Now we're getting down to brass tacks - what the various features
are and how to know if they're important to you.
Shutter Speeds
Back in the 1960s and 70s, entry level cameras often topped out at
1/500 sec., and almost all other SLRs had a maximum shutter speed of
1/1000. A rare few could reach 1/2000. Today there are cameras hitting
1/4000, 1/8000, and even 1/12,000 of a second - but do you really need
those speeds?
Let's start with the old "sunny 16" rule: On a sunny day, set your
lens to f/16 and the shutter speed to match your film speed - for ISO
100 film, that means 1/100. Pretty much any lens ever made for a 35mm
SLR (except for mirror lenses) will have an f/16 aperture, and some go
further to f/22 or f/32. Here's a table of equivalent exposures for a
sunny day:
ISO 25 ISO 100 ISO 400 ISO 1600
f/32 1/6 1/25 1/100 1/400
f/22 1/12 1/50 1/200 1/800
f/16 1/25 1/100 1/400 1/1600
f/11 1/50 1/200 1/800 1/3000
f/8 1/100 1/400 1/1600 1/6000
f/5.6 1/200 1/800 1/3000 1/12000
f/4 1/400 1/1600 1/6000 n/a
f/2.8 1/800 1/3000 1/12000 n/a
f/2 1/1600 1/6000 n/a n/a
f/1.4 1/3000 1/12000 n/a n/a
Back in the days of Kodachrome 25, a top shutter speed of 1/500 was
plenty, even with a moderately slow (by the day's standards) f/4 lens.
And 1/500 stops all but the fastest action.
With "normal" ISO 100 print film, you didn't have to go beyond
1/1000 unless you really wanted limited depth of field. As we move to
the ISO 400 film that's common today, having a 1/2000 top shutter speed
becomes helpful if you want to limit depth of field - but if you're
after limited depth of field, you should probably shoot a slower
film.
As for the ISO 1600 stuff, it has its place, but shooting this
expensive film outdoors is far from ideal. You can do it, but I
recommend something slower when the sun is shining bright.
You may encounter very bright light situations, such as snow and
beach scenes, that are a stop brighter than your typical sunny day, but
chances are that you'll rarely need shutter speeds beyond the 1/2000
mark.
Flash Sync
The focal plan shutter in today's 35mm SLR cameras and some medium
format cameras uses two curtains or sets of blades to cover the film
before and after exposure. The speed at which these blades move and the
distance between them creates different shutter speeds.
Both blades need to be completely out of the way at the instant the
flash fires, so 35mm SLR cameras have had sync speeds ranging from as
low as 1/30 to as high a 1/300. Today's entry-level SLRs typically have
a sync speed in the 1/60 to 1/125 range, while advanced amateur models
tend to be in the 1/125 to 1/250 range. On most cameras, you can select
a lower speed.
Benefits of a higher shutter speed flash sync include minimizing the
effect of existing light and making it easier to use fill flash in
bright light. I consider a faster flash sync one of the main benefits
of more advanced cameras.
High Speed Flash Sync
There is an exception to the flash sync rule - some cameras will
work with certain flash units at higher shutter speeds by reducing the
flash unit's normal output to a lower level and precisely triggering
the flash several times as the shutter blades zoom past the film. This
can be very useful for fill flash outdoors, and if that's something
you'd like to be able to do quickly and easily, buying a camera with a
built in flash that supports high speed sync can be a real plus.
Second Curtain Sync
Another nice flash feature when shooting moving subjects in low
light and with slower shutter speeds is second curtain sync. Normally
the flash fires as soon as the shutter is fully open; this is exactly
what you want most of the time. But if you're shooting a subject that
moves during the exposure leaving an image trail in your photo, this
can result in an unnatural looking blur that comes after the
initial flash exposure. Second curtain sync fires the flash just
before the second shutter curtain fires. If you shoot with flash
at low shutter speeds, this can be an important feature.
Built-in Flash
All of the entry level AF SLRs have flash built into the camera, and
it's making inroads on pro cameras as well. The internal flash has
limited power (a guide number of 40 in feet with ISO 100 film is
typical), limited range, and increases battery consumption. If you plan
on doing a lot of flash photography, seriously consider a more powerful
add-on flash unit. This will also greatly reduce the chance of red eye
in your flash photos.
