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My experience with the 50SL f/1.4


vcalanog

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Brought it with me on a trip over the holidays. Nowhere near as comprehensive review as Sean Reid's - but here's my take on the lens, published by Leica San Francisco:

 

http://www.madeinwetzlar.com/on-vacation-with-the-leica-sl-summilux-50mm-f-1.4

Nice post with images.

One comment and question – why did you need to shoot with the ND3? Did you overlook the fact that SL can shoot with the electronic shutter at 1/16,000 sec ?

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Nice post with images.

One comment and question – why did you need to shoot with the ND3? Did you overlook the fact that SL can shoot with the electronic shutter at 1/16,000 sec ?

I think if you have an ND filter that would always be preferable than having to resort to using an electronic shutter. I've read elsewhere that on the Sony A7rII, the electronic shutter reduces the IQ. I am guessing it would do the same on the SL so if you have an ND filter better to make use of it.

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I think if you have an ND filter that would always be preferable than having to resort to using an electronic shutter. I've read elsewhere that on the Sony A7rII, the electronic shutter reduces the IQ. I am guessing it would do the same on the SL so if you have an ND filter better to make use of it.

 

But the quality of the filter matters, too...  http://www.l-camera-forum.com/topic/268234-nd-filter/?p=3207820

 

Jeff

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I think if you have an ND filter that would always be preferable than having to resort to using an electronic shutter. I've read elsewhere that on the Sony A7rII, the electronic shutter reduces the IQ. I am guessing it would do the same on the SL so if you have an ND filter better to make use of it.

 

1.  This ^^^

 

2.  And the fact that I DID bring a large a** E82 Heliopan 3-stop ND filter with me. Figured I'd use it. 

 

3.  Plus, sometimes I was shooting about a hundred feet from shore, by one of the longest sand bars I'd ever seen, on a rather windy day.  Much preferred cleaning the sand and beach gunk out of a filter versus my lens.

Edited by vcalanog
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Hi

Nice article. Have you tried M 50 APO on SL. If so where do you sit regarding AF versus compactness?

 

More generally, can someone point me in the direction of the pros and cons of electronic shutters? Just reading IQ points made above.

 

Best and thanks

 

Murray

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I think if you have an ND filter that would always be preferable than having to resort to using an electronic shutter. I've read elsewhere that on the Sony A7rII, the electronic shutter reduces the IQ. I am guessing it would do the same on the SL so if you have an ND filter better to make use of it.

 

 

No reason I am aware of that an electronic shutter would be inferior to a ND filter.  The electronic shutter in the Leica is not a true EFCS or a "silent" shutter as in the Sony cameras.  On the Leica, the mechanical shutter runs for most exposures, but a rolling electronic shutter is added in at very high shutter speeds.  

 

Here is what happens at slower shutter speeds--when the electronic shutter is turned off:

 

1) When you look through the viewfinder, the shutter is left open and a rolling electronic shutter is used to provide an image to the EVF; that's purely an electronic shutter.

2) You press the shutter release.

3) The EVF function is turned off, the mechanical shutter is closed, and the CMOS chip is emptied of charge, preparing it for an exposure

4) The lens iris is stopped down to your chosen f-stop

5) The first curtain of the shutter is released and starts to pass in front of the CMOS chip, exposing it to light; the CMOS chip collects the light as charge.

6) At the right point in time, the second curtain of the shutter is released to close the shutter; this may be before or after the first curtain has completed its trip across the imaging plane, depending on the shutter speed selected.

7) At some point after the second curtain has been released, the individual rows are read out by the camera.  The rate chosen for readout is carefully chosen since the faster you choose to read out the image, the more read noise you introduce; typically, readout is something like 1/15s - 1/30s for most modern CMOS chips since that provides a reasonable compromise between read noise and the ability to maintain good performance with regard to image black-out, frames per second, etc..

8) Once the last row has been read out, the shutter is opened again, and the electronic shutter is again used to provide an image back to the viewfinder.

 

If you enable the highest shutter speeds on the Leica SL, there is a slight modification to the above process.  The entire CMOS chip is NOT made light sensitive as soon as the shutter has closed (step 3 above).  It is still emptied of charge, but it is NOT turned back on into a light sensitive mode.  Then, after the first curtain has started to drop (step 5 above), the individual lines are turned on only a tiny fraction of a second (1/16,000s or 1/8,000s) before the second curtain is about to pass in front of that part of the chip, thus providing a shorter exposure window than the mechanical shutter could have on its own.  

 

There should be no image quality issues related to this process in the SL.  The issues on the Sony A7RII are somewhat different.  In the Sony, an EFCS mode allows you to reduce shutter shock by having the first curtain stay out of the way for virtually the entire exposure.  The individual lines are only turned on at the right time before the second curtain comes down.  No problem at faster shutter speeds--it would be just like the Leica implementation in practice--but at slower shutter speeds you can get banding issues with non-continuous light sources like fluorescent lights or even LED's (can especially be an issue with dimming LED's where you don't really have any idea what the pulse width is going to be so you can't just avoid multiples of 60Hz like 1/30s or 1/15s).  

