Guide Number vs Light Meter

Frank Dean,  Blacksmith

A
Frank Dean, Blacksmith

  • 5
  • 3
  • 45
Woman wearing shades.

Woman wearing shades.

  • 0
  • 1
  • 52
Curved Wall

A
Curved Wall

  • 5
  • 0
  • 81
Crossing beams

A
Crossing beams

  • 9
  • 1
  • 104
Shadow 2

A
Shadow 2

  • 5
  • 1
  • 75

Recent Classifieds

Forum statistics

Threads
198,840
Messages
2,781,687
Members
99,725
Latest member
saint_otrott
Recent bookmarks
0

chassis

Member
Joined
Jul 17, 2011
Messages
294
Location
Midwest, USA
Format
Multi Format
To the OP, it looks like you have consistent results. You have characterized your equipment. Is it possible to use this information and continue shooting? If further accuracy is needed, testing with your chosen film and lighting setup would be one method. If the photo project is not ultra critical, I would suggest you are good to go.
 

AgX

Member
Joined
Apr 5, 2007
Messages
29,973
Location
Germany
Format
Multi Format
But thus without walls and a ceiling or with them but with direct metering without dome (but calculating for the lacking opacity of it) one would likely get underexposure. (Reflections are part of the lighting that makes up the GN.)

I have to correct myself: Guide Numbers are established with non-reflective walls.
 

Chan Tran

Subscriber
Joined
May 10, 2006
Messages
6,817
Location
Sachse, TX
Format
35mm
The GN should be tested in incident mode but with a flat receptor and not the dome. I don't know if the OP meter has the flat receptor but if it does, please retest and you will find a little higher reading but I don't think it's as high as the GN would suggest. Flash manufacturers tend to inflate their GN.
Just checked the 308S manual. The OP should use the Lumidisc and not the Lumisphere. Using the lumidisc the OP should get about 4/10 of a stop higher reading.
 
Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links.
To read our full affiliate disclosure statement please click Here.

PHOTRIO PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Ilford ADOX Freestyle Photographic Stearman Press Weldon Color Lab Blue Moon Camera & Machine
Top Bottom