Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Digital Photography > Using Flash Beyond The Guide Number Distance.

Thread Tools

Using Flash Beyond The Guide Number Distance.

Posts: n/a
On Feb 2, 1:39 pm, "Pat" <(E-Mail Removed)> wrote:
> Another option, but quite a bit more expensive, is to hide a few
> flashed around the image to light up what you want. Your flash can be
> used as a master to fire either dedicated to dumb slaves that are down
> near your subject.

One combination I have used is a tripod and manual flash. With any
exposure longer than the flash recycle time, you can fire the flash
twice. With even longer exposures, you can fire the flash many
times. Keep in mind that you have to fire the flash (at full power)
four times to double the distance. I've even been known (in my
younger days) to run to a new location while the flash was recycling.

The technique works OK, (not really well) because noise still
accumulates with the long exposure.


Reply With Quote
Morton Linder
Posts: n/a
Mardon wrote:
> At 105mm & ISO100 my Canon Speedlite 580EX has a guide number of 58
> (meters). At ISO3200 (maximum ISO of the Canon 20D) the 'effective' guide
> number becomes 328. My lens has a maximum aperture of f/2.8. This
> indicates that in darkness, the maximum distance from the flash, at ISO3200
> and f/2.8, is 117 meters for a 'properly' exposed photo. My question is
> how far beyond this distance is a flash useful at night? The other night I
> photographed a piece of snow removal equipment at 200 meters, f/2.8,
> ISO3200, but it was badly underexposed. Even though the equipment was
> still well beyond the guide number distance of my 580EX, would the use of
> my flash have helped?.
> Related question for the 'oldies'. I seem to recall that the large
> flashbulbs I used back in the '60s really packed a wallop. I can't recall
> the guide numbers of those things. Does anyone know? I suspect they were
> well over 100 at ISO100 (expressed in the equivalent ASA in those days,of
> course.)

Tripod, beanbag, or use self-timer to trip shutter with least camera shake.

Reply With Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to add rows beyond 65535 in excel using Perl? IJALAB Perl Misc 1 05-10-2010 12:22 PM
Guide number for off camera flash Olin K. McDaniel Digital Photography 3 08-12-2008 12:03 AM
OT: Number Nine, Number Nine, Number Nine Frisbee® MCSE 37 09-26-2005 04:06 PM
how to choose specs: sensor type CMOS or CCD ? lense speed ? flash guide number? Mario Digital Photography 3 04-23-2004 01:25 AM
SONY Guide Number for HVLF32X Flash Light Master Tech © Digital Photography 1 07-21-2003 06:12 AM