TTL or Manual?

[WhiteLight]

What do you use? And recommend? Why?

I've seen the advantages of both, but am yet to perfect the art of exposing correctly with flash.
Inputs from members with knowledge or experience would be very helpful

 

[WayneF]

One flash is pretty easy to tweak in manually, no big deal at all (whereas multiple manual flashes really need to be metered, with respect to each other).

With just a little experience, we pretty much know where to start with manual flash power (it ought to be pretty much same as last time in a similar situation). But, we do have to watch, and tweak it a little with another try.

TTL is self metered, perhaps not always perfectly, but normally can be a closer starting point, and sometimes is right on first try. Again, we do have to watch, and maybe tweak it a little (using Flash Compensation to control TTL automation).

So... speaking of one flash, the only real difference is the starting point, which always needs evaluation.
We can choose to feel smug for using manual flash, or we can choose to do it the easy way.
Either way, we watch, and we tweak when necessary.

 

[WhiteLight]

As always, thanks Wayne..
Shouldn't the same principle apply for multiple flashes as well?
Also from what you say, TTL would be a better way to go as it makes life much easier....

Sent from my HTC Incredible S using Tapatalk 2

 

[WayneF]

Well, I am sure it is all opinion, but my opinion is that we really need to adjust multiple flashes not just for overall image brightness, but also accurately with respect to each other. It's why we use multiple lights, for their ratio. Suppose you want the fill flash to be -1.3 stops down from the Main light. Sure, you can guess at it and set it any way you want to see it, your choice. But ... if the plan includes repeating that same setup next time, and every few days, you really need to meter them so you have some clue what you are doing, and specifically, can repeat it. You don't want to be doing that guessing every time, not for multiple lights. We are not that good at guessing. Do you really want to do that every time with four lights?

Metering manual lights works great, because we use a handheld incident meter, which is independent of the subjects color and reflectivity. Pretty much zero error, every time. Simply set each one exactly like you want them (speaking of a fixed studio situation). Say main light f/8, fill f/5.6, background say f/f8, and hair depends on hair color, maybe a stop more than main for dark hair, and a stop less than main for light hair. You just set then, then you know what will happen. After this perhaps more tedious setup, (but it is certainly not the horror of guessing), then your first picture will be good when the subject arrives. You know exactly what you have.

If it is going to involve following action, kids running around, etc, TTL is about your only chance.

Manual flash and guessing works much better with only one flash. Fewer choices to be concerned with. But, you will need opportunity for retries (near a fixed situation again).

One TTL flash is easy, the system uses reflective metering, but often gets it mostly right, and we may tweak it only a little, if at all. Possibly about the same way every time. SB-700 does TTL BL, and indoors, I would start with +1 EV Flash Compensation, and tweak from there. And we know when our background is white or black, and we quickly come to know what to expect before we press the shutter.

Two TTL flashes are easy with the Commander, it will meter them to equal at the subject (regardless of their distances or their modifiers, etc), and then will apply the compensation you set in the Commander menu, to reduce fill light to the specified -1.3 EV. More flashes become a Commander problem though, groups for one, but in part because hair and background are not really meterable at the camera.

Anyway, the skill to be polished with TTL flash is Flash Compensation.
And the skill to be polished with one manual flash is adjusting its power level.

(or adjusting aperture works to adjust Manual flash too, but note that aperture or ISO does NOT work with TTL, because TTL automation simply responds to the change, to keep doing exactly what it did before, in spite of your change). Flash Compensation is the tool for TTL.

But both of these two skills are about watching the result (image on rear LCD, possibly with zoomed in magnification so you can see it), and watching the three RGB histograms for that image.

Same thing, same skill, just a different starting point. TTL probably involves fewer tries.

 

[WhiteLight]

Hmm... So everything about manual metering is guess work? Have not
Used a flash meter so dunno how that would help or make things easier..

People say to expose correctly, then lower the exposure by two stops or so and then to fill with flash.. haven't really had too much success..

Have read quite a bit to be hand honest, but that everything clicking in place ain't happening!

Sent from my HTC Incredible S using Tapatalk 2

 

[WayneF]

Hmm... So everything about manual metering is guess work? Have not
Used a flash meter so dunno how that would help or make things easier..

Metering Manual flash is very precise and intentional, not guess work. I meter to 0.1 stop.
Guessing at Manual flash levels is always guess work.

There are two types of metering however, Reflective and Incident.

Meters in cameras (at camera, aimed at subject) are Reflective. They see light reflected from subject.

A subjects white dress or a white background reflect light very well, and will be bright. A reflective meter will see it bright, and will stop down to make it be middle gray (underexposure).

A subjects black dress or a black background reflects light poorly, and will be dark. A reflective meter will see it dark, and will open up to make it be middle gray (overexposure).

This is a fault of TTL metering, but it is simply the way the camera meter always works. It is AT THE CAMERA, and has no other choice. It has ALWAYS worked that way, for many decades. This is a standard skill photographers learn, about the first one.

Reflective meters are even dumber. They see some light, and can measure it, but they can't tell a white thing in dim light from a black thing in bright light. So they make all results be about middle gray, not to bright, not too dark. This is good stuff to know.

Please know that I'm not speaking to you WhiteLight, I've seen a lot of your work, and it is impressive, and going strong. But I am posting in public forum for anyone that it could help. I want to shout (in general): WAKE UP, and learn a thing or two. You will love photography.

An incident meter (which flash meters are) are held at the subjects position, but aimed at the camera, and never sees the subject (not affected by the subject). It reads the light directly, that light which is falling on the subject. These incident meters are not affected by the subject, and they are generally very accurate. No difficulties. But less convenient, they only work from the subjects position.

TTL metering probably works to 1/6 stop, but it is necessarily reflective. So is the camera's sunlight metering, same thing, reflective. Affected by the reflectivity of the subjects colors. So reflective meters are always questionable, we have to think it out, but incident meters are rock solid.

People say to expose correctly, then lower the exposure by two stops or so and then to fill with flash.. haven't really had too much success..

Have read quite a bit to be hand honest, but that everything clicking in place ain't happening!

That sounds like fill flash in bright sun, and -2EV is pretty close for TTL mode.

However, my suspicion is this:

You are using a SB-700, which does not have a TTL vs TTL BL menu, and it does TTL BL by default (unless Spot Metering, which is TTL). So -2EV is about right for TTL, but you are not using TTL.

TTL BL tries to do this -2 EV (fill in bright sun situation) Automatically itself. That is what TTL BL is, balanced means reducing flash for the ambient. So if you also set -2 EV FC, then it will do about -4 EV, which is about zero flash, insignificant.
For SB-700 and its TTL BL, start there with -0 EV, and tweak from there, if desired. It will be about right, you will like it.

If you had actual TTL mode (for example, your Spot Metering would be), and used 0EV fill in bright sun then, you would overexpose the subject by one stop. Two proper exposures added is 2X. But the purpose of TTL BL is to back off (on that case) by about 2 stops. Good stuff to know.

Read Four Flash Photography Basics we must know - Flash pictures are Double Exposures, it is all there. See esp towards the end.