Flash-Sync vs FP mode flashes - DPChallenge Forums

08/08/2006 10:49:40 PM · #1

Ok, so I'm still working on making my decision on what flash to get, but it's got me thinking about this FP mode thing...

A lot of higher end flashes have a FP (Flash Pulse) mode which allows a kind of 'sync' for speeds up to 1/4000 or thereabouts...

Now I'm guessing that the function of this is something along the lines of firing multiple flash pulses expecting to miss a couple of pulses, but having most of them actually fire appropriately.

But I have no idea in reality.

I'm actually a little concerned about the possible issue here of strength because 1/4000 is starting to get fast enough that it might even start to encroach on the flash output especially when you are trying to balance against sunlight.

Does anyone have any good information here?

The reason I am asking is that I keep seeing people praising CCD's for their electronic shutter and its faster sync speed of 1/500. My brain is telling me that FP flashes render this totally unimportant AND insignificant, as the difference between 1/250 and 1/500 is one stop, but the difference between 1/500 and 1/4000 is three stops.

To be honest, if there is anyone that actually thinks this is a major issue with a camera probably ought to have an additional hotshoe type flash and most of the better ones do seem to have this function...

?

fotomann_forever

08/08/2006 11:14:20 PM · #2

I'm clueless, but here's a bump.

Canon EF 70-200mm f/2.8L USM

08/08/2006 11:53:37 PM · #3

BUMP!

I really want to know!

hsteg

Fujifilm X-T20

08/09/2006 12:15:30 AM · #4

Originally posted by eschelar:

FP flash doesnt fire nearly as powerful as a normal flash does.

08/09/2006 07:32:40 AM · #5

I was guessing that.

Is it enough to use as fill flash? If not, what is its purpose?

Not many other purposes aside from high shutter speed bright light fill flash for 1/4000 sync speed...

hopper

Canon EOS-80D

Canon EF 35mm f/2 IS USM

08/09/2006 08:03:08 AM · #6

FP mode flash solves this problem by letting the shutter speed exceed the X-sync limit and reach the cameraâ��s maximum shutter speed (usually 1/2000 or 1/4000 sec) instead. The primary drawback is that pulsing the light causes a reduction in overall light output and thus range.

When you have FP mode engaged you typically get about a third less range than you would if you were shooting with normal flash. With a powerful flash unit like the 580EX this may not be a big problem, particularly if your flash subject is fairly close to you. But this loss of range could be a serious impediment if youâ��re using a smaller flash unit (eg: the tiny 220EX), if the subject is far away, or if youâ��re using slow film. Of course, if youâ��re using FP mode simply for a little fill flash (rather than relying on it to illuminate your subject) then this loss of range shouldnâ��t be a huge problem.

taken from here

Message edited by author 2006-08-09 08:04:08.

Sigma 30mm f/1.4 EX DC HSM for Nikon

08/09/2006 12:17:30 PM · #7

Thanks for the link hopper. had a good bit of a read there...

No real surprises though.. I kinda understand the way FP works...

What I'm wondering is how well it works in practice...

How about on a bright sunny day...

Will I have to bring my maximum range down by a third, by a ninth by a sixteenth?

How will it affect my range in real terms... Sunlight at midday is fairly predictable in terms of brightness...

How well does it work? The shutter blades will be very close together at 1/4000, so how will the FP thing work out... No banding, fairly even?

Thanks!

ShaneBlake

Nikon D7100

08/09/2006 12:28:42 PM · #8

seems to me that any pulsing would render this useless for stopping motion... it would just cause ghosting...

if you're wanting this for fill flash in bright sunlight, it also seems to me that it would be easier to simply use a nutral density filter to get a slower shutter speed...

of course, i could be completely wrong on this...

hyperfocal

Nikon D7000

Nikon MF 105mm f/2.5 AIS

08/09/2006 12:32:06 PM · #9

I'm not familar with the Canons, but with Nikon's D70 (or any other camera with CCD electronic shuttter) flash sync can be at any shutter speed. This is not a FP (pulsing mode) so the only limitation is if the flash duration excedes the length shutter speed (that would cause calculated or auto exposure to be off). Newer Vivitar 283s have a sync voltage below 10 volts, and are excellent flashes with lots of power and accessories. Nikon flashes can not work in this manor unless all but the center sync contact is covered by tape, so it is obvious that for some reason they don't want it as a feature.

hankk

Canon EOS-5D

Sigma 24-70mm f/2.8 EX Aspherical DF for Canon

08/09/2006 12:40:21 PM · #10

Here's an example of FP flash in another forum
//www.fredmiranda.com/forum/topic/434726

Mr_Pants

SiPix Blink

08/09/2006 12:52:24 PM · #11

Originally posted by hyperfocal:

The key feature there is the electronic shutter, where the sensor is actually exposed completely, rather than the focal plane shutter, where only a portion of the sensor is actually exposed at any instant (at high shutter speeds, anyway).

