OM-D E-M10 flash: 2nd-C vs SLOW2?

I have an Olympus OM-D E-M10.

In A mode, my flash options include SLOW and SLOW2, but no 2nd-C.

In S mode, my flash options include 2nd-C, but no SLOW or SLOW2.

I would like to use A mode and have the flash fire synced to the 2nd curtain.

Testing A/SLOW2 vs S/2nd-C:

I am pointing the camera at a dark corner under my desk, just to compare.

With S/2nd-C and the speed set to 1/60, the camera takes a photo just as I'd expect (the flash fires once) and it looks good. The camera used ISO 200 (in ISO-A mode) and f/3.5.

With A/SLOW2 and the aperture set to f/8, when I release the shutter, the flash fires and the shutter seems to stay open for a really long time - 30 seconds and ISO 400, if I believe the Info page in Review - the flash fires again, and the shutter finally closes. The resulting picture is a bit overexposed and blurry (apparently, from some camera movement, even though I tried to hold it still the whole time the shutter was open).

I changed the aperture setting to f/3.5 and it appears to have done a 15 second exposure with ISO 200. Again it fired the flash once at the beginning and then again at the very end. I wonder if the first flash is really a pre-flash, but it's pretty dang bright and I thought a pre-flash was supposed to be barely visible.

I have consulted the manual and I really do not understand what SLOW2 is supposed to be doing. But, according to the manual in P and A modes, SLOW2 is the only flash option that syncs to the 2nd curtain. S and M modes have 2nd-C and do not have any of the SLOW options.

Why is that?

Why can't I use 2nd-C in A mode?

Is this just a camera with really dumb flash control options? I'm guessing this is just a case of me being too ignorant to understand why it's setup the way it is....?

Am I daft for wanting to use A mode with 2nd-C for shooting fish?

Thanks for any help.

Okay, I've done more googling and reading and I think I understand what SLOW and SLOW2 are. But, I do not understand how the camera decides how long to make the exposure before it fires the flash. If it's letting it get a full exposure from ambient light, then it would not need to fire the flash at all. So, why does it choose, for example, a 30 second exposure with one flash value versus, say, a 15 second exposure and a stronger flash? Does the SLOW mode tell it to use its weakest flash setting and use the length of time with an open shutter to make up the rest? Because, apparently, comparing Forced Fill mode to SLOW mode, SLOW mode just slows the shutter and reduces the flash burn time. But how does it decide how much to reduce the shutter speed and decrease the flash time?

I still do NOT understand why my flash fires twice when I'm in A mode with flash set to SLOW2. What I read says it should fire once.

I still do NOT understand why there is no 2nd-C flash setting for A mode.

And, I also have a theory on why my flash was not firing at all in A mode. Does this sound right:

I was in A mode, set to f/11. I had not messed with it, so I believe the flash was set to Auto.

I suspect that the camera metering determined that, with f/11, a shutter speed of 1/60 was too fast for the amount of light available, or it was too dark to even determine the correct exposure value. So, it just didn't fire the flash at all. That doesn't really make sense to me, but that's all I can come up with. It seems like if that WERE the case, it would do a full dump with the flash instead of doing nothing.

I've got an M10 too, but I've never used it in any mode other than Manual, so I can't help you. Sorry.

I still do NOT understand why my flash fires twice when I'm in A mode with flash set to SLOW2. What I read says it should fire once.

 

I still do NOT understand why there is no 2nd-C flash setting for A mode.

 

Anyone? Bueller? Bueller?

Slow modes use ambient light for exposure with the flash illuminating the foreground only. A typical situation is a night shot. This mode is not very useful underwater. For second curtain shots I use manual mode with long exposures. The second curtain ensures the blur is behind the moving fish and not ahead of it

Thanks, everyone, for trying to help me. I still haven't been getting why A and P modes wouldn't allow a normal 2nd curtain sync flash. Until I was reading the manual for my Z240 strobes. Now I think I get it.

According to the Z240 manual, some cameras have "Real Time TTL Exposure Control" and some have "Pre-flash TTL Exposure Control".

I presume that my camera has Real Time TTL and I am guessing that is why it doesn't have 2nd-C in A or P.

With S or M, the camera knows exactly how long the shutter will be open, so I can time the flash correctly for right before the 2nd curtain.

