Can someone give me a real dummies guide to using sf24d on my MP please?

[Jodad]

Advertisement (gone after registration)

Hey everyone. I picked up an sf24d the other day and I’m trying to use it on my film MP in Automatic mode.

using Manual mode seems slow(er) and perhaps too much for my little brain so, for now, I’d rather stick with A mode.

I know I need to set my film iso on the flash. As for the aperture on the flash, should I meter the scene with my ambient meter, set the settings on the camera using whatever setting combo want at or below flash synch speed and then set that same aperture on the flash?

Say I’m shooting at night, do I meter for the ambient and transfer those settings to camera and flash? So f2 @ 1/8 on camera and f2 on the flash? Or do I just set shutter on camera to 1/50 (to minimise shake as much as poss) and f5.6 on lens (bit more dof) and flash to 5.6 and just shoot?

What about during the day?

it’s just not clicking for me…

 

if you could please give me a dummies step 1, step 2, step 3, that would be really appreciated!

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[giannis]

I don't know that particular flash, but what I'm gonna say applies to all flashes.

When the flash is used in an "auto" mode (non-ttl), it uses its own lightmeter to determine exposure. Its only way of controlling exposure is by the duration that it keeps firing, so using its lightmeter, the moment that appropriate exposure is reached, it will rapidly cut off the flash light. To be able to do that calculation, it needs the ISO and the aperture used. Shutter speed doesn't play a role in this calculation.

Roughly speaking, shutter speed will affect the exposure of things that are not considerably lit by flash. At night for instance, those would be the some distant streetlamps, roads, building windows, etc. . Regardless whether you choose 1/50 or 1/2, your subject's exposure will be the same (and controlled by the flash), the only thing that will be differently exposed is anything not lit by flash. Similarly, camera shake is not an issue, shake will only affect anything not lit by flash (like the examples above). Your subject will be frozen, because it'll be predominantly lit by the flash which has a duration between 1/500 and 1/20,000 (depending on powerlevel, flash type, etc.), so this will be the "effective" shutter speed as far as your subject's motion is concerned.

In general don't overthink it. Do you want distant objects (not lit by flash) to be brighter or to be a bit motion blurred? Slow shutter speed. Do you want them darker a nd less motion blurred? Faster shutter speed.

About aperture, you can choose any you like, depending on DoF you want *and* how far you want the flash to reach. The flash has a finite amount of light it can emit, and it modulates that amount to give you correct exposure for the aperture chosen (again, shutter speed is irrelevant). However if you stop down a lot, the flash even at full power might not be able to provide enough light for correct exposure. Similarly if your subject is further away (twice as far away means 4 times as much power needed from your flash). Usually, in night photos, you open up the aperture (aside from DoF concerns) if you're using a smaller flash and/or want the flash to be able to illuminate adequately subjects further away. To give you an example, say you have a small flash with guide number of 22 (in metres). This means, at full power and ISO 100, for a subject at 2m the flash can illuminate them properly at an aperture of f/11 (because 2*11=22, your guide number). What if you needed a group photo though and your subjects were at 5,6m? Then you'd need an aperture of f/4 (5.6*4=~22). In this case, if you chose a narrower aperture, your flash at auto would still try but fail to adequately illuminate the subject. Most flashes give an indication (in form of flashing light on the back or something) when this happens, after the exposure. (the flash has no way of knowing this is gonna happen before the exposure is taken). So, in general, a good rule of thumb is, not to use very stopped down apertures for further away subjects at night, especially with smaller flashes.

 

8 hours ago, Jodad said:

Say I’m shooting at night, do I meter for the ambient and transfer those settings to camera and flash? So f2 @ 1/8 on camera and f2 on the flash?

Just to be clear, no you don't meter for ambient. If you did so and put those settings in your flash, the flash probably wouldn't fire at all (or fire at the lowest possible level), because measuring for ambient means you're giving the camera correct exposure just with ambient light, no need for flash. Measuring ambient light only becomes relevant with manual flash in scenarios like fill flash. Or any scenario when you try to have the flash not dominate the exposure (for instance, trying to balance your settings so ambient light is 1 stop darker than what you set on the camera shutter speed, with the intention that flash will contribute the other stop, making the exposure 50-50 in terms of ambient and flash contribution. In typical, non-fill flash exposures, ambient is 3-5 stops darker than flash, so it contributes very little to the exposure).

