Marinjo (and maybe a few others) -- note that this is for the M mode only.

Using the method shown at http://www.libarts.ucok.edu/journalism/Basicflash.htmlI have determined the guide number of the DX7630.

Since the DX7630 and the DX7440 have the same body, I'm guessing that the flash is the same.

The guide number is (feet) 34; (meters) 10.

You plug it in this way: distance/guide number = f/stop

This means that if you are 10 feet from your subject, your f/stop should be 3.4. (The all-time standard manual shutter speed for flash is 1/60).

If you are 3 meters from your subject, your f/stop should be 3.0... but you have to use an f/stop that is near this figure but whichis available in the camera -- either 2.8 or 3.4.

If you are 2 feet from your subject, your f/stop should be 17 -- f/8 + a 1-stop neutral density filter.

If you are 1 meter from your subject, your f/stop should be 10...really8

What happens if you are further than 10 ft / 3 m from your subject? The flash doesn't reach much farther. The DX7630 spec says, beyond 13.8 ft / 4.2 m at wide, you're out of luck.

Or you need an external flash (with a slave trigger).

Thanks! It's easy. I'll try some day...

Maris

Thanks Big D. I'll tell my daughter to check out the post. Again thanks.



Gonna go home Dawg

To DGehman. I've been careless because I found the Flash guide number in my DX7440 manual. You've been quite precise- it's 9.5. There is not mentioned if it reffers to feet or meters,but I'm sure it's meters.

Marinjo wrote: Well, I'll be...

Before running my own test, I looked and looked through my DX7630 manual, but I found it only after you dug it out of your manual:

Granted, it's in text form and missing the feet/meters detail (which is not really a detail), rather than typical specification form... but it isthe first element in the specs under Electronic flash: "Guide no. 10 @ ISO 100."

Dave