Hi every one.
Does any one have an idea how to shoot over that speed with Ikelite strobs without getting the top 1/3 frame dark ?

Thank u !!!

The maximum stutter sync speed is a limitation of the camera not the housing or strobes. There is nothing you can do about it. The way the sutter works at high speeds (for example at 1/500 of a second) is that the shutter only opens a small slit: this Slit then slides down the Frame. Although no part of the shutter is exposed for more than 1/500 of a second, the top half of the frame is exposed at a different time than the bottom half of the frame so the actual amount of time it take for the exposure to happen is much longer. Because the shutter never exposes the entire frame at once - there is no time during the exposure that the flash can go off and be seen by the entire frame.

The solution is that for higher shutter speeds you need to not use a flash (an instantaneously short burst of light) and instead use an always-on light source that keeps the same intensity for the entire duration of the exposure.

The way your land flashes deal with this is that at high stutter speeds they switch from flash mode to always on mode. No underwater flashes are capable of creating an always on light source(they were made to be a flash - not a flashlight). So if you really need artificial lights and above synch shutter speeds you will have to use a video light(super bright flashlight).

A Nikon SB800 or 900 can do a sort of rapid, "stutter" type of output that can sync at any shutter speed. Quite amazing, but it works. Won't happen with Ike strobes I'm afraid.

Jack

Strobe output with FP sync is considerably lower than X-sync (and it is further reduced with increase of shutter speed). It might have some niche applications, but I don't think it would be useful in counterlight situations we like to shoot underwater.

Thank you so much !!!
I have 2 more questions :
1.Why does it work with my 10-17 and not with my 105 macro ?
2. If I"ll leave the flash on - on w/light, will it work ?

It is not working with your 10-17. But I can think of 2 reasons why you might think it was (not see the dark band at the top of the frame).

1. You just don't notice it as much because when you are shooting macro 99% of the light is coming from the flash. But when you are shooting with the 10-17 the primary light source in your images is sun light. Since the sun is an always on light source, you don't have a black band at the top of your ambient light photos. Instead you will have a band where nothing is red at the top of the frame. And if the top of the frame is all water where there would not be anything red even if it had been hit by the flash - you don't notice anything at all.

2. I don't know if your camera/housinig/flash will do this. But with the Canon 5D in an Ikelite housing with Ikelite strobes the camera will let you dial in the fast shutter speed setting, but when the camera talks to the flash just before the exposure, the camera realizes that you have chosen an incompatible set of settings (too fast of a shutter with a flash) and automatically fixes the problem (by using a slower shutter speed) for you. Because photographing while diving is similar to photographing while drunk, you don't have a chance of figuring out what is going on until you get back on land and see that the embedded info in the EXIF does not match what you thought you told the camera to do.

It is possible that something similar is happening to you, but for some reason the non-name brand lens is making your camera 'smart', while it is 'dumb' when mated with a name brand lens. Does not seem very likely but worth checking the EXIF to make sure that you were actually using the shutter speeds you thought you were.

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The modeling light on your strobe is not close to bright or wide enough enough. But yes you get the idea. What you need is a always on flashlight that is as bright and as wide and as your strobes.

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Finally I find it interesting that you are having the most trouble with the macro lens. If that is the case that you are only running into this problem when trying to shoot macro, the solution is very simple. Don't use such a high shutter speed. For macro shooting there is no reason why you would need such a high shutter speed.

In flash photography you use the shutter speed to control the background color. High shutter speed gives you a dark background, low shutter speed gives you a blue background. 1/200 s is plenty fast to give you a black background at typical macro aperatures. So unless you are using f/2.8 and/or have the sun ball directly behind your macro subject there is no reason why you would desire a higher shutter speed.

Now in wide angle photography we tend to use larger apertures(to compensate for insufficient strobe power) and shoot directly into the sun. This is when you really wish you could use 1/1000s to darken the background.

Thank you, William !!!
I need the high speed when I"m useing my Nikin 105 Vr + 1.7 T.c on my D300.
I really appreciate your educated answers.

Udi622@yahoo.com

But why do you think you need it for that lens/TC? With that combination you are not likely to be using big aperatures so you arn't likely to be having troubles with over-exposed backgrounds.

If you think that higher shutter speeds are going to help you get sharper images - think again. When 100% or nearly 100% of the light is coming from your strobe as it will be in your scenario, the shutter speed does not influence motion blur at all. When the strobe is your primary light source, the only effect shutter speed has is the color of the background.

If you don't believe me try it for yourself. Go into the closet and turn all the lights off.

Put the camera in manual mode with the following exposure: 2 second shutter speed | F/10 | ISO 200 | Flash Auto

Take a picture.

Now change the shutter speed to 1/200 leaving everything else as it was before.

Take another picture.

Now upload these two pictures to your computer. You will notice they are identical.


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If you are unhappy with the sharpness of your macro shots with that combination I am going bet that your problem is either with the razor thin DOF or with Diffraction. If the problem is the thin DOF a smaller aperature will help. On the other hand if your problem is diffraction - a larger aperture is required to fix the problem. With a 12MP small sensor I would recommend F/14 as a good compromise between the two.

Huh? You have some things backwards I think..