All in all, I'd say choose a reasonable aperture in terms of DoF but also how far away your subject is (better be safe and choose wider than narrower aperture when in doubt), and secondarily whatever shutter speed you like depending on how bright or dark you want the distant objects to look (they'll always look darker than your flash lit subject, so this choice is more about whether they'll be pitch black or somewhat discernible).

If you 

[Huss]

If you use the flash, you have to manually set the shutter speed to the sync (1/50) or slower.  Depends on how much motion blur you want.

Set the SF24D to A. Set the ISO on the SF24D.  Set the aperture on the SF24D - and as you change it you will see the effective distance covered change. 

For the flash to sync properly you need 1/50 or slower.  If that is not available in daylight shooting (too bright) then you will not get a 'correct' exposure.

 

[Jodad]

21 hours ago, giannis said:

I don't know that particular flash, but what I'm gonna say applies to all flashes.

 

Giannis, this was so good and clear to read that i literally went out of the house with my camera and flash at 01:30 I the morning because I was so excited that I now knew what to do.

Flash was always something I thought  would be very useful for me and now thanks to you it seems really quite intuitive and i feel like a door to low light photog has been opened to me. Thanks again Giannis :))

[Jodad]

21 hours ago, Huss said:

If you use the flash, you have to manually set the shutter speed to the sync (1/50) or slower.  Depends on how much motion blur you want.

Set the SF24D to A. Set the ISO on the SF24D.  Set the aperture on the SF24D - and as you change it you will see the effective distance covered change. 

For the flash to sync properly you need 1/50 or slower.  If that is not available in daylight shooting (too bright) then you will not get a 'correct' exposure.

 

thanks Huss, this was also very clear and simplified to me  very glad I asked in this forum!

[Huss]

Just remember the aperture set on the flash and camera must match!  And of course the ISO on the flash must match the ISO of the film in the camera.

[Jodad]

Advertisement (gone after registration)

5 hours ago, Huss said:

Just remember the aperture set on the flash and camera must match!  And of course the ISO on the flash must match the ISO of the film in the camera.

I’ve finished off a roll of 36, I’ll develop it this week and see what I get. Very excited! If I’ve gotten it right(ish) this will be a whole new way for me to photograph in situations that I otherwise would have left the camera at home. 

[grahamc]

On 1/29/2022 at 8:10 AM, giannis said:

I don't know that particular flash, but what I'm gonna say applies to all flashes.

When the flash is used in an "auto" mode (non-ttl), it uses its own lightmeter to determine exposure. Its only way of controlling exposure is by the duration that it keeps firing, so using its lightmeter, the moment that appropriate exposure is reached, it will rapidly cut off the flash light. To be able to do that calculation, it needs the ISO and the aperture used. Shutter speed doesn't play a role in this calculation.

Roughly speaking, shutter speed will affect the exposure of things that are not considerably lit by flash. At night for instance, those would be the some distant streetlamps, roads, building windows, etc. . Regardless whether you choose 1/50 or 1/2, your subject's exposure will be the same (and controlled by the flash), the only thing that will be differently exposed is anything not lit by flash. Similarly, camera shake is not an issue, shake will only affect anything not lit by flash (like the examples above). Your subject will be frozen, because it'll be predominantly lit by the flash which has a duration between 1/500 and 1/20,000 (depending on powerlevel, flash type, etc.), so this will be the "effective" shutter speed as far as your subject's motion is concerned.

In general don't overthink it. Do you want distant objects (not lit by flash) to be brighter or to be a bit motion blurred? Slow shutter speed. Do you want them darker a nd less motion blurred? Faster shutter speed.

