Light Meter 101...Revisited

[jml]

As you will recall, last week I needed help to understand the basics

of my new Sekonic 358. All the instruction was most helpful.

Especially from Marc. I found I was so busy during my first

(outdoor) wedding last weekend however that I didn't even use it.

 

But, last night I took it with me to a class I'm taking on

wedding/portrait photography. We set up studio lights, just

strobes, etc. The instructor with his trusty old Minolta told me

that on the one set-up ( a single strobe bounced into an umbrella)

that it always....ALWAYS, metered out to F/8 and I think 1/60th and

the other set up with two was f/16 @ 1/60th I think. Anyway, I

figured this was a great opportunity to use my new meter. I changed

the setting from ambient to the first flash mode, he watched me do

this....flashed the strobe and metered.....and could absolutely not

get it to meter at his settings and properly expose! To do it on my

10D it showed me being overexposed by at least 2 stops, and the

histogram showed that as well.

 

So, he tells me there is something wrong with the meter (he says he

doesn't know Sekonic), and that I should ignore my cameras exposure

meter that I'm viewing, and that the histogram is wrong too! Sheesh!

 

And then when I took the shot according to his values, he thought it

looked fine. While to my eye and to the camera it was overexposed?

I uploaded it when I got home, and even though I opened it up to 5.6

rather than f/8 it still is terribly underexposed...just like the

histogram showed.

 

But, I watched him meter the same set-up and lo and behold it did

indeed meter at F/8 etc. just like he said! So could it be the

meter? Did I do something incorrectly? Albeit he doesn't know

Sekonic products, but he did watch me meter and said I did it

correctly The man is a bozo I feel, but still I can't explain how

my meter differed from his. I don't know what to do at this point.

Help!

[john_clare1]

Did you set the correct ISO speed on the meter?

 

Regards,

 

John

[ben_rubinstein___mancheste]

Was he trying to tell you that with that setup the metering will always be the same regardless, or only his setup in that room? If he is telling you that one light into an umbrella will always meter at one value then find a better teacher, there is no light combination in the world than always gives the same reading no matter when why or how.

[jml]

John; Good question, and no I didn't at first. My meter was at 100 and the camera at 400ISO. I fixed that and still couldn't meter as he did.

 

Ben- He just said "that light and umbrella" always meters at f/8. And on his meter it did! Mine...did not.

[steve_hovland]

I recommend using the histogram in photoshop as your final arbiter.

 

Take a shot with your meter set at recommended reading, load into photoshop, bring up levels. Does the histogram bump the right side without blowing out? Look at all 3 colors.

 

For instance, I set my meter about 1/3 stop faster than the ISO on my digital camera.

[wedding-photography-denver]

You will need to calibrate the ISO of the camera to the meter. Just an idea but my sekonic 508, reads 125ISO to get 100 on a 10D. Its not an exact instrument unless you do this to get the ISO on both the same.

 

I have seen a light meter read off by as much as 2/3 stops compared to my camera. I find the 1Ds2 does about 1/2 under the meter, so I have to always deduct about 0.2 sotp in post processing to have an exact exposure.

 

Try setting the meter for 200 iso and the camera at 100 iso, meter and shoot with the settings it gives. See what your exposure is like. Next, adjust the meters ISO setting until the reading it gives renders a perfect exposure in camera. This will take a little testing to get right. When you get the exposure dead on check to see if the ISO on both match. Mostly they will be close, but not the same.

 

Try it.

[watchin]

Jan your instructor is not instructing...

 

A given light with a given umbrella for a given distance light to subject with a specified ISO and a given shutter speed will

USUALLY give the same lens opening, if you can ignore or reduce the

ambient light to a non-issue.

 

This is why you need a meter. :{) If the meter is off from the camera

meter by more than 1/4 stop then something is out of calibration. Light is light it doesn't know what's reading it and doesn't change.

 

On the Sekonic you should set the ISO and the cameras sync shutter speed, make sure the bulb is extended and pointed at the camera position (not the light) from where the subject will be, connect the cable and fire - or - trip the Sekonic in auto mode and then fire the flash.

 

An example is my AB800 on 1/4 power in MY 36inch silver lined

umbrella at 8 ft from subject ISO 100 1/125th = f8 with low to moderate ambient.