Auto mode with EC -1 and FEC at -1

alaios

Senior Member
Hi there,
I look for a semi auto mode where I can shoot fast on changing light intensities with my flash. Ideally I would like to have my background underexposed one stop and then use some fill from flash at -1 or 0.
When I do not use flash I am at aperture priority, with a minimum shutter speed of 1/200 and auto iso. Since I understand how matrix metering can over or understimate I use EC compensation. This works quite well.

Problem being when I use my flash guns and I want to have a similar semi auto mode. When I am at aperture priority camera drops me at 1/60 which is not enough shutter speed for me. I can still stay at 1/200 at manual mode which is an okay workaround.
The problem I have with flash is that I have to shoot fast under very different lighting condition.[FONT=&quot] Think me shooting at the door of a church where I need to cover fast events going on both sides (outdise and inside).

Auto ISO and flash does not allow me to set a relation between ambient light and flash exposure and even worse if I set auto iso at 800 for inside the church I can easily forget when I am outdoors and so son.

What do you do for my case?
Regards
Alex[/FONT]
 

WayneF

Senior Member
Hi there,
I look for a semi auto mode where I can shoot fast on changing light intensities with my flash. Ideally I would like to have my background underexposed one stop and then use some fill from flash at -1 or 0.
When I do not use flash I am at aperture priority, with a minimum shutter speed of 1/200 and auto iso. Since I understand how matrix metering can over or understimate I use EC compensation. This works quite well.

Problem being when I use my flash guns and I want to have a similar semi auto mode. When I am at aperture priority camera drops me at 1/60 which is not enough shutter speed for me. I can still stay at 1/200 at manual mode which is an okay workaround.
The problem I have with flash is that I have to shoot fast under very different lighting condition. Think me shooting at the door of a church where I need to cover fast events going on both sides (outdise and inside).

Auto ISO and flash does not allow me to set a relation between ambient light and flash exposure and even worse if I set auto iso at 800 for inside the church I can easily forget when I am outdoors and so son.

What do you do for my case?
Regards
Alex

The normal Nikon procedure for Exposure Compensation has always been that EC affects both ambient and flash. So if you set EC to -1 EV, flash and ambient are both -1 EV. EC is added to FC, however we do NOT see the sum in the menus (the Exif data will show the sum afterwards). And we can set EC -1 and FC +1 to give what we think of as EC -1 and FC 0 EV.

However, for the D750, you can forget that. Because some later models, including the D750 add a new E4 menu which will interest you. This provides for separating EC and FC, so that EC only affects ambient, but not flash. The E4 description in the manual uses the word Background to mean Ambient.

The 1/60 second with flash in A mode is menu E2, the Minimum Shutter Speed with flash (in modes A or P).
It can be faster in bright light, for example in bright sun, it will be as metered, much higher, perhaps 1/250 second (menu E1, which also can have other HSS effects). But indoors, the ambient meters very dim, and if you turned the flash off to see it, perhaps it might say maybe 1/4 second (just for example, in your indoor situation). But if using flash, system doesn't think you need to be bothered with 1/4 second, so it sets the Minimum Shutter Speed with Flash, which default and E2 maximum is 1/60 second. Shutter will be at least that fast with flash. If you see 1/60, the ambient probably actually metered slower.

Now if the ambient without flash does meter 1/4 second, this 1/60 Minimum is 4 stops underexposure of ambient. But no matter, if you are using flash instead. If for some reason you wanted to use the 1/4 second actually metered, use Slow Sync (or Rear Curtain Sync), and they will do that.

Flash compensation will adjust the TTL flash output, but it has very little meaning as fill ratio if the ambient is already 4 stops down.

The flash exposure is NOT AFFECTED by shutter speed, so the TTL flash exposure will be the same in A mode 1/60, or M mode 1/250 second. Assuming the 1/4 second that I made up, at 1/250, the ambient will be underexposed 2 more stops (than would 1/60), but it is already pretty black at 1/60, so it really doesn't matter. It might be a consideration in a brighter ambient that actually registers some light (which is probably outdoors).

Using M mode with flash indoors is very common practice. It offers choice of shutter speed for ambient. TTL flash is still automatic even in camera M mode, and the flash exposure is not affected by shutter speed. Indoors (insignficant ambient) TTL will allow you to shoot fast (if the flash is able to recycle fast enough). Also S mode allows setting other shutter speeds, but a) indoors likely is always maximum aperture in S mode and b) flash is not affected by shutter speed, so M mode seems preferable.

