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Arthur Morris
06-21-2008, 06:45 PM
This thread originally appeared in Avian Free & Wild. Scroll down to learn how to set High Speed Synch on the Canon 580 flashes. I will ask James Shadle to let us know how that works with Nikon flashes. Users of older Canon or other brand flashes will need to consult their flash instruction manuals.

In a Zodiac on a rough morning with a huge feeding spree going on and gannets right above the boat, I created this image with the Canon 70-200mm f/4L IS lens (handheld at 100mm) and the EOS-1D MIII. Evaluative Metering +1 2/3 stops. Manual Flash at 1/1 with the Better Beamer.

I went with the flash at full power because when using High Speed Synch the flash output is cut drastically.

All comments welcome; don't be shy.

Vincent Grafhorst
06-22-2008, 05:23 AM
Nice image Artie. Looking at your settings I would have thought this would turn out completely over exposed, even with high sync. What was your Aperture and SS, did you use aperture priority or manual mode? Maybe a silly question but what is the advantage of using manual flash in this case? Isn't it more controllable to use ETTL (with a higher output)? Thanks.

Arthur Morris
06-22-2008, 05:48 AM
Nice image Artie. Looking at your settings I would have thought this would turn out completely over exposed, even with high sync. What was your Aperture and SS, did you use aperture priority or manual mode? Maybe a silly question but what is the advantage of using manual flash in this case? Isn't it more controllable to use ETTL (with a higher output)? Thanks.

1/2500 at f/4. (I was sure that I posted that...) I was in Av mode for this image. The advantage of using manual flash at 1:1 as I understand it is that the flash is putting out full power. At 1/2500 sec. the flash needs to fire three times (with High Speed Synch). Thus, as above, flash output (and therefore its range) is drastically reduced. This technique really works well on sunny days. In dull conditions I often use the flash in ETTL at -1 or zero and shutter speeds from 1/500 to 1/1250 sec., but here I wanted a really fast shutter speed as the boat was rocking.

Eleanor Kee Wellman
06-23-2008, 07:25 AM
Artie,

Another flash question.

Did you have the flash on the camera hotshoe? Did you use a Better Beamer or other device?

Eleanor

Arthur Morris
06-23-2008, 07:45 AM
Artie, Another flash question. Did you have the flash on the camera hotshoe? Did you use a Better Beamer or other device? Eleanor

I no longer use a flash bracket when doing handheld flight with intermediate telephoto lenses; the flash goes right in the hot shoe. Bad for sales :) but much lighter and easier to work with. With a flash bracket, there is a lot of torque which makes things tough. I did use a Better Beamer as noted in the original post.

MichaelAlmon
06-24-2008, 09:13 PM
1/2500 at f/4. (I was sure that I posted that...) I was in Av mode for this image. The advantage of using manual flash at 1:1 as I understand it is that the flash is putting out full power. At 1/2500 sec. the flash needs to fire three times (with High Speed Synch). Thus, as above, flash output (and therefore its range) is drastically reduced. This technique really works well on sunny days. In dull conditions I often use the flash in ETTL at -1 or zero and shutter speeds from 1/500 to 1/1250 sec., but here I wanted a really fast shutter speed as the boat was rocking.
Dear Artie,

First time visitor to this site so please bear with me:-) I am a little confused at reading "1/2500 at f/4 in AV mode. I just tried Av mode and when I put my 580EX flash (in manual mode) on my Mark IIn on AV f4, it goes automatically to shutter speed of 1/250. I don't understand how you can get a shutter speed of 1/2500 in AV mode with the flash set on manual mode?

Sharna Lee
06-24-2008, 09:26 PM
Artie,
What a wonderful shot. I too was wondering what the settings were. Thank you for the details in your later post. I really am very excited about learning all of this stuff. I can't wait for your book ABPII to arrive, nor can I wait for your first book ABPI to be reprinted.
I love the colors in these shots. That bird is so photogenic isn't it? hehehe You've done a masterful job of portraying this species and I look forward to all of your posts. Excellent job on getting both eyes here. They really stand out. As for the flash, COOL! I'll have to try that. As mentioned when you put the flash on the camera it does drop the shutter speed to 250 but off camera manually is a very brilliant idea. Thanks for sharing this info with us. You ROCK!!

