More fun with the Metz flash

[deluco]

That's certainly confusing to me. The whole idea behind Auto is to read the amount of light coming back to the flash and stop the strobe when the correct amount of light is reached. So you're actually reading reflective light (off the subject). When a subject is bright, light reflected will be bright and the strobe will shut off earlier than it will when a subject is dark.
I'd love to test it with a meter myself. I tend to be a cynic anyway.

That would be why when you are in a church and there's dark background your Auto flash will output more light because not much is being reflected back to the flash sensor.

Of course, I'm not an engineer so maybe there's something else going on there. All I know is that people who own Metz swear by them (not AT them).

Conway is a bit of a drive for me, but not out of the question. Would be great to link up. Please email me when your plans firm up.

[Mark McCall]

Jim,
That's true. .....BUT....you need a longer exposure time for ambient to be measured, where flash doesn't.
The sensor is only measuring the flash during the flash duration (about 6,000th of a second).

Right now, I'm scheduled to appear at the NHPPA Convention with Kevin Kubota on April 22nd, '06.
We're still trying to hammer out travel details and what NH is budgeting for.

I'll keep you posted.

[dvdowns]

Mark , on another note , you will see that I have added another reply to my " Now convince me to go manual " post . I did an entire circus shoot in manual alone and was very content with the results I achieved and the fact that I eventually knew what results a setting would give . I have taken very seriously your statement " never let the camera make decisions for you " , it makes a lot of sense .

[deluco]

Originally Posted by Mark McCall

Jim,
That's true. .....BUT....you need a longer exposure time for ambient to be measured, where flash doesn't.
The sensor is only measuring the flash during the flash duration (about 6,000th of a second).

Yes, that makes sense. The flash sensor may only be reading the flash because of the short duration. It still can be fooled by extremely dark or bright subjects because it's bouncing either more or less light than you expect (based on 18% grey).
It still has to assume that the subject that it's bouncing off is 18% grey. So it's not really reading ambient.

So in your example you probably do have a 2-1 ratio of f4 from the flash and f4 ambient.

I have a Sekonic handheld 358 meter that reads both ambient and flash and tells me what percentage of the complete reading is the strobe. So I generally shoot for around 30-50% so that I'm getting about a 2-1 ratio.

[Mark McCall]

Desmond,
I've never seen anybody take a concept and run with it the way you do.
Congrats on taking charge!

Jim,
All Metz's (at least the ones I've worked with, and the ones my competitors/friends use), fire one stop hot.
So F4 really delivers F5.6.
F5.6 really delivers F8.
F8 really delivers F11, so for and so on.

The exposure was F5.6 @ 100th if memory serves.
Flash was set to F4, because I know it will deliver F5.6 at that setting.
Weird, but consistent.

I've been asked before about shooting bright or dark subjects with the Metz.
Once again, conventional wisdom would say your right.

Believe it or not, when you change from a bright wedding dress to black tuxes, the exposure stays the same. Exposure is the same on the face of a subject wearing white or black.

To test, I used a technique called the Facial Histogram.
In PS, select the face with the lasso tool, then bring up the histogram.
I make no adjustments whatsoever for the color of the subject's clothing.

I know alot of people will scratch their heads at this concept....I still do. I can't figure it out.
I'm glad it works, but I just can't understand why.

It took my Bogen rep almost a year to convince me. By golly, he was right.
I now own 3 Metz's, and 4 other studios in town use them exclusively.
At ShootSmarter University, Metz is the only on-camera strobe they teach with because of it's accuracy in Auto mode.

[deluco]

I apologize in advance for my "anality".* I wasn't arguing that the image isn't properly exposed.* Clearly it's pretty much dead on.
My point is that if the flash were outputing F5.6 and you set the camera to F5.6 at 100th/second (200 ISO), then the image would probably be about a half stop over exposed.* The reason is that the F5.6 must be added to the ambient to calculate the proper exposure.* While your flash may not be measuring ambient, your camera is recording both the flash AND the ambient.* Now we really don't know exactly what the ambient exposure is, however, I presume that at 200 ISO 1/100th second (based on your metidata) that you are getting about f4 or even higher.* I just did a reading with a light meter outside in open shade (sunny day).* *With no sky light on the subject's face (based on your first image), at 200 ISO, 1/100th second I get between f4 and 5.6 ambient.

Assuming on the low end of ambient..add f4 to the 5.6 from the flash and you are at f6.7, 1/2 stop over if your camera is set to 5.6.* That is why I suspected that your flash was really outputing F4 and not 5.6.* *Also, that the lighting ratio of your image appears to be a 2-1 and that there is detail in the shadow.* Detail in the shadow means that your camera is recording significant ambient light.

Again, I apologize for being so anal.* I can't argue that you know the equipment because I don't own a Metz and you're the one who's presenting the exposures.* It's just that the information didn't add up.

[dvdowns]

Jim , I have also wondered about this before and your analysis sounds pretty good . I also like to know exactly why something works in a certain way , as soon as I read someone saying that something can't be explained I see it as another learning point to be conquered once understood ...

[Mark McCall]

You guys are overlooking something.

F5.6 @ 100th may have been the exposure for the background, but it certainly isn't for the foreground.
The exposure for the background is MUCH brighter than the exposure for the subject. I'm guessing as much as 3 stops.
The ambient light is greatly reduced in the area between subject and camera, as the subject is under overhanging trees.
(The 1st image is overexposed to show more detail where my equipment is.
The subject's face is even underexposed in that image).

If I would have shot this without flash, the background would have looked great, but the subject would almost have been a silhouette, because of the huge difference in exposure values between* background and foreground.

Flash is the only light source (main light to be exact) on the subject because F5.6 @ 100, ISO 200, isn't a long enough exposure to allow a significant amount of ambient light to bleed into the subject's face.

Again, shot #1 is misleading....it wasn't nearly that bright out.

Turn the bride around and shoot with the sun (or bright sky) to your back, and you've got a comletely different situation.

[Krymedogg]

Thanks Mark for this insightful thread..........my goal in my photography career is to learn something everyday......this thread made me get out this afternoon and work on my lighting technique....

Krymedogg

[Mike_e]

Hi Mark! Sorry to drag this thread up but I felt that it was better than starting a new one.

First, I bought a Metz 60 ct_1 with battery pack on e-bay last night (it's supposed to work ) and I have done a bit of browsing but I can not find a definitive answer on whether or not it is safe to plug into my D200. If you have the time could you please speak on this subject?

Second, the 60 has plastic issues from the description, is it possible to get parts for this flash? I am also unsure whether or not there will be a charger, do you know what voltage the battery for this is and will this flash work plugged into the wall? (I read some where that it would but how is it worth the trouble?)

Also I have seen you posts on your Metz set ups but have not seen you fire one into an umbrella, do you not like the look or is moving the flash back enough (how far?) soften the light to approximate an umbrella?

Any other information would be greatly appreciated.

A new (old)Metz owner.

mike eubanks