Ambient is affected by shutter speed, so therefore Manual and Shutter Speed is a useful tool to control the ratio of ambient to flash. Shutter affects ambient, but not flash. Yoiu can choose shutter speed to allow more ambient in, or to keep more out.
 
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TieuNgao

Senior Member
.......................
if I set auto iso at 800 for inside the church.................

I wonder why you set Auto ISO at 800, why not at 100?
I think by setting Auto ISO at something higher than 100 the photos will be taken at higher ISO than necessary.
 

WayneF

Senior Member
But if you did want to use ISO 800 with flash, you have to set the D750 Minimum ISO higher than ISO 100. The D750 and a few of the later models will limit Auto ISO, allowing ISO to advance by only 2 stops (or from ISO 100 to ISO 400) if a hot shoe flash is detected present. No so of the internal flash, it will still allow Auto ISO to fully advance for the dim ambient, but a use of a hot shoe flash stops at 4x Minimum ISO. Seems reasonable, because we're using flash instead.
 

alaios

Senior Member
so this is my workaround semi auto flash mode.

I have set EC to be controlling both ambient and flash. For a reason when EC only controls ambient the EC button does not look like affecting ambient that much (do not ask me why I am testing it since yesterday).

So then I am to manual mode to push shutter speed to 1/200
I set my flash to -1 and the I am at ISO AUTO with a base ISO based on the situation.
When I am outdoors this will be 100
When I am indoors well lit that would 400 or 800
and when light is dim I will be at 1600.
I test typically the shot with only base ISO to make sure that ambient registers as I need.
Then I take shot with flash. I only then work with EC +1 (is a typical value) that raises most off the time the ambient light (camera raises ISO) and in that sense I get the shots I like in "semi-auto" flash mode"
Do not ask why this works but it does
Alex
 

WayneF

Senior Member
EC does not affect the camera Manual exposure. Because Manual exposure is whatever you have set it to be.
EC will affect the light meter reading, which possibly you may or may not use to adjust exposure settings yourself, but the light meter reading is not automatically used by camera Manual mode. EC will not change Manual camera shutter or aperture settings. Manual is Manual.

However, EC will affect Auto ISO, which will increase trying to make your Manual camera settings be correct, except presence of a hot shoe flash (not the internal flash) will limit the Auto ISO increase to only 4x your Minimum ISO setting (i.e., ISO 100 can increase to ISO 400). But EC cannot change Manual shutter or aperture settings.

Manual flash mode - will be the flash level exposure you have set on it. Manual flash will not be automatic, EC will have no effect on it. And Auto ISO cannot increase at all with a manual flash (Manual flash cannot respond to ISO changes).

TTL flash mode - IF EC is also affecting TTL flash (E4) , it will affect metered TTL flash exposure. TTL flash will try to be correct for EC and for ISO (within the 4x ISO limit). And flash of course will contribute to the overall scene exposure.
 
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alaios

Senior Member
EC does not affect the camera Manual exposure. Because Manual exposure is whatever you have set it to be.
EC will affect the light meter reading, which possibly you may or may not use to adjust exposure settings yourself, but the light meter reading is not automatically used by camera Manual mode. EC will not change Manual camera shutter or aperture settings. Manual is Manual.

However, EC will affect Auto ISO, which will increase trying to make your Manual camera settings be correct, except presence of a hot shoe flash (not the internal flash) will limit the Auto ISO increase to only 4x your Minimum ISO setting (i.e., ISO 100 can increase to ISO 400). But EC cannot change Manual shutter or aperture settings.

Manual flash mode - will be the flash level exposure you have set on it. Manual flash will not be automatic, EC will have no effect on it. And Auto ISO cannot increase at all with a manual flash (Manual flash cannot respond to ISO changes).

TTL flash mode - IF EC is also affecting TTL flash (E4) , it will affect metered TTL flash exposure. TTL flash will try to be correct for EC and for ISO (within the 4x ISO limit). And flash of course will contribute to the overall scene exposure.

Yes you wrote it precise.
I am talking aboutt manual mode, auto iso and ttl ratios. Then with EC I adjust and "boost" alltogether which is a nice way for semmi auto
 
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