Sharna

Arthur Morris
06-25-2008, 05:43 AM
Dear Artie,

First time visitor to this site so please bear with me:-) I am a little confused at reading "1/2500 at f/4 in AV mode. I just tried Av mode and when I put my 580EX flash (in manual mode) on my Mark IIn on AV f4, it goes automatically to shutter speed of 1/250. I don't understand how you can get a shutter speed of 1/2500 in AV mode with the flash set on manual mode?

Hi Michael, No probelma; we are here to help. You missed the fine print: High Speed Synch. In order to get your camera to fire at shutter speeds higher than your camera's synch speed, you need to set High Speed Synch on your flash. In the row of four buttons on the back of the flash, the third one, from left ot right, is the High Speed Synch/Rear Curtain button. Depress it once and the HIgh Speed Synch symbol (a lightening bolt in front of a small capital H) appears either to the right of the ETTL symbol or just above and to the left of the Manual Flash ratio, for example 1:1. Press it again and the Rear Curtain Synch symbol appears just above and on the left side of the distance range scale. Perss it again and neither symbol appears.

Once the High Speed Synch symbol appears, you will be able to set shutter speeds higher than the camera's synch speed. Here's how High Speed Synch works: If your camera's synch speed is 1/250 sec., and you set your shutter speed to 1/500 sec., then the flash has to fire twice during the exposure. And so on and so forth as you choose higher and higher shutter speeds. Heres the rub: the higher the shutter speed that you choose, the more the flash output is reduced. That is why I almost always set the flash to 1:1 in Manual Mode when do High Speed Synch flight flash; in effect, the flash is going nowhere at 1/2500 sec so you mazimize the flash output by setting 1:1 (full power) in Manual Mode.

I am going to copy this thread to Educational Resources and title it High Speed Synch. Thanks for asking a good question.

Arthur Morris
06-25-2008, 05:51 AM
Artie, What a wonderful shot. I too was wondering what the settings were. Thank you for the details in your later post. I really am very excited about learning all of this stuff. I can't wait for your book ABPII to arrive, nor can I wait for your first book ABPI to be reprinted. I love the colors in these shots. That bird is so photogenic isn't it? hehehe You've done a masterful job of portraying this species and I look forward to all of your posts. Excellent job on getting both eyes here. They really stand out. As for the flash, COOL! I'll have to try that. As mentioned when you put the flash on the camera it does drop the shutter speed to 250 but off camera manually is a very brilliant idea. Thanks for sharing this info with us. You ROCK!!
Sharna

Hey Sharna, Thanks for your kind words. Do read the High Speed Synch explanation just above as you are slightly confused: It is the setting of High Speed Synhch on the flash that allows the use of the higher shutter speeds...

James Shadle
06-25-2008, 11:00 AM
The Nikon set up High Speed Flash is very straight forward.

The setting is on the body and not the flash.
Go to the custom function menu, select "Bracketing / Flash"
Under "Bracketing / Flash", select "Flash Sync Speed"
Under "Flash Sync Speed" select 1/250s (Auto FP) or 1/320 (Auto FP).

The maximum flash sync speed depends on your camera and maximum flash sync speed is the factory default. To use High Speed Flash aka FP it must be enabled to work on Nikons

It's that easy. When using a Nikon High Speed capable flash, it will default to high speed mode when your shutter speeds exceeds the normal maximum sync speed.

The back panel of the flash will display "FP" to indicate "High Speed Flash" is enabled.

James

John Chardine
06-26-2008, 11:28 AM
Artie- I have noticed the torque with the Mongoose flash extension arm which ruins the nice balance you have with the head and makes it critically important to always remember to tighten the gimbal before moving. So you have given me a thought which I suppose I should test- what about mounting the flash on the camera bracket for long-lens photography as well- say the 500 F4?? I predict the main problem might be red-eye/steel eye but I am getting this occasionally anyway with the arm. What do you think?