But, I speculate, with Real Time TTL and A or P mode, the camera doesn't know how long the shutter will be open. It opens it and then closes it again when it's internal light meter says it has had enough exposure. Thus, it would have to predict the future in order to know when to fire the flash, if it was to be just before the 2nd curtain. It would be different if it used Pre-flash TTL in those modes, since Pre-flash means that it does the pre-flash then calculates the shutter speed before the shutter actually opens. So, in that case, it would know when the 2nd curtain was going to happen and could time the flash for just before that.

Of course, none of that really explains two questions:

How does it know in advance when the 2nd curtain will close in A/SLOW2 mode? If it knows it then, why can't it know the same thing for an A/2nd-C mode?

It uses pre-flashes for TTL in Auto mode (I believe). Why not in A or P modes? Or am I wrong about it using pre-flashes in Auto mode?

Anyway, rather than spin my wheels over it any more, I'm going to just go on with the assumption that my above explanation is correct and move onto spinning my wheels about something else. :-)

Your camera does not have real time TTL as you would need a light meter that usually does not exist in a built in strobe

so you are left with pre-flash this is why it fires twice in Slow mode but it fires anyway on first curtain. As I said I do not find this very useful

For second curtain you really want to shoot manual to be honest and you are correct the reason why it does not have the option in A mode is because it can't predict when to fire as you press the shutter

Your camera does not have real time TTL as you would need a light meter that usually does not exist in a built in strobe

so you are left with pre-flash this is why it fires twice in Slow mode but it fires anyway on first curtain. As I said I do not find this very useful

 

For second curtain you really want to shoot manual to be honest and you are correct the reason why it does not have the option in A mode is because it can't predict when to fire as you press the shutter

But, if it doesn't do real time TTL, then that means it calculates the shutter time when you press the shutter release button. In that case, it should know exactly how long the shutter will be open and, thus, when to fire the strobe for a 2nd curtain sync. Or what am I missing here?

Slow synchro and second curtain are two different things depending on the camera both 1st and 2nd curtain are available in slow mode. In both cases the flash will fire twice but if you use second curtain the pre-flash will be immediate and the second flash at closing. My camera does do second curtain and slow in A mode so the limitation is not physical. The only purpose of the slow mode is to overcome the minimum speed in normal mode that usually is 1/60. What is that you want to achieve? Are you just trying to avoid a full manual shot??

Slow synchro and second curtain are two different things depending on the camera both 1st and 2nd curtain are available in slow mode. In both cases the flash will fire twice but if you use second curtain the pre-flash will be immediate and the second flash at closing. My camera does do second curtain and slow in A mode so the limitation is not physical. The only purpose of the slow mode is to overcome the minimum speed in normal mode that usually is 1/60. What is that you want to achieve? Are you just trying to avoid a full manual shot??

Yes, I want to use A mode to ensure the Depth of Field I want. I want the camera to figure out the shutter speed for me, so I don't have to. I want 2nd Curtain sync so that if the subject is moving fast, I will get trailing motion rather than leading motion.

I'm envisioning shooting photos of sharks where I don't have time to take multiple exposures to get my M settings all just right.

Sharks are not good for second curtain or slow modes. Even slow sharks will be at 1/60 to avoid motion blur unless you want some artistic trailing effect?

Sharks are not good for second curtain or slow modes. Even slow sharks will be at 1/60 to avoid motion blur unless you want some artistic trailing effect?

I don't want to use Slow mode. If I did, I would be all set. As I said before, my camera has a SLOW2 mode, which is just that. Slow mode with 2nd Curtain sync.

And no, I don't want trailing effects. But, if the shark is moving fast enough, I might still get some blur, even at 1/60, right? In which case, I'd rather have it appear to be trailing, not leading.

Or, if the shark is coming out of a bait ball, I might get motion blur from the bait ball in the background, right? Again, I'd rather have it trailing than leading.

At 1/60 there is no difference between 1st and 2d curtain that you will be able to see. The time is too short

Using 2nd curtain is interesting but I have not figured out how to make it work properly.

I am shooting with EM5 + Inon Z-240 (the magnet pushed down). When shooting with M mode and wanting this artistic trailing effect I would obviously need to use 2nd curtain.

But when pressing the shutter, Z-240 pre flashes. After pre flash, does it have enough power for the second flash? Certainly it does not have time to charge!

Or does the pre flash effect on the picture?

Or have I understood this completely wrong?

Is there a way to disable pre flash on EM5?

