What is EV mode

[sarah_lange]

<p>Hi, Could someone explain what EV mode is when using a light meter and how it is different from measuring ambient light using either aperture or shutter priority? I am using a Sekonic L358. Thank you!</p>

[pete_s.]

<p>EV stands for Exposure Value. It is the combination of aperture and shutter speed (often at ISO100) rolled into one. For instance EV5 @ISO100 means a certain amount of light (80 lux). The exposure could be f/1.4, 1/15s or f/5.6 1s or any other equivalent combination. More about it here: http://en.wikipedia.org/wiki/Exposure_value</p>

[mendel_leisk]

<p>Hybrid auto owners refer to Electric Vehicle mode as EV mode as well, which might complicate your search.</p>

[georg_s1]

<p>On certain cameras (old style Hasselblads for instance) you can set a Exposure-Value and lock it with a button. If you lower the shutterspeed the (cross-locked) aperture will close accordingly. Pretty neat for doing flash-bracketing outdoors for example.</p>

[kelly_flanigan1]

<p>****An EV of 0 is defined as F1 at 1 second over 1/2 century ago; with NO ie ZERO ties to ASA; DIN or ISO at all.<br>

<br /> An EV of 13 is 1/125 at F8; what many of us used with old Kodachrome II (asa 25) on a bright sunny day.<br /> Tying a EV of say 10 to an iso of 25 means one is in open shade; tying it to an iso of maybe 200.<br /> Since the internet many errors have been introduced about EV; many newcomers preach wrongly how it is based on asa/iso 100; when EV has nothing to due with asa or iso; it is an exposure setting; a combo of f stop and shutter speed.<br>

<br /> With bright sun and asa 25 film ;the exposure meter may give out an EV of 13; or 15 for asa/iso 100 film.<br /> With a 1950's camera; an EV system was a fad on many models; the meter gave out an EV number; then one set the EV ring on the camera; maybe a Retina IIIc. Thus with an EV of 13; one could use 1/125 at F8 for family shots; or 1/250 at F5.6 for sports; maybe 1/30 at F16 with a tripod for alot of DOF with a scenic with a foreground too.<br>

<br /> I mention about the EV not being tied to asa because this is rather a new event in the last decade; trying to rewrite what EV is in the SPIE handbooks.</p>

<p>If you yell out to set ones 1950's camera to an EV of 13 and it is bright sun; one should of course knwo waht film he has. If its is asa 800 print film; one has a gross overexposure. But to yell out what EV to use using a meter; one has to set the asa/iso dial on the meter first to get an EV number to yell out to another.<br /> As mentioned before; an EV of 0 is F1 and 1 second; whether one has as 6 microfilm; or 6400 tri-x pushed with eye of newt.<br>

<br /> An EV of 10 is 1/1000 second at F1; no matter what asa or iso is used.</p>

[kelly_flanigan1]

<p>An EV value is a combo of shutter speed and fstop; ie exposure.<br>

One can used EV values with reflective or incident light meters.<br>

in older ancient cameras of the 1950's and sometimes later; the shutter speed dial and fstop wer linked togther; thus if one set the camera to an EV of 13; turning the ring/assembly changed the fstop and shutter speed in step; so the combo still had the same EV of say 13.<br>

When your Sekonic L358 is set to iso 100; it will readout an EV value of -2 to 22.9 according too its specs. A dumb low cost Sekonic leader here only goes from 2 to 19 at an iso setting of 100; it is a simpler meter with an less active meter cell and circuit. A 5 buck self powered 1960's selenium unit here only goes from an EV of 7 to 18; it is a Joni-Mini.<br>

The EV system should have nothing to do with shutter or aperture priority.</p>

<p>Is your question about using EV with a flash?; since the meter you have also has a flash mode too?</p>