Mr_Pants

SiPix Blink

08/09/2006 12:58:19 PM · #12

FP mode (I always thought it was 'Focal Plane' mode) works fine as fill-flash for portrait shots as far as I have seen. With the Canon units, FP mode remains engaged all the time, whereas with the Sigma 500, if the shutter speed falls below 1/200, FP mode is cancelled. That latter is a bit of a pain, as then the camera refuses to select a higher shutter speed until FP mode is engaged again.

Sigma 30mm f/1.4 EX DC HSM for Nikon

08/10/2006 12:19:16 AM · #13

Originally posted by kudzu:

Yes, I realize that flash pulse would not be used for stopping motion. If you read up, you will see that we are specifically talking about:

Originally posted by eschelar:

Not many other purposes aside from high shutter speed bright light fill flash for 1/4000 sync speed...

What I was wondering though is perhaps if in certain motion shots (such as jumping or running on a sunlit day), perhaps the ghosting you mentioned might become a bit of an issue...

Using a neutral density filter for slowing down the shutter speed is not the same thing as fill flash... Fill flash helps to increase the light in the shadows. Shadows are defined as areas not lit by a primary or specific light source.

Outside, there is all kinds of secondary light bouncing around which allows our eyes to see shadow areas fine, but cameras don't have as wide a dynamic range, so the difference in light is accentuated, leaving strong and harsh shadows.

Fill light fills these in from the direction of the camera.

An ND filter will decrease the overall light coming into the camera, but will not address the actual issue which is the DIFFERENCE in the BALANCE of the amount of light in the shadows compared with the light in the lit areas.

Hyperfocal - quite so. This thread is about trying to figure out if this is really a major benefit or not... There seems to be a lot of information and a lot of very strong opinions about the importance of this feature. To my mind, it is a benefit and a very cool thing indeed, but it's not really a major one... It will only become a major benefit in my eyes when I can see that using FP mode is insufficient... The stunning photo posted by Hankk shows me that it's probably pretty damned sufficient albeit a bit battery hungry. The flash units that use FP mode don't seem to be significantly more expensive than Nikon units.

If it is a major benefit, it might be worthwhile to pick up a Nikon D70 as a second body just for that very reason.

Hankk - great link with an excellent example thanks. Any more that address the issue of fast moving subjects and the possibility of ghosting?

AJAger - the first link in this thread has a bit of info on the reason it's called Flash Pulse mode...

Have you used it outdoors?

Thank you very much for the real-world use report. That's very useful.

ShaneBlake

Nikon D7100

08/10/2006 01:16:04 AM · #14

Originally posted by eschelar:

Using a neutral density filter for slowing down the shutter speed is not the same thing as fill flash...

perhaps i didn't quite make clear what i ment... yes, using fill flash and cutting light w/ a nutral density arn't the same thing... obviously...

my suggestion was to use both in conjuction... use the flash for fill, but use a ND filter to cut down the shutter speed to your camera's top sync speed (1/250 on the 30D, yes/no?)

ND cuts _all_ the light, slowing down the shutter into optimal sync range... flash provides fill and you get your desired "DIFFERENCE in the BALANCE"

unless, of course, you really need 1/4000, which i can't see the need for unless your stopping motion, really... or have _really_ shakey hands...

Nikon AF Zoom-Nikkor 70-200mm f/2.8 VR DG IF-ED

08/11/2006 12:36:55 AM · #15

Now I understand your meaning a bit better. Thanks.

Correct. the 30D is 1/250.

If I have an aperture where I would want to use 1/4000, and I wanted to bring that down to 1/250, that would mean 4 stops. That's a pretty significant amount of filtering.

That just seems like a clumsy way of dealing with things, mucking about with filters for changing light situations.

I already have some ND filters for this of course.

erschmitt

Nikon D200

08/12/2006 12:51:15 PM · #16

//www.naturescapes.net/082006/rp0806.htm

There's another page with some info on the High Speed sync modes of canon/nikon.