Chủ Nhật, 6 tháng 1, 2008

Control Your World With Ultra-High Sync

UPDATE: The main body of this post now has an expanded list of high-sync cameras and a link to a .pdf tutorial on both Nikon and Canon proprietary high-speed pulsing flash features. -DH
___________
Anyone can nuke their environment late in the evening, when just a little twilight is left in the dusk sky. In fact, the usual problem is failing to open up your shutter to let the ambient burn in for some flash/ambient balance.

This speedlight-lit photo would be a very good example -- except for the fact that it was taken at about 1:30 p.m. on a sunny day at a recent Strobist meetup near Baltimore, MD. That little patch of dark grey up top is sunny mid-day sky.

More after the jump.
________________________


The exposure for the above flash-lit shot was at ISO 200 at f/16 and a 1/4000th of a sec. It's that last part which makes everything possible. High-sync cameras are the little hidden jewels in various manufacturers' lines. We have talked about them before, but I came across these two photos which really show just how far you can go with it while archiving the other day.

There are a few special cameras with electronic shutters which do not really have a hard maximum sync speed. At some point while going up the shutter speed scale, the mechanical shutter does not actually continue to speed up. Instead, the chip just uses software to take a smaller and smaller slice of time to create the picture.

This totally rocks, because for every shutter speed you can climb up and can still sync the flash, the aperture can open up a full stop. So the flash has to put out half the light to get the same effect. And you can have it both ways, too, by walking that shutter up and leaving the aperture closed down to turn day into night. Or wherever you want it to be.

The trick is, you have to fool the camera into thinking there is not a flash attached to it. This way it will not restrict itself to its normal maximum sync speed.

These days, the camera normally knows it has a flash on it from the TTL circuitry that talks between the two. You can get around this pesky restriction by using a non-TTL PC cord if the camera has a PC jack. You can also use an adapter such as the Nikon AS-15 (~$20) which turns a TTL-enabled hot-shoe into a dumb PC jack. Works fine, but it needs a PC cord and a sync jack on the flash to complete the connection.

Even cheaper and better is a used Nikon SC-17 cord, which is normally TTL until you neuter the little guy by opening it up and snipping all of the wires except for the ones that are connected to the center post and the edge strip. This turns the TTL cord into a dumb (non-TTL) hot-shoe extension cord.

You can also high-speed sync with a Pocket Wizard, which does not make use of TTL signals, either.


Cameras to Control the Sun

Before we go any further, lets review some of the cameras which have the ability to sync right on up there through the shutter speed scale past their nominal sync speeds. None of them are particularly expensive, and they make ideal second cameras. Just keep an eye out for them on Craigslist or eBay -- especially right after a hot new model comes out (cough, D300, cough) and people get a case of upgrade-itis.

Number one on the list is my very favorite sleeper DSLR, the Nikon D70s, and to a slightly lesser extent, it's older sibling, the D70.

The 6.1MP D70s is now my primary body. I have three, and I am pretty sure my wife is now considering an intervention. But you can buy four of them is great shape for about the price of one D300.

The Nikon D40 (but not the D40x) can do this sync trick, too. It's a newer chip than the D70/s, but it is not compatible with many Nikon lenses. Make sure you check your charts if you are considering buying one.

Also, the old D1 (and /h and /x) bodies are said to sync up high in the range, too. I have no first-person experience with this, so check it out if not sure.

(UPDATE: According to a couple commenters, the Nikon D50 does the high-sync thing, too. Ditto the Sony R1, Olympus E-1 and E-3. Cool.)

On the Canon end, I am told the EOS 1D's do it. Again, never owned one. But I have heard they work from several people.

What I have owned are both the Canon G7 and Canon G9, which are neat little 10- and 12-MP point-and shoots. You have to turn off the in-camera flash and sync via a Pocket Wizard or a PC adapter (like the Nikon AS-15) and a PC cord. I love both of them. They'll sync up to a 1/2000th. The neutered Nikon TTL cord works great with them, too. (Works best, actually, IMO.)

You should be able to find any of these cameras new (G9) or used (all of the older models) for under $500.00.

Schweet.
________________________


Now, just because a camera will sync with a flash does not mean a flash will sync with a camera.

(Huh?)

Follow me for a sec. A full-power flash from a speedlight usually has an actual duration of about 1/1000th of a sec. Which means that no matter what, you will not be able to sync one at full power at a 1/4000th of a sec. The actual flash pop lasts too long for the length of time the shutter is open. Rule of thumb is, the more you dial the flash down, the faster it will sync higher up with one of these special cameras.

If you are using remotes, they will limit you, too. My PW's limit me to about a 1/1600th of a sec with a D70s. But the neutered TTL cord will sync at right up to an 1/8000th(!!!) of a sec at lower flash powers (and thus, durations -- and higher manual flash power settings as you walk down the shutter speed scale.

So, working in relatively close, we might just open up the shutter until the sky was at a tone that we liked, as in this example which was shot at f/14 at 1/500th of a sec. I know, the trees are a little cluttered, but the point was to show the other meetup-ers that we could place the sky tone wherever we wanted with high-sync.

If you want to do multi-light setups this way, no problem. (A nice rim light coming from back camera right would have amped our example quite a bit.) You can add another PW, but it is usually easier to slave the other flash(es).

A couple of thoughts about the flash mode: If you are working with static subjects, manual is an easy way to go. But if you are in a dynamic setting, consider the old-fashioned "auto" mode. This'll get you some flexibility, considering you cannot go with TTL. (Remember, we don't want your camera to find out there is a flash attached and start telling us what shutter speeds we cannot use.)

Some high-end cameras have a special, pulsing, high-speed flash mode, too. If you are lucky enough to have both a flash and camera that supports these sophisticated functions, definitely enable them. No reason not to.

(UPDATE: A commenter pointed to a pretty good paper on this high-speed, pulsing flash setting here. (Via Naturescapes.net.)

But you'll find that you'll actually get more light out of your flash at super high sync speeds with the above neat little supercameras, if you are able to scrounge one for your bag.

___________________________

Related Post (using High-Speed Sync)

:: On Assignment: Parking Lot Ambush ::

Không có nhận xét nào:

Đăng nhận xét