if our actual shutter speed is near this 1/320 limit, then it can vary with lighting, and one shot might be below it and next shot above it. Then it is switching in and out between speedlight mode and FP mode, and the flash power varies greatly, and our results probably vary greatly, if we are not aware of what's happening.
 
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alaios

Senior Member
Indoors (assuming low and reasonable ISO), ambient will be insignificant and flash is the main light, so flash compensation is only used to adjust desired TTL flash exposure. More to be brighter, less to not be so bright, as seen needed for the result you want.

Outdoors in sun, flash compensation is usually set perhaps near -2 EV to provide a lower fill level, to prevent overexposing the subject with two exposures, flash plus ambient. Some like to underexpose ambient a bit, others don't. It depends...

one more question on the above.
How much fill do you allow in outdoor conditions? Lets say that you are at 100 iso, shutter speed of 1/250 and around 2.8. Would you start with a FEC of -2?

Why do not you assume that available light of a living room is not good for main light? Iso 3200 is very usable at my d750. If you use FEC of -2 to lift a bit the shadows you do not need to gel your flash since you have not raised the shadow areas much, the white imbalance to be really visible.

Great answers
Alex
 

WayneF

Senior Member
one more question on the above.
How much fill do you allow in outdoor conditions? Lets say that you are at 100 iso, shutter speed of 1/250 and around 2.8. Would you start with a FEC of -2?

For flash fill in bright sun, I would say -1.7 or -2 EV flash compensation for TTL mode (as opposed to default TTL BL mode).

Note however that the Nikon flash system default is TTL BL, which does automatic flash compensation, normally around -2 EV in bright sun (much less in dimmer scenes). It is automatic, and does not show this -2 number anywhere, but that's what the result will do with default TTL BL flash in bright sun. Things we need to know... So if you do -2 and it does -2, that will be -4 which you may not like. Wouldn't be any flash illumination left. :)

I have a page about this, at Flash pictures are Double Exposures- Outdoors

A few older flash models, and the SB-910 flash, have a menu to select TTL or TTL BL. Nikon gave that up, and the SB-500 or SB-700 or the Yongnuo flashes do not have that menu, they just say "TTL" which means whatever the system metering does. The Nikon system will default to TTL BL (meaning, automatic flash fill compensation). In which case, your 0 EV flash compensation may be the correct number (which will still be about -2 EV result if TTL BL in bright sun). I suppose Nikon is proud of their "balanced" flash system, but it is just automation, point&shoot, offers less control to the photographer. Manual flash mode is still very popular though.

Spot metering mode will force TTL mode (which is Not default TTL BL, TTL has no automatic fill compensation). Spot metering with flash works great indoors, but Spot metering is a whole new thing in outdoor lighting. Spot meters the ambient, which is generally insignificant level indoors if using flash, but Spot has a large effect outdoors, better know how to use Spot metering then.

Spot metering does not otherwise apply to flash, flash always does a central metering (but Spot does force TTL BL off, and TTL mode on).


Why do not you assume that available light of a living room is not good for main light? Iso 3200 is very usable at my d750. If you use FEC of -2 to lift a bit the shadows you do not need to gel your flash since you have not raised the shadow areas much, the white imbalance to be really visible.

Great answers
Alex


When I suggested -2 EV FC might be a bit much, you had said umbrella, and did not say Sun, and I assumed indoors, with an umbrella as main light, which is different than bright sun being main light. I'm having trouble pinning down the specific situation we discuss. :)

At least bright sun and flash generally about agree about white balance, close to the same, not very mixed lighting.

My complaint with high ISO indoors with flash is that it brings the ambient up to be fully exposed, which then shows the orange color of incandescent lights, or maybe green of fluoresents. Whatever, it normally becomes very mixed lighting sources, probably very incompatible with flash white balance. Portrait situations carefully control the light much better than that. Typically ISO 100 and maybe f/8 and maximum sync speed shutter, which in indoor ambient, without triggering the flash, is a totally black picture (no light, so no orange). Then the flash is setup to provide the pristine lighting desired.

You also said f/1.8 once, which to me, is simply not the way I would ever work for formal portraits. Poor in a few ways, but if you are using ISO 3200 and f/1.8 and intending to mix with fill flash, you will want to add filters to the flash to match the ambient white balance. CTO filters (Color Temperature Orange) to match incandescent. However, there are degrees of CTO shading. It is not an easy solution to get right, especially since every situation is likely different.

Shut out the incandescent, and use only flash, and you have a stable environment that you can control. Just one notion... Others have different ideas of course (and enjoy the challenges), but I just like sharp pictures, with depth of field, and proper lighting. f/1.8 and ISO 3200 are not on that road.
 
