fivetoad Garland, US Registered since 23rd Feb 2002
Mon 02-Feb-04 04:53 AM
A number of people are excited about the 1/500th flash synch speed of the new D70, but I don't completely understand the significance of it; can somebody help me understand the importance of the higher speed?
As I recall, back in the early 70s my Nikkormats had an unusually high synch speed at 1/125th, while most other cameras only synched up to 1/60th. But no one seemed to think that was important because the electronic flash duration was less considerably than either synch speed.
But today folks are talking about the D100 being limited some how by a max 1/180th synch speed, and how the higher synch speed of the D70 is really a great improvement. It may well be that it is, but I don't understand why. Who can help me understand?
Dan Johnsen Garland, TX Time is what keeps everything from happening at once.
If you shoot a lot of fast moving action/sport using flash the 1/500 sync speed is VERY valuable. It basically means that you have better action stopping power as well as the option to use wider apertures. I often want to underexspose the background slightly and in order to do this with 1/250 sync speed I need to shoot at +- f11 (100 ASA film in bright daylight) So on your digi-cam with 200ASA the 1/500 sync is essential for daylight flash work.
Fast sych speed is great for outdoor portraits using flash. You can use a technique where the subject is illuminated much brighter than the background, so the background is say 2 to 3 stops less than the foreground.
You can't get this effect with slow shutter speeds.
Basically how it works is like this: For film speed say 100-400, you'll get a reading to set your apeture to something like 5.6 - 11 (depending on flash power).
The thing to remember is 1): The Apeture controls how flash is exposed. 2) The shutter controls ambient exposure (light not lit by flash) - background.
In fairly bright conditions once you have set your apeture, the only other control you have is control over ambient light, ie. the shutter speed. If this is 1/125 it will be too slow to make the background darker.
A fast shutter speed of 1/500 will do the job very nicely, giving you a nice dramatic flash lit portrait with a moody sky/buildings in background.
Fill flash is the 'opposite' technique where the flash is now under exposed by a couple of stops compared to the ambient light, to give a natural 'fill-in' for shadows that doesn't look unatural.
Check out this guy Neil Turner, he's a press photographer who uses a flash over daylight technique and explains how to do it on his excellent site.