About aperture, you can choose any you like, depending on DoF you want *and* how far you want the flash to reach. The flash has a finite amount of light it can emit, and it modulates that amount to give you correct exposure for the aperture chosen (again, shutter speed is irrelevant). However if you stop down a lot, the flash even at full power might not be able to provide enough light for correct exposure. Similarly if your subject is further away (twice as far away means 4 times as much power needed from your flash). Usually, in night photos, you open up the aperture (aside from DoF concerns) if you're using a smaller flash and/or want the flash to be able to illuminate adequately subjects further away. To give you an example, say you have a small flash with guide number of 22 (in metres). This means, at full power and ISO 100, for a subject at 2m the flash can illuminate them properly at an aperture of f/11 (because 2*11=22, your guide number). What if you needed a group photo though and your subjects were at 5,6m? Then you'd need an aperture of f/4 (5.6*4=~22). In this case, if you chose a narrower aperture, your flash at auto would still try but fail to adequately illuminate the subject. Most flashes give an indication (in form of flashing light on the back or something) when this happens, after the exposure. (the flash has no way of knowing this is gonna happen before the exposure is taken). So, in general, a good rule of thumb is, not to use very stopped down apertures for further away subjects at night, especially with smaller flashes.

 

Just to be clear, no you don't meter for ambient. If you did so and put those settings in your flash, the flash probably wouldn't fire at all (or fire at the lowest possible level), because measuring for ambient means you're giving the camera correct exposure just with ambient light, no need for flash. Measuring ambient light only becomes relevant with manual flash in scenarios like fill flash. Or any scenario when you try to have the flash not dominate the exposure (for instance, trying to balance your settings so ambient light is 1 stop darker than what you set on the camera shutter speed, with the intention that flash will contribute the other stop, making the exposure 50-50 in terms of ambient and flash contribution. In typical, non-fill flash exposures, ambient is 3-5 stops darker than flash, so it contributes very little to the exposure).

All in all, I'd say choose a reasonable aperture in terms of DoF but also how far away your subject is (better be safe and choose wider than narrower aperture when in doubt), and secondarily whatever shutter speed you like depending on how bright or dark you want the distant objects to look (they'll always look darker than your flash lit subject, so this choice is more about whether they'll be pitch black or somewhat discernible).

If you 

This is extremely useful, thanks.    I hope the OP doesn’t mind me asking a question here as I’m curious to know how this logic differs for TTL flash (I own the M6 TTL and SF24D ).  
 

I often wonder the difference between TTL and Auto and have thought it’s simply that the flash will ‘read’ the ISO automatically.   I still believed that I need to set aperture on the flash to correspond with aperture on the lens.  
 

However the other day I shot a roll where I’m pretty sure I forgot to alter the aperture setting on the flash to match the lens , and to my surprise the exposures came out very well.  This has made me question whether setting aperture is needed when using TTL flash metering.  Perhaps not if it’s “through the lens” ?

If aperture is not needing to be set for TTL flash use, then it is definitely a good choice for forgetful people like myself  

thanks in advance if you can help. And I’ll definitely use the logic you have explained on my non-TTL M6 

[Huss]

2 hours ago, grahamc said:

This is extremely useful, thanks.    I hope the OP doesn’t mind me asking a question here as I’m curious to know how this logic differs for TTL flash (I own the M6 TTL and SF24D ).  
 

I often wonder the difference between TTL and Auto and have thought it’s simply that the flash will ‘read’ the ISO automatically.   I still believed that I need to set aperture on the flash to correspond with aperture on the lens.  
 

However the other day I shot a roll where I’m pretty sure I forgot to alter the aperture setting on the flash to match the lens , and to my surprise the exposures came out very well.  This has made me question whether setting aperture is needed when using TTL flash metering.  Perhaps not if it’s “through the lens” ?

If aperture is not needing to be set for TTL flash use, then it is definitely a good choice for forgetful people like myself  

thanks in advance if you can help. And I’ll definitely use the logic you have explained on my non-TTL M6 

The OP has an MP which does not have TTL flash, nor does it communicate ISO set from the camera to the flash. 

Your TTL cameras do communicate the ISO from camera to the flash, and in TTL mode it reads the light through the camera not through the flash (if the flash was in A mode) so you have a much larger selection of apertures that you can use.  As you found out, you do not set the aperture on the flash in TTL mode, the camera takes care of it.

[giannis]

18 hours ago, grahamc said:

I often wonder the difference between TTL and Auto

TTL uses the camera’s meter, through the lens, to control flash exposure rather than using the separate meter on the flash. (And yes with TTL you don’t set the iso since it’s communicated automatically by the camera). 
 

