A little "light meter 101" please

[jml]

Hey kids, added a Sekonic L-358 to the cache today. I should have

known I was in trouble when on the opening page it read.."Because of

its many features, the L-358 requires this rather extensive manual".

 

I very much need a little basic operation instruction to get me

started.

 

For incidental light operation primarily first. Appparently I can

choose aperture or shutter priority. Would I choose either based on

how I was setting the camera, or why would I choose one over the

other? And if lets say I chose shutter priority, and took a

measurement (according to what I've read I should do), then is the f

stop that shows up what I set my camera to? And vice versa? A duh

question?

 

And it has an ev mode which means what? It averages different

measurements....and why would you want to do that? And as it also

does flash measurement.....if I'm using fill, then flash and meter?

I did buy the optional wireless flash radio triggering module,

although I only know the rudiments of why, but as I got the meter

(for those of you who already own this model) for $219 w/25.00 for

the module, it was a good price for this meter, from my research.

 

Anyway, for an "extensive manual" it doesn't explain things as in

depth as I need. I'll get to the more advanced features in time I'm

sure....but for now....just the basics of how and why please!!!

 

I would really like to utilize it to the best of my limited ability

this weekend for a wedding. Thanks so much.

[beauh44]

Hi Jan, I'll take a stab . . . <P>

 

<I>Would I choose either based on how I was setting the camera, or why would I choose one over the other?</i><P>

 

Yes, you'd choose either based on how you want to set your camera. I'll give you some examples of why you might choose one over the other. <P>

 

Let's say you want to shoot with a very narrow depth of field to isolate your subject. Your lens will open up to f/2.8 which should get the job done, so you'll want to know what shutter speed you'll need to use at f/2.8 to get a good exposure.<P>

 

Conversely, let's say you want to freeze the action at a football game. You decide 1/125th of a second will do it. You can use the meter to tell you what aperture will give you a good exposure if you set your camera to that shutter speed. <P>

 

<I>And if lets say I chose shutter priority, and took a measurement (according to what I've read I should do), then is the f stop that shows up what I set my camera to? And vice versa? </i><P>

 

Yes. <P>

 

<I>And it has an ev mode which means what? </i><P>

 

EV stands for Exposure Value. It's not used quite as much as it was in the old days but there are still some out there who do. It's just a different way of measuring light using a different scale - I wouldn't worry about it for now; chances are you won't be using the EV scale.<P>

 

If you're using a fairly modern SLR camera then in many cases you can trust the meter in it. Most have Aperture priority modes (usually designated Av) and Shutter Priority modes (usually designated Tv). They should work fine and will be much quicker than using the handheld meter to take a reading then setting your camera, then taking the picture. These two modes work the same way as described above.<P>

 

Most people use Av mode on their camera for fill flash - the camera figures that's what you want if you put it in Av mode - as opposed to Manual or Tv mode. Just select Av mode, then select the aperture you want to use (in the above example, f/2.8) and the camera will figure out the shutter speed and flash amount. I usually only use a handheld meter in the studio myself but everyone's different. Good luck!

[Ed_Ingold]

Well, manuals tell you how, not why or when...

 

You would use aperture priority when the depth of field or image quality is most important, or when using flash for fill-in. Use shutter priority when stopping action is the most important issue. Probably more people use aperture priority than any other, and program mode (which combines aperture and shutter priority) is held in (unjustifiably) low regard - as a point-and-shoot option. Camera meters are so good, that correct exposure is hardly an issue any more.

 

EV (exposure values) are numbers that represent any combination of shutter speed and aperture that give the equivalent exposure - called "reciprocity." You get the same exposure at 1/125 at f/8 as with 1/250 at f/5.6. The EV also takes the film speed into account. ISO 400 is twice as fast (1 f/stop) as ISO 200. Starting with an EV value, you (the photographer) choose the shutter/aperture combination that best meets your needs.

 

Averaging takes several readings (it varies with light meters) and provides the average. Theoretically, you measure the brightest spot and the darkest spot you want to record detail, and shoot in the middle. It's a lazy version of the Zone System, and doesn't work very well. Film and digital are assymetric, so the middle is usually not the best place to be.

 

Find a book that explains film, settings and exposure. "The Negative" by Ansel Adams is a good read, as is "The Camera" and possibly "The Print."

[bruce_rubenstein___nyc]

Here's some 101 on the L-358 re: Av/Tv ambient light metering -

 

The factory default setting for the DIP switches gives whole stop changes to the shutter speed with 1/10 readings for the f stop. With the switches set this way, the only sensible way to use the meter is in Tv mode: you set the shutter speed, the meter reads out the f stops.

