SF-24D flash question

[A miller]

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Trying to figure out whether my camera is not working properly or whether my finger is not working properly.

 

Do others find that the hot shoe does not get the charge necessary to fire the flash if the shutter is pressed too aggressively hard or fast?

 

This is my experience. In some street shooting that I have been doing, the flash was only firing every second or third exposure. It was like playing Russian roulette

 

But then I tried to be a little slower and softer on the shutter, and low and behold the flash fired 8-9 times out of 10 (the one or two times out of ten it didn't was probably due to me pressing to hard/fast).

 

Anyone else experience this phenomenon?

 

Thanks in advance for your time.

 

Adam

[Tom Johnston]

sounds like your flash has to refresh before it has enough power to fire.

[A miller]

I don't think this is the reason b/c I could go several minutes b/n shots and if I press too aggressively on the shutter the flash doesn't fire. If I press much more gently, the flash fires as soon as the "ok" light turns green, which is after only a few seconds b/n shots.

[pico]

I suspect the TTL is 'computing' between the half-press to full-press of the shutter release. It needs time to do the calculations.

.

[A miller]

I suspect the TTL is 'computing' between the half-press to full-press of the shutter release. It needs time to do the calculations.

.

 

Aha, so if there aren't enough nanoseconds b/n the half-press and full-press of the shutter the calculations won't be made and the flash won't fire?

[Luke_Miller]

Aha, so if there aren't enough nanoseconds b/n the half-press and full-press of the shutter the calculations won't be made and the flash won't fire?

 

That is pretty much my experience using the SF-24D in TTL mode. A slight pause at the half-press point produces more consistent performance. I mostly use "A" mode - it gives better exposure if the background is bright (fill flash) or there is a light source in the frame. It eliminates the need for the pause and also tends to prevent the closed eyes shots from the TTL preflash.

[A miller]

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Thanks for the reply, Luke. Unfortunately for me, this happens in all modes. But I am probably. Ore aggressive with the shutter than you as I tend to be shooting strangers in the street trying to capture an expression, etc

[swamiji]

It's your finger, defiantly. Cut down on the coffee

 

All kidding aside, the M240 is the slowest M to date. It always takes an extra second or two to decide anything. Like starting, waking, this is just another one.

 

To do this type of photography I use my Monochrom.

[A miller]

Very funny!

I having this issue on my MM (I don't own an M(240))

I never try to lure anyone to my flickr page; but if you click the link you'll see some of the street photos that I have been taking recently with this flash and you'll get an idea of my workflow.

But you're right; I could definitely use less coffee...

[Luke_Miller]

Thanks for the reply, Luke. Unfortunately for me, this happens in all modes. But I am probably. Ore aggressive with the shutter than you as I tend to be shooting strangers in the street trying to capture an expression, etc

 

If you are experiencing failure to fire in Manual, Auto, and TTL - it sounds like a different problem. In TTL the camera calculates the proper flash exposure based on the pre-flash. It requires a brief time to perform that calculation, hence the pause at the half press (when the pre-flash is triggered). Typically when I am "too fast on the trigger" I get a full dump from the flash and overexposure. In Auto all flash exposure control is done by the flash. There is no pre-flash, so no pause is needed. The camera sends the ISO data to the flash, but (unlike TTL mode) the shooter needs to enter the aperture data for proper exposure. I find this mode the most consistent (other than manual). If you are getting different results it suggests a problem other than being too quick with the shutter release. Don't know about the M-240, but its been reported in this forum that with the previous digital M bodies a low (50% or less) camera battery can cause flash issues. And of course the same is true for the flash batteries.

 

I will have to verify this, but my recollection is that in TTL, if the camera thinks it can achieve proper exposure without the flash it will either not fire the main flash, or allow only very low flash output. This is why I find Auto mode much better for fill flash. In TTL the camera's meter sees the bright background and calculates little or no need for the flash. In Auto the sensor in the flash ignores the backgroubd and instead monitors the amount of flash output reflected from the subject and quenches the flash when proper exposure is achieved.

 

Another plus for Auto is that any number of non-Leica flashes work perfectly well on the M bodies. You just need to enter both ISO and aperture into the flash.

[A miller]

Many thanks, Luke, for that thorough explanation. I don't use the TTL b/c I don't like the pre-flash. So I use mostly A mode.

 

I thought I may have a faulty flash and so I purchased another one and it acted the same way. in A mode. An aggressively hard and fast press on the shutter left me shooting blanks most of the time. A gentler press worked wonders.

 

It is still possible that my hotshot on my MM is faulty. Perhaps I'll raise this with Leica NJ the next time I go there to have my sensor cleaned

 

Thanks again.

[Tom Johnston]

enjoyed seeing your pics on flickr. nice work, nice use of flash.

[Luke_Miller]

It is still possible that my hotshot on my MM is faulty. Perhaps I'll raise this with Leica NJ the next time I go there to have my sensor cleaned

 

It does sound like a hotshoe problem since it occurs with two different flashes. With a full charge on the camera body battery and fresh lithium CR 123As in the flash it should work beautifully. Some rechargeable 123As apparently cause issues.

[pico]

It does sound like a hotshoe problem...

 

 

Does anyone know if there are tests in which we can use a multimeter to find the issue?

.

[swamiji]

 

I having this issue on my MM (I don't own an M(240))

 

 

 

I would have to concur, it sounds like a hot shoe issue. My MM behaves like the M8/9 that came before it. No lag with the SF24D. My M240 however desperately needs a cup of Coffee!

[A miller]

Many thanks and sorry for the delay in my responding. Somehow I got out of the loop of my own post!

 

I think I am going to maintain the theory that my issue is due to my hyperactive, steroid-infused finger and not the hotshoe. A little while ago I installed my original flash and was able to fire off sucessive exposures with the flash with ease. I guess that something happens to my finger when I get out in the street.

 

For the avoidance of doubt, and in respect of the considered comments made herein, I will make sure that I raise this with Leica when I make my next visit, which will likely be within the next month. I will report back.

 

Thanks again and all the best,

Adam