PS I have tried the physics of mounting flash and beamer on camera bracket and it is all very easy to balance again and produces no catastrophic flopping of the lens.


I no longer use a flash bracket when doing handheld flight with intermediate telephoto lenses; the flash goes right in the hot shoe. Bad for sales :) but much lighter and easier to work with. With a flash bracket, there is a lot of torque which makes things tough. I did use a Better Beamer as noted in the original post.

Stuart Dahne
06-26-2008, 01:58 PM
Hey Artie,
I found this thread when looking for some info on how to use the Better Beamer. I bought one from you quite some time ago and gave up on it with absolutely no success. I shoot with an MkIII, a 580EX, and either a 100-400 f/4.5-5.6 or a 70-200 f/2.8 and I sometimes use a 1.4 tele.
Are there any tutorials on the Better Beamer? Quite frankly I haven't had any luck with the MkIII and the 100-400 with or without the flash. Its been back to Canon and they say that everything is "within specifications"! whatever that means? However I have had this Better Beamer and I would like to give it a try again.
Thanks in advance,
Stuart

Arthur Morris
06-26-2008, 05:50 PM
Hey John,

You have confused me...

I have noticed the torque with the Mongoose flash extension arm which ruins the nice balance you have with the head and makes it critically important to always remember to tighten the gimbal before moving.

That is always a good plan with or without the flash... Are you saying that there is more torque with the flash on the Mongoose Integrated Flash Arm than there is with no flash mounted? As for the nice balance with the head, that happens with the Mongoose 3.5 and the 500mm f/4 lens only with certain camera bodies. And even then, when you add a TC that balance is off a bit. With either Wimberley head, you can raise or lower the platform so that the rig will sit like a dog when you point it up or down. Most folks are not that careful... With the Mongoose what you get is what you get. In other words, you are almost always gonna get some front to back torquing. I live with that as a trade-off for the incredibly light weight of the 3.5.

So you have given me a thought which I suppose I should test- what about mounting the flash on the camera bracket for long-lens photography as well- say the 500 F4??

Do you mean in the camera's hot shoe???

I predict the main problem might be red-eye/steel eye but I am getting this occasionally anyway with the arm. What do you think?

The closer the flash is to the center line of the lens the more the chance of eye shine in one form or another. And the lower the light levels the more chance of eye shine. Furthermore, I am fairly sure that there will be a front to back torque problem whereever you mount the flash. It will of course be marginally more with the flash higher.

PS I have tried the physics of mounting flash and beamer on camera bracket and it is all very easy to balance again and produces no catastrophic flopping of the lens.

As Joe Pesci said in "My Cousin Vinnie," "Are you saying that the laws of physics were suspended when you cooked your grits???" I would need to see that in person...

Arthur Morris
06-26-2008, 05:56 PM
Hey Artie, I found this thread when looking for some info on how to use the Better Beamer. I bought one from you quite some time ago and gave up on it with absolutely no success. I shoot with an MkIII, a 580EX, and either a 100-400 f/4.5-5.6 or a 70-200 f/2.8 and I sometimes use a 1.4 tele.
Are there any tutorials on the Better Beamer? Quite frankly I haven't had any luck with the MkIII and the 100-400 with or without the flash. Its been back to Canon and they say that everything is "within specifications"! whatever that means? However I have had this Better Beamer and I would like to give it a try again. Thanks in advance, Stuart

Hi Stuart, Hate to be brutal, but the fact is that if someone does not know how to use flash and they put the beamer on they still do not know how to use flash... Imagine a bucket that shuts the water off when it is full. It does not matter if you use a skinny hose or a fat hose, when the water gets to the top of the bucket it shuts the hose off. All the Better Beamer is is a fatter hose. When you are using ETTL and the amount of flash that you have set is reached, the flash turns off. Thus, there is no need for a BB tutorial.

To learn the basics of flash as fill and flash as main light, I would humbly suggest that you get a copy of ABP II and study the "Flash Simplified" section. And from the rest of your questions it would seem that the other 900+ pages of my CD book would be of great help to you.

Respectfully posted.