Autofocus
Although there are a handful of manual focus cameras made today,
most models and the best sellers offer autofocus (AF). Where early
autofocus cameras could only focus on subjects with good contrast in
the middle of the picture, many of today's AF SLRs have multiple
sensors and work with a wider variety of subjects.
Multiple Sensors
With multiple sensors, your subject needn't be in the middle of the
picture. Old timers like me are used to focusing in the middle and
recomposing our shot, but a lot of cameras will let you choose which
sensor to use, letting the camera easily autofocus on the correct
subject. Canon even has some models that can track your eye to
determine which subject to focus on.
Wide Area AF
Since I got my hands on a Nikon N90s, I've become a
huge fan of wide area autofocus, Nikon's term for a larger AF area. The
subject need not be as critically centered, and the camera seems to
sense just where to focus within that space.
AF Aid Light
Autofocus has limitations in low light, so a lot of AF cameras
include an autofocus aid light. On more expensive models, this tends to
be deep read and send out a pattern of vertical bars in the near
infrared range that the AF sensor is well attuned to. This light is
fairly inconspicuous, and most external AF flash units include an even
more powerful AF aid light.
More recently, less costly AF cameras have switched to a white aid
light, sometimes using the flash for this purpose. I think it's as
annoying as all get out, and your subjects will definitely know you're
preparing to take a picture. White lights are cheaper, but I'm not a
fan.
Continuous AF
Autofocus SLRs can usually be set to focus and lock or to focus
continually - sometimes right through the shot and into the next one.
Single-shot AF is fine for static subjects, but for moving ones
(sports, kids), you'll probably be happier with continuous AF.
Film Handling
Loading 35mm SLRs used to be a chore, and almost every photographer
would botch it once in a while. That's much harder to do with today's
autoload, autowind cameras. All the AF SLRs include automatic film wind
at 1 frame per second (fps) or better - and at least one entry-level
model clips along a 3 fps. Unless you're shooting sports or other fast
action, though, the convenience is being ready for the next shot, not
the ability to fire off 36 shots in 12 seconds.
These cameras will also rewind the film when the roll is
finished.
Another wonderful innovation from the 1980s was DX film encoding. It
used to be that photographers had to manually enter the film speed. DX
changed that by putting sensors in the camera and a code on the 35mm
film cartridge to automate the process. Result: You have to work to set
the wrong film speed. (But I've done it!)
The only drawback is that some of today's SLR cameras, such as the
Nikon N65, have no way to manually set the film speed if you want to
push film or use film that isn't inside a DX encoded cartridge (rare,
but infrared film is one example). This isn't an issue for most of us,
but some schools insist that their photography students have a camera
which allows manual ISO settings.
Metering
Another brilliant innovation was intelligent metering. Minolta
started this with the CLC (Contrast Light Compensation) metering system
in their SR-T 101 way back in 1966. The unique feature of CLC? I was
designed to ignore a bright sky and expose for the rest of the picture
- assuming you were shooting a horizontal.
The next step in metering evolution was the matrix metering of the
Nikon FA, which metered the center and four quadrants of the screen,
determined which areas should be given more weight, and calculated
exposure accordingly. Some of today's cameras have over a dozen
metering areas, but for real world picture taking, I think you'll find
the matrix metering in any of today's 35mm SLRs does a fine job over
95% of the time. Each brand may promise superior results, but you're
unlikely to see the difference.
If you want sophisticated metering, you'll want to learn how to use
a spot meter. A spot meter works by only measuring light in one spot on
the screen, usually a small circle right in the middle. The smaller the
spot, the more precisely you can meter your subject.
Spot metering is a thinking photographer's tool, since you have to
not only decide where to meter, but also whether what you're metering
should be lighter or darker than average - and by how much. For the
rest of us, spot metering is best reserved for situations like concerts
where a spotlight shines on the artist and you want him/her to be
exposed correctly despite the dark background.
Most casual photographers will be perfectly content with matrix
metering, especially since today's color print films build in a nice
margin of error. But if you're serious about photography, consider a
camera with a spot metering option.
Next: Picking a Brand and Model.