 

Set DIP switch 3 to the UP/ON position and then both the shutter speeds and f stops read out in 1/2 stops. Set both DIP switchs 3 and 4 up, and the meter works in 1/3 stops. In most cases set the DIP switches to match the granularity that your camera is set to, e.g. if your camera adjusts aperture and shutter speed in 1/3 stops, then set the meter to 1/3 stops. Then set the Av/Tv mode of the meter to the way you're working.

 

So, why does it mix whole shutter speeds with 1/10 f-stops? Because almost all pre AF cameras adjusted shutter speeds in whole stops in manual mode. 1/10 f-stop readings are useful for checking eveness of lighting.

[jay ott]

You need to first ask the question what am I trying to accomplish? e.g. blurred background? Then large aperture etc. ect. A basic rule of thumb is smaller f/stops for landscapes and fast shutter shutter speeds to stop motion which may mean you have to use big f/stops but not necessarily depending on your lighting. Those basic guidelines without factoring in the focal length you are using should help you decide how you should set your meter.<p>

[jml]

Thanks to all, your information was very helpful. I do understand aperture/shutter concepts, I just didn't understand that you could prioritize one or the other on the meter as well. Never having even held a meter I just assumed you pushed a button and it displayed both for you! I did follow Bruce's advice and adjusted the dip switches. I can custom function my camera to 1/3 stops, but I just left it on 1/2 stops and likewise the meter.

 

There seems to be two schools of thought on metering. I've read many posts who feel metering through the camera (I use a 10D btw), produces inferior results, while others feel the newer cameras do just as good a job as a hand meter. Both can't be correct, surely, can they? I bought the meter for better exposure!

 

However, that leads me to a problem I had while experimenting....so I must not be using it correctly. I stood in my kitchen and metered a vase about 6 feet away (yes, I walked over to it) on aperture priority. Then, I metered it from my camera, and got two very different shutter speeds. The hand meter had a speed of 1/8 but my camera metered it at 1/90. The camera produced the better shot, as the other was extremely over-exposed! I did this several times, dragged my husband into the game and shot him closer and in varied light and still had the differences. I don't get it. Can you help here?

 

And lastly, and don't laugh at this, but it's the way my brain works.....if the meter gives me the settings, and I turn the dial are those changed f stops and speeds also accurate?

 

Thanks again.

[fotografz]

Hi Jan, please forgive me, but I'm going to go to zero based input to start, and then go

from there. This is just to be sure you have the meter's settings correct for the type of

metering you want to do. If you already have done all of this, maybe another reader will

benefit ; -)

 

See attached photo:

 

 

A) be sure the incident ball is in the upright position for general ambient light metering.

(White dot to the position shown below "A"). The down position is generally for more

precise readings of multiple areas, like when flash metering for specific flash heads or

figuring light ratios for a portrait. In the down mode you may get a skewed "general"

reading ... like if it is pointed at a shadow area, you'll get an overexposure. If pointed at a

light source you'll get an under exposure. Be sure the ball is up for general, one measure

ambient metering.

 

Point the ball toward the camera lens, or where you will be when you will be shooting and

be sure you aren't casting a shadow over it.

 

B) Make sure you have set the meter to read ambient light (sun burst graphic). The other

modes are for flash metering... with or without a sync cord attached, or with a Pocket

Wizard trigger ( that's why there are 3 lightening bolt selections).

 

C) Make sure the ISO speed is set the same as your camera. Don't yell at me if this seems

to remedial, but I've seen it happen before ; -)

 

D Select which is preferred for the shots you'll be taking; Box around the F (f/stop) means

you select the aperture and the meter tells you what shutter speed is necessary. Box

around the T (Time) means you select the shutter speed, and the meter tells you what

aperture needs to be set. When testing against your camera be sure all compensation is

set to zero. That way you can see the value of separate incident metering which you do not

have to compensate as it is reading the light falling ON the subject as opposed to

reflecting OFF of the subject, which can trick the camera's meter. An Incident meter

doesn't care if the the dress is white or black ... it only cares about how much light is

falling on the subject.<div></div>

[iskandar_azaman___kuala_lu]

Yeap...What Marc said. Most probably you've got the wrong ISO set on the meter.

 

THe 358 is a nice piece of kit. I use it and it's real easy to use. You can set it to have 2 different ISO's so that when you click the button it shows you the reading for a different ISO so you don't need to be fiddling around much with it. When you do take a reading you can just turn the jog dial around to see different combinations of shutter speed and aperture so that makes it real easy rather than calculating it.