John Chardine
06-26-2008, 07:15 PM
Artie- All I'm saying is- what if you mounted the flash/beamer combo on the camera hot shoe when using a super tele like the 500, as you do with the 70-200? Is there something about do this with a super-tele that causes problems compared to your experience with the smaller tele-zoom?

I have no problem at all balancing the 500 and the 40D on the Mongoose. Just find the right place fore and aft to fit the Arca-Swiss plate on the Mongoose and you are away. If you add more weight to the camera end, like a 1.4 tc, just slide the plate forward a little. As suggested in the Mongoose instructions, I have nick-marks on the plate which I line up depending on whether I have the tc attached or not. Either way the system sits like a dog as you say, at all angles. I will soon add a battery grip to the 40D and expect that there is enough room on the plate to move the rig forward again to another balance point. The problem with the extender arm is that suddenly you are placing a mass some distance away, and right above the pivot point on the Mongoose. If you have the system balanced, as you tip the lens forward, the flash eventually wants to pull the system more forward with nothing to counteract this. Same if you tip the lens back. The distance the flash is from the pivot point gives it quite a bit of leverage. I like a balanced system at all lens angles in case I forget to tighten the Mongoose.



Hey John,

You have confused me...

I have noticed the torque with the Mongoose flash extension arm which ruins the nice balance you have with the head and makes it critically important to always remember to tighten the gimbal before moving.

That is always a good plan with or without the flash... Are you saying that there is more torque with the flash on the Mongoose Integrated Flash Arm than there is with no flash mounted? As for the nice balance with the head, that happens with the Mongoose 3.5 and the 500mm f/4 lens only with certain camera bodies. And even then, when you add a TC that balance is off a bit. With either Wimberley head, you can raise or lower the platform so that the rig will sit like a dog when you point it up or down. Most folks are not that careful... With the Mongoose what you get is what you get. In other words, you are almost always gonna get some front to back torquing. I live with that as a trade-off for the incredibly light weight of the 3.5.

So you have given me a thought which I suppose I should test- what about mounting the flash on the camera bracket for long-lens photography as well- say the 500 F4??

Do you mean in the camera's hot shoe???

I predict the main problem might be red-eye/steel eye but I am getting this occasionally anyway with the arm. What do you think?

The closer the flash is to the center line of the lens the more the chance of eye shine in one form or another. And the lower the light levels the more chance of eye shine. Furthermore, I am fairly sure that there will be a front to back torque problem whereever you mount the flash. It will of course be marginally more with the flash higher.

PS I have tried the physics of mounting flash and beamer on camera bracket and it is all very easy to balance again and produces no catastrophic flopping of the lens.

As Joe Pesci said in "My Cousin Vinnie," "Are you saying that the laws of physics were suspended when you cooked your grits???" I would need to see that in person...

Robert O'Toole
06-26-2008, 07:57 PM
John I find the same thing with the 600x40DxMongoose M3.5X low profile foot with flash arm and flash. You have to be careful and keep the tilt control tightened when you step away from the rig or take your hands off of it.

You can use the cameras hotshoe to mount the flash but you will have more problems with flash eye/red/green.


Robert

Robert O'Toole
06-26-2008, 07:59 PM
The Nikon set up High Speed Flash is very straight forward.

The setting is on the body and not the flash.
Go to the custom function menu, select "Bracketing / Flash"
Under "Bracketing / Flash", select "Flash Sync Speed"
Under "Flash Sync Speed" select 1/250s (Auto FP) or 1/320 (Auto FP).

The maximum flash sync speed depends on your camera and maximum flash sync speed is the factory default. To use High Speed Flash aka FP it must be enabled to work on Nikons

It's that easy. When using a Nikon High Speed capable flash, it will default to high speed mode when your shutter speeds exceeds the normal maximum sync speed.

The back panel of the flash will display "FP" to indicate "High Speed Flash" is enabled.

James


Dont forget some of the lower end Nikons have different syncs, the D70 has an electronice shutter and can do 1/4000 without FP. Also the D40 has 1/500 top sync but the D40X has a lower sync.

