Alternative to HSS in bright sunlight?

PhotographersWorldWide wrote in post #15286817
Wrong.

Adding an ND filter effectively reduces ISO. (It affects both ambient and flash equally). Reducing ISO reduces GN. (GN = ft x Distance @ a specific ISO).
At 1/400s f/8 you had no range - because it doesn't work.
1/400s - f/8 - No flash range

With a 2x ND gives:
1/100-X - f/8 - flash range 8ft.

You gained the use of your flash along with an 8ft range. Theres no loss of range. You can't lose what you don't already have..

Adding ND only reduces the LIGHT passing into the lens!!! It does not alter the sensitivity of the sensor to that light (ISO).


Since you continually argue only from the point of 'not being able to use flash' to 'being able to use flash' is not a 'decrease in range', let's alter only the amount of ambient light by minus one EV in the previously used scenario of mine...


If I have subject at 16' and 1/200 f/8; with GN130 flash my max range with flash is 16' .
If I put -2EV ND filter on the lens AND keep my lens at f/8, I can use 1/50. But the flash now only reaches the distance imposed by effective aperture f/16...8'. 8' is less range than 16', right?

bobbyz wrote in post #15286613
Dave, shouldn't "shutter speed only affects the ambient light" should add "as long as shutter speed is with the max sync speed"?

Bobby, that qualifier is valid. Perhaps that's what is part of the problem here; One should be able to expect that a photographer, with reasonable experience, knows that a statement like the one I made is valid only at speeds below x sync. (Although, its probably also accurate when the speedlite is within its effective HSS range.)

Canon speedlites offer some help; Setting 5DIII to 1/200, F2.8, ISO 100 a 600EX-RT suggests the effective range is between 7.0 and 60 Ft. Changing the shutter speed to 1/250 the speedlites suggests 5 to 30 Ft. At 1/500 its 4 to 20 Ft; at 1/1000 its 2.3 to 15 ft; at 1/2000 its 2.3 to 10.0Ft; at 1/4000 its 2.3 to 7.0Ft. and at 1/8000 its 2.3 to 5ft.

In manual the 600EX-RT suggests 1/32 power at 10 ft with shutter at 1/200. At 1/250 it suggests 1/32 at 5ft and 1/8 power at 10ft.

With a 1.4 lens the speedlite suggests 10 to >60ft at 1/250; 5.0 to 30Ft at 1/1000; 2.3 to 15ft at 1/4000; and 2.3 to 10ft at 1/8000.

Sunny 16 equivalents at ISO 100 are 1/100 at F16, F11 at 1/200 sync speed, 1/6400 at F2.8 which means that the speedlite can match the sun within a range of 2.3 to 5ft at F2.8.

FEC gives back, as one would expect, distance for effective exposure.

Practical experience indicates that these distance suggestions are reasonable.

Another practical reality; Speedlite suggested range at 1/200, ISO100, F11 (sunny 16) is 2.3 to 15 Ft. It requires a 4 stop ND filter to get the aperture open to F2.8. which means the speedlite is delivering about 1/8th power effectively. Which means 15Ft. HSS suggests 2.3 to 7.0ft. at 1/3200, F2.8

Make your own choices.

Wilt wrote in post #15286851
Adding ND only reduces the LIGHT passing into the lens!!! It does not alter the sensitivity of the sensor to that light (ISO).


Since you continually argue only from the point of 'not being able to use flash' to 'being able to use flash' is not a 'decrease in range', let's alter only the amount of ambient light by minus one EV in the previously used scenario of mine...


If I have subject at 16' and 1/200 f/8; with GN130 flash my max range with flash is 16' .
If I put -2EV ND filter on the lens AND keep my lens at f/8, I can use 1/50. But the flash now only reaches the distance imposed by effective aperture f/16...8'. 8' is less range than 16', right?

LOL !!

READ MY FIRST POST !!
https://photography-on-the.net …hp?p=15284307&p​ostcount=7

"If you desire to keep your aperture and use a longer shutter speed, your range will reduce then - but whats the point in that - you could have just turned down your flash power?"

Wilt wrote in post #15286851
If I have subject at 16' and 1/200 f/8; with GN130 flash my max range with flash is 16' .
If I put -2EV ND filter on the lens AND keep my lens at f/8, I can use 1/50. But the flash now only reaches the distance imposed by effective aperture f/16...8'. 8' is less range than 16', right?

Wilt; Your example is mathematically correct. I think the disconnect is that, when attempting to use flash with ambient light (particularly bright ambient) an ND filter is used for its influence on aperture rather than shutter speed.

The givens are; max shutter speed (1/200 for my 5DIII) and lowest ISO* (100 for my 5DIII). Now I have choices for proper exposure blend between ambient and flash; a) small aperture to get ambient where I want it, then add flash power to get desired ratio and accept DoF. b) use F stop required for desired DoF and add ND filter to correct to proper exposure, then add sufficient Flash to get desired ratio. Presuming the ratio between ambient and flash is the same, the flash power would remain constant. i.e. 4 stops open on aperture for DoF and 4 stop ND filter are a light source neutral adjustment.

One of the first things a photographer learns about filters (hopefully) is how to adjust for their impact on exposure. With constant light source all three exposure adjustments are available. With flash lights (below sync speed) ISO and aperture are available.

And with (ISO 100, 1/200, F11) speedlite at full power is 15ft; at ISO 100, 1/200, F2.8 1/16 power for 15ft. HSS option for same ambient requires 1/3200; the speedlite range is 2.3 to 7.0 ft.

