jkutler Posted September 21, 2011 Share #1 Posted September 21, 2011 Advertisement (gone after registration) Hi, What is the difference between the SF 24D vs 240? Do they both have DX film speed reading. My SF 20 does not? In fact what are the improvements of those two new ones over the 20? thanks a newbie:) Jonathan Link to post Share on other sites More sharing options...
Advertisement Posted September 21, 2011 Posted September 21, 2011 Hi jkutler, Take a look here flashes SF 24D vs 240. I'm sure you'll find what you were looking for!
lars_bergquist Posted September 21, 2011 Share #2 Posted September 21, 2011 The SF24D does read the ISO from the camera. But the main point of it is that it does the GNC pre-flash routine when it is set to that mode. With a digital camera, a flash cannnot (obviously) read reflected light from the film, and doing it from the shiny front surface of the sensor would give erroneous readings. So the apparatus fires a weak pre-flash, reads it from the front of the closed shutter and adjusts by the reading for subject reflectance and distance, and the aperture, whereupon the shutter opens and the properly calibrated exposure flash is fired. The SF58 uses the same procedure. The older SF24 can only be used on external automatic (A) and manual (M) with a digital M. Similarly, the SF24D can only be used on A and M with a film camera. The old man from the Age of Flashpowder Link to post Share on other sites More sharing options...
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