Robert

Robert O'Toole
06-26-2008, 08:03 PM
Heres the rub: the higher the shutter speed that you choose, the more the flash output is reduced. That is why I almost always set the flash to 1:1 in Manual Mode when do High Speed Synch flight flash; in effect, the flash is going nowhere at 1/2500 sec so you mazimize the flash output by setting 1:1 (full power) in Manual Mode.


Artie I have seen 580EX output tests that 1:1 power in HSS is equal to about 1:8 power in normal mode.

FYI


Robert

Stuart Dahne
06-26-2008, 10:19 PM
Artie,
I can take brutal, thats why I asked. Flash is one of my weakest spots although I am not bad with it on macro. I will take your cue and order your CD first thing tommorrow morning! Thanks & I will keep you posted as I attempt to learn more!
Thanks Again,
Stuart Dahne

Arthur Morris
06-27-2008, 05:50 AM
Artie, I can take brutal, thats why I asked. Flash is one of my weakest spots although I am not bad with it on macro. I will take your cue and order your CD first thing tommorrow morning! Thanks & I will keep you posted as I attempt to learn more! Thanks Again, Stuart Dahne

You are both welcome and a smart man. Once you have studied the CD, get in touch here if you need anything clarified.

Francis Bossť
07-02-2008, 06:56 AM
Hi Artie,

I'm a bit confused with your explanation of how High Speed Synch works... I always thought in High Speed Synch the flash was actually firing constantly at 50 KHz for the full duration of the shutter opening.

Here a link: http://photonotes.org/articles/eos-flash/index.html#fp

What you think??? This reference is good???

Thanks,

James Shadle
07-02-2008, 11:57 AM
Dont forget some of the lower end Nikons have different syncs, the D70 has an electronice shutter and can do 1/4000 without FP. Also the D40 has 1/500 top sync but the D40X has a lower sync.

Robert

However the D70 and D40X are not FP compatible.

Arthur Morris
07-17-2008, 09:32 AM
Hi Artie, I'm a bit confused with your explanation of how High Speed Synch works... I always thought in High Speed Synch the flash was actually firing constantly at 50 KHz for the full duration of the shutter opening. Here a link: http://photonotes.org/articles/eos-flash/index.html#fp (http://photonotes.org/articles/eos-flash/index.html#fp) What you think??? This reference is good??? Thanks,

It took me a while to hear from Chuch Westfall but it turns out that Francis is indeed correct and that I was wrong. It is however, correct to state that the faster the HS Synch shutter speed, the less the effect of flash on the image will be.

Here are the three e-mail exchanges with Chuck:

Hi, Artie:
Your reader is correct. High-speed sync works by firing the flash at an extremely rapid rate for the entire duration of the exposure. It effectively turns the flash into a constant light source when used at shutter speeds higher than maximum X-sync speed, which is 1/250 for the 40D and the 1D series digital SLRs. It has to be that way in order to provide even illumination across the frame as the moving slit of the focal plane shutter executes the exposure. That's also why the exposure level drops as the shutter speed increases, because you are in effect reducing the amount of time that the light is reaching the sensor.
You can see a diagram that shows the difference between standard flash exposure and high-speed sync in our Flash Work web site here:http://web.canon.jp/imaging/flashwork/ettl2/high/index.html (wlmailhtml:{77FAFFD2-E675-42EF-82DE-55A22E44257D}mid://00002608/!x-usc:http://web.canon.jp/imaging/flashwork/ettl2/high/index.html). The bottom line, the 'high speed' in high-speed sync refers to shutter speed, not flash duration.
Best Regards, Chuck Westfall

Hi Chuck,

Thanks. I got that part. Now, here is the question: is the effect of the flash the same or reduced as you set higher and higher shutter speeds (all other things like aperture, ISO, and distance to subject remaining constant)?thanks and later and love, artie


Hi, Arthur:

Sorry if I wasn't clear enough, but the answer is yes. Assuming all other factors remain the same, exposure levels from high-speed sync flash are reduced as shutter speeds increase, because in effect high-speed sync is a form of constant illumination.

