Newbie question: Strobes and auto exposure?

[john_sack]

I am new to lighting -- taking a few steps beyond on camera flash

and reflectors -- and I may be confused about exposure control when

using studio lights. (I'm investigating White Lightning and

Lumedyne lights right now, for a class in commercial lighting I'll

be taking.) I've gotten helpful advice before from this bboard, so

I thought I'd return and ask some more questions...

 

Since lighting heads and power packs seem to be systems (like

cameras and lenses, I mean) I thought I'd better understand my

options before I spend much money. I use a Canon 20d, and for

lighting now I have a 580ex, 420ex, ST-E2, and umbrellas, stands,

etc.

 

My shooting situations so far have been those requiring portability

and pretty quick set up (impatient subjects, on their locations).

So I'm concerned about investing in lighting equipment that will

have me take much more time with a subject than I do now. However, I

hope to get equipment that will let me grow (for an advanced

hobbist) into some non-people shots.

 

I'm attracted by the idea of auto exposure (whether eTTL or other

AUTO modes) because it would seem to eliminate a lot of the time

that would otherwise go into measuring/metering and taking test

shots, while people wait impatiently for me to get it right.

 

In the Lumedyne product family there is something called an "auto

exposure module":

http://www.lumedyne.com/auto.html

which seems like it would do just what I'd like.

 

I don't see anything like that in the White Lightning line and I'm

wondering why not (I also don't see it in other product lines). So

either that function is provided some other way in other systems

that I haven't figured out yet, or it is pretty useless. How do

other people who have the need to move quickly from setup to setup

manage exposure if not with an auto module such as this?

 

Can someone help me figure that out?

 

John

[david_goldfarb]

As soon as you have more than one light, auto exposure is an iffy proposition, and many cameras used in the studio don't have auto exposure anyway, so most studio lights are manual and require the use of a flash meter. If you need to do it quickly, then the solution is to develop a few standard setups and practice doing it quickly. If you're shooting digital and can view the histogram on the spot, you've got more to confirm exposure than someone shooting film with an all-manual camera, and people do this sort of thing with manual cameras all the time.

 

If you want TTL auto flash with your system, you could look at Lumedyne or Quantum, and you would want to consider what you can do with one light and reflectors--which is actually quite a lot. By using slow sync indoors and high-speed sync outdoors, you can also vary the level of ambient light in relation to the flash, so you can control the brightness of the background. In a typical situation, the strobe will be your key or main light, the reflector provides fill, and ambient (controlled by shutter speed) will be the background light (though this doesn't give you as much control as another strobe for the background).

[ellis_vener_photography]

get there early and set up & test before your subject arrives.

[ellis_vener_photography]

<I>As soon as you have more than one light, auto exposure is an iffy propositio</

I><P>not necessarily. the past couple of weeks I've been working with a kit of two N ikon

SB-8800 and two SB-600 Speedlights and they work incredibly well together in iTTL

matrix mode on a D70.

[picturesque]

Lumedyne has an auto exposure module (and TTL module with their Signature line) because these units are often used on-camera (on a bracket) for events such as weddings. Quantums are, too. White Lightning units aren't typically used on-camera and are used more as studio strobes. As others have pointed out, studio strobes are usually used in manual mode with hand metering and placed in ratios with other units (either on-camera or other off-camera). Auto (which refers to thyristor flash) is technically not supposed to work in ratio lighting. The sensor on the flash will receive erroneous information due to the other flash's light affecting it. In practice, I've found it does work to an extent. Only if the units in question are the same (same sensor) and you do some testing so you know how they will respond.

 

When I use multiple lights at weddings, I use a manual off-camera flash and a TTL (plain TTL, not E-TTL or i-TTL) on-camera flash. I don't meter. I know where to place the off-camera flash for the f-stop I want, but I use film, which has a wide exposure latitude. If I were using digital, I would meter, which does not have to take very long, even without an assistant. Again, TTL is not supposed to work well in multiple light situations where it is not part of a closed system such as with your ST-E2 system. In practice, it works as long as you know how it reacts with your off-camera flash. Usually, you can get away with only metering the key light.

 

If you aren't unhappy with your present methods using the ST-E2 for fast-moving situations, I'd just continue to do so. And when you say non-people situations, what do you mean?

[john_sack]

Nadine,

 

By "non people" situations I meant some "commercial" lighting in which I might be doing a still life, an interior, etc. Generally that isn't what I do, but I'd like to at least know how.

 

It sounds like the advice on auto exposure with multiple strobes is not to expect it to work, and that metering is quick anyway. I sure hope the course I take on this gets me through the cookbook "here's how you boil water" stage so I can feel good about that.

 

As for why not stick with my current auto exposure setup (Canon 20d, 580ex, 420ex, ST-E2, umbrellas, etc.), I have been told (the course instructor) that it is not powerful enough to do much more than fill in flash. So I assumed I needed to get to something significantly more powerful (and expensive). And there is probably something to learn there. Auto exposure seems to be the training wheels for lighting.

 

I guess even with something more powerful I still want portability and easy setup. It may be that that is not possible with strobes and I just need to get over it.

 

John

[ellis_vener_photography]

<I>As for why not stick with my current auto exposure setup (Canon 20d, 580ex, 420ex,

ST-E2, umbrellas, etc.), I have been told (the course instructor) that it is not powerful

enough to do much more than fill in flash.</I><P> i'd try it rather than just take one

person's

word. but manual units will force you to think about what you are doing --always a good

thing in the long run.

[picturesque]

Some event photographers use multiple 580/550/420s and the ST-E2 to accomplish multiple/off-camera lighting. Especially with digital, where you can use wider f-stops (if you have the smaller sensor) and higher ISOs than with film (to accomplish the equivalent quality/image), it has become feasible. It is even workable for some kinds of portraits--both retail and corporate, and even some (not all) kinds of commercial work. Do a search on this forum. I've seen a number of posts in the past about this.

 

Based on the kind of photography you want to do in the future, I'd step back and study my options and learn more about lighting for a while before buying. Do searches on this forum and the lighting forum lessons about studio lighting systems. In the meantime, use what you have. It will become obvious when you need to get a more powerful system (the day you get a job that you can't do with your current flashes) and by then you'll know what system will fit your needs the best.

[Jochen_S]

I'm no expert and not interested in modern gear yet. But as far as I know your 20D works fine at 800 ISO. So I'd realy suggest you find out where and what for you need plenty of power before you buy it. With my old full power only strobes and the Pentax *istD unable to go below 200ISO I'm sometimes already forced to use ND filters, to reach f32-f16. If you want to do portraits f5.6 - f11 should do fine and I wouldn't see a reason to invest in unneccessary equipment. Maybe your teacher was brought up when products or groups where shot at f64 on 25-64ISO films? Who knows? Never satisfy a need you don't feel! But well, it's good to have a plan for the case...