L-358 + 5d Calibration

[XpLoiT]

Hi, i just picked up an L-358 with PW trigger after claiming i never need a light meter. Well i was wrong. After 1 shoot with it, u are stupid to not have one. :)

However before purchasing i decided to go do some reading and find out what the go is with them.

It seems that out of the box they arent calibrated, however it seems mine is. I am by no means in any imagination knowing what im doing. However this is what i did to test:

Set camera on tripod.
Aimed at pen holding cup, and placed 18% grey card on the pens facing the camera.
Under standard tungsten down lights at home
i put camera in spot metering and ensure that the grey card fills way over the area which is for spot metering.
The camera meter was f/4 @ 200iso @ 1/20th

i put the sekonic into the ambient mode, set to F4 and iso 200, click the button, and it says 1/20th. I take a shot, perfect. (well perfect pens lol)

So does this mean that for some lucky reason i got a fully calibrated one? or am i doing the test completely wrong (thats what i think)

Dave

[steveathome]

I'm sure they are all highly calibrated before leaving the factory, but its making sure the offset matches your particular camera body and lens combination that matters.

ie, Canon iso of 100 has been known to be closer to iso 125, plus different lens's may also have a slight bearing on the outcome. The way you use a meter can also make a big difference to the results you get.

So rather than calibrating the meter, you are really just matching your equipment and maybe also technique for best results.

[TMR Design]

HI Dave,

The Sekonic meters are calibrated and very precise but as Steve said, they are not and can't be calibrated to your camera/sensor.

Your method is only good for ambient reflected readings and if that is what you'll be shooting then you're good to go.

Regardless of mode (ambient, flash) or type of reading (incident, reflected) you want to follow the same procedure.

You set your gray card (true 18% gray exposure card, not a white balance card or WhiBal), and light it so that you get even coverage and no more than 1/10 stop variance across the card. Be careful of reflections and hot spots.

Set up your camera, making sure the gray card fills the frame. Use the sweet spot on your lens ( f/8 is a common sweet spot). Se the ISO to the ISO you use the most since this is a global calibration.

Shoot a RAW image of the gray card. Open that image in your RAW editor making sure no default settings (contrast, saturation, auto exposure/levels/curves, etc) are applied.

You should see a single spike in the center of the histogram representing middle gray. If the spike is to the right of center then you're camera/sensor is overexposing. If the spike is to the left of center then your camera/sensor is underexposing.

Make an exposure adjustment in your RAW editor to center the spike. Then take that value and use it as your calibration offset in your meter. Once you have the offset entered, adjust your light and meter again for f/8. Take another shot, go back to your computer and confirm that you now have a spike that is dead center.

Remember that on the L-358 you are not entering the offset as you would exposure compensation on a camera. You have to think of it as entering the amount that you're under or overexposed and not the value that you needed to compensate.

In other words, if you find you're .3 stop overexposed and in your RAW editor you had to reduce exposure by .3 stop to center the spike then +.3 is what you enter in your meter because you were .3 stop over.

[Edbee]

Just purchased the L-358 and using the grey card checked for calibration. Delighted to find it was right on. My old analogue Sekonic was 1 1/3 stops low. Gave it to my son!!:D

[TMR Design]

Just purchased the L-358 and using the grey card checked for calibration. Delighted to find it was right on. My old analogue Sekonic was 1 1/3 stops low. Gave it to my son!!:D

Great to hear Ed. Was that for all 4 modes and at all ISO's?

[XpLoiT]

thanks for all that info - i dont have a grey card, i only have a WB card looks like i will need to get me one.

The other thing is that i normally shoot on f8 @ 100-200iso cause the majoirty of my work is strobed in some particular way. So that will mean i need to get some lights setup too to correctly expose at f8 (or shoot in day light but i guess i should try and simulate my normal shooting styles).

Dave

[Edbee]

No, only tried it with incident light (the intended use) and at ISO 200 and 400. Guess I should do more and find out exactly where I am with it:D At eighty you're not inclined to do a hell of a lot at one time. Hopefully I'll get to it!

[TMR Design]

Hi Ed,

Don't make yourself nuts if you're getting good exposures. It's probably not worth it. If exposures are looking good and you're not losing detail then I think it's pretty safe to say that there's no reason to calibrate or give it much thought. Just shoot and be happy :D

[chris78cpr]

Very interesting thread, im thinking of picking up a 358 soon.

Chris