Best Regards, Chuck Westfall

Jonathan Michael Ashton
07-18-2008, 02:43 AM
This is interesting stuff, I have been using flash for most of my macro work, I have exchanged some post with James previously. I have tried the gun on manual at 1/8 power and provided the background is close and the day is bright the results are good. The background and light are however not always obliging so I have reverted to the following scenario:
I have been using the high speed sync setting on the flash gun and setting the gun to -1/3 down to more recently -1 stop. My logic has been that if it is a particularly bright day and the shutter speed is faster than 1/250 sec then the flash produces the goods and if the shutter speed is slower, well the flash still delivers.
Jon

Arthur Morris
07-18-2008, 11:53 AM
This is interesting stuff, I have been using flash for most of my macro work, I have exchanged some post with James previously. I have tried the gun on manual at 1/8 power and provided the background is close and the day is bright the results are good. The background and light are however not always obliging so I have reverted to the following scenario:
I have been using the high speed sync setting on the flash gun and setting the gun to -1/3 down to more recently -1 stop. My logic has been that if it is a particularly bright day and the shutter speed is faster than 1/250 sec then the flash produces the goods and if the shutter speed is slower, well the flash still delivers.
Jon

As far as generically using the flash at 1/8 power do understand that the power setting is totally dependent on the distance to the subject, or are you always working at the same distance (that does not seem to likely....)

When it is bright and sunny and clear I tend to you MORE flash on the birds, not less.

Jonathan Michael Ashton
07-19-2008, 03:40 AM
I understand your point Arthur, for the flash to have some effect upon a subject that is in part light and partly dark (the latter being the significant issue) against a light background, it is a case of relatively speaking a little on a lot is a little but a little on a little is significant, clumsily put, but I think I am right!
Regards the manual power issue I suppose the best thing I could do would be to take various shots at 1:1, 1:2, 1:3 magnification and set the flash to the various power settings to determine which output is optimal for each magnification. The trouble would probably be that if I had to keep making power adjustments I would in many cases lose the shot.
Jon

Arthur Morris
07-19-2008, 12:10 PM
Hi Jon,

re:

I understand your point Arthur.

Not sure that you do...

for the flash to have some effect upon a subject that is in part light and partly dark (the latter being the significant issue) against a light background, it is a case of relatively speaking a little on a lot is a little but a little on a little is significant, clumsily put, but I think I am right!

#1: I almost never create images of birds in filtered light--not sure where that came from.
#2: I have no idea in the world what you are trying to say in the rest of the sentence...

Regards the manual power issue I suppose the best thing I could do would be to take various shots at 1:1, 1:2, 1:3 magnification and set the flash to the various power settings to determine which output is optimal for each magnification. The trouble would probably be that if I had to keep making power adjustments I would in many cases lose the shot.

It is a lot easier to make one image with a given manual flash power setting, check the histogram, and then adjust any or all of the following: ISO, aperture, or the power setting, again as explained so well in ABP II.
Jon[/quote]

Jonathan Michael Ashton
07-19-2008, 03:23 PM
It OK Arthur, re your point on the histogram - point taken I agree, what I was trying to say with the flash - for my purpose it is primarily to fill in some shadow i.e. where relatively speaking the light level is low, so a little additional light is significant. As this little light is also added to a brightly lit area it is not really having a great effect there because it is a little additional light to what is already a bright area In other words the effect is greater on the dark areas and pretty well almost ineffective/insignificant on the lighter areas.
Jon

Arthur Morris
07-19-2008, 03:51 PM
I agree that a little flash makes a big difference but am not sure why some of the scenes you are describing are in shadow while parts are in shade.... On rare occasion the combination of subject in shadow and BKGR in sun can work out fabulously but that does not sound like what you are trying to describe...

Jim Neiger
07-19-2008, 05:22 PM
The effectiveness of HSS flash will also vary with the aperture. Larger less effect, smaller more effect.

Robert Amoruso
08-01-2008, 08:25 AM
The effectiveness of HSS flash will also vary with the aperture. Larger less effect, smaller more effect.

Jim, I know what you mean here but I want to offer a clarification to others reading the thread.

For those reading the thread.

