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02 December 2010

Modern Exposure

Photographic technique is a continuous process of shooting, analysis, and then applying that new knowledge to the next shot.
I've been doing this for 40 years, and learn new tricks all the time because I'm paying attention.
For the first 15 years I was an idiot. I thought the way to get better pictures was with a better camera. I thought the camera was responsible for metering and making the correct exposure. I was too inexperienced to realize that, like driving a car, you always have to apply intelligent corrections to get perfect exposure, just as even the best cars need a driver to keep them in-lane.
Exposure and keeping a car on-course are the same: you have to keep your eyes open and turn the wheel (or the lighten/darken control) to keep the car (or exposure) where you need it. The best ones need less correction, but they all need help some of the time.
Only an idiot like me lets the car or camera drive itself. Look out the window (or at the LCD) and make course (or exposure and color) corrections as needed.
Today I shoot all my cameras on full automatic (matrix/evaluative metering, program exposure, and Auto ISO) and alter the lighten/darken (exposure compensation) control if needed.
No longer does anyone need to worry about ISOs, apertures or shutter speeds; most cameras do this automatically. All you need to know is when to apply a little bit of correction to the camera's decisions, and you do this by looking at your LCD.
Modern exposure technique is optimizing the exposure compensation as needed, not setting exposure manually. The manual part is making the slight corrections to the automatic exposure, not setting apertures or shutter speeds as in the 1950s.
Film
In film days, I'd shoot and take notes. I'd look at my film, see what was good and bad, and apply changes the next time to do more of what's good and change what was bad. Ditto for color: I'd try different filters in different light, and use what looked best next time.
By repeating this process over the decades I got the colors you see in my gallery.
Pros used Polaroid backs to let them see what they were doing without having to go to a lab.
Most film cameras and meters were off by as much as a full stop, so we simply applied corrections to them. The world has always been this way.
My Nikon L35AF was 1/3 stop off, so I shot ISO 50 Velvia at a setting of EI 64 and everything was perfect.
My Minolta X-700 was off 2/3 of a stop, so I shot Velvia 50 at EI 80 and got great results.
My Nikon SLRs were always dead-on.
Digital
Digital makes this much, much simpler.
Instead of waiting for film developing and looking at written notes and trying to correlate them to film frames, you just look at the LCD. Duh!
Even easier, every digital camera has a lighten/darken control, usually a button marked +/-, and cryptically called "exposure compensation." You tweak it to fix the next picture. Easy!
This is easy:
1.) Take a picture.
2.) Look at the LCD.
3.) OK? If yes, you're done. If not:
4.) Adjust +/- control to lighten or darken, and repeat from step 1 until perfect. Some cameras may hide the +/- control in a menu; on Canon compacts, press FUNC and click down one.
Experience
With experience you'll learn under what conditions. to apply what compensation, and save yourself some of the steps to get there.
In film days we had to test and know from experience what conditions required what compensation. Applying this experience let us get great shots every time. Less experienced photographers had to rely on guessing, called bracketing.
This same experience with your digital camera will help you get the right look with fewer tries each time. Any idiot can do today what took me years of running back and forth to the lab.
Today only a super-idiot allows himself to get a bad exposure and blame it on a digital camera. These are the same kind of people George Carlin called the Stupidest People on Earth: people who run out of gas in a car with a perfectly good gas gauge. A camera's gas gauge is the LCD. Use it.
Better and Worse Cameras
The actual amount of compensation needed or used is irrelevant.
What is important is how consistently you can use the same setting over a broad range of conditions.
Getting great results with a camera to -2/3 all the time is much better than a camera which usually needs no compensation, but just as often needs to be changed. This jacking around wastes time, which makes you miss shots.
Auto Exposure
In the old days (1950s) we had to read a meter and set manual apertures and shutter speeds by hand. We chose film for the light conditions, and were stuck with that ISO for the whole roll.
