Light Meter

[greg_cornish]

I have a Minolta Auto Meter IV F. I understand how to set the meter up to read ambient light but not sure

how to measure it. If I'm standing in a street scene do I face the meter toward the direction of the photo?

Toward the ground? Shade it with my body?

[garry edwards]

Depends.

 

Use it in incident mode (with the dome in place) and either go to the subject and point it at at the camera or go to a place that's getting the same light as the subject and point it at the camera. Incident measurement is measurement of light incident upon (or reaching) the subject, therefore it takes no account of the reflective properties or colour of the subject and is usually far more accurate than reflected light measurement, which assumes that the subject has average reflectivity and gives a reading that will render the subject a mid grey tone. Camera meters meter in this way.

 

If you want to use it in reflective mode, remove the dome and point the meter at your subject.

[greg_cornish]

Thanks Garry. Here is a small problem. I'm somewhere between a paraplegic and a

quadriplegic. I can use my hands a little, but its difficult to go to my subject as I'll explain.

I don't mind the results using the cameras meter

(reflective?) but not all my cameras have meters. So far (I haven't tried removing the dome

and point the meter at my subject) no method comes very close to my cameras readings

and most of my subjects are distant landscapes.

1. Is the a light meter that is best suited for this?

2. Would the light reading from one camera with a meter transfer to any other camera

without a meter?

 

Thanks, I'm anxious to exoirement with removing the dome tomorrow. If that works I

guess I should get a clear plastic lens to replace the dome.

[al_kaplan1]

As long as you and the distant landscape are in the same light you'll be OK. Both in direct sun or both under a cloudy sky, for instance.

 

You might be getting different reflected readings because the angle of coverage isn't the same. Try reading a plain surface that fills the frame, any color or shade, with both meters. The two readings should agree within maybe 1/4 of a stop.

[greg_cornish]

Thanks Al, Is that incident light? So if I assume correctly incident light would be like

exposing it to direct sunlight or flash. If I have three choices (two really) corded and

uncorded and ambient i suppose for an incident reading I'd use uncorded?

[garry edwards]

Greg,

 

Yes, you can use one camera to meter for another, assuming that they're both on the same ISO.

 

Different cameras have different ways of 'deciding' which part of the scene to measure (e.g. evaluative, average, centre weighted, spot etc) so as Al points out there may be differences, but it will work fine. I assume from the other questions you've asked that you're using medium format camras - usually, when meters are fitted at all, they tend to be simpler ones than on smaller cameras, but effective.

 

My own photographic speciality is studio, where everything is controlled, and I know very little about landscape. If you're using your Minolta in reflective mode to measure distant landscapes it might be a very good idea to run a simple test to make sure that the reading isn't being influenced too much by the sky - take a shot pointing the meter straight ahead and take another with it angled down a bit and see which works better.

 

Hope this helps

[greg_cornish]

Hey Thanks guys.

[heller_harris]

If mobility is an issue for you, then you might want to consider getting one of the Sekonic incident meters that feature a built-in spot meter. If it's difficult to get an accurate reading in incident mode, then you can switch over to spot. It takes a little bit of experimentation to get used to spot reading - you have to learn to adjust for the reflectivity of the exact spot that your metering - but it sounds like the best solution.

[pacorosso]

Put the dome and make a incident read. Aime the dome:

1 To the camera.

2 To the main light.

 

If the difference is greater than 1,5 stops then you can have a specular bright if the main light is too "lateral".

Otherwise expose for the camera measure.

[greg_cornish]

I left the dome on, set it to ambient, went to the subject which was in 4 oclock sun and

got a reading of f8 at 1/250 Thats what my camera said. I set it to non corded and got a

reading of f11 in incident mode. I removed the dome and metered the subject direction in

ambient mode and again got a reading of f8 consistant with camera at 1/250. I once

again went to the subject with the dome on and got a incident reading of f11 then got a

"dome on" ambient reading of f11. The instruction say I should be using a 5 degree or 10

degree diffuser to get ambient readings. Some internet things suggest a 40 degree

diffuser. 40 degrees are cheap. http://www.bhphotovideo.com/bnh/controller/home?

