What f/stop and shutter speed to use at a night time crime scene?

Question by kkkaaaait: What f/stop and shutter speed to use at a night time crime scene?
I’m writing a paper for my crime scene technology class and I’m having some trouble. Photography is the only part of this class I don’t understand. I cannot grasp f/stops and shutter speeds. My example is: let’s say I’m photographing a homicide at night. My film speed is 400 and the only light I have is a flash light and a flash/flash cord. I am taking an overview of the body. What f/stop and shutter speed would I use to make sure that I have plenty of light?

Best answer:

Answer by Paul O’brien
If you’re using a manual camera and a manual flash you’ll need to understand guide numbers. Find out the guide number of your flash, divide that by the distance in feet and you will have your F/stop for 100 film speed. From there if you are using 400 film speed need to multiply that number by 2 to get the F-stop to use in the end. Shutter speed doesn’t need to be taken into consideration to the exposure, but to ensure the whole film is exposed you won’t want a speed faster than 125/s
For further reading i suggest you look up guide numbers and apertures, you can forget about film speed for now, so long as you don’t have it too short for the flash to fire. hope this helps

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One Response to What f/stop and shutter speed to use at a night time crime scene?

  1. Josh Jefferies says:

    Shutter Speed: 1/60
    -Your shutter needs to sync with your flash. 1/60 is an old standard and a safe number. However most new DSLRs can flash sync at 1/125 and 1/250

    Aperture
    f/5.6
    – Your aperture effects depth of field. For forensic photography you will want a lot of depth of field so no evidence is bury. At the same time you do not want too small of an aperture because it is dark. f/5.6 will give you enough depth of field from the tip of your bodies noes to the ground.

    Flash power
    Distance 3 feet/1 meter
    Aperture f/5.6
    (if you are using manual flash you will need a guide number)

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