PDA

View Full Version : Exp. Comp. Brain Reboot.


oops
4th of June 2001 (Mon), 22:03
I bought the G1 Short Course by D. Curtin and was doing well until I hit the section on exposure compensation. I brain re-booted about four times and am still confused. I just hope I didn't blow the whole fuse box.

I understand exposure compensation (EC) as a way to darken or lighten my exposure. If the shots come out too dark, try + 1/3 or so; if the shots are too light, try - 1/3 or so. Am I right?

D. Curtin gives a "Tip": "Use + EC when the subject is bright and - when the subject is dark." He goes on to explain examples, like "use +1 for very light subjects like a white cat on a white pillow and -1 for very dark subjects like a black cat on a black pillow."

Is it just me or is his explaination opposite of my original thinking? Wouldn't a -1 with the black cat give you a black blob without definition? Shouldn't I lighten the image to improve contrast?

I trust he is saying the correct thing but not in a way I can understand. Can anyone help?

Pekka
5th of June 2001 (Tue), 07:12
It's because the cameras expose for 18% gray. This means full white will be grayish (you have to compensate to get it white) and also that full black is not full black (you have to decompensate to the get it black). In theory.

I'd forget the exposure compensation altogether, and use P mode to see what the camera suggests and then use M mode to shoot, using the LCD as a guide (tip: look LCD from 'side' and you'll see overexpose area CA in it).

Even though the LCD is not perfect, you can learn how to read it (e.g. in bright light it shows almost ok, in darker it shows correct exposure as too bright).

oops
5th of June 2001 (Tue), 18:34
Thanks! That helps, and the tip is a good one. I happened to photograph a white Ford Explorer today in bright sunlight and all the shots were dark and dismal looking. The white SUV was just too light with the reflected light so the G1 darkened the images way down. I even had one shot in P mode @ 1/1000 F8 with the red warning display. I took the shot anyway and it was the best of the lot, though still too dark. New Mexico has the sun in abundant quantities!

The most frustrating aspect of the G1 (and probably all digitals) is what you see on the LCD as a final shot is not what you see when you download your camera. Thank God for Adobe. I am determined to learn this camera and am having the time of my life trying.

Also, as a footnote to those who post "Dropped my G1; is it OK?" I dropped the hell out of mine today and even kicked it six feet in an attempt to break it's fall. It "Took A Licking And Kept On Ticking!". Not as pretty as it was a few seconds beforehand but neither am I. :)

ega1
5th of June 2001 (Tue), 19:26
oops wrote:
I dropped the hell out of mine today and even kicked it six feet in an attempt to break it's fall.

That's my patented cellular phone manoever.

John - NJ
5th of June 2001 (Tue), 20:00
oops:

Since you have a lot of bright days, why not try a neutral density filter to darken the shot. You could also try a polorizer.

Another trick, if you don't have the filters, may be to use the exposure compensation in the camera.

Let us know how it works out.

Andrei
5th of June 2001 (Tue), 20:05
The metering system is adjusted on 18% Grey. In Zonal system it is Zone 5. Black - usually 2, and White - 7-8 (usually 7). What your camera does, is:

Black 0% ---> Grey 18% Zone 5

oops
6th of June 2001 (Wed), 08:08
Thank you John and Andrei-

The white/grey % related to stops is interesting and opens another chapter to explore and try. Sometimes the simplistic explaination, like in the Short Course, just leaves too many question marks. We all benefit from more in depth study of the "whys" rather than the pat "just do it this way".