 Elaine S. Robbins |
Shutter Speeds w/flash on Canon Rebel 2000 I just (today) bought a new Canon Rebel 2000. This is my first SLR and I'm really excited to have it. One thing I noticed, however, is that when I use the built-in flash the shutter speed always defaults to 1/90. Isn't that awfully slow? I thought anything under 1/125 you should have a tripod, but I can't use a tripod for ALL my flash photography!! Thanks. Elaine
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Jeff S. Kennedy |
1/90 is probably the sync speed for that camera. Anything faster would result in shots that are not entirely well exposed. As far as hand holding it depends on the focal length of the lens you are using. The rule of thumb is use a shutter speed numerically equal to your focal lenghth. For example, a 50mm lens should be good down to 1/60 an 85mm lens should be good to 1/90 etc. The beauty of flash is that the flash duration in essence becomes your shutter speed. Your built in flash probably fires at 1/500 I'm guessing so that becomes your shutter speed. Now, that being said, you have to be careful when shooting with a flash when there is strong ambient light. In this instance your slow shutter speed will record a blurred image on the film along with the sharp image the flash put there. There, now are you really confused? Let me know if you have any questions, I'll be glad to clarify.
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John A. Lind |
Elaine, I verified the electronic flash X-sync for the Rebel 2000 is 1/90th. This is plenty fast. Four of my five camera bodies with focal plane shutters X-sync at 1/60th. The fifth's X-sync is 1/50th. I've never had a problem with hand holding any of them at these speeds using an electronic flash. You should be able to shoot with an electronic flash as slow as 1/30th without much trouble provided your subject is not moving fast. This was the typical F-sync or M-sync shutter speed used with flash bulbs several decades ago. This presumes you are not using a lens much longer than about 100mm. When using an electronic flash strobe, the strobe itself will stop action in nearly all situations as its flash duration will be somewhere between 1/1000th and 1/50,000th second. The light from the flash is normally much, much brighter than ambient, so it tends to remove any blur. You shouldn't need a tripod for most flash photographs . . . I cannot remember when I last used one with a flash. The general rule of thumb for needing a tripod without flash to prevent blur from camera shake is shutter speeds slower than 1/(lens focal length). Even then you can often push that to twice as long with lenses 135mm and shorter if you are well braced in a good, steady stance. I routinely shoot without flash at 1/30th and 1/25th using a 50mm lens and have done it successfully a few times with an 85mm lens. With a flash duration of 1/1000th and faster, why do you need a much longer shutter speed for an electronic flash? It has to do with the focal plane shutters used in SLR's and how they work. This type of shutter has two curtains. When the shutter is closed, the edges of them overlap slightly just past the edge of the film frame. When you release the shutter, the edge of the opening curtain starts traveling toward the other side of the film frame. After a time delay, the closing curtain is released and its edge starts traveling toward the other side of the film frame to close the shutter again. These curtains can travel only so fast. For slow shutter speeds, the first curtain will fully travel before the second is released. For fast shutter speeds, the second is released _before_ the first one has completed its travel. This results in a slit traveling across the film frame. The faster the shutter speed beyond your flash X-sync speed, the narrower the slit. When using a flash, the entire film frame must be open to light when the flash fires. The shutter speed for flash use must have the first curtain fully open before the second curtain is released. Otherwise, part of the film frame would be blocked by one or both curtains and you would end up with a photograph that has shows only a band properly exposed with the rest very, very dark. Been there, did that _once_, about 25 years ago, by accidentally using 1/125th shutter speed on a manual camera body. Ruined about a half roll of film before I noticed it; about 1/3rd of each frame was almost black. (Haven't failed to double-check the shutter speed when using flash on the manual cameras since.) My cameras are older and their shutter curtains travel slower . . . which is why their X-sync speed is slower. -- John
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Elaine S. Robbins |
Thank you - that's helpful. One question about hand holding though - how does it apply to zooms? I have a 28-80 lens. Is the rule of thumb that I can hand hold at 1/30 at 28 mm but only 1/90 at 80 mm or is it just 1/90 for the whole lens since it goes out to 80 mm? Also regarding the filter thing - how do you clean filters? DO you need lens paper or are they tougher? Thanks again, Elaine.
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Jeff S. Kennedy |
Yes, the rule of thumb applies to whatever focal length you have your zoom set to. As John says though, you can experiment with slower speeds. You may have very steady hands and therefore may be able to handhold at slower speeds. Treat your filters just like your lens. Take great care in cleaning them to avoid scratches and damaging the coating (the best filters are coated like lenses to cut down on lens flare).
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