Question about flash...

controld

Hi All,

I am contemplating a flash unit as the next upgrade to my gear. I have a question I am trying to wrap my head around and I can't seem to find a clear answer online.

Is there a relationship between using a Speedlite flash (I have a 10D) and faster shutter speeds when compared to the builtin flash? The fastest glass I have is a Sigma 28-70 2.8 and it is obviously not fast enough even at 800 ISO to catch people in animated conversation in low light.

Does using an external flash allow you to increase your shutter speed with the light it throws or is it primarily the quality and "fill" of the light you are benefiting from?

I hope this question makes sense... thanks for any insight you can provide.

- Mike

wxwax

Both.

But that's about where my knowledge of flash ends.

An off-camera flash is usually more powerful than your onboard flash, so it has the potential to throw more light over a greater distance. It generally provides a larger light source, which makes for less harsh shadows. And it's off-set from your lens, which also makes less harsh shadows.

Shay Stephens

controld wrote:

Does using an external flash allow you to increase your shutter speed with the light it throws or is it primarily the quality and "fill" of the light you are benefiting from?

You can only increase your shutter speed up to the sync speed, which is around 1/250 +/- on many cameras. The real benefit comes from the flash providing the equivalent of a fast shutter speed. The light only lasts a fraction of a second, and effectively stops the action regardless of the shutter speed you are using.

What you do with the light regarding quality, modifying, etc is an artistic choice.

Shay Stephens

ban the word harsh

wxwax wrote:

...which makes for less harsh shadows. And it's off-set from your lens, which also makes less harsh shadows.

Ban the word harsh from your vocabulary, it is deceptive and damaging to understanding lighting.

There are two kinds of shadows, hard and soft. Hard shadows, the kind you get from a small unmodified light source like a flash head, provide great contrast, are very dramatic, and add zip and sparkle to a photo.

Soft shadows, the kind you get with a large diffused light source lower contrast and provide soothing beautiful photos that hide surface texture, imperfections, etc.

What most people object to in direct, on-camera flash shots is not hard shadows, it's the flat lighting. "Flat lighting" (look it up) is generally boring, ubiquitous, and unflattering for many subjects.

Moving the light up and/or to the side, be it hard or soft, changes the lighting to one that is more flattering (butterfly, loop, etc), shows dimensions, volume, and detail.

Until one can learn the language of lighting, one will be stunted and held back in their growth. And I think *that* learning begins with banning the word harsh from their vocabulary

DavidTO

Shay Stephens wrote:

Until one can learn the language of lighting, one will be stunted and held back in their growth. And I think *that* learning begins with banning the word harsh from their vocabulary

Whoa, Shay. That's harsh.

pathfinder

Harsh indeed.:):

But accurate as well

Antonio Correia

Shay gives always good advices.:):

Shay Stephens

Don't make me do it...


Using the name "harsh" in vain? Oh, you better believe that's a paddlin'

hahahaha

DavidTO wrote:

Whoa, Shay. That's harsh.

wxwax

Shay Stephens wrote:

Ban the word harsh from your vocabulary, it is deceptive and damaging to understanding lighting.

There are two kinds of shadows, hard and soft. Hard shadows, the kind you get from a small unmodified light source like a flash head, provide great contrast, are very dramatic, and add zip and sparkle to a photo.

Soft shadows, the kind you get with a large diffused light source lower contrast and provide soothing beautiful photos that hide surface texture, imperfections, etc.

What most people object to in direct, on-camera flash shots is not hard shadows, it's the flat lighting. "Flat lighting" (look it up) is generally boring, ubiquitous, and unflattering for many subjects.

Moving the light up and/or to the side, be it hard or soft, changes the lighting to one that is more flattering (butterfly, loop, etc), shows dimensions, volume, and detail.

Until one can learn the language of lighting, one will be stunted and held back in their growth. And I think *that* learning begins with banning the word harsh from their vocabulary

Gee, what'd I do to you?

:beatwax

Shay Stephens

Your supposed to say, "thank you sir, may I have another"...sheesh!

hehehe, no, actually, I was using your post as a topic springboard. I tried generisizing, generic-i-sizing, er, making it generic, but it looks like I failed

Sorry if you felt jumped on :

now drop and give me twenty!!!

wxwax wrote:

Gee, what'd I do to you?

:beatwax

wxwax

Revenge shall be mine.

Bob Bell

I'll bow down to the wedding photographer on hard and soft shadows since harse lighting is usually used in relation to a high sun and high contrast conditions.

I am not sure about the 20D and it limits flash guns and what its xsync is.

