Comments

johnmeyer wrote on 5/17/2008, 11:30 AM
I have the FX1 and have wondered as well. What I have done is set AE shift to zero while viewing a static scene. Then, I set everything to manual.

Next, I used the manual f-stop control and stopped down one stop at a time. I noted when things started to disappear (maybe there is a more scientific way to "remember" the effect of the f-stop).

After I did this for about 6-7 fstops, I set everything back to automatic and then used the AE function. When moving it one "stop" at a time, it seemed to me that the effect was MUCH less than one f-stop, and probably something like 1/3 - 1/2 of an f-stop.

Now that was on my FX-1, but the same technique might work for you.

Of course if you can find someone that has a document that describes this, that would be even better.

farss wrote on 5/17/2008, 4:09 PM
"ev" is exposure value, good explaination here:

http://en.wikipedia.org/wiki/Exposure_value.

If I read that correctly then a shift of 1 in EV should be the same as 1 stop but the 'clicks' in value are in smaller increments.

I've used it a bit on several cameras. If you still need AE but maybe just want the exposure dialled back a bit (or up) then adding an offset can make the camera dance the way you want. For example instead of Spotlight use Normal with AE Shift - 0.5EV or -1.0EV.

Bob.
ushere wrote on 5/17/2008, 5:04 PM
thanks bob,

interesting article, very informative, but still doesn't answer what +/-7 represents on the camera.

bit cold and wet (thankfully) today to go out and play, but from a brief assessment (none technical), it looks like maybe 1.5 stops?

i ask because i was shooting an interview the other day and since i usually find the ae exposure a little too light, tried -2 on the ae shift, which brought the picture down to a very pleasant level that i didn't seem to get using the iris - the iris being more 'stepped'.

also found it gave (-2) a more natural feel to outdoor shots without the 'saturation' usually accompanying shooting 1/2 to 1 stop below ae.

of course, this is all subjective, hence i'd like to know what i'm actually doing technically...

leslie


johnmeyer wrote on 5/17/2008, 5:37 PM
I use spotlight and a -2 to -4 EV all the time with stage productions. At least with the FX1, -1 EV is definitely not even close to one f-stop. If you meant that 1.5 stops was equal to 7EV, I think that is pretty close to what I have been seeing.
farss wrote on 5/17/2008, 6:44 PM
I must admit that even with my DSC which reads out EV a reading of -1.0 EV certainly doesn't look 1 stop underexposed. And yet every reference I can find from a Google would indicate it should be it seems. Technically the EV is the measure of subject brightness with EV 1 being 1 seconds at f1 with 100 ASA. All else being the same EV2 is f1.4.

Perhaps shooting a grey or white card with various EV offsets and scoping the result will reveal more than my speculation.

Bob.