Stupid question time - flash

[Ari]

Ok so probably another stupid question but here goes.

I'm trying to gain a better understanding of flash photography using a Speedlight rather than the inbuilt flash.

Now I understand that I can vary the power, and obviously I can vary the length of exposure.

But is the actual flash duration fixed, or can that be altered?

[Magic919]

Varying the power is generally achieved by changing the duration.

[Ari]

Aha! Interesting, thank you. That had never occurred to me.

[covboy]

Be careful varying the exposure. Get the shutter speed too slow and the ambient light may affect the result. (sometimes used deliberately for blur effects.)

[Simpo Two]

If you had a long flash it wouldn't be a flash...

In normal photography flash duration isn't important, it is simply 'very fast'. What matters is the power of the flash (not just for correct exposure but to blend with ambient light if required), and at a more advanced level whether it fires at the start of the exposure or the end.


A decent Speedlight will have a strobe function which you might enjoy experimenting with.

[markmullen]

covboy said:

Be careful varying the exposure. Get the shutter speed too slow and the ambient light may affect the result. (sometimes used deliberately for blur effects.)

And too fast and you'll go over the flash sync speed meaning the shutter curtain may appear in the shot as a black bar.

[Magic919]

Don't forget rear curtain sync too.

[Ari]

Brilliant, thank you.

What I'm looking at is the type of photo where the flash freezes something close to the camera and a longer exposure captures movement in the background. Which is why I wondered whether there's a variation in the flash length to consider as well as the exposure.

I've been reading up on second curtain sync and I think I have a handle on that but the book I have doesn't really go into all the other controls. There just seems to be a lot going on on the back of the flash and I was wondering what it all does to be honest!

SEL seems to allow me to adjust the power (although from the post above that appears to work by affecting duration), there's obviously the two sliders that adjust the amount of angle and how it meters, beyond that I'm a bit lost...

[Simpo Two]

Time to read the manual

It is very complicated... but there's no other way to understand it all.

[Ari]

RTFM! But but... I'm a bloke!

Ok, here's a maybe easier one. what is "flash sync speed" and "flash shutter speed" in the camera menu?

[Magic919]

I would look for a book on the topic. Simon Stafford did one, though aimed at D7000 owners. He is a good writer and knows his stuff.

[Ari]

I bought one specifically on flash photography but it doesn't seem to go into much depth on the more technical aspects.

[Magic919]

Is it Nikon Speedlight specific!? That's what I'm recommending.

[Simpo Two]

Ari said:

Ok, here's a maybe easier one. what is "flash sync speed" and "flash shutter speed" in the camera menu?

The flash synch speed is the maximum shutter speed the flash can synchronise with (ie go off while the shutter is open). It's usually around 1/200th second. Any faster than that and the flash can miss the open shutter giving a black or partially black frame. Unless you have High Speed Flash mode which synchs faster but has less power.

Not sure how flash shutter speed is different - maybe its the high speed function. Hey, look it up in the index!

You won't learn all the functions by poking and prodding.

[Pickled]

Ari said:

RTFM! But but... I'm a bloke!

Ok, here's a maybe easier one. what is "flash sync speed" and "flash shutter speed" in the camera menu?

Sync speed on most Nikons is 1/250, although this can be upped by putting it into auto FP, but you lose a lot of power, increasing the exposure time lets more ambient in.

Flash shutter speed is the slowest speed your shutter will fire with flash, normally set on 1/60th but can be as long as 30s, but think it only applies in certain modes - front or rear curtain sync, and in P or A, there are others combinations but cant recall them off the top of my head.

For a good understanding of Nikon CLS I really recommend any of Joe McNally's books, I've got The Moment it Clicks and Hot Shoe Diaries, both make it simple to understand in a non techy way.

Edited by Pickled on Wednesday 13th March 17:45

[Magic919]

The point about the highest sync speed for normal flash is it's the highest speed that the front curtain fully opens before the rear curtain starts to close. Above that speed, without strobing, you get a partially obscured frame.

[Simpo Two]

Pickled said:

Flash shutter speed is the slowest speed your shutter will fire with flash, normally set on 1/60th

Oh that one. Yes, I have it set to 1/60th. It's not a 'real' setting as such but a custom function added by Nikon. As well as the flash manual, go through the camera manual and gasp at all the custom functions.

[Pickled]

Simpo Two said:

Oh that one. Yes, I have it set to 1/60th. It's not a 'real' setting as such but a custom function added by Nikon. As well as the flash manual, go through the camera manual and gasp at all the custom functions.

Even pressing the info button on the back of the camera can help sometimes

[cornet]

Site recommendations for you.

For on camera stuff start here:

http://neilvn.com/tangents/flash-photography-techn...

link to next article is always at the top (next one is "natural looking flash")


Then once you've mastered that lot it's time for off camera flash:

http://strobist.blogspot.co.uk/2006/03/lighting-10...



There is quite a lot to take in at first but will start to make sense... Any questions then ask away

[Simpo Two]

I think 'off-camera' flash in this context is over-rated. If you want to get creative, buy proper studio lights (not expensive these days thanks to those Chinese fellows) and do it manually. Proper power, proper modifiers, much easier.