View Full Version : Sekonic L758-DR low battery behavior

26-Aug-2017, 16:32
How does this unit behave at lowish battery? The on screen indicator says battery is 50%. I notice I have been overexposing Portra 400 by 1/2 to 1 stop. It could be my film processing workflow, or shutters a tad slow. It could also be the way I am metering.

Ignoring the other things for the moment, does this unit, or other Sekonic meters, change behavior as the battery indicator drops?

Are these meters calibratable? That is another variable in the mix.

26-Aug-2017, 18:38
Since the meter indicates that your battery is half dead, you will be needing to buy a new battery sooner rather than later. So get the new battery you will be needing anyway, and you can answer your own question. You should ALWAYS carry a spare battery, anyway.

26-Aug-2017, 19:11
Thanks xkaes. I do have a spare, and will replace the battery. Just wondered if meters drift as the battery drains.

26-Aug-2017, 19:34
I have the same light meter. I certainly would be concerned if accuracy drifted as the battery lost power. :eek:

26-Aug-2017, 22:05
I always carry a spare battery but I always use my 558 until the battery is dead and have never noticed any metering drop off as the battery wears.

27-Aug-2017, 19:03
Thanks all. I replaced the battery today and have a shoot on the calendar tomorrow. My feeling is the overexposure is coming from how I meter. I have exposed TMX and C-41 film to my satisfaction with the meter in a 50% battery condition, using spot metering. I think my C-41 incident metering technique needs tweaking.

Strobe metering seems to be ok, maybe 1/2 stop overexposed. But there is some variation in how precisely I aim the dome at the camera.

More problematic for me is a high contrast scene with C-41 film using incident metering (outdoor portrait in open shade with midday sun), does anyone deviate from the meter reading? Or just point the dome at the camera from the subject position, take the reading, and be done with it? Subject highlights (forehead, caucasian skin) get problematic for me in this situation.

27-Aug-2017, 21:09
It meters same way till battery is dead

27-Aug-2017, 21:09
Ps - never meter towards camera.

28-Aug-2017, 05:00
If you are using a meter in incident mode, you ALWAYS point the dome (or flat diffuser) toward the camera. It's best to hold it where the subject is, but if the light is the same anywhere else -- such as at the camera -- you can hold the meter there, as long as you point it in the same direction.

On SOME meters, there needs to be an adjustment made when switching from reflectance to incident. Check your manual. Otherwise, you should not need to change the exposure -- the dome mimics a spherical subject.

You can check this yourself by holding the dome in front of your subject and taking a reading. Then hold a gray card in front of the subject and take a reflectance reading of it. The two should be the same.

28-Aug-2017, 07:38
Let's just say - I will keep doing what I do and meter how I meter then..
I believe for all of us - our results speak better than words.

28-Aug-2017, 07:51
There have also been those (such as on this forum) who take multiple incident readings in order to determine the best exposure, rather than a single incident reading. In the end, if you get an appropriately exposed shot who cares how you metered it...

28-Aug-2017, 08:00
Thanks again. Sekonic's website mentions using incident metering with the dome facing toward the strobe, to measure highlights, and with the dome pointing away from the strobe on the dark side of the subject to measure shadows. This gives an incident reading of the range of values. In my mind it is analogous to spot metering but from the subject position. This is where I think I am losing the plot.

I am exposing for the average incident meter reading with the dome facing the camera from the subject position. For a higher contrast subject it is likely the highlights will be blown which for me is not ok if the highlights are on the subject's face or clothing.

28-Aug-2017, 16:03
If I'm reading you right, it seems to me that you need to consider the difference between flash metering (which uses the dome pointed toward the strobe) and incident light metering (which uses the dome in natural light pointed toward the camera). I haven't read the Sekonic manual in a long time and can't recall what terminology they use in both metering situations but seem to recall both metrering techniques discussed separately.