Aren't options nice?

(* there is am L option but experience suggests that this is a manipulation of info collected by the sensor and detrimentally impacts dynamic range so I stay away from it.)

dmward wrote in post #15287132
Wilt; Your example is mathematically correct. I think the disconnect is that, when attempting to use flash with ambient light (particularly bright ambient) an ND filter is used for its influence on aperture rather than shutter speed.

It depends! Lots of folks put ND on a lens to permit a longer shutter speed, for blurring moving water, too! Yes, this context is not the same as OP context, but it does represent a scenario for using ND.

dmward wrote in post #15287132
Aren't options nice?

Yup.

PhotographersWorldWide wrote in post #15287021
"If you desire to keep your aperture and use a longer shutter speed, your range will reduce then - but whats the point in that - you could have just turned down your flash power?"

How does this impact flash exposure "range"? Longer shutter speed, presuming its at or below sync speed has no impact on speedlite output.

Wilt wrote in post #15287165
It depends! Lots of folks put ND on a lens to permit a longer shutter speed, for blurring moving water, too! Yes, this context is not the same as OP context, but it does represent a scenario for using ND.

Wilt, let's stay on topic please. That is a completely different lighting situation when the aperture has been selected for creative purposes and then there is a need to adjust shutter speed given the confinement of ISO and the lighting conditions. Its unlikely that flash would be incorporated.

Regardless, if a photographer understands how shutter speed, ISO and aperture control light and how flash lights differ from constant light sources, then its a matter of applying that knowledge to the situation.

dmward wrote in post #15287226
Wilt, let's stay on topic please. That is a completely different lighting situation when the aperture has been selected for creative purposes and then there is a need to adjust shutter speed given the confinement of ISO and the lighting conditions. Its unlikely that flash would be incorporated.

Waitasec, now YOU have strayed from the thread topic..what you accuse me of doing! The OP wondered about using ND to change the SHUTTER SPEED in order to use flash when otherwise the X-sync speed is exceeded!!! At least I am consistent, with change in shutter speed, even with my different scenario of moving water as the reason.

dmward wrote in post #15287180
How does this impact flash exposure "range"? Longer shutter speed, presuming its at or below sync speed has no impact on speedlite output.

Because in getting there by adding an ND, range is reduced because of the lower effective ISO in play.

PhotographersWorldWide wrote in post #15287347
Because in getting there by adding an ND, range is reduced because of the lower effective ISO in play.

Let us draw an analogy. I have a film camera with ISO 100 color film loaded. On an overcast day, I have my lens set to f/4 and shutter speed for that is 1/100. I put a -2EV ND filter on my f/4 lens, and my shutter speed needs to be 1/25 now. My film is still ISO 100...there is no 'effective ISO' speed concept at play! Now put a dSLR on the tripod, and the EXACT same situation applies, there is no 'effective ISO' change, as what changed for both film camera and for dSLR is the amount of light available at the front element of the lens.

PhotographersWorldWide wrote in post #15287347
Because in getting there by adding an ND, range is reduced because of the lower effective ISO in play.

That you're going to have to explain in more detail. How does the ND lower the effective ISO.

To reiterate; When trying to use a large aperture in "bright sunlight" this implies that the lowest ISO is already being used. And that the aperture has also been decided on (F2.8 for example) Now its the shutter speed that is causing the problem. i.e. if it has to be over sync speed then the options are HSS or ND filter.

Yes, Wilt, in this context you are right, the ND filter is affecting shutter speed.

One does have to take some care when using illustrative examples.

Wilt wrote in post #15287357
Let us draw an analogy. I have a film camera with ISO 100 color film loaded. On an overcast day, I have my lens set to f/4 and shutter speed for that is 1/100. I put a -2EV ND filter on my f/4 lens, and my shutter speed needs to be 1/25 now.

So, the effective ISO is now ISO 25.

PhotographersWorldWide wrote in post #15287643
So, the effective ISO is now ISO 25.

Where in the exposure control triangle is there room for "effective" anything?

In the illustration above the ISO is and will remain 100 because film's sensitivity to light is specified as an ISO number.

In a digital camera ISO is one of three adjustable controls for exposure.

Where in the exposure control triangle is there room for "effective" anything?

ISO is a value that is set in the camera. Shutter speed is a value set in the camera, aperture is a value set in the camera. If you change one you change the exposure, if you change one in a positive direction and one in a negative direction the exposure stays the same.

I suppose one can say that introducing an external element that affects exposure and the corrective action being taken is to open the aperture is "effectively" reducing whatever of the other two controls can not be changed because it has reached a limit.

For me the problem with introducing a term like "effective" is that it confuses the basic logic of exposure control that photographers learn. Its more consistent for a photographer to remember that when reaching the limit of one of the exposure controls they can either use one of the other two or introduce an external aid such as an ND filter.

Naturally, introducing an artificial light source can be considered an external aid. Then power settings, distance to the subject etc. all come into the equation.

dmward wrote in post #15287432
That you're going to have to explain in more detail. How does the ND lower the effective ISO.

Adding an ND filter affects both ambient and flash equally. It has an effect of reducing your working ISO equivalent to the factor of the filter used. Grasp that, and you'll understand.

PhotographersWorldWide wrote in post #15288164
Adding an ND filter affects both ambient and flash equally. It has an effect of reducing your working ISO equivalent to the factor of the filter used. Grasp that, and you'll understand.

Makes sense to me. Like I would lower ISO to 50 from 100 when I need 4 stop filter and only have 3 stop on hand.