Apaflo Loc: Anchorage, Alaska

In the True Macro-Photography Forum member CLF initiated a thread "First post in macro", and then member robertjerl made a post which was responded to by Macronaut (a section manager). Macronaut's post was flawed with incorrect statements, but it seems he cannot tolerate discussion of his misstatements. So I'm responding in this section where he can't delete it.

The topic is using flash to freeze blur from camera shake, and whether it can work in bright daylight. The very valid statement by robertjerl was,

"I disagree, I have tried both flash and no flash on the same subject hand held in daylight outdoors and with my 6D and 7DII the image often gets a blur because the flash sync SS is too slow. I get a ghost blur because the camera is still recording the image after the flash duration. So either use high speed sync or a tripod, mirror lock up and delay. This only works if nothing is moving of course."

Macronaut then said,
"It's hard to say what the issue is but, I never use a tripod and get very crisp images. I suspect that it's something very simple, such as the flash duration may be too long. Or, the flash is cancelled out by direct sunlight, causing spectral highlights (I hate those and rarely shoot in direct sunlight because of it."

Along with deleting my follow up (shown below), Macronaut edited out the incorrect parts from his article, tacitly admitting that my deleted article was precisely correct and should not have been deleted.

The follow up discussion that he cannot live with was:

"Flash is not "cancelled out by direct sunlight", ever. Nor is this specific problem the flash duration, though that can be a problem but is unrelated to shooting in daylight. If you don't ever shoot in direct sunlight you simply won't experience what robertjerl describes.

The high speed of the flash duration is only effective at freezing camera shake motion blur if the ratio between flash and ambient is high enough. A 1:1 ratio would mean that without the flash, using ambient light only would be 1 stop under exposed and only the speed of the shutter would affect motion blur. Adding the flash corrects the exposure but has zero effect on the blur! As the power of the flash is increased the parts of the image unaffected by the short duration of the flash are increasingly limited to the darker parts of the scene.

If no tone mapping is done and highlights are at or near clipping the dynamic range of a print will probably be about 6 or 7 stops at the most, and 7 or 8 for viewing on a monitor. That means a ratio that puts ambient light that low will not show any motion blur due to ambient light. If ambient light is 5 stops darker than the flash only shadows will show motion blur from camera shake and highlights will be sharp. But even that is a higher ratio than most speedlights can produce outside in bright sunlight. Shooting with multiple speedlights can help, and shooting in the shade helps too. Using high power studio strobes with a battery powered AC supply is another alternative."

In fact robertjerl is correct that probably the best method is to use HSS, at a high shutter speed, to provide whatever fill light is needed.

Macronaut Loc: Redondo Beach,Ca.

First of all, I am NOT a section manager and can delete nothing.
Second, thank you for pointing out my typo. I meant Flash duration not shutter. I would go back and edit that error if I had the power.
Thirdly, You are not 100% correct 100% of the time as you would like to think.
Forth, what's the point posting here????

Apaflo Loc: Anchorage, Alaska

That article was 100% correct. The information it contained is useful to people who get confusing results using flash. The article explained the minimum detail needed to analyze a specific situation to determine how effective flash will be for freezing motion blur from camera shake. It's an interesting topic and might generate more discussion if someone is learning and wants to know.

We can no longer really know who is and isn't a Manager in the True Macro section. There used to be a list of 2 or 3 who were, and now it seems to have been replaced with a surrogate name meant specifically to allow denying who deletes or edits articles that are embarrassing.

gvarner Loc: Central Oregon Coast

Shoot in Manual with TTL flash, on camera or using compatible remote trigger/receiver. Set camera if possible to shutter speed higher than 250 up to the max if needed to control ambient light. Set your aperture for desired DoF and ISO at 400 for starters. The flash itself controls the exposure. The high shutter speed stops motion and eliminates the effect of ambient light. This works pretty well for me. You can easily darken a bright background by cranking up the shutter speed. Take a few test shots and enjoy.

Apaflo Loc: Anchorage, Alaska

That works great! Of course it only works great if the flash is HSS enabled...

One point though, "flash itself controls exposure" isn't actually true.

gvarner Loc: Central Oregon Coast

I know but people tend to get overwhelmed with the details. They just have to try it and and see what combination works best for them.

Apaflo Loc: Anchorage, Alaska

True enough. But that can cause Macronaut's "rarely shoot in direct sunlight because of it", which accurately stated means simply that because he doesn't understand it he is unable to do that.

Studying a technical problem by reading what credible sources have to say about it before and during the process of experimenting with it will make the details less overwhelming. Most important though, it results in a personal knowledge base that allows the photographer to easily select the right technique for whatever the job may be. That is the difference between remaining basically a beginner forever and becoming a journeyman photographer that can do everything well enough. Or lead perhaps to becoming a master photographer that can do almost anything to a very high degree of artistry too.

bdk Loc: Sanibel Fl.

