Shutter speed limitation—why?

[Jared]

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I just noticed in doing some tripod work that the electronic shutter has a maximum length of 1s. Why? Why cut it off at a different value from the mechanical shutter? Anyone know?

[jmahto]

I just noticed in doing some tripod work that the electronic shutter has a maximum length of 1s. Why? Why cut it off at a different value from the mechanical shutter? Anyone know?

How different is that from EFC (electronic first curtain)? I use EFC on tripod all the time for slow shutterspeed (often more than a sec) for Nex6. 

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[Jared]

Fully electronic shutter where both the start and stop for any given exposure is controlled on the chip

 

Vs

 

The start of the exposure is determined by the chip, but the stop is done by the shutter blocking the light.

 

Both have the potential to reduce camera motion from the shutter itself—so called shutter shock. A fully electronic shutter has the added advantage of being completely silent, and the added disadvantage of rolling shutter and potential banding under artificial light. This is because an electronic shutter typically takes 1/30s to cycle through all the rows on the chip, while a first curtain shutter can stop the exposure in perhaps 1/200th of a second (depending on the shutter).

[jmahto]

Can CL use EFC? If yes, then I won't worry too much about time limit in full electronic shutter.

[SrMi]

Can CL use EFC? If yes, then I won't worry too much about time limit in full electronic shutter.

There is no EFC on CL. If you need silent shutter then you must use the full electronic shutter.

Edited December 24, 2017 by SrMi

[jmahto]

There is no EFC on CL. If you need silent shutter then you must use the full electronic shutter.

Then 1sec limitation (if conformed) is a problem for tripod work, isn't it. With EFC, you can get away with lighter tripod for long exposure.

[SrMi]

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Then 1sec limitation (if conformed) is a problem for tripod work, isn't it. With EFC, you can get away with lighter tripod for long exposure.

You can use mechanical shutter for longer exposures. I have not noticed camera blur caused by the mechanical shutter.

[LocalHero1953]

The SL had a much faster limit on the electronic shutter until the latest firmware, when was also brought up to 1s. 

I don't know why a slower speed is not available but I suspect it's Leica's perception of heat generation, sensor noise etc, and how to keep them under control.

[helged]

The 1 sec limitation for the electronic shutter (ES) is a constraint that Leica has put on the ES. It's the same on the SL. Leica is conservative regarding to the ES, as well as noise reduction (NR) for long exposures (always on). So at present, ES is limited to 1 sec and long exposures have NR. Both might be changed in FW updates - or at least on newer versions of the CL and SL.

[jmahto]

You can use mechanical shutter for longer exposures. I have not noticed camera blur caused by the mechanical shutter.

Maybe it won't be a problem. With M240 I have noticed blur at shutter speed around 1/5 sec if I use a travel type carbon tripod. The blur disappears in longer (multi second) exposure. My theory is that for longer (multi second) exposures, the camera settles soon after shutter opening and then has no effect on blur (since shutter stays longer). Of course a sturdier tripod minimizes this effect.

 

It maybe that CL doesn't have this issue and is probably fine for multi second exposures but I certainly would have preferred EFC. I am on the fence for CL and these small things don't help. On Nex6 I can use a long lens on a much flimsy tripod without vibration. 

[Jared]

The 1 sec limitation for the electronic shutter (ES) is a constraint that Leica has put on the ES. It's the same on the SL. Leica is conservative regarding to the ES, as well as noise reduction (NR) for long exposures (always on). So at present, ES is limited to 1 sec and long exposures have NR. Both might be changed in FW updates - or at least on newer versions of the CL and SL.

Conservative in what way? What are they protecting against? Heat buildup will be the same with electronic vs. mechanical shutter, thus image degradation from thermal noise will be the same. What problem or potential problem is addressed by this limitation? I understand the required dark subtraction. Don’t like it, but I understand it. But I can’t think of any reason to allow the mechanical shutter to go longer than the electronic shutter.

[SrMi]

Maybe it won't be a problem. With M240 I have noticed blur at shutter speed around 1/5 sec if I use a travel type carbon tripod. The blur disappears in longer (multi second) exposure. My theory is that for longer (multi second) exposures, the camera settles soon after shutter opening and then has no effect on blur (since shutter stays longer). Of course a sturdier tripod minimizes this effect.

 

It maybe that CL doesn't have this issue and is probably fine for multi second exposures but I certainly would have preferred EFC. I am on the fence for CL and these small things don't help. On Nex6 I can use a long lens on a much flimsy tripod without vibration. 

 

I did some indoor test shots with my 'flimsiest' tripod (Sirui T1205X) with 55-135mm @ 135mm, switching between electronic and mechanical shutter at 1 sec and 1/25 sec. Did not notice any difference, e.g., camera blur. If there is no difference at 1 sec, I assume there would no difference at longer exposures neither. Unless others observe different behavior, it seems "shutter shock" is not an issue on CL and EFC would not solve any issue.

[Jared]

If true that theee is nonshutter shock, great. I haven’t tested with all my lenses yet, so not sure. I still haven’t read any explanation on why the limitation, though... It was clearly a conscious choice. Same limitation in the SL. Why do that?

[scott kirkpatrick]

On the SL, the electronic shutter's longest speed gets shorter as the ISO is increased.  Is that also done on the CL?  Set it to 6400 and the effect should be obvious.

[Jared]

No, it’s not like the SL. It’s just fixed at 1s. The SL approach is even dumber.

[thighslapper]

I'm sure Leica have logical and deeply Germanic reasons for limiting electronic shutter range, limiting exposure times and mandatory noise reduction..... amongst other decisions that seem at odds with other manufacturers. 

 

The real problem is they never actually explain what the logic is ...... so for the uninitiated it seems just idiosyncratic and daft. 

Edited December 25, 2017 by thighslapper

[Jared]

While I don't necessarily agree with the Tuetonic reasoning for:

• Applying mandatory aperture reduction at close focus
• Applying mandatory noise reduction when exposures exceed a certain length
• Limiting maximum exposure duration at various ISO's

They all make sense to me.  All are decisions based upon what Leica considers acceptable image quality.  They have shown that they have minimum standards and will not allow certain photographic choices if those choices would result in Leica's standards not being met.  Again, I may not agree but I can certainly understand.  

 

I have struggled with this one, though.  What could be the reasoning?  Why put a cutoff at 1s?  

 

I think I have finally come up with an explanation, though...  If the exposure is more than 1s, then Leica would want to apply--the Teutonic brain would NEED to apply--long exposure noise reduction.  But one can't take a multi-second dark frame without a shutter actuation.  And electronic shutters are supposed to be silent shutters.  The camera wouldn't be silent with a multi-second electronic shutter.  The actual exposure would be silent, but the following dark-frame would not be.  The dark frame would require the shutter to be closed.  So what to do?  1s exposure cutoff.  No dark frame required. Problem solved.  Phew.  My brain can settle down now.  I have been successfully thwarted from lowering the overall Leica image quality standard by having either: (1) a long exposure that didn't receive long exposure noise reduction; or (2) an electronic shutter that made a noise.  What a disaster those two would have been!  Thank goodness Leica has again saved me from the error of my ways.  

Edited January 3, 2018 by Jared

[jaapv]

I am sure you have hit upon the right explanation.

[scott kirkpatrick]

@Jared  -- I sent you a PM a while back about this.

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[geetee1972]

I am not sure I understand why you would need to use ES rather than mechanical shutter for long exposures. What am I missing?