Lens Aperature: The larger the f/stop number like f/16, the smaller the aperture's diameter. So f/16 let's in less light then say f/5.6. The smaller the f/stop number like f/4, the larger the aperture's diameter. So f/4 let's in more light then say f/11.

Flash Exposure: Is a constant. Once flash exposure is set (i.e., exposure compensation, etc.) and you take the picture, the flash outputs a constant amount of light. Don't nit-pick over the high-speed flash sync thing here as that is not my point.

So with a constant flash output, f/4 will let more flash illumination strike the camera sensor then say f/11 or f/16. Larger number = smaller diameter = less light reaching sensor = less flash exposure to the image.

So what Jim says is true, a numerically smaller f/stop (larger diameter) will increase the flash's affect on the image and a numerically larger f/stop (smaller diameter) will decrease the flash's affect.

Jim Neiger
08-07-2008, 04:45 PM
Jim, I know what you mean here but I want to offer a clarification to others reading the thread.

For those reading the thread.

Lens Aperature: The larger the f/stop number like f/16, the smaller the aperture's diameter. So f/16 let's in less light then say f/5.6. The smaller the f/stop number like f/4, the larger the aperture's diameter. So f/4 let's in more light then say f/11.

Flash Exposure: Is a constant. Once flash exposure is set (i.e., exposure compensation, etc.) and you take the picture, the flash outputs a constant amount of light. Don't nit-pick over the high-speed flash sync thing here as that is not my point.

So with a constant flash output, f/4 will let more flash illumination strike the camera sensor then say f/11 or f/16. Larger number = smaller diameter = less light reaching sensor = less flash exposure to the image.

So what Jim says is true, a numerically smaller f/stop (larger diameter) will increase the flash's affect on the image and a numerically larger f/stop (smaller diameter) will decrease the flash's affect.

Robert,

It's just the opposite of what you said. The larger the aperture (smaller F number), the less effective the flash is in HSS mode.

Robert Amoruso
08-07-2008, 07:50 PM
Robert,

It's just the opposite of what you said. The larger the aperture (smaller F number), the less effective the flash is in HSS mode.

Let's try to sort this out Jim. I am sitting here with my 1DMKIII and flash - both in manual, HSS mode on.

Example 1:


At f/4 I change the shutter speed starting at 1/50 increasing steady to the sync speed - the distance scale on the flash remains constant.
When I go over the sync speed the distance scale starts to move left indicating that the flash output is decreasing. This is expected as the higher the shutter speed over the sync speed, the less flash output we have as the flash must strobe more to compensate.


Example 2:


At 1/200 shutter speed (below sync speed) I change the aperture from f/4 to f/22. I am closing down the lens (smaller aperture) and letting less light in.
The distance scale starts to move left indicating that the flash output is decreasing. This is expected as the smaller aperture letís in less light.


Example 3:


At 1/2500 shutter speed (above sync speed so HSS mode is being used) I change the aperture from f/4 to f/22. I am closing down the lens (smaller aperture) and letting less light in.
The distance scale starts to move left indicating that the flash output is decreasing. This is expected as the smaller aperture letís in less light.
To further test this out, I took one image at f/4 and one at f/22. f/22 image very underexposed and f/4 image very overexposed.
My test subject is 5 feet away, so I change my aperture until the distance scale reads 5 feet. That is f/9 and I take picture and the exposure is good.
I then change my shutter speed to 1/8000 and adjust the aperture to f/5.6 to get the distance scale to read 5 feet and make image which is exposed correctly.


It seems to me that example 3 disproves your statement or I am misunderstanding you.

Jim Neiger
08-08-2008, 09:36 AM
Robert,

If you open up to larger aperture (smaller F number), this will require you to increase shutter speed to arrive at the same exposure. This in turn reduces the distabce that the flash will be effective. This means that using a larger aperture will reduce the distance that the flash is effective in HSS mode.

Robert Amoruso
08-08-2008, 09:41 AM
Robert,

If you open up to larger aperture (smaller F number), this will require you to increase shutter speed to arrive at the same exposure. This in turn reduces the distabce that the flash will be effective. This means that using a larger aperture will reduce the distance that the flash is effective in HSS mode.