In wide angle photography, typically larger apertures are used (smaller number) not so much to compensate for under powered strobes but to get a nice blue color (allow more natural light in). Which leads me to the other issue with what you are saying. Using the aperture to control the color of the background is much more effective than using the shutter speed. The shutter speed is good for stopping the action and as a second means to control exposure, but the aperture controls how much light is going to enter the camera (and of course DOF). Sometimes we balance the two settings of course to get the optimal effect, but generally the shutter changing the blue color is going to be more problematic. Wide angle for me would be something like a shutter of 1/60 to 1/125 (unless I am shooting into the sun and want to catch the sun rays of the sun ball) and an aperture of up to F/11 or so (each camera / lens being different). Macro on the other hand is going to be 1/200 or 1/250 to stop the action since it is harder to keep things steady and then an aperture of F/22 or something like that which will give me better DOF for the macro shot and darken the background.

Just wanted to clarify the advice and the aperture / shutter.

Nikon has 2 shutters, called curtains. a front and rear curtain. The front curtain opens exposing the chip to light and then the rear curtain follows behind shutting off the light reaching the chip. At shutter speeds higher than the maximum sync speed, the rear curtain will descend before the image is properly exposed by the strobes, rendering a part of your image darker than the other. That is what you are seeing. The official maximum sync on the 300 is 1/250th.
There was a great slow speed video posted by Eric showing the mirror and two curtains in action. I can't find the link but perhaps someone else knows where it is.

I would quite like to see that video.

Paul C

Slow Motion Shutter release (Jeffrey Friendl's Blog)

I agree with William on this. And I think you missed his first sentence:

For me, and I'm sure this is what William intended, flash photography means where flash is the primary light source. Underwater, you are generally using the flash to provide most if not all the illumination of the subject and that is especially true for macro photography. Underwater, available light is typically not great and isn't enough to light macro shots, unless you are in shallow water and using a large aperture (or high ISO). The light from the flash is going to be significantly higher than available light for the foreground.

As the flash is primary light source in macro photography, you don't need to a fast shutter speed to "stop the action" because the flash itself is the "fast shutter speed". At full power, a flash's duration is something like 1/1000s (4 to 5 times faster than what you recommended for shutter speed). I regularly shoot macro at 1/100s to 1/60s to get a lighter background and have no problem with subject movement (or even camera shake).

Okay, but by your method, the spill over light from the strobe will expose parts of the background in macro photography at slower shutter speeds and at higher shutter speeds, whereas, if you use the aperture to control the background, you can still keep your shutter speed at 1/100 or 1/250 or whatever and end up with a blacked out background on macro if you choose because it will limit the light entering the camera and the "dimmer" lit areas behind your subject will be blacked out.

I agree there are two things controlling exposure here and the shutter will darken the background also. I mainly have an issue with the statement that a faster shutter speed does not increase the ability to get a sharper image when doing macro based on movement. I have seen it in many pictures taken of the same subject and there is a difference. Wide angle is not an issue since minor movements are not as noticeable as they are when you are taking a picture of something the size of a pencil eraser. I also have an issue where William said.. "Use a smaller aperture to let more light in".. If he meant "smaller aperture NUMBER which relates to a larger aperture.." well then that would be better and it would be confusing to readers.

I am not debating anyone's own personal technique to get the results they want since there are several ways to an end. I was mainly debating the two assertions of a smaller apterture letting more light in and that shutter speed has no effect on if a subject is blury or not in flash photography.

Thanks for the link Matthew.

Ingenious piece of work.

Paul C

hey RJ

I am sure William made a typo, he meant "a smaller aperture number lets in more light", not a smaller aperture.

Regarding shutter speed having no effect on sharpness of the subject, this has been discussed many times, and its true.

Unless the subject is being by incredibly bright sunlight, changing the shutter speed will have no visible effect on the sharpness of the subject, when using strobes, a relatively small iso, and a small aperture. this is because almost all of the lighting is coming from the strobes, and the strobes fire very fast, regardless of the shutter speed.

Scott

If you are getting light spilling over to expose parts of the background, you will have that happening no matter what aperture you are using. The fall off in light with distance will be the same the only difference will be the ratio of light from the flash to the ambient light. The smaller the aperture (and the brighter the flash to compensate) the more the flash light will over power the ambient light.

As shutter speed (assuming it is within the range of flash synchronisation) has no effect on exposure of light from the flash, it can only have an effect on the exposure of ambient light.


If you use flash in the dark, the shutter speed (assuming it is within the synchronisation speed range) will make no difference. This is because the flash duration is typically 1/1000s or faster, much shorter than any shutter speed you could use. e.g. even if you have the camera on Bulb, the flash will freeze motion. (Note I said in the dark).

Now, when there is ambient light, how much difference shutter speed makes will depend on how bright the ambient light is relative to the flash. Certainly, if the ambient light is bright (within 1 stop of the flash) you may well see motion blur. If the ambient light is two stops or more darker than the flash, it would be very difficult to see any motion at all.


I can't find anywhere in this thread where William said "Use a smaller aperture to let more light in". In fact, you are the only one to say that.


A blurry subject can also be caused by improper focus.

Well there isn't. If your pictures are blurry it must be because they are out focus



Well of course he meant that and we did get it



The flash is the only significant source of illumination in 99% of typical UW macro photography. So William is correct because as stated before the flash exposure is faster than one thousandth of a sec so the shutter speed is irrelevant. Take him up on the closet test if you still dont believe it.