Modern cameras have the metering and apertures and shutter speeds automated, saving us the manual jacking around. I used to be so stupid, even as recently as 20 years ago, to think that blindly following a meter and setting these manually on myF2AS gave better results than electronic automated cameras. Wrong: the automation does the same thing I was doing, just faster and better.
The only lenses on which I make manual settings are those which have no automation, which are my large-format film lenses.
Auto ISO
In the early days of digital SLR cameras (before 2004) we had to set ISO manually. We thought it was cool that we could change the ISO with a button instead of having to change a roll of film.
Modern DSLR cameras (Nikons since 2004) can set the ISO for us as well as they set our exposure. This lets me spend more time finding cool things to photograph and waste less time as a potential crime victim stopped and dickering with ISO settings.
Auto ISO, like automated exposure, is the way we shoot today. Screwing with manual ISO adjustments is as pointless as I was 20 years ago jacking around with manual shutter settings on my Nikons.
All or most compact digital cameras have had auto ISO settings as defaults for years.
Nikon DSLRs have had this since the D70 of February, 2004. Today they all have programmable Auto ISO. I always use this.
Auto ISO is deactivated by default in most SLR cameras, except in the green and dummy modes. I always find Auto ISO and turn it on.
The Nikon DSLRs even let you program the Auto ISO to exactly how you would like them to work as the light changes.
On my Nikons, you go to MENU > Custom Setting Menu (pencil) > ISO Auto and turn it on. You tell it the lowest shutter speed at which you can get a sharp shot (default is 1/30).
In Auto ISO, the camera cranks up the ISO as it gets darker from the speed you set. In other words, if you're set to ISO 200 and it gets dark enough to need 1/15 of a second, the camera magically will set ISO 400 and 1/30 of a second. In the old days I had to tweak the ISO as the subject or light changed. After the ISO hits the top ISO as it gets darker, usually ISO 1,600, only then does the camera use slower speeds than what you selected in the Auto ISO menu.
Newer Nikons, like the D200 and D80, even let you select the maximum ISO you wish to permit. By default, this is ISO 1,600. If you'd rather the Auto ISO function stop at a lower ISO, tell the camera so in the same menu.
Auto ISO starts at the ISO you have set on-camera, and goes up to the maximum you've allowed in the menu (ISO 1600 on D70) as it gets darker.
Auto ISO will also drop the ISO if you have the camera set to a high ISO and it gets too bright for conditions
One defect still in the Nikons is that once set, they stay on Auto ISO, even if you revert to manual exposure mode. This drives me crazy, since the camera starts jerking around the ISO to do what the meter says, even though the reason you went to manual was to lock in one exposure. Nikons should give us an additional menu option to defeat Auto ISO in manual mode, which would save us steps disabling Auto ISO when we go to manual exposure mode.
One of the biggest reasons I prefer my Nikon DSLRs to Canon is because Canon is still back in the 1970s: they have NO Auto ISO in their DSLRs, except in the dummy modes. This gives me lower image quality, because I either have to leave the camera on a higher ISO to cover all conditions, including daylight, or leave it set lower and get more blurring if I point the camera into a dark hole, unless I want to stop and be a crime target twiddling with a manual setting. Having no modern Auto ISO gets in the way of making pictures, just like having to pop a hood on a 1960s car and jerk around with a stuck choke just to start the car.
The Future of Auto ISO
No longer do we set ISOs manually. What we do set is the lowest permissible shutter speed for conditions. That shutter speed is usually dictated by the subject, and usually the lens. I set 1/8 with my Nikon 18-200mm VR, and a higher speed if I'm shooting at the longer end of the range.
Nikon and Canon: please include me on your patent applications for this. I don't expect a cut, and would like to be named.
In the future, hopefully 2007, we'll be able to set the Auto ISO functions to change the lowest shutter speed automatically to track a factor of the focal length of the lens. As we zoom to longer focal lengths, the Auto ISO function will be smart enough to increase the minimum shutter speed below which it increases the ISO.


credit:© 2006 KenRockwell.com

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