The main difference with TTL is that you can bounce your flash, or shoot it off the camera or through modifiers (softbox/umbrella/etc.) and the metering will be correct, since you’re measuring what’s reaching the lens. In “Auto” (using the flash’s light meter), if you bounce the flash or take it off camera to fire it from an angle, what’s reaching the lens is not gonna be the same as what light is reaching the metering cell on the flash (which is now pointing at a different direction), so exposures will be off. Similarly, many modifiers will actually cover the metering cell of the flash, giving wrong exposures. 
 

Secondarily, with TTL the metering area in your camera is well known so you have a more accurate idea of how metering will work. This is not much of an issue in terms of accuracy with focal lengths around 35mm, but for longer focal lengths (and shorter), the TTL meter will be increasingly more “accurate” since the area metered changes to correspond to a specific percentage of the image. With Auto, the flash has a fixed angle for the metering. Use a long enough lens (could be just 75mm), and the metering spot covers your whole frame (and even stuff outside it). Use  a wide enough lens, and the metering area only covers a part of your frame (like a partial metering partent).

Edited February 8, 2022 by giannis

[grahamc]

Thanks @Huss, Thanks @giannis this is very helpful 

That's interesting about the bouncing or diffusing, I hadn't thought of that 

Thanks again 

[philipus]

Excellent explanation. The SF24D is really a superb flash in TTL mode.

 

3 hours ago, giannis said:

TTL uses the camera’s meter, through the lens, to control flash exposure rather than using the separate meter on the flash. (And yes with TTL you don’t set the iso since it’s communicated automatically by the camera). 
 

The main difference with TTL is that you can bounce your flash, or shoot it off the camera or through modifiers (softbox/umbrella/etc.) and the metering will be correct, since you’re measuring what’s reaching the lens. In “Auto” (using the flash’s light meter), if you bounce the flash or take it off camera to fire it from an angle, what’s reaching the lens is not gonna be the same as what light is reaching the metering cell on the flash (which is now pointing at a different direction), so exposures will be off. Similarly, many modifiers will actually cover the metering cell of the flash, giving wrong exposures. 
 

Secondarily, with TTL the metering area in your camera is well known so you have a more accurate idea of how metering will work. This is not much of an issue in terms of accuracy with focal lengths around 35mm, but for longer focal lengths (and shorter), the TTL meter will be increasingly more “accurate” since the area metered changes to correspond to a specific percentage of the image. With Auto, the flash has a fixed angle for the metering. Use a long enough lens (could be just 75mm), and the metering spot covers your whole frame (and even stuff outside it). Use  a wide enough lens, and the metering area only covers a part of your frame (like a partial metering partent).

[grahamc]

1 hour ago, philipus said:

Excellent explanation. The SF24D is really a superb flash in TTL mode.

 

Agree on both points ! 

[Huss]

Funny thing is I have two SF24Ds - because I thought the first one was defective as it would not consistently work/sync with my old M-E (M9).  It ended up that the M9 series of camera was at fault.  If the battery in the camera gets below 1/2-1/3 full, it no longer works properly w the flash!!

No issues using my SF24D with any other camera - film Ms, M240, R7, R9, even Nikons!

[madNbad]

When used with TTL enabled bodies, the SF24/24d shows a proper exposure conformation in the viewfinder. After the flash has fired, the lightning bolt will flash several times to indicate enough light has reached the subject. 

[grahamc]

3 hours ago, Huss said:

Funny thing is I have two SF24Ds - because I thought the first one was defective as it would not consistently work/sync with my old M-E (M9).  It ended up that the M9 series of camera was at fault.  If the battery in the camera gets below 1/2-1/3 full, it no longer works properly w the flash!!

No issues using my SF24D with any other camera - film Ms, M240, R7, R9, even Nikons!

Interesting ! That’s not great for a Leica-Leica product 

[Huss]

4 hours ago, grahamc said:

Interesting ! That’s not great for a Leica-Leica product 

The blame was on the camera, not the flash.  The flash works great with every other camera.  The M8 and M9 were really half baked products. .