I don't get it...

[OrionsByte]

Just one thing to add to what smarter minds than me have already mentioned - it looks like the background has got a touch of motion blur to it in the 2nd and 3rd shots as well (in addition to being intentionally out of focus due to depth of field), so I'm gonna say there is an element of camera shake involved here as well.

 

[paigew]

Just one thing to add to what smarter minds than me have already mentioned - it looks like the background has got a touch of motion blur to it in the 2nd and 3rd shots as well (in addition to being intentionally out of focus due to depth of field), so I'm gonna say there is an element of camera shake involved here as well.

You know I bet that is it.... I am not a very still shooter, I tend to chase around my subjects :blushing:

 

[robbins.photo]

Ok, well I think everybody overlooked the obvious on this one. Demonic possesion. Oh ya, sweet and innocent and adorable one second, blurred out of control engine of death the next.

Hmm.. then again that could just be my kids.. lol

 

[Derrel]

Whats weird is you can SEE the catchlights from the flash in the 2nd blurry shot so I know it fired.....right?

Yes, the flash was firing. A few posts up jaomul remarked that, "It looks like a mutliple exposure"? That's because it **is** a multiple exposure, in a manner of speaking.

This image fault is called ghosting; look at the second image large; see the faint "ghosting" on her green shirt sleeve and below her elbow? In shot #2, look at her left hand; the red writing is visible "through" her left hand, which was moving during the ambient exposure, but was frozen by the flash.

At 800, 100>200>400>800...you have in effect, made the flash "eight times more powerful" than it is at ISO 100.

 

[Gavjenks]

So I guess I am wondering how I prevent this? I supposes allow less ambient :*(

Easiest way would be to slip a couple of Valium in the children's lunch-time milk before the shoot so they don't move as much, but failing that, yeah, you could expose for strobed light only!

No just use this

 

[KmH]

I highly recommend setting rear/second curtain sync for shooting animate/moving subjects.

 

[Overread]

KmH how does that work?

If you've got a duel exposure of flash and ambient then any motion will blur no matter if the flash fires first or second. I guess a second firing might over-right some of the blur with the flash component, but I'd still expect the lines to be blurred.

 

[paigew]

KmH how does that work?

If you've got a duel exposure of flash and ambient then any motion will blur no matter if the flash fires first or second. I guess a second firing might over-right some of the blur with the flash component, but I'd still expect the lines to be blurred.

I'm interested to hear more as well.

 

[480sparky]

EXIF data will tell if not only the flash fired, but whether any return light was detected.

 

[Derrel]

KmH how does that work?

If you've got a duel exposure of flash and ambient then any motion will blur no matter if the flash fires first or second. I guess a second firing might over-right some of the blur with the flash component, but I'd still expect the lines to be blurred.

I'm interested to hear more as well.

In the situation in this post, there needed to be an exposure correction. Using a setting like say, ISO 100 at 1/200 second at f/5.6 to f/8 would have dropped the ambient light wayyyyyy down, and the shots would have been exposed by the flash.

If you have a higher-end flash meter, you can use it to calculate the PRECISE percentage of flash and the precise amount of flash exposure.

Lacking a flash meter, the easiest thing to do is to shoot a test frame with the flash turned OFF, and look for a very dark, weak exposure; that is what you want on the foreground subject, the child. Of course, the windows in this setting would be fairly bright, since they are actual sources of light.

Alternately, you could also dial the flash wayyyyyyyy down, about three stops below the ambient exposure, so the flash is just enough to fill in the shadows a little bit.

In the example shots, there "are no shadows", because the flash is so powerful that all the shadows are nuked.

Here's the basic issue Sekonic Support FAQs: Balancing flash with daylight/fill flash

Here's a page that has links to several Sekonic-sponsored articles on how to avoid this type of problem:
Fill-Flash Tutorial

Again--this is a great example of why owning a flash-capable light meter can avoid disasters.

 

[Overread]

But Derrel that doesn't explain why one should use rear-curtain sync with moving subject and flash dominate lighting as it will still blur.


Although thinking on it I guess KmH means that at least the blur will lead into the sharp content so it seems more deliberate; but it would have to be motion with a driving direction and a clear single direction of motion rather than, for example, a shake.

 

[astroNikon]

Derrel / John - Are the older Minolta IV / V flash capable light meters?

I was going to get one because, well .. WTH 'ya know. I've been using the iphone light meter software but have been thinking of getting one to understand more.

I try to stay above 1/200 so this thread was very interesting to read.

 

[Robin Usagani]

Rear curtain flash does not accomplish anything other than reversing the placement of the blurred shadow. If the kid is just moving left and right, it will just be the same shot rear curtain or not. If the kid is running one direction, then yes I agree that rear curtain will improve the photo because the shadow is behind the kid instead of in front of the kid.

derrel's assessment is spot on.

 

[pgriz]

I get that problem when I shoot in Av mode with flash - the camera exposes for the ambient light, regardless of the flash firing. If my flash didn't charge enough to fire, the camera will still take the shot, but without the flash it will adjust the shutter speed to whatever it thinks is needed for the amount of ambient, and I do get blur. I find that shooting in manual + ETTL gives me better control of the exposure, with the manual exposure being whatever I decide is appropriate for ambient, and the flash computing its power level through the pre-flash.

 

[paigew]

Okay am I not getting something here?...why are the first and fourth photos totally sharp. At the same settings, same subjects not even a second apart.

I personally like the fact that there is very little flash. I exposed for the ambient and then added flash (ttl). I bounced the flash off my left shoulder to fill (there was a bit of light on her left side from a window). With ambient only the iso would have had to have been 6400, probably more. Maybe I am going about things wrong....

Oh I always shoot Manual mode on my camera