 

If you're taking flash measurements you better read up on the manual. It's more difficult than just taking ambient light reading since you need to know what those measurements mean and the ratios and stuff.

[fotografz]

Now here's a real life test. Strictly ambient light. Four exposures with the camera on a

tripod and the light source a constant. No compensation used on camera at anytime.

Camera meter set to Matrix with ISO @ 1600. Color subject on a bright white background.

All files transferred directly from camera and resized and saved for web exactly the same

way for all:

 

P: Camera set to program. Bright white background fools the camera into underexposure.

Also, this demonstrates the error of using P in lower light as it selected an f/stop that

placed part of the subject out of focus.

 

TV: Camera set to Shutter Priority. Also underexposed due to bright whites.

 

AV: Camera set to Aperture Priority. Even a tad more underexposed (probably due to the

ability to set 1/3 stop increments?)

 

L-358: Camera set to Manual Mode, L-358 placed near subject and pointed toward camera

lens. Settings transferred to camera. Exposure almost perfect. Colors cleaner, white

background just held at top where there was a slight hot spot in the scene.<div></div>

[bruce_rubenstein]

I often find that ambient light measurements differ between the L-358 and the camera's meter, and the camera does better (slide film). I only use the meter for incident light measuments. I prefer the camera for reflected light readings. There are a whole host of reasons why this happens. What I would suggest trying is to use a very average, typical scene where both meter should give the same reading. If they don't, see which one works better. You may find out that the D10's sensitivity is higher than indicated for a given ISO rating (I've used a D10 a few times and found this to be the case.)

 

I primarily use the meter for flash work. For shooting film it's the only way to know what's going on. With digital and using the histogram you can see how the overall exposure is without a flash meter. The meter is still good for establishing lighting ratios when multiple light sources are used. It's good to know exactly what stop difference gives what look.

[fotografz]

In fact, the L358 indicated f/8.4 and I set the aperture at f/9. If it was set at f/8.4, the

exposure would have been completely perfect. But with digital it pays to very slightly

underexpose when dealing with predominate whites ... which is an easy tweak in the RAW

developer.<div></div>

[clauder]

Marc,<br><br>

 

One additional question, how do you meter for backlight? If you point the dome at the lens, it will be in shadow as the light is coming from behind the dome... do you lay it down flat, or measure directly into the light source?

[fotografz]

Well, that would depend on what you want in the end. If you have a really strong back

lighting situation and want the subject to be exposed correctly, then you'd put the meter

in front of the subject pointed toward the camera, and let the background go... or split the

difference and have neither the background or the subject properly exposed but closer in

balance ...but the subject would be underexposed some and the background would be

overexposed some, which could be fixed in printing depending on the latitude of the

medium used. Other wise if you wanted to balance the shot you'd need to use fill flash.

 

Remember, the meter is only measuring the light. Some shots will be outside the latitude

of the medium (film or digital), and without flash to help balance it out, you have to decide

what will be sacrificed.

[jml]

Thank you Marc, and all! No prob. on the remedial, It confirmed that I am doing most things correctly. I think I may have had a different ISO than the camera. I thought I checked that though. Hmmm.

 

#1. Marc can you define exactly what you mean by "When testing against your camera be sure all compensation is set to zero. That way you can see the value of separate incident metering ...."?

 

#2. Should it have mattered that I was standing in a better lighted area shooting into a darker area of the room?

 

#3. And did I get that right from what Iskankar said; that if after taking a measurement that if I turn the dial, those varied combinations will all produce the same results?

 

#3. Is it better to have your camera/meter to measure in 1/3 rather than 1/2 stops?

 

And now, what about flash and reflector use? The wedding I'm shooting Sat. is an outdoor affair, and I will be using a reflector and at times flash for the formals. Just an off-camera 580EX, probably diffused. Like I said in my post, I did purchased the little transmitter module.

 

#4. So how does this change things in using the meter, and to use the module is there something else I need?

 

Thanks guys, I so appreciate the time you are taking out of your (no doubt) busy schedules to help me here.

[rich_taylor____mequon__wi]

"I would really like to utilize it to the best of my limited ability this weekend for a wedding."

 

You're scaring me. Are you a guest who just wants to take some better pictures or are you being paid to shoot the wedding? If it's the former, then I applaud your wanting to learn as much as you can by asking questions here. If the latter is the case, well, like I said... you're scaring me.

[patricks]

articles/responses like this should be bookmarked or rated to come up higher/highest when searching on PN.

[fotografz]

#1. Marc can you define exactly what you mean by "When testing against your camera be

sure all compensation is set to zero. That way you can see the value of separate incident

metering ...."?

