How to meter properly/Ground glass vs.spot

[andy_hall]

I have recently purchased the Sekonic L-508 and am considering buying the booster attachment which allows metering directly from the ground glass.Has anyone tried metering in this way? Are there any problems associated with this method.I somewhat of a beginner to LF and would welcome good sound advice. If I cannot accurately(hopefully within 3rd stops)meter directly from the ground glass(due to stray light hitting it etc.)how do you compensate for a polarizing filter whose filter factor can change as you dial in the desired amount of polarization? Thanks in advance for any help or advice.Sincerely Andy

[n_dhananjay3]

I've used a Calculite meter and a fibre optic to take readings off

the ground glass. You need to ensure two things. First, calibrate to

your ground glass (which is easily done, take a reading off a grey

card with your meter and take a reading with the fibre optic through

the GG - the difference is what you will need to compensate your

readings by. Second, you will need to ensure that no light enters

through the back of the camera when you take a reading i.e., the rest

of the ground glass, except for the spot you are taking your reading,

needs to be blocked off. I've used my dark cloth for this. Re a

polarizing filter, you do not adjust exposure according to how much

polarization you dial in. The PL needs a constant exposure

compensation, usually 2 stops. Good luck. DJ

[william_levitt1]

I used the Sinar GG metering method for a short time and quickly

gave up on it. It was just too, for lack of a better word,

complicated. I found that I couldn't be as accurate when

choosing my shadow and highlight areas. With a 1° spotmeter, I

can really dial in the tonal range.

As far as the polarizing filter is concerned, trial and error will be

the best teacher. You can also try selecting the amount of

polarization, then hold the filter over the lens of a spotmeter while

taking the reading.

[sean_yates]

You haven't told us what kind of work you do, or intend to do. Or

has that been in another thread I missed?

 

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Metering from the ground glass can be indispensible when shooting

macro and you can't get the meter in between the subject and the

light source and things are just too constricted "O.K. you move the c-

stnad out of the way so I can get in here to meter but put it back so

that the flag cuts in right here".

 

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In the three studios I worked in, those kind of conditions didn't

come up enough to warrant the expense. In my own work I've always

found the lowly Weston Master and Sekonic L398 adequate.

 

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I once watched a group of students set up to shoot 8 X 10 Polaroid of

the Robey house in Chicago. Granted, that's not the best example -

but it took them a good half hour just to decide on exposure while

using a metering back and they weren't using any filtration.

 

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Although B&W does say the Polarizer will affect the exposure by

anywhere from 2.3 to 2.8 stops, I have always gotten by with a

straight compensation of 2.5

[garry_edwards2]

I've never quite seen the point of metering the screen, other than

with extreme close-ups. It takes for ever and there is a lot of trial

and error involved the first time you do it, and every time that you

break a screen and have to replace it!

I have used the Minolta, not the Sekonic, but the problems of stray

light are bound to be the same.

The best answer is usually not to use a spot metering, just use an

incident metering from the subject back towards the camera, then

check with a polaroid.

Hope this helps.

[audidudi]

Although I don't meter on the ground-glass, I often meter in _front_

of it using a Horseman Exposure Meter 69, which slips underneath the

ground-glass assemblies of my 6x9 cameras (Toyo 23G and Galvin).

 

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I find it useful for close-focus shots since I don't have to make an

allowance for bellows extension and also while bracketing exposures,

since I can watch the meter needle move while adjusting the aperture

in 1/3-stop or 1/2-stop increments.

 

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It also serves as a backup meter in case my spotmeter dies (although

as a full-frame averaging type, it's not a direct replacement) and I

sometimes find it handier to use than my spotmeter, particularly for

closeup shots where there isn't much space between the the lens and

the subject.

 

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And, of course, it lets me easily determine how much compensation is

needed when using various filters, including a polarizer.

[james___]

Sheesh you guys make it too hard on yourselves. james

[bill_glickman]

Andy, unless you do extreme close ups or use a ton of filters don't

even consider it...and if you do buy it, be sure the place you buy it

from offers returns, it is a special order item. I bought one and

returned it, it is very poor. The meter was off by 3 stops, and it

was not predictably off, it varried from area to areas based on the

amount of light... This is a very tricky thing to accomplish, and

these add on type devices are an attempt to match the effectiveness

of the dedicated units costing 10x more... It's good in theory, but

the products don't live up to their billing in practice!

[paul_owen]

Andy I've been using the L508 for some time now and I am very

pleased with it. I wouldn't bother with the booster attachment for

all the reasons mentioned above. One of the reasons I chose this

meter was because it simplifies the metering procedure, especially

when employing the zone method. Using and calibrating the booster

introduces unecessary complications.The L508 has 2 ISO buttons so it

is easy to dial in filter compensation and recall it at a touch of a

button. With partial polarizing you would do just as well by exposing

both sides of the film holder applying bracketing to the second sheet.

Also I find it is easier to locate and measure shadow and highlight

areas through the meter eyepiece rather than through a dimmer GG.

Save your money for film (LF is a steep learning curve!!!!!)

Regards Paul

[larry_huppert1]

I recently saw a photo of the setup which a local food photographer

uses. It looked like he used one of those fancy and very expensive

meter probes on the lens side of the ground glass. But then, he does

lots of work at 1:1. Of course most of his setups are done with

stand-ins, and he shoots Polaroids after exposing the film so the

real exposures are with the food at its freshest.

 

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Regarding polarizers - I've used a constant factor of 2.5 with

success. For what it's worth, Ansel Adams recommends not changing

the exposure as a function of degree of polarization as a general

rule. The exception being where the effect of polarization uncovers

detail which you then might want to account for in determining your

exposure.

[jim_roof]

I have been shooting large format architecture (exteriors and

interiors) in the Atlanta area for just under 20 years and the best

thing I ever did was decide (about 12 years ago) to exclusively use a

1 degree spotmeter and when taking my film to the lab uttering these

two very scary words - "Process Normal".

 

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I once shot an interiors job using incident readings (14 years ago)

and I still am haunted by the poor outcome of that assignment. The

only way to meter is with a spotmeter. I don't care how much light

is falling on a navy blue upholstered chair. I only want to know how

much light is bouncing OFF of that chair. Same goes for walls,

artwork, carpet... you name it.

 

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I have always had good success making a 2 stop allowance for may

polarizers, but different brands so vary in density.

[dan_smith]

I will give another vote to the Calculite with the probe. It is easy

to use and give readings quickly. But I got tired of working with the

meter under a dark cloth & mainly use a spot meter now. More because

I like watching the image area than because the ground glass metering

did not work or was difficult. Only a matter of personal preference.

As for the Calculite meter, it is still in my bag & used as a backup.

Small, lightweight & accurate and it meters in light lower than most.