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alaios

Senior Member
I made an example to show you my problem and I hope it highlights successfully what my problems are
I am at matrix metering at f/2.8 iso 800 (that is typical for indoor). AUTO ISO is off. Shutter speed is around 1/8 that allows enough light to register. According to ambient light meter I am at +0 which is what I am going for.

Lets see the shot now, that is a typical shot with ambient light. Some light is coming from the living room bulbs and thus the orange color and some color behind the bed giving that blue hue at the back

APA_4455.jpg


now I plug the sb-700. And I see the image TTL BL. I dial in camera FEC -2 (I also tried with FEC 0 at camera at -2FEC At the flash body). Both settings give the below shot.
I tried with an sb-500 as well with FEC -2 and I got exactly the same shot
APA_4456.jpgAPA_4457.jpg


Now to me this is not a FEC -2 but closer to FEC 0. Unfortunately I do not know thow to share the histograms of those two shots here.
For me FEC -2 is fire that much flash to lift shadows from the black point closer to the mid tones.
What I get is closer to what I think FEC 0 should be. The shadows are lifter over midtones. This flash shot above has blinking highlights as well.

Where I am wrong with that then?
Regards
Alex
 

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WayneF

Senior Member
I made an example to show you my problem and I hope it highlights successfully what my problems are
I am at matrix metering at f/2.8 iso 800 (that is typical for indoor). AUTO ISO is off. Shutter speed is around 1/8 that allows enough light to register. According to ambient light meter I am at +0 which is what I am going for.

FWIW, Exif says ISO 1600 in the first one.

Lets see the shot now, that is a typical shot with ambient light. Some light is coming from the living room bulbs and thus the orange color and some color behind the bed giving that blue hue at the back

I assume Incandescent white balance, or Auto WB giving similar, so the blue background is window light, Daylight light, wrong for Incandescent WB. Mixing light sources is generally impossible, WB can only correct for one of them. Any try at a "compromise" WB will simply be wrong for both then.

now I plug the sb-700. And I see the image TTL BL. I dial in camera FEC -2 (I also tried with FEC 0 at camera at -2FEC At the flash body). Both settings give the below shot.
I tried with an sb-500 as well with FEC -2 and I got exactly the same shot

FEC in camera and in flash body simply add to a total, so these two are the same thing, they add to the same total. And camera EC also adds to it, unless overridden in D750 menu E4.

Now to me this is not a FEC -2 but closer to FEC 0. Unfortunately I do not know thow to share the histograms of those two shots here.
For me FEC -2 is fire that much flash to lift shadows from the black point closer to the mid tones.
What I get is closer to what I think FEC 0 should be. The shadows are lifter over midtones. This flash shot above has blinking highlights as well.

Where I am wrong with that then?
Regards
Alex

The camera meter we see (indicating 0 EV now) is only reading the ambient exposure. It is not affected by flash. Flash has not fired yet, and flash has its own invisible metering system anyway. But flash will contribute to total exposure.

It does seem a bit bright, but you are fully exposing the ambient with ISO 1600 and 1/8 second and f/2.5. Any additional exposure from flash adds to add to be more than that existing full ambient exposure. -2 EV flash compensation will add and lift fully exposed ambient by 25%, which is 1/3 stop overexposure of the near foreground affected by flash (flash percentage calculator at Flash pictures are Double Exposures- Outdoors ).

Remember that you are affected by Nikons TTL BL automation. If the scene is brightly and fully illuminated (as here, with your ISO 1600 and 1/8 second and f/2.5), then it automatically provides less flash fill, trying to minimize overexposure by adding flash. Automation interferes with your own efforts, automation knows what it is trying to do, and it can sometimes tend to ignore you.

Saying, in this TTL BL case, I really doubt you will see any difference between -2 EV flash compensation, and 0 EV flash compensation. Automation has its own goals. I am agreeing with you, but you may not like my reasons.

The default TTL BL mode really expects to do its own automatic flash compensation. Your events will be much more controllable if you use manual flash mode, and then do what you see you need to do to get the results you want.
But automation will generally give automated results, the opposite of user control.

But if you set ISO 100 and 1/200 second and say f/5.6, the ambient would be dark, black even, and the flash would try harder. Your -2 EV would hold it back however, it would not be fully exposed by flash then. That should show a strong difference between -2 EV and 0 EV flash compensation.

Or you could set some exposure compromise, to handle ambient and flash individually as you wish them to be.

Or, switching to TTL mode (as opposed to default TTL BL mode) will be different, no system compensation automation trying for its own goals.

