Digitek DFL 002/003 – Speedlight Flash Gun review and How to use a Manual Speedlight
This review is for the actual Digitek 002 model; however this may also apply easily to the 003 model as they have the same specifications. Advertised specifications: Guide Number: 38 m (100 ISO) You can easily increase the guide number if you need to by increasing the ISO. For, example, my D3100 gives good performance up to ISO 400, after which there appears consistent noise. If the parameters of the exposure triangle are increase by one stop, the guide number increases by multiples of 1.414 (square root of 2); with the exception of shutter speed. E.g., If ISO is increased from 100 to 200, the guide number increases to 38 x 1.414 = 54. So how do you use guide Number? Guide Number = FOD x Distance from the Subject. OR FOD = Guide Number / Distance from the subject. Example, if your GN is 38 and distance from the subject is 4 metres, the f number for proper exposure should be 38/4 = 9.5. If distance is 10 metres, then, FOD = 38/10 = 3.8...