O=Search&A=details&Q=&sku=274601&is=REG&addedTroughType=search My reflected

light without any diffuser seems to coincide with camera. Do I need a diffuser on this

meter ever for protection?

[dennis lee]

Hi Greg, first, non-cord and cord are for using flash. They may give you accurate readings

but for general good work habit, use ambient whenever measuring existing light.

 

The meter always reads for an 18% gray. That's what it see's.

 

The dome reads light that is actually hitting it. The dome diffuses the light and the sensor

reads that diffused light. So the dome is reading the amount of light falling on the

subject.

 

The reflected light reading you get when you remove the dome is the amount of light that

your subject is reflecting.

 

So, if you wanted to take a picture of a white dot on a black wall... you would get two very

different readings from these two forms of measurement, follow me? In other words, the

black wall is going to absorb a lot of your light and the meter is going to try and make it

the 18% gray mentioned above. The incident dome is going to read more accurately in

this case because it is simply measuring the amount of light falling on the wall and not the

reflected light.

 

So, on a normal sunny day with 100 ISO film, your incident meter will tell you 1/125 @ f11

or 11.5 for your black wall. Remember, you're measuring the light that is hitting

your subject, so you always point the dome back at the camera. Imagine the dome is a

face which you are measuring the light falling on. Also, it doesn't matter where you are in

relation to your wall, if the light hitting the wall is the same as the light hitting you,

measure it where you are.

 

Your reflected reading on the other hand, meter pointed at

the wall, will want you to open up so the wall becomes 18% gray and will give you a

reading of 1/125 @ 8 or maybe even 5.6. The reflected reading without a spot attachment

is also very wide, so it is difficult to tell exactly what it is reading. That's why they suggest

a narrower angle of view for reflected light readings. A reflected reading with your camera

will be much more accurate than the reflected reading with your meter. Unless you are

very close to your subject of course.

 

The thing about light meters is that they leave a lot up to your judgement. As in the

black wall scenario. Having made both these measurements I would probably take the

picture at 1/125 @ f/8,5 and split the difference but go closer to incident. I would do this

to give me a little more detail in the black. If I were shooting chromes, I would shoot at f/

11 for the richness.

 

Now if you were trying to take a picture of a small white dot on an 18% gray wall, the

meters should give you the same exposure. Make sense? A white wall would give a higher

reflected reading, because it's reflecting more light and again, the meter is measuring

gray, not white. So it would want you to underexpose your white wall to make it gray.

This is why you open up your exposure by a stop or two when you photograph snow. The

meter, reflected, is trying to make it gray.

 

Remember, a bright sunny day's exposure is the shutter speed closest to your ISO @ f/11.

Brighter than normal (like snow or beach), f/16. Open shade f/8, darker shade...? 5.6 or

slower.

 

Use your Minolta meter, use this rule of thumb, use your camera meters, they all do the

same

thing, they just do it in different ways. If you pay close enough attention, you won't even

need the meter after a while. That's when the fun begins.

 

One final note, most meters, especially the Minolta's measure about 1/2 stop under what I

like to expose my film at. In other words, if it says 11.5 (especially in incident), shoot at

f/11.

 

Finally, no, you do not need to protect the sensor when the dome is off. It has a cover, but

if it gets dirty the meter will give you inaccurate readings for both methods. So leave the

dome on when you're not measuring reflected light.

 

Good luck.

[greg_cornish]

Sounds like the old graphs on the backs of the rollei TLRs might be good to memorize then?

[kenneth_dougherty]

Ansel Adams, the creator of the zone system, was noted for his exposure technics. His system may be right up your alley. He used film but with todays PP it could be adapted to digital.

 

http://www.luminous-landscape.com/tutorials/zone_system.shtml

[greg_cornish]

Thanks, but I'm using medium format film. Just made this yesterday http://

www.significantudders.com/chairpod/ unfortunately the guy that was helping me grabbed

my camera by the back and popped it open exposing a who roll of my light expirements. I

was wondering why my manual kept referring to zones without explaining what zones were.

I read this, thien I'll know.

[w._ditto__iii]

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