Flash guns can be used for a lot of things, bouncing creating a soft light for portraits. Using a Better Beamer(fresnel lens) to focus the flash increasing its intensity. And with a 550ex and I assume the 580ex you can use HSS to push the flash duration to a point to stop almost any action.

The thing about flash is its very simple to use, but difficult to master for advanced techniques.

I was testing a 550ex the other day with a 20D and was getting 1/8000 sync in HSS mode. That will stop motion a bullet.

ziggy53

Bob Bell wrote:

... I was testing a 550ex the other day with a 20D and was getting 1/8000 sync in HSS mode. That will stop motion a bullet.

Bob,

Unfortunately, FP mode (Focal Plane), sometimes called, High-Speed Sync (HSS), does not have the stop motion capabilities that many folks think. It is best explained here, http://photonotes.org/articles/eos-flash/#fp, but briefly, in FP mode the motion stopping capability is the same as the shutter-sync. It's just that the slit is much smaller moving across the image plane at 1/8000 sec, but it still completes the motion in the time of shutter x-sync, which varies by camera body, and the e-flash is strobing the entire time. As a result, much of the flash energy is wasted and the resulting equivalent power output is diminished according to the width of the shutter slit.

FP mode is mostly useful in controlling ambient light with subjects that are not moving faster than the x-sync shutter speed can stop.

Most Canon digital SLR cameras sync at 1/200th or 1/250th sec, as does the Nikon D2X. The 1D syncs at 1/500th as do many of the Nikon digital SLRs. (Nikon D100 is 1/180th sec.)

Interestingly ...

Many digicams have no mechanical shutter, and they can legitimately sync at ridiculous speeds. I have regularly synced both a Sony F828 and a KM A2 at very high shutter speeds with full x-sync, and neither has an FP mode.

Also see: http://www.kenrockwell.com/tech/syncspeed.htm#fp and http://www.canon.co.jp/Imaging/flashwork/ettl2/high/index.html for some additional information on FP mode.

ziggy53

Shay Stephens

ziggy53 wrote:

Many digicams have no mechanical shutter, and they can legitimately sync at ridiculous speeds.

Good post!

Cameras with leaf shutters can sync at very high speeds too. There are a number of digicams that fall under that category.

Bob Bell

ziggy53 wrote:

Bob,

Unfortunately, FP mode (Focal Plane), sometimes called, High-Speed Sync (HSS), does not have the stop motion capabilities that many folks think. It is best explained here, http://photonotes.org/articles/eos-flash/#fp, but briefly, in FP mode the motion stopping capability is the same as the shutter-sync. It's just that the slit is much smaller moving across the image plane at 1/8000 sec, but it still completes the motion in the time of shutter x-sync, which varies by camera body, and the e-flash is strobing the entire time. As a result, much of the flash energy is wasted and the resulting equivalent power output is diminished according to the width of the shutter slit.

FP mode is mostly useful in controlling ambient light with subjects that are not moving faster than the x-sync shutter speed can stop.

Most Canon digital SLR cameras sync at 1/200th or 1/250th sec, as does the Nikon D2X. The 1D syncs at 1/500th as do many of the Nikon digital SLRs. (Nikon D100 is 1/180th sec.)

Interestingly ...

Many digicams have no mechanical shutter, and they can legitimately sync at ridiculous speeds. I have regularly synced both a Sony F828 and a KM A2 at very high shutter speeds with full x-sync, and neither has an FP mode.

Also see: http://www.kenrockwell.com/tech/syncspeed.htm#fp and http://www.canon.co.jp/Imaging/flashwork/ettl2/high/index.html for some additional information on FP mode.

ziggy53

Ziggy, That is interesting. When I put the camera in M(Im always in M or AV) and the flash in M I don't see any strobing. I wonder if the flash can strobe faster in HSS than it can in multi. I always thought FP was only in TTL.

ziggy53

Bob Bell wrote:

Ziggy, That is interesting. When I put the camera in M(Im always in M or AV) and the flash in M I don't see any strobing. I wonder if the flash can strobe faster in HSS than it can in multi. I always thought FP was only in TTL.

Bob,

I'm not sure if I understand your question, but the shortest duration for any modern electronic flash unit is in an "auto" mode, flashing across an extremely short distance. I believe this includes E-TTL (Canon) and I-TTL (Nikon) when they are not pre-flashing.

Manual mode can also be extremely fast at extremely small output, i.e. the Sigma 500 Super at 1/128 is probably down around 1/10,000 sec or better. (The full output duration is around 1/700 sec.)

FP/HSS mode causes the flash duration to increase to cover the entire time the shutter curtain is moving, whatever the x-sync is for the given camera. During this time, the flash is strobing at around 50,000 Hz.