Your words suggest you expect TTL mode, but the Nikon flash metering default is TTL BL instead. Balanced flash, in its own way.

Spot metering will make that switch, TTL flash mode overrides TTL BL mode, but then you get Spot metering for the ambient, which introduces other issues, perhaps unexpected. Spot metering is not a point&shoot effort, instead we must understand how to use it. But if you can get the ambient exposure as you want it, then TTL mode will respond properly to flash compensation.

I like to use an older Nikon SB-800 flash, which has its own menu to force TTL or TTL BL mode. I think Nikon should provide that menu in the camera, but they don't. They only provide Spot metering, which is NOT for beginners, and unfortunately, also does Spot metering for the ambient (but the flash is Never Spot metering).

Spot metering generally works great with flash indoors, which causes no effect when we ignore the insignificant ambient. But if fully metering the ambient, then spot metering is spot metering, for ambient.

You and I have different goals. My goal is to suppress ambient in flash pictures, which makes it easy. Your goal is to fully support the ambient, much more complicated. But I think you would like manual flash mode to do that, so you can control it.
 
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alaios

Senior Member
Thanks for the detailed answer. I appreciate your time. I need to ask back some questions I have.





FEC in camera and in flash body simply add to a total, so these two are the same thing, they add to the same total. And camera EC also adds to it, unless overridden in D750 menu E4.


The camera meter we see (indicating 0 EV now) is only reading the ambient exposure. It is not affected by flash. Flash has not fired yet, and flash has its own invisible metering system anyway. But flash will contribute to total exposure.


I agree totally with the above.




It does seem a bit bright, but you are fully exposing the ambient with ISO 1600 and 1/8 second and f/2.5. Any additional exposure from flash adds to add to be more than that existing full ambient exposure. -2 EV flash compensation will add and lift fully exposed ambient by 25%, which is 1/3 stop overexposure of the near foreground affected by flash (flash percentage calculator at Flash pictures are Double Exposures- Outdoors ).


and how I can set my flash to only lift the shadows? What would be the correct setting for that? -3 FEC? Btw, I think I tried it as well but the exposure was the same





Remember that you are affected by Nikons TTL BL automation. If the scene is brightly and fully illuminated (as here, with your ISO 1600 and 1/8 second and f/2.5), then it automatically provides less flash fill, trying to minimize overexposure by adding flash. Automation interferes with your own efforts, automation knows what it is trying to do, and it can sometimes tend to ignore you.

Saying, in this TTL BL case, I really doubt you will see any difference between -2 EV flash compensation, and 0 EV flash compensation. Automation has its own goals. I am agreeing with you, but you may not like my reasons.



Can this be the reason that the SB-500 also works as that? Is TTL BL the default for all available TTL flashes for nikon available (third manufacturers as well?) How I make sure I overcome it in all flashes (question about spot metering below)





The default TTL BL mode really expects to do its own automatic flash compensation. Your events will be much more controllable if you use manual flash mode, and then do what you see you need to do to get the results you want.
But automation will generally give automated results, the opposite of user control.

Yes but is not easy to shoot and go events to handle with manual flash. Think of wedding like reception. I would like to have a FEC of -2 just to fill in shadows in eye areas for example




Or, switching to TTL mode (as opposed to default TTL BL mode) will be different, no system compensation automation trying for its own goals.


I will test it. How I can use SB-500 and SB-700 withouth TTL BL.



Your words suggest you expect TTL mode, but the Nikon flash metering default is TTL BL instead. Balanced flash, in its own way.

Perhaps yes. That is how I learned to work with my tiny sony.





Spot metering will make that switch, TTL flash mode overrides TTL BL mode, but then you get Spot metering for the ambient, which introduces other issues, perhaps unexpected. Spot metering is not a point&shoot effort, instead we must understand how to use it. But if you can get the ambient exposure as you want it, then TTL mode will respond properly to flash compensation.



I expect the above to be really hard for events. Or kids running in the playground




You and I have different goals. My goal is to suppress ambient in flash pictures, which makes it easy. Your goal is to fully support the ambient, much more complicated. But I think you would like manual flash mode to do that, so you can control it.

I like to turn ambient to pitch black in my studio type of work. But outdoors and on events it is a nightmare.



Thanks again
Alex
 

WayneF

Senior Member
and how I can set my flash to only lift the shadows? What would be the correct setting for that? -3 FEC? Btw, I think I tried it as well but the exposure was the same

Getting out of TTL BL, into TTL mode, would do it. I used to imagine that additional flash compensation worked with TTL BL, and indoors in insignificant ambient, it will vary the flash level, but when the ambient is fully exposed, TTL BL has its own mind about what fill compensation is to be used. That's what the TTL BL mode does.