HUH!!!

sterrill Loc: missouri

I dont use flash to cancel out camera shake but i have lots of experience using flash to stop high speed motion when I photograph hummingbirds. The amount of ambient light matters greatly.I shot yesterday with really bright sunlight and got very few keepers. even with four off camera flashes I could not overwhelm the ambient light. Because of the limitations of the flashes, I accept images with some wing blur during the bright of day. the best shots come in the evening when i can overwhelm the ambient light. The best solution for camera shake has 3 legs.

I would continue to urge everyone to please be nice to each other.

martinfisherphoto Loc: Lake Placid Florida

Just so ya know you don't need HSS to freeze motion with a flash.. In fact, the Lower the Power setting on the flash the higher the speed the camera can freeze. Now that's Assuming the exposure is correct and the flash is providing the light for the exposure.

martinfisherphoto Loc: Lake Placid Florida

I would try lowing your ISO and closing down your aperture to the point your flashes provide the correct amount of light for the exposure.

Apaflo Loc: Anchorage, Alaska

HSS allows the use of a higher shutter speed. The light from the flash, in HSS mode, is essentially continuous. But shutter speed is limited to 1/8000 of a second, and the actual amount of light from the flash is very low and is used only as fill light.

The low power settings on a flash can be faster than 1/8000, but then the camera's shutter speed is limited to probably 1/250 of a second depending on the camera's X-sync speed. Even at ISO 100 and stopping down to f/16 that can leave too much ambient light to eliminate blur on a hummingbird's wings.

Read article from member Sterrill, just above yours, where he cannot get enough light using 4 flash units on a bright sunlit day!

The speed of a typical speedlight will be slower than 1/10000 second at 1/16 power and about that or faster at 1/32 power. Such flash unit's maximum output is about 80 Ws, so getting a flash duration of 1/10000 with 4 units means shooting with a total flash power of about 10 Ws.

Roughly the same effect would be had by using the flash units in HSS mode and shooting with a shutter speed of 1/8000. The flash provides fill light and does not stop motion.

But consider another method, and use the right kind of a studio strobe. Paul C. Buff Einstein models in "Action" mode have a 1/10000 second duration when set to 40 Ws, so just one such strobe would have 4 times the light power of the 4 speedlights. Obviously either 2 or 4 units would provide even greater amounts of light, probably sufficiently overcoming the ambient sunlight.

Of course hummingbirds are a worst case scenario that is far more demanding than is the typical camera shake from hand holding at macro magnifications. HSS is more likely to work if for no other reason than the flash can be much closer to the subject and thus provide more light. A studio strobe will provide better light at a short enough interval but it is not as mobile when chasing insects.

Again, all of these require the photographer be aware of the ups and downs with each, and be able to choose the right method for any given shoot.

sterrill Loc: missouri

On hummingbirds I will set the flashes to 1/16 power and the camera to f8 to f11 with a shutter speed of 1/200 or 1/250 of a second. Iso at anywhere from 200 to 400. Interestingly as the evening darkens I can shoot at a little lower iso. I have been using 4 flashes. I added another this year but it has fewer manual settings. Specifically it soesnt have 1/20 power which seems to work well.

blackest Loc: Ireland

Isn't there a difference between the operation of the shutter that makes a major difference between high speed flash and regular flash? Most Dslr shutters are only fully open for as short as 1/180th to 1/250th of a second The actual flash duration is much much shorter but the key thing is the flash needs to overwhelm the ambient light by a couple of stops at least in order to freeze action. (It also gets interesting when you balance the flash with the ambient and also where the flash fires front or rear curtain sync). The effect of the flash is controlled by aperture where ambient light is a combination of aperture and shutter speed.

For higher shutter speeds rather than exposing the whole of the sensor instead you have a moving slit. So with a regular flash only the part of the sensor that is exposed at the moment of the flash will receive the light. For high speed flash either you need a long pulse for the duration of the frame or a series of rapid pulses.

So it would seem that for hss flash to match the intensity of a regular flash it will have to provide the same energy for each section of the frame. Not only that but there will be a time difference between the exposure of the top of the frame and the bottom of the frame.

So the high speed flash needs more more power and doesn't freeze action as well as a regular flash. Another peculiarity of flash is that if you use 2 unmatched flash units in the same location relative to the subject the lower power flash makes a small fraction of a stop difference to the exposure 2 equal power flash units will provide 1 stop more light than the single flash and 4 units to provide 2 stops more power to achieve another stop would take take 8 flash units.

The effect of the flash also depends on the subject flash distance. If you can half the subject flash distance you can effectively double the effect of the flash on the subject the closer the flash is to the subject the quicker the fall off too.

Most of this information can be confirmed on the strobist 101 website.

I'm sure there are more experienced photographers who can say if I have a good handle on this or am talking complete rubbish.

Nikonian72 Loc: Chico CA