SLR / DSLR Flash sync speed, front / rear curtian, auto-fp.

Here I attempt to walk through what front and rear curtian sync mean, as well as what affect the shutter speed has on your image. Auto-FP is a mode that allows you to shoot at speeds faster than the max flash sync but at a pretty huge cost and usually the opposite the desired effect.
Forcing the camera to shoot the flash at 1/8000s exposure causes a longer flash duration than 1/250s exposure!

Category:

People & Blogs

Tags:

• SLR
• DSLR
• Flash
• sync
• speed
• front
• rear
• curtian
• auto-fp.

[smcs]

i got confused after the 1st flash lesson

[bastian74]

@smcs My animation skills leave sometihng to be desired, and it's a complicated process to explain.

Basically when you set your shutter to faster than the sync speed the shutter becomes more of a scanner than a camera as it lets light in through a slit that moves top to bottom. Think of two overlapping doors, as one opens the other door follows closely behind closing. You never see the whole door open at once, just the slit between them.

[niallswand]

Stupid question -

Can you connect your DSLR to a computer, so when you take photos you can see them appear? So if in a studio, you can review your photos immediately ?

[bastian74]

@niallswand yes, with the nikon capture software, now called nikon nx. pictures are stored on the computer bypassing the cf memory. you can enable real time image review as well, though there is some delay.

[bastian74]

If none of the ambient light is sufficient to "show up" in a 1/250s exposure the exposure will be completely lit from the flash and will be the duration of the flash which is around 1/900s or faster depending on the flash power.

The flash power setting does not change the brigtness of the flash, it changes the duration it fires, the slowest is usually around 1/900. If you exceed the sync speed you force the flash to fire the entire duration the shutter blades are moving

[niallswand]

@bastian74 Thank you very much!

[grazstarr]

awesome. thanks heaps for taking the time to do this!

[kwanyx]

VEry good discription! I bought a Nikon D70s used just for the 1/500 native flash sync.

Also, the D70s has a DOF preview button, 1/8000 sec max shutter speed, LCD panel display light, CF card.

[karatedog]

Thanks, this helped me a lot.

So whatever shutter speed I choose, the longest duration the flash ever needed to be firing (in FP mode) is the time of the minimum non-FP flash shutter speed? (1/250 or 1/320 on Nikons, except D40 where 1/500 because of the electronic shutter)

[shaviezz]

great learning !!! and this kind off video is rare to find...