 

Meaning compensation of the Camera meter. When faced with a very bright scene, like in

the snow or at the beach, the reflective light camera meter will try to make brights into

medium gray, thus underexposing the photo. Counter to what seems right, you would

actually compensate the camera to the PLUS side for a bright scene in order to expose it

correctly. BUT, to do a test like the one above, the camera should be set to zero

compensation as a demonstration of how the L-358 incident meter reads the light falling

on the subject and isn't fooled by bright reflective light the way a camera meter was.

 

#2. Should it have mattered that I was standing in a better lighted area shooting into a

darker area of the room?

 

Yes, you should take incident readings at the subject level in the lighting that is hitting

that subject. I'm sure you've seen where someone is using one of these meters, and they

walk up to the subject and take a reading ... often near the subject's face. Some

photographers enter a room, walk around and take readings, and just remember that this

area or that area has a f stop difference or so. Al Kaplan works like that.

 

#3. And did I get that right from what Iskankar said; that if after taking a measurement

that if I turn the dial, those varied combinations will all produce the same results?

 

Correct. Each f stop on the lens is the equal to a shutter speed in the camera. f/5.6

aperture @ 1/500th shutter speed = f/8 @ 1/250th and so on. When you use the camera

meter with any of the automatic modes like P, AV or TV, it automatically couples the two

together for you. In manual mode, you have to to adjust both for a proper reading.

 

#3. Is it better to have your camera/meter to measure in 1/3 rather than 1/2 stops?

 

With slide film and some digital SLR formats like J-Pegs, you have less latitude for

exposure error. So 1/3 stop is often preferred. Negative film has more exposure latitude

(especially to the overexposure side) so 1/2 stop or even a full stop is adequate. When I

shoot film or RAW digital files in the studio, I bracket in full stops ... the latitude allows me

to do that.

 

And now, what about flash and reflector use? The wedding I'm shooting Sat. is an

outdoor affair, and I will be using a reflector and at times flash for the formals. Just an off-

camera 580EX, probably diffused. Like I said in my post, I did purchased the little

transmitter module.

 

The little transmitter RT module-32 inside the L358 meter is for radio triggering of Pocket

Wizard receivers. The Profoto line of studio generator boxes has that receiver built-in to

trigger big studio strobe lights. That eliminates the need for a sync cord from the camera

to the generator box. The radio receiver in the 580EX does not work with that L-358

module. You need a Canon STE-2 sender in the hot shoe of the camera to trigger remote

Canon EX flashes and use the ETTL flash metering... or set one 580EX to "Master", put it in

the camera's hot shoe to wirelessly trigger another remote Canon EX flash that is set to

Slave.

 

#4. So how does this change things in using the meter, and to use the module is there

something else I need?

 

Yeah, some studio strobes and Pocket Wizard receivers ... ; -)<div></div>

[fotografz]

Actually, you CAN use the meter with off camera Canon flash. You can set the mode on the

L-358 meter to the first lightening bolt next to the sun burst graphic. BUT, you need

someone by the Canon flash to hit the test button and fire the flash for you.

 

So, you would select a shutter speed like 1/200th on the meter AND the camera, and set

the L-358 on the 1st lightening bolt (box will now be around that graphic), walk up to the

subject and aim the ball toward the camera lens just like an ambient reading (don't stand

where you will block the flash), press the button ( the little box around the lightening bolt

will start flashing on-and-off to indicate it is ready to take a reading). Then have someone

press the test button on the remote Canon flash. The meter will tell you what f stop to set

on the camera lens.

[fotografz]

BTW, that has nothing to do with the little module. You could do that without the module

installed. AND, BTW, the reading you get takes into account the ambient light also. No

math involved. Just trigger the flash and take the reading ... then set the camera

accordingly.

 

This is good to measure a formal shot to be sure it's evenly lit. Read the far groom side

Groomsmen, the B&G in the center, and the bride side Bridesmaids end ... with an incident

reading it doesn't matter if they are dressed in black at one end and white at the other. All

it does is read the light falling on the subject. If it is widely different then you may have a

problem in the final result, and may have to adjust the lighting to even it out.

[bruce_rubenstein]

I have two sets of radio slaves (but not PW). I keep one of the transmitters in my pocket so I can pop the flashes while holding the meter. Not as elegant as having everything in the meter, but it works.

 

When metering in cordless flash mode watch out for fluorescent lights. They flicker and can trigger the meter. If there are several fixtures, flickering at different times, there won't be any problem.