Flashes like SB-800, SB-600, SB-900, SB-910 have a menu to force TTL or TTL BL mode. Makes it very easy. Why Nikon is giving that up is a mystery to me. It ought to be a menu in the camera.

Can this be the reason that the SB-500 also works as that? Is TTL BL the default for all available TTL flashes for nikon available (third manufacturers as well?) How I make sure I overcome it in all flashes (question about spot metering below)


It is not the flash. TTL BL is the Nikon flash metering system default, unless overridden into TTL mode. It is Yongnuo flash too, etc.

Balancing background with a Spot is not feasible (is nonsense), so Spot Metering shifts the flash mode to TTL (does not balance).
The flash metering Never does actual Spot metering, but the ambient does.

Yes but is not easy to shoot and go events to handle with manual flash. Think of wedding like reception. I would like to have a FEC of -2 just to fill in shadows in eye areas for example

That can work indoors, with insignificantly exposed ambient (at least reduced significantly, when Spot metering problems of underexposed ambient is not a concern). It is still TTL BL (in Exif), but it acts like TTL flash with insignificant ambient. Flash compensation works. But moving outdoors into sunshine can bring diffrences of Spot metering of ambient.

Novices imagine Spot metering should produce the spot as correctly exposed. It does NOT... it only produces middle gray at the spot. Which can be correct if the spot should be middle gray, but if spot metering on a face, we sure better open exposure about 1 stop more. Faces are typically not middle gray. Spot metering is not point & shoot, we have to consider the spot, carefully. But it only affects ambient, and indoors with insignificant ambient (underexposed), it doesn't have other effect on the flash (except TTL mode).

The alternatives when trying to properly expose the ambient indoors with flash is a slow shutter speed, and a high ISO, and mixed white balance, etc.

Just some notions. Everyone has their own ideas. But Nikon default flash metering is TTL BL, which is automaton for flash compensation.
 
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alaios

Senior Member
Thanks for the answer.
I searched quite a lot and it looks like that the advantage of TTL-BL is that tries to expose correctly your focus point. This is useful feature when there is an out of focus area that is damn white or black and it would fool out your TTL system.

I tried some indoor shots close to my big window office window. It looks like that dialining FEC -2 or -3 for TTL BL gave me the look I am looking for.


The question though stil seems to be the indoor shot at very high iso I shared yesterday (the man sleeping). Why my FEC -3 gives that much exposure?

I would do couple more of tests tonight.
I will demistify that.

Purpose is to move from the camera flash to a simple two lights setup. The camera flash would be a basic room fill and the second one would be the main light. I am not sure if then the camera flash should be at pure TTL mode with -2 and the other flash at TTL BL.

It gets weird and I want to do something that simple
 

WayneF

Senior Member
Thanks for the answer.
I searched quite a lot and it looks like that the advantage of TTL-BL is that tries to expose correctly your focus point. This is useful feature when there is an out of focus area that is damn white or black and it would fool out your TTL system.

Matrix metering mode watches the full frame, but it does give added importance to the focusing point for ambient. And of course, Spot metering is at the focus point, for ambient.

Matrix, Center Weighted, or Spot metering methods are about the ambient.

Flash instead always meters in a central area (a little smaller area than Center Weighted metering). A different metering system.
TTL BL mode does try to balance the flash level with the ambient, if the ambient is significant.
TTL flash mode ignores any ambient, and comes ahead on strong regardless of ambient.

I tried some indoor shots close to my big window office window. It looks like that dialining FEC -2 or -3 for TTL BL gave me the look I am looking for.

The question though stil seems to be the indoor shot at very high iso I shared yesterday (the man sleeping). Why my FEC -3 gives that much exposure?

I would do couple more of tests tonight.
I will demistify that.

TTL BL is an automation system that tries to determine flash compensation for itself. You might fight it, but it's a good bet it will win. In bright fully exposed ambient needing balancing, then your added efforts are like two cooks salting the soup, unknown to each other -but the system can ignore your efforts in some cases, to achieve its own goal. You however need TTL flash mode to be able to ignore the systems efforts. TTL BL would not be described as user control. However, if the ambient level is left underexposed a couple of stops, then nothing for the system to balance, and then TTL BL and compensation works more like TTL mode. This is my experience and notions. A little experimentation bears it out.

