use of flash unit SF58 in a strong backlit situation

[ronnysoh2009]

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Would appreciate advice from seasoned users of SF58 (or seasoned flash users).

 

I bought the SF58 a few weeks ago, and have been really pleased with it. It

really opens up more avenues of indoor photography for me.

 

 

However, in a strong backlit situation (dark foreground subject, bright background)

the flash refuses to fire, just when I need it the most! My M8.2's exposure meter

seems to be tricked into thinking there's enough light, consequently the flash

steadfastly refuses to fire.

 

I tried all sorts of things:

 

(i) dialing up the exposure setting on the flash unit to EV+1, even all the way to EV+3.

But the flash stubbornly does not fire! (This is in cases of a dark foreground subject

against a very strongly lit background, say the afternoon sun.)

 

(ii) lightly cupped my lens, and then half-pressed the shutter trigger and didn't let go,

in efforts of fooling the camera's exposure meter into thinking there's not much light.

What happens is: the flash fires alright, but the photo's overexposed.

 

(iii) as a variant of (ii) above, I fool the camera's exposure meter by first rotating the

aperture ring on my lens to a larger f-number, i.e., artificially reducing my lense's

aperture opening beyond my compositional intention, then watch for the flash icon at the

bottom of the camera's viewfinder. [The camera is set in aperture-priority mode.

The red flash icon is the symbol next to the red digits indicating shutter speed.] When

the red flash icon appears, this means the camera's exposure meter thinks there is

insufficient light, and prepares the flash to fire. What I do next is: I don't let go of the

half-press, but I rotate my len's aperture ring to a smaller f-number (for selective focus

compositional reasons).

 

(iv) the only thing that forces the flash to fire without all this tricking is to set the Mode

in the flash unit to Manual mode. In this mode, the flash fires for sure, but I lose the

TTL feedback. Consequently I have to adjust the intensity of the flash by changing

the p setting by trial and error, until I get a satisfactory balance between flash-exposed

foreground subject and the bright background.

 

 

 

So far, I use method (iii) as a workaround to this problem of coaxing the flash unit to fire.

When I want to compose using selective focus (say a portrait shot at f2 with my 35

summicron), I dial the aperture ring to f5.6 or f8, that's a 3- or 4-stop dupe, and the

red flash icon starts to appear in the M8.2's viewfinder. I then dial the aperture ring

back to f2 without letting go of the half-press, and then fully press down to shoot.

The flash invariably fires, and I get a foreground subject with enough illumination to

hold against the bright background. But the problem is the resultant photo is almost

always overexposed, and in Lightroom I have to dial down Exposure or dial up

Recovery, or both.

 

Am I missing something? Is there a TTL setting that force-fires the flash? Or some way

to isolate the needed exposure of the foreground subject, instead of averaging the bright

background into the mix?

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[Luke_Miller]

I don't have an SF-58, but back in the day before TTL and balanced fill we would put the flash in auto thyrister mode and lie to the flash about the lens aperture setting. For normal daylight situations one stop was a good rule of thumb. That might be an approach that would work here.

[nzav]

Would appreciate advice from seasoned users of SF58 (or seasoned flash users).

 

I bought the SF58 a few weeks ago, and have been really pleased with it. It

really opens up more avenues of indoor photography for me.

 

 

However, in a strong backlit situation (dark foreground subject, bright background)

the flash refuses to fire, just when I need it the most! My M8.2's exposure meter

seems to be tricked into thinking there's enough light, consequently the flash

steadfastly refuses to fire.

 

I tried all sorts of things:

 

(i) dialing up the exposure setting on the flash unit to EV+1, even all the way to EV+3.

But the flash stubbornly does not fire! (This is in cases of a dark foreground subject

against a very strongly lit background, say the afternoon sun.)

 

(ii) lightly cupped my lens, and then half-pressed the shutter trigger and didn't let go,

in efforts of fooling the camera's exposure meter into thinking there's not much light.

What happens is: the flash fires alright, but the photo's overexposed.

 

(iii) as a variant of (ii) above, I fool the camera's exposure meter by first rotating the

aperture ring on my lens to a larger f-number, i.e., artificially reducing my lense's

aperture opening beyond my compositional intention, then watch for the flash icon at the

bottom of the camera's viewfinder. [The camera is set in aperture-priority mode.

The red flash icon is the symbol next to the red digits indicating shutter speed.] When

the red flash icon appears, this means the camera's exposure meter thinks there is

insufficient light, and prepares the flash to fire. What I do next is: I don't let go of the

half-press, but I rotate my len's aperture ring to a smaller f-number (for selective focus

compositional reasons).

 

(iv) the only thing that forces the flash to fire without all this tricking is to set the Mode

in the flash unit to Manual mode. In this mode, the flash fires for sure, but I lose the

TTL feedback. Consequently I have to adjust the intensity of the flash by changing

the p setting by trial and error, until I get a satisfactory balance between flash-exposed

foreground subject and the bright background.

