How much automation with flash and auto iso

alaios

Senior Member
[FONT=&quot]Dear all,
[FONT=&quot]Many times at events I shoot at manual mode to have a fast enough shutter speed a fixed aperture and then I use auto iso. IF needed I use Exposure compensation to fix situation a bit since this is a semi automatic mode for me.

[FONT=&quot]It allows me to shoot very fast and I can trust the very good iso performance and improve things if needed later in post. This has worked very good with kids as well that run a lot and I really need to chase the expressions (so there is no time for adjustments).[/FONT]
[FONT=&quot]The above works very good when I am shooting available light. At indoor environments though some times I need to use flash to fill in, especially flash bouncing at ceiling. The question I have now is what is the automation I can expect when I really need to chase expressions and there is not time for adjusting settings a lot.[/FONT]
[FONT=&quot]Especiallyy for the case of shooting kids many times it might be that I have moved one kid or child close to window to have at least a better lighting situation and while shooting another kid at the back of my side does something funny. I need to turn fast and since perhaps that kid might be in shadow the settings I have in camera are not any more correct.[/FONT]
[FONT=&quot]That means for such cases I need to trust a bit the camera on providing an okayish exposure that I can improve later on in lightroom.[/FONT]
[FONT=&quot]The question here though is that is known that ISO Auto and TTL does not work very good with nikon bodies. What would you do in that case where you work very fast with a mixture of light and you just need to shoot when you see a nice moment.[/FONT]
[FONT=&quot]Thanks[/FONT]
[FONT=&quot]Alex[/FONT]
[/FONT]
[/FONT]
 

RocketCowboy

Senior Member
What Fred said. I'll lock in my ISO based on ambient conditions, and then let TTL adjust to scene changes as necessary. Having TTL and auto-ISO means there's too much variance from picture to picture ... at least for my tastes.
 

WayneF

Senior Member

The question here though is that is known that ISO Auto and TTL does not work very good with nikon bodies.


There are a few ifs and buts, esp if Auto ISO is On, but a quick summary:

With Auto ISO turned Off, then in camera A or P or S modes, the camera first meters for the ambient. The settings that are selected (aperture or shutter speed) depend entirely on the ambient metering. I will qualify this more for Auto ISO just below, but other than Auto ISO, the TTL flash necessarily has to work into whatever shutter and aperture settings it discovers has just been selected for the Ambient (then TTL meters and selects flash power for those settings). This is one reason that camera mode M is so useful for indoor flash, it allows our selected settings.

Except, if flash is detected present (TTL or Manual flash), there are additional limits added, of Maximum shutter Sync speed (typically 1/200 or 1/250 second maximum, menu E1 on the D750), and in A or P modes, also a Minimum Shutter speed With Flash, commonly 1/60 second default Minimum (menu E2 on the D750). Maybe the dim indoor ambient metered slow like 1/4 second, but if flash is detected present, then the logic is that we would not want such a slow shutter because we're using flash (or we could specify Slow Sync mode and still use the slow metered value). In dim indoor situations, in camera A or P mode, the shutter speed is likely always this 1/60 second Minimum (which is just a limit, and is NOT a selected proper exposure). These shutter speed limits can affect the ambient exposure, but not the TTL flash exposure (which just selects power level to compensate for aperture settings and ISO). Using camera M mode indoors with flash allows choice of the these settings.

So indoors in dim situations, at Minimum ISO and these shutter limits, the automated ambient is likely well underexposed, but not much concern when the plan is to use the TTL flash instead.

However, if Auto ISO is On, then there have been three modes with TTL flash, depending on camera model used.

In the first early iTTL camera models (first were D2H and D70, 2003 and 2004... up through D300 and D700 and D90 through 2008), Auto ISO is automatically turned OFF if a flash is detected present. Manual flash cannot react to ISO changes. TTL flash always selects Minimum ISO, instead of Auto ISO, because we are using flash. This had always been common practice before, high ISO is not needed if using flash instead. I for one found this to be most reasonable and expected.

Then around 2009 (cameras D300S for sure, and I think D5000 were the first), this changed, and Auto ISO was NOT turned off if TTL flash was detected present (it still was necessarily turned off if Manual flash was detected). This means in a dim ambient, TTL indoors was probably always working into maximum ISO (unless Auto ISO was turned off). This was not so great. The Orange color of incandescent light was just one reason. This means the default flash was TTL BL mode, becoming Fill flash for the brightened ambient. My notion is that Nikon was just pushing their TTL BL balanced flash, to extremes, wanted or not. Their flashes started providing the color filters to compensate for it. But at least we could turn Auto ISO off.

But that was poor, and it was soon changed again around 2010, for D7000 Sep 2010, and the D5100, D4, D800, D3200, D600 and all the current more recent models). Now (including current camera models), if TTL flash is detected present, Auto ISO will be allowed to increase 2 EV maximum, like from ISO 100 to 400, but no more than 2 EV from whatever Minimum was (which could still be set high). ISO 400 is normally desirable for bounce flash, so that's not so bad.

So that was 8 years ago, but there are still many older camera models in use.
Anyway, how Nikon Auto ISO works with flash depends on the camera model. Early iTTL cameras turned Auto ISO off with flash. Current cameras almost do, but there there was time for cameras around 2009 to 2010 when IMO, it was bad news. But Auto ISO could be turned Off - the camera will still work. :)


Auto ISO can work pretty well without flash. Nikon Auto ISO can even use 1/6 stops (for ISO), where the other settings are limited to 1/3 stops. My own philosophy is to never consider Auto ISO in any kind of critical situation where I really care about the result. I want ISO to be exactly what I want, no surprises. However, for walk-around-all-day-on-vacation snapshots, in all kinds of situations from bright sun to rather dark cathedrals or castles, Auto ISO sure makes casual snapshots easy then. It might use your maximum ISO limit more than you like however.

However, we do need to understand the Minimum Shutter Speed found in the Auto ISO settings. If Auto ISO has to react and increase, that necessarily means this is THE SHUTTER SPEED THAT WILL BE USED (it could be even slower if high ISO is not sufficient). But it will not be faster if Auto ISO is needed. So setting this minimum shutter speed too low is bad news. It is not Minimum except in bright sun, otherwise it is the most commonly expected value, possibly always too slow. So choose it accordingly.
 
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Horoscope Fish

Senior Member
What Fred said. I'll lock in my ISO based on ambient conditions, and then let TTL adjust to scene changes as necessary.
This is what I would do as well...

.....
Having TTL and auto-ISO means there's too much variance from picture to picture ... at least for my tastes.
And for these exact reasons. Auto-ISO and flash, in my experience, is just a bad combination. Maybe there's some secret to making it all come together but for me, it's just faster and easier to pick an ISO, stick with it and let TTL handle the heavy lifting.
 

alaios

Senior Member
This is what I would do as well...

.....

And for these exact reasons. Auto-ISO and flash, in my experience, is just a bad combination. Maybe there's some secret to making it all come together but for me, it's just faster and easier to pick an ISO, stick with it and let TTL handle the heavy lifting.


locking iso at ambient with ttl flash looks to work considerably good giving very balanced exposures (and if I am not wrong TTL is doing the fill in that case). I am not sure though what should I do when I am mixing different color temperatures. Using gels to adapt on the go it is not easy.

Thanks
Alex
 
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