TTL mode instead comes ahead on strong, always planning to honor its metered flash goal, regardless of presence of any ambient. So in a fully metered ambient, then that is full ambient exposure plus full flash exposure, which at the subject is 2x exposure, or one stop over exposed, needing manual flash compensation of course. -2 EV FC is typically good, like one flash in bright sun. TTL BL does that automatically, at your 0 EV FC level.
This is with respect to ambient, it is not about two flashes in a portrait situation. In such portrait situation, ambient is intentionally kept insignificant, and then normal lighting ratio of two lights makes sense. But if you also have fully exposed ambient and TTL BL automation messing with flash level, then bets are off.

It is just becoming more difficult to switch out TTL BL, to choose TTL mode.

Purpose is to move from the camera flash to a simple two lights setup. The camera flash would be a basic room fill and the second one would be the main light. I am not sure if then the camera flash should be at pure TTL mode with -2 and the other flash at TTL BL.

It gets weird and I want to do something that simple

That will work fine and as expected, indoors, if the ambient is ignored, and left at low level and insignificant to the overall exposure.

But if you use high ISO and wide aperture and slow shutter to also fully expose the ambient, then TTL BL flash compensation automation becomes a factor, with its own goals and actions. Also other problems like mixed lighting ruining white balance.
 
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alaios

Senior Member
That will work fine and as expected, indoors, if the ambient is ignored, and left at low level and insignificant to the overall exposure.

But if you use high ISO and wide aperture and slow shutter to also fully expose the ambient, then TTL BL flash compensation automation becomes a factor, with its own goals and actions. Also other problems like mixed lighting ruining white balance.



Thanks great and detailed answer. Respect.
More questions on my desired two lights setup. One fill flash to raise background shadows and one as main light. Do you recommend me then to shoot with the ambient being under expossed one or two stops or to kill it entirely?

I need to find where my two light setup falls short.. and especially to understand
1. what happens at high iso and
2. what my camera think is a high iso behavior.

That is all for now I guess
Alex
 

WayneF

Senior Member
Thanks great and detailed answer. Respect.
More questions on my desired two lights setup. One fill flash to raise background shadows and one as main light. Do you recommend me then to shoot with the ambient being under expossed one or two stops or to kill it entirely?

I need to find where my two light setup falls short.. and especially to understand
1. what happens at high iso and
2. what my camera think is a high iso behavior.

That is all for now I guess
Alex

I don't think it is about "high ISO" as such, or wide aperture or slow shutter speed. Instead it is about fully exposed ambient, vs a less significant amount. These factors like high ISO just tend to fully expose the ambient. Which affects TTL BL automation for balancing flash, and also white balance of course.

I'm not aware of a difference in ambient two stops down vs at a zero black level. Neither should interact much with flash, and I suspect very little difference in flash compensation response. I think the main thing is an ambient level that is not significant towards the exposure is good (normal places flash would be used). If ambient is significantly important to exposure, TTL BL will have the goal to attempt to reduce the flash level, to not overexpose the total. It has its own mind. Which is generally good if the user stands back and leaves it alone. Just not very controllable, automation does not mix well with user control.

There are a couple of effects in the TTL BL flash system where Nikon has made it difficult for users to affect what the automation is doing, or to turn off the automation. TTL flash mode is superior in that way, in that it does the expected, but Nikon has made that be unnecessarily difficult to do now. Novices may like TTL BL automation, but pros, less so. The camera itself seriously needs a TTL vs TTL BL metering menu for our selection. Why not?
 

alaios

Senior Member
So I have spent one more evening trying.
I think I get closer to what might be the problem. I think it is not that the camera ignores my -3 FEC but it does not have any more latitude for weaker flashing.

Let me try to explain
at f/2.2, 1/200 iso 1600 and subject being around 2-3 meters if I turn to manual my flash and fire it at 1/128 (which is the weakest output) that simply blows out completely the shot. With all the histogram being from the middle area to highlights area full.
When I turn to flash to TTL at FEC -3 I get a better shot that looks just properly exposed (like +0 FEC) which I guesss hows that my flash can not simply flash at a lighter intensity (and this also explains why FEC -3, FEC-2, Fec-1 and FEC 0) are all alike.

Now the tough part would be to know in advance when I get on these "areas" and being able to make aperture smaller or reduce iso.
Since I use manual mode so to have my shutter speed at 1/200 it is still a question on where I should have my iso to still
1. allow my background to register
and
2. being at a region where my lowest power of my flash would not make shot to be blown completely.

Last question since I am using manual mode to have a shutter speed I need, I wonder since I have my iso fixed and aperture, then turning the EC dial would make it equivalent to FEC.. right? Since now the EC only can change flash output since everything else is dialed in.
Let me know where I am wrong in all above
Regards
Alex
 
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