If I understand the technology, no guarantees here, the FP mode flashes are triggered by the first curtain signal, and the flash starts strobing at 50,000 cycles-per-second. Either the flash simply times out at 1/150th sec or so, or simply sumps it's entire capacitor, or the second curtain signal shuts down the burst. It's not known which of these technologies are employed, because the manufacturers are strangely not revealing how the technology of their individual flashes work. I only found vague references to any of these methods, so I consider them all to be somewhat suspicious and rumor.

ziggy53

Bob Bell

ziggy53 wrote:

Bob,

I'm not sure if I understand your question, but the shortest duration for any modern electronic flash unit is in an "auto" mode, flashing across an extremely short distance. I believe this includes E-TTL (Canon) and I-TTL (Nikon) when they are not pre-flashing.

Manual mode can also be extremely fast at extremely small output, i.e. the Sigma 500 Super at 1/128 is probably down around 1/10,000 sec or better. (The full output duration is around 1/700 sec.)

FP/HSS mode causes the flash duration to increase to cover the entire time the shutter curtain is moving, whatever the x-sync is for the given camera. During this time, the flash is strobing at around 50,000 Hz.

If I understand the technology, no guarantees here, the FP mode flashes are triggered by the first curtain signal, and the flash starts strobing at 50,000 cycles-per-second. Either the flash simply times out at 1/150th sec or so, or simply sumps it's entire capacitor, or the second curtain signal shuts down the burst. It's not known which of these technologies are employed, because the manufacturers are strangely not revealing how the technology of their individual flashes work. I only found vague references to any of these methods, so I consider them all to be somewhat suspicious and rumor.

ziggy53

Its not a question its an observation that I don't see the flash strobe. If a 550ex is capable of 50,000 cycles a second I would be surprised. I understand how FP works in TTL I just cant find anything about shooting in manually or using only the center pin on the flash to do a straight trigger and not communicate to the flash.

I can't think of a single use that I would every use this for, for me that is, but it is a pretty interesting topic.

ziggy53

Bob Bell wrote:

Its not a question its an observation that I don't see the flash strobe. ...

Bob,

Humans can't distinguish the 30 frames-per-second of television. If you said you could see the strobing action, I would worry about you. :

Bob Bell wrote:

... If a 550ex is capable of 50,000 cycles a second I would be surprised. ...

One of the links I included in the previous post is from Canon itself: http://www.canon.co.jp/Imaging/flashwork/ettl2/high/index.html

On that page Canon explains, "... the FP high-speed sync flash setting fires repeatedly at roughly 50kHz intervals during the exposure to achieve flash synchronization at all shutter speeds." So I guess we can call you "surprised". :

Bob Bell wrote:

... I can't think of a single use that I would every use this for, for me that is, but it is a pretty interesting topic.

You use FP/HSS mode to control ambient light against the light coming from the flash. You can increase the shutter speed beyond normal x-sync speeds, allowing the use of larger apertures. Daylight fill is a classic application. That's a major benefit. Outdoor event photography, as long as you don't exceed the reduced effective distance (reduced effective GN), would benefit greatly, for instance.

It's just not appropriate to use FP mode for, "... stop motion a bullet.", which, by the way, I also mistakedly believed before I researched the technology. (Although, if you "tossed" a bullet into the air, and photographed it at it's apogee, FP mode would be appropriate to control ambient light. )

Thanks,

ziggy53

Bob Bell

ziggy53 wrote:

Bob,

Humans can't distinguish the 30 frames-per-second of television. If you said you could see the strobing action, I would worry about you. :



One of the links I included in the previous post is from Canon itself: http://www.canon.co.jp/Imaging/flashwork/ettl2/high/index.html

On that page Canon explains, "... the FP high-speed sync flash setting fires repeatedly at roughly 50kHz intervals during the exposure to achieve flash synchronization at all shutter speeds." So I guess we can call you "surprised". :



You use FP/HSS mode to control ambient light against the light coming from the flash. You can increase the shutter speed beyond normal x-sync speeds, allowing the use of larger apertures. Daylight fill is a classic application. That's a major benefit. Outdoor event photography, as long as you don't exceed the reduced effective distance (reduced effective GN), would benefit greatly, for instance.

It's just not appropriate to use FP mode for, "... stop motion a bullet.", which, by the way, I also mistakedly believed before I researched the technology. (Although, if you "tossed" a bullet into the air, and photographed it at it's apogee, FP mode would be appropriate to control ambient light. )

Thanks,

ziggy53

Thx again for your explanation