[jml]

Rich - Yes, be afraid...be very afraid. No j/k....it's going to be a very small not too difficult (or so I'm telling myself) wedding. It is my first. And a good one to be starting out with. I'm just finishing up a class on wedding/portrait photography and told my instructor yesterday, that if I didn't show up next week for the final they would know I'd left town. He said "they need good photographers in Canada too"! Ha. Oh, and the day he was going to discuss meters....his Minolta broke...wouldn't you know it. Thus my questions. I just decided to up my success factor by using a hand meter rather than just relying on the camera. But I appreciate your concern. I've been working in Photoshop for a number of years...so that will indeed be helpful.

 

Marc! Do you teach somewhere? You have the best way of explaining things. Sometimes it makes me chuckle...."set the L-358 on the 1st lightening bolt (box will now be around that graphic). But I think its great, because you cover all the bases, and we the happy learners have but to find our own skill range withing your precise instructions. I love it, and can't say enough how much I appreciate it. Yeah, yeah, I know....everyone tells you that....but certainly, credit where credit is due.

 

Anyway, I bought the module knowing that I would be investing in lighting later on. I may not know much, but I do know a good deal...and $25.00 with the meter new, seemed like a good one so I got it for when I would need it and understand how to use it.

 

Clarification on question #2. I took the shot from the better lighted area, but walked over to the subject in the darker area to meter back to the camera first. I guess what I was asking is, does the ambient light have to be even. I wouldn't think so as I could be standing outside in a sunny area, posing my subject in the shade and it would be the same scenario right?

 

Also, you mentioned readings...in the plural. Is that the EV feature of this meter? Take a couple readings and then average it? Isn't that what Edward said to avoid? Or not? I mean, if you take 2 or 3 readings per your example.....does one just get more skilled in time at "guessing" the right exposure if not utilizing this feature? I see an oxymoron here...:-) Or am I just not understanding this point? And the only moron is.....moi?

[fotografz]

Just like to answer questions the way I like them explained to me.. as if I knew absolutely

nothing ... which is often the case ; -)

 

I'm still not sure I understand the other question. All I can say is that if you read at the

subject level, it doesn't matter what's going on elsewhere.

 

Multiple readings help determine if you have an even lighting ratio, like with a group shot.

1 to 1 is usually best (same amount of light falling on all the subjects in a formal ), or

someone could end up in the shadows.

[tana_minnick]

This thread has been most helpful and timely, as I am comtemplating which light meter to buy. My question is about how to meter backlit scenes. Outdoors on a sunny day, with the subject in shade and using fill flash, how do you meter so that the sunny background is not blown out? Do you meter the sunny area behind the subject, then adjust camera and flash accordingly? Thanks, I have learned more here than the few photo classes I have taken. You guys rock!

[jonathon]

Tana, if you wanted to get the whole scene (subject and background) fairly even, then you would need to match the background light with light from your flash. So if the background was f8 at 1/125th, then you need to use your flash meter to measure your flash so that the subject under a tree in the shade is also around f8 1/125th. The only other catch is that afternoon sun might be quite orange in colour and your flash will be a very white light (known as different light temperatures and usually expressed in Kelvins).</p>

Each medium (neg, slide, digital) has a certain number of stops of light that it can photograph and still retain the details at both ends (shadow and highlight). If your scene has a 10 stop range from the brightest to darkest part of the scene and your neg film is also capable of a 10 stop range, then you can record both highlights and shadow detail with the correct exposure. If a digital camera has only 7 stops, then there is no way to record the scene's full spectrum. You have a 7 stop window and you need to decide whether to sacrifice the brighter areas (which will come out as just white) or the shadow details (which will just come out dark and muddy). You then position your 7 stop window over the 10 stop range of the scene to suit which detail you are trying to capture.</p>

The fill flash makes the light range of the scene smaller. Using flash on the subject (which might be the darkest are of the photo because it is shaded) will allow you to lift the shadows so the scene is now only 5 stops and so can be captured by your 7 stop window. Marc recently posted in a thread with a girl in black dress walking down an aisle whilst backlit. If I can find the thread I'll post it.

[tana_minnick]

Thanks, Jonathan, for your reply, that makes sense. I read that thread you mentioned (several times) but I am still a tad bit confused on the actual metering. Say you're photographing a subject in shade. Do you actually walk behind the subject into the sun and meter the light? Also, on Marc's post, he mentioned he metered the sky (in the black dress photo). Would you use your in camera meter (set on partial metering), and aim at the sky to get your reading? If not,how would you do what he described? I realize that on shots with extremes (deep shade, bright glaring sun) you probaly won't be able to capture all the detail, something will be compromised. Also I've read about gels or filters for use on flash to help match the light. On a sunny day, what color what you use? Thanks!