Now I understand what you are saying. My discussion and examples assume one constant and one variable whether that be shutter speed or aperture. Thanks for your clarification Jim.

Jim Neiger
08-08-2008, 09:48 AM
Here is something else to consider when using HSS flash. Flash, under the sync speed, is often used to freeze motion. The very short duration of the flash will freeze motion. When using HSS flash, the flash strobes to simulate a constant light source. This strobing reduces freezing effect. To summarize; HSS flash will not freeze motion the way that flash used within the syc speed of the camera will.

Robert Amoruso
08-08-2008, 10:08 AM
Here is something else to consider when using HSS flash. Flash, under the sync speed, is often used to freeze motion. The very short duration of the flash will freeze motion. When using HSS flash, the flash strobes to simulate a constant light source. This strobing reduces freezing effect. To summarize; HSS flash will not freeze motion the way that flash used within the syc speed of the camera will.

Very good point Jim.

MichaelM
08-28-2008, 08:58 AM
Under "Flash Sync Speed" select 1/250s (Auto FP) or 1/320 (Auto FP).

The maximum flash sync speed depends on your camera and maximum flash sync speed is the factory default. To use High Speed Flash aka FP it must be enabled to work on Nikons

James,

I'm using SB-800's on a D300 & D2X..

If I select either 1/250 (Auto FP) or 1/320 (Auto FP) and can set EV to any shutter speed available on the body. I understand the dramatic reduction in output (1:8...crazy), but what is the difference between choosing 1/250s or 1/320s in CSM if I can then set any shutter speed I want in the EV settings?

IE... say I want a shutter speed of 1/800s. I can set this on the body with the SB-800 attached and the CSM setting to either 1/250 (Auto FP) or 1/320 (Auto FP).. why choose one sync speed over another?

MichaelM
08-28-2008, 09:21 AM
Here is something else to consider when using HSS flash. Flash, under the sync speed, is often used to freeze motion. The very short duration of the flash will freeze motion. When using HSS flash, the flash strobes to simulate a constant light source. This strobing reduces freezing effect. To summarize; HSS flash will not freeze motion the way that flash used within the syc speed of the camera will.

Sounds like chasing your tail here...

I'm very eager to learn so I'd like to be sure I am understanding.

If you choose HSS in hopes of freezing action with a faster shutter speed, you limit yourself with much less output/shorter distance and the lack of ability to freeze with a shorter flash burst due to the continuous flash out put under HSS mode.

On the other hand, if you set max sync speed of say 1/250th, you gain the ability to freeze action with the shorter duration flash, plus have greater out put and distance..

The post Arthur had earlier in the thread stating that when in HSS the speed light is essentially on all the time, resulting in the lessened ability to freeze action, is critical information.

So why choose HSS at all??

Stuart Dahne
09-03-2008, 11:27 AM
O.K. if the output is then lessened, would a Better Beamer help to pick that up and if so how would you set the flash (580EX)?

Jim Neiger
11-17-2008, 09:30 PM
Sounds like chasing your tail here...

I'm very eager to learn so I'd like to be sure I am understanding.

If you choose HSS in hopes of freezing action with a faster shutter speed, you limit yourself with much less output/shorter distance and the lack of ability to freeze with a shorter flash burst due to the continuous flash out put under HSS mode.

On the other hand, if you set max sync speed of say 1/250th, you gain the ability to freeze action with the shorter duration flash, plus have greater out put and distance..

The post Arthur had earlier in the thread stating that when in HSS the speed light is essentially on all the time, resulting in the lessened ability to freeze action, is critical information.

So why choose HSS at all??

When photographing action such as BIF, 1/250 is often not fast enough to freeze action or produce a sharp image. If the subject is close enough HSS flash can be used for fill flash.

Arthur Morris
06-16-2009, 04:55 AM
O.K. if the output is then lessened, would a Better Beamer help to pick that up and if so how would you set the flash (580EX)?

Hi Stuart, Yes, using a Better Beamer will always give you increased flash output, even with HSpSynch.