Or should I just forget this effect with EM5 + Inon Z-240?

Using 2nd curtain is interesting but I have not figured out how to make it work properly.

 

I am shooting with EM5 + Inon Z-240 (the magnet pushed down). When shooting with M mode and wanting this artistic trailing effect I would obviously need to use 2nd curtain.

 

But when pressing the shutter, Z-240 pre flashes. After pre flash, does it have enough power for the second flash? Certainly it does not have time to charge!

Or does the pre flash effect on the picture?

 

Or have I understood this completely wrong?

 

Is there a way to disable pre flash on EM5?

 

Or should I just forget this effect with EM5 + Inon Z-240?

What is this "magnet pushed down" thing that you're talking about? I have 2 x Z240 Type 3s and I have no idea what that is or means.

What is this "magnet pushed down" thing that you're talking about? I have 2 x Z240 Type 3s and I have no idea what that is or means.

 

What is this "magnet pushed down" thing that you're talking about? I have 2 x Z240 Type 3s and I have no idea what that is or means.

The push button under the power setting.

 

The Automatic Cancel Circuit (I think it's called) button? Push and twist it to lock it down and that tells the strobe that the camera does not use a Pre-flash. That thing?

If your camera is doing a pre-flash and you have that pushed down, I think that's your problem. It needs to be up so that it doesn't fire a full flash when the camera fires a pre-flash.

Unless you have the flash on the camera set to manual mode.

In other words, as I understand it, even if the camera mode is M, the flash mode is still independent and can be set to Auto or Fill-in Flash or Off or 2nd-C. Or you can set the camera's flash to Manual, too, and then set its intensity to whatever value you want. On my camera, when I go into the flash menu where it shows a lightning bolt for Fill-in Flash, an icon for Red-eye reduction, a symbol for 2nd-C, etc.. The last symbol on the right is a lighning bolt with the word Full on it. That's the manual flash setting. If you arrow over to that and then pretty Info, you can cycle through the manual flash settings. And that is even when the camera itself is in Manual mode.

I THINK, in any of the automatic modes, it will pre-flash. And in manual flash mode, it will not pre-flash.

At least, that's how it is on my E-M10.

 

The Automatic Cancel Circuit (I think it's called) button? Push and twist it to lock it down and that tells the strobe that the camera does not use a Pre-flash. That thing?

 

If your camera is doing a pre-flash and you have that pushed down, I think that's your problem. It needs to be up so that it doesn't fire a full flash when the camera fires a pre-flash.

 

Unless you have the flash on the camera set to manual mode.

 

In other words, as I understand it, even if the camera mode is M, the flash mode is still independent and can be set to Auto or Fill-in Flash or Off or 2nd-C. Or you can set the camera's flash to Manual, too, and then set its intensity to whatever value you want. On my camera, when I go into the flash menu where it shows a lightning bolt for Fill-in Flash, an icon for Red-eye reduction, a symbol for 2nd-C, etc.. The last symbol on the right is a lighning bolt with the word Full on it. That's the manual flash setting. If you arrow over to that and then pretty Info, you can cycle through the manual flash settings. And that is even when the camera itself is in Manual mode.

 

I THINK, in any of the automatic modes, it will pre-flash. And in manual flash mode, it will not pre-flash.

 

At least, that's how it is on my E-M10.

I have no idea of how Automatic Cancel Circuit works but I have tested it and this is how it works with me.

With these settings

- EM5: M mode and manual flash setting 1/64

- Z-240 Automatic Cancel Circuit locked down and using power settings with M position (left side knob)

everything works fine.

If Automatic Cancel Circuit is up, the results are the same no matter what strobe power I use with the right side knob (just above of Automatic Cancel Circuit button).

The conclusion is that Automatic Cancel Circuit needs to be locked down.

When using 2nd-C there will be two flashes of Z-240 (in the beginning and in the end).That means 2nd-C is not useful.

 

When using 2nd-C there will be two flashes of Z-240 (in the beginning and in the end).That means 2nd-C is not useful.

I think the first is a pre-flash. I think if you unpress the ACC button, so it is out, then the strobe will not flash along with the first flash (the pre-flash) and it will fire with the 2nd flash.

That's what the ACC is for. To tell it that your camera is going to flash twice and that the strobe should not fire until the 2nd time the camera flashes.

With 2nd.C

- ACC down, there is a pre flash.

- ACC up, there is a pre flash.