Q&A: Controlling the Sun When Using Flash - A Comparative Guide
Yes, there are different ways to do it -- namely ND, high-speed sync and special-chip cameras. Each method has advantages and disadvantages. The full how-to and scorecard, inside.
First off, I have a do use all three ways to bleed some depth of field from my photos. Depending on your situation, or the gear you already have, one way might be best for you.
We have posted in detail on some of the individual techniques before, so I'll link to those posts where appropriate for more info.
High-speed sync (also known as "Focal Plane," or FP sync) is a special protocol that some cameras and flashes share.
The camera controls the flash (whether remote or on hot shoe) in a way that causes the flash to pulse through the exposure.
1. If you shoot with one brand of gear (i.e., Nikon cameras and flashes) you may already have everything you need.
2. You can work in manual or TTL.
1. If you are going to be using more than one flash, this is the most expensive way to do it. With proprietary systems you will pay through the nose for every additional light. And even with deep pockets, you'll be capped to speedlights, as this does not work with studio flashes.
2. The inefficiency of this pulsing method, wherein much of the light actually is wasted on the black part of the curtain, robs you of power progressively as you move up the shutter speed scale.
(For all but the closest-lit portraits, #'s 1 and 2 above will stack up against you. Congratulations.)
3. Since the pulsing actually happens over about a 250th of a second, your flash will not have the action stopping power of, say, the 1/1000th of a sec your shutter speed might be set to.
Examples of using HSS in bright ambient:
:: Joe McNally's Tree of Woe ::
:: Dave Black: Flashing Surfers at Distance ::
Magic Chip Cameras
If you have no specialized gear and want a cool entry into flashing at most any shutter speed, you can pick up one of a few different "special" chip cameras, which utilize electronic shutters. For these cameras, the mechanical shutter maxes out at or below the hard sync speed, and the higher so-called shutter speeds happen by taking smaller and smaller electronic slices of time from the chip.
Nikon D40 (but not D40x) D70, D70s and the original D1/x are, I believe, all electronic shutter cameras. Ditto the original Canon EOS 1D. My favorite, by far, is the Nikon D70s. Caveat: If you physically connect (i.e., via hot shoe or off-camera cord) a same-brand flash to the camera, you have to trick it into the sync overdrive thing by taping over the TTL connections.
1. Real, full-sync at high shutter speeds. This is great for daytime action shooters, because both the shutter speed and the flash can be action-nailing speeds.
2. Cheap. Those old cameras can be had pretty easily on eBay these days, because many people do not know of their special powers.
3. Flexible. You can use a variety of speedlights and/or monoblocs, subject to limitations described below.
1. Your shutter speed cannot exceed the actual length of time it takes your flash to fire at a given power level. For example, with my Nikon D70s and SB-800s this means that I can get a full power pop at 1/500th (almost -- the SB-800 has a slow t.1 time at full power). But at 1/2000th of a second, you don't want to go past 1/4 power. At a 1/4000th, stay at or below 1/8th power, etc. Still, you can do a lot within those limitations. If you have a fast-pulse big flash -- an Einstein, for instance -- this can be an incredibly powerful combo.
2. All of these bodies are discontinued. So you are married to an old chip, with all of the above being both old tech and 6MP or less in size. And there are no full-frame chip options. But if you already have the camera (or score one cheap on Craigslist) go for it.
More on magic chip cameras:
:: Control Your World with Ultr-High Sync ::
:: Neuter Your SC-17 Cord to Fool Your Camera ::
Neutral density filters (used on the lens) will allow you to shoot with any sufficiently powered flash (speedlight or mono) and any camera / lens combo throughout your full range of apertures. And one filter on your lens covers any number of lights being used simultaneously.
We talked about the step-by-step process of using ND on Monday, so I won't repeat it here.
1. Assuming you will at some point want a choice of camera model, platform or flash, even the ne plus ultra $340 Singh-Ray Vari-ND filter is actually the cheapest of the options listed here. You buy it once and use it forever, on all of your gear. It is tack sharp and gives no color cast, which is very hard to do with a 2-8 stop ND filter -- and why it is so expensive. There are other ND options, but I do not recommend them.
2. One size fits all: Buy it in the 77mm size and use it on any lens with a universal filter adapter ring kit.
3, Any of you who are also landscape shooters will gain the ability to make exposures in full sun of up to 4 secs long (@ ISO 100, f/22). Great for landscapes that involve moving water or implying wind.
1. With neutral density filtration on your lens, it can be hard to read subject expressions. Especially since you'll usually be shooting into backlight. It will take a little getting used to. Fortunately, your autofocus will probably be fine. It is actually more dependent on the max aperture of the lens design (usually needs at least f/5.6) rather than the absolute amount of light coming through.
2. Psychology. Obviously, it is awful hard to bring yourself to cough up $340 for a filter. But if you are going to do a lot of this kind of work, the Vari-ND is the way to go. Try to think of it as buying the universal ability to light outside at wide apertures -- and not as buying a filter. I have never regretted the purchase. In fact, if it got lost or broken I would replace it immediately.
More on working with NDs:
:: Using ND Filters to Kill Depth of Field ::
:: Soccer Through Sunset ::
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