 

 

 

So far, I use method (iii) as a workaround to this problem of coaxing the flash unit to fire.

When I want to compose using selective focus (say a portrait shot at f2 with my 35

summicron), I dial the aperture ring to f5.6 or f8, that's a 3- or 4-stop dupe, and the

red flash icon starts to appear in the M8.2's viewfinder. I then dial the aperture ring

back to f2 without letting go of the half-press, and then fully press down to shoot.

The flash invariably fires, and I get a foreground subject with enough illumination to

hold against the bright background. But the problem is the resultant photo is almost

always overexposed, and in Lightroom I have to dial down Exposure or dial up

Recovery, or both.

 

Am I missing something? Is there a TTL setting that force-fires the flash? Or some way

to isolate the needed exposure of the foreground subject, instead of averaging the bright

background into the mix?

 

Check your shutter speed - if the camera (or you) select anything over 1/250s, the flash will fail to trigger.

[marknorton]

Slower than that on an M8.2, M8u and M9 - 1/180th; very likely the camera is metering off the strong backlight to a faster shutter speed - reduce ISO, stop the lens down, use an ND filter.

[Luke_Miller]

Am I missing something? Is there a TTL setting that force-fires the flash? Or some way to isolate the needed exposure of the foreground subject, instead of averaging the bright background into the mix?

 

I don't think you are missing anything. In TTL the camera body is in charge. If it believes flash is not needed it is hard to over rule that decision.

 

If you put the flash in Auto, it is in charge of the flash exposure. It will fire and meter the flash on foreground subjects. It will quench the output when it thinks proper exposure is achieved. Since you must manually enter the lens aperture you have the ability to adjust flash exposure to your liking. By setting a larger aperture on the flash than is set on the lens you reduce the flash component of the forground exposure. And vise versa

[nzav]

Slower than that on an M8.2, M8u and M9 - 1/180th; very likely the camera is metering off the strong backlight to a faster shutter speed - reduce ISO, stop the lens down, use an ND filter.

 

Thanks for the correction Mark - I forgot the replacement shutter dropped the flash synch speed in addition to the top 1/8000s!

 

When I use fill-flash in daylight, my M8 is ususally set at 1/250s.

[ronnysoh2009]

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Thanks for all the helpful advice.

 

All the responses about shutter speed made me realise

I should switch to a different mode.

 

I finally managed to coax the flash into cooperating with me

by snapping out of Aperture-priority mode (which was my

default mode) and go into Shutter-priority mode.

 

The shutter speed is set at 1/180. Because the backlit

background is very bright, the ISO is turned down to base 160.

Aperture on the camera is set to whatever is my first compositional

intent (typically wide open), then subsequently I stop down if the

shot is over-exposed.

 

In shutter priority, at 1/180, I find the flash always fires, in those

strong backlit situations when I want its cooperation the most.

 

Thanks again .

[ho_co]

Great to hear you're getting it squared away.

 

It's likely just a case of the camera- and flash-designers trying to do our thinking for us.

 

Not something we often have to worry about with Leica.

[jaapv]

Shutter-priority mode:confused: The M8/9 don't have a shutter priority mode. Either aperture priority or manual. Of which manual is the best mode to use with fill flash to prevent the camera from running out of sync speed. Actually it is the best mode to use on the camera at any time. Far more simple to exposure-compensate in general.

[ronnysoh2009]

Hahaha, you are right. I meant user-selected shutter speed,

that's properly called Manual, isn't it? - not shutter-priority? I'm

getting a headache.

 

<Actually it is the best mode to use on the camera at any time.>(jaap)

 

During my R-D1 days I used Manual mode, but came to realise

that the camera tells me in small red digits at the bottom of the

viewfinder what the proper shutter speed needs to be. And I

then dutifully rotate the shutter speed dial to follow the camera's

suggestion. It sort of dawned on me eventually - if I'm going

to be merely a conduit to carry out the camera's suggestion,

why don't I just set the camera to Aperture-priority mode, and

avoid dialing the shutter dial up and down?

 

This habit continued on to my current M8.2 usage. I set to

Aperture-priority. However, I adjust the EV compensation as

I feel the scene or composition needs. If the scene is low-lit,

and I want the preserve the dimly-lit ambience in my shot, I

dial down the EV to -2 or -2 1/3. If there is reflection off shiny

metal surfaces and I want to capture that, I dial up the EV to +2.

 

In my mind now I'm thinking that shooting with Aperture-priority

with EV adjustments ultimately gives me the same results as full

Manual shutter speed selection. Since I have ISO electronically

committed and lens aperture manually committed, the only other

variable that EV compensation adjusts would be shutter speed.

Or am I missing something here?

[jaapv]

Yes - the exposuremeter of the M8 and M9 is strongly centre-weighed, near-spotmeter even. That means you can measure part of the scene and use that in setting your exposure. Also the configuration will tell you : red dot= spot-on, red dot+ triangle = 1/2 stop compensated only red triangle = full stop (or more if youy turn further) compensated.