 

In addition, the Sony has a silent shutter mode that allows the camera to rely on the electronic shutter alone--no mechanical shutter at all.  This can cause issues with rolling shutter effect, depending on your subject and shutter speed.  A mechanical shutter tends to reduce these effects since, for the most part, all areas of the CMOS chip are exposed at or near the same time.  In addition, though, the silent shutter mode in the Sony has a second problem.  The way the electronic second curtain works is by reading out the row.  That means the read-out needs to be faster than with a mechanical second shutter since the read out can't lag or you'd throw off your exposure.  When you read out the chip that fast, you increase read noise and Sony even resorts to lowering bit depth to get a fast enough rear curtain electronic shutter.  That definitely will degrade image quality somewhat, but it's really only relevant in cameras that have a "silent mode" (full electronic shutter) rather than EFCS with a mechanical second curtain.  You can see this in the tests of the A7RII; the EFCS and mechanical shutter have identical read noise while the silent mode has higher read noise.  In general, I think many users of the A7RII have been pleased with silent mode for situations like weddings where it really is nice to be silent, but the advantages for street photography are less obvious because of the rolling shutter effects you get.

 

Sony introduced the EFCS mode into the A7 series of cameras because of the extremely high resolution CMOS chip.  Shutter shock was, in many instances, throwing away all the extra resolution the 42mp camera should have been capable of.  I don't know whether that's because Sony did a poor job of damping the shutter, or whether it's just not possible to remove enough vibration to allow the high resolution sensor to shine without EFCS.  In any case, it certainly shows that even tiny differences in technique will have an impact on picture resolution once you start raising the megapixel count really high.  

 

I know, that was kind of a long winded explanation, but the net result is that there is no reason to avoid using the electronic shutter mode in the SL vs a neutral density filter.  The issues with image quality and electronic shutter functionality in the Sony are related only to "silent mode" not to any modes where the second curtain is mechanical.  

 

- Jared

Edited by Jared
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Regarding the electronic shutter, I don't know if i'm right here, but my impression is that it is definately silent. There is no hint like sound or vibration when I fire at 16000. The mechanical shutter appears to have no active role at all..?

 

Maybe my misunderstanding of what you wrote/meant

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No, you're not misunderstanding.  If it is completely silent, then I was mistaken in my post above.  It means that it is a fully electronic shutter, not just a high-speed EFCS.  That has the potential to be bad in terms of ultimate image quality.  When implementing a purely electronic shutter at high shutter speeds the manufacturer has to make a choice.  The mechanical shutter is simply left open for the entire experience (hence the silence).  Then, the rows are emptied of charge, made light sensitive one row at a time for a very brief interval, and read out.  

 

If you read the lines out at the normal rate (something like 1/15s to 1/30s is typical in order to get through all 4,000 rows--with overlap, of course), then you run the risk of seeing rolling shutter effects.  The other option is to speed up the readout process and try to get through all 4,000 rows much faster.  This is what Sony did with the A7RII, for example.  This will avoid the rolling shutter effect, but will increase read noise (and in Sony's case also required that they lower bit depth).  

 

So I should back away from what I claimed earlier.  With a silent, fully electronic shutter vs. an EFCS there IS potential for image quality degradation, depending on implementation.  I made the mistake of working off memory, that the second curtain still was used with the high shutter speeds on the SL.  My apologies for not confirming this before posting earlier--should have double checked.  

 

Assuming you are correct, Lynx, that it is a silent shutter, Leica may have taken either approach.  They may still read out at the same rate and run the risk of rolling shutter effect, or they may speed up the readout process and trade some increased read noise for less risk of strangely distorted images.  Honestly, I don't know which approach they took or which I would consider "superior" since they each have advantages depending on the situation.  It is probably easier to make a firmware change that leaves the read-out speed in tact, but the only way to tell for sure would be to measure the noise levels in both situations.  And you'd have to do it in a fairly well let situation to make sure read noise dominates over shot noise or you won't find a difference.  I'll see if I can run a test this weekend to see.

 

- Jared

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OK, I did some testing this morning to see how Leica implemented the electronic shutter.  I'll post a separate thread in order to avoid moving any farther off topic, but in case anyone checks here...

 

- The electronic shutter at 1/12,500s and at 1/16,000s is not an electronic first curtain (as Lynx pointed out above).  It is completely silent, and the mechanical shutter is not used at all.  Sorry for getting that wrong earlier.

- I measured the signal to noise ratio on multiple images taken at 1/8,000s (mechanical) and at 1/16,000s (electronic), and the signal to noise ratio is measurably better with the mechanical shutter, so theoretically one would get a higher quality image with a neutral density filter than with the electronic shutter.  I doubt the difference is enough to be visible unless you are pushing the exposure pretty hard in post processing, but it's easily enough to measure, so if you want to shoot wide open at base ISO with your Noctilux under bright daylight and want to preserve the best possible technical image quality in terms of SNR, you are, indeed, better off using an ND filter rather than the electronic shutter.

 

I'll create a new thread for anyone who is interested in reading more.

 

- Jared

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OK, I did some testing this morning to see how Leica implemented the electronic shutter.  I'll post a separate thread in order to avoid moving any farther off topic, but in case anyone checks here...

 

- The electronic shutter at 1/12,500s and at 1/16,000s is not an electronic first curtain (as Lynx pointed out above).  It is completely silent, and the mechanical shutter is not used at all.  Sorry for getting that wrong earlier.

- I measured the signal to noise ratio on multiple images taken at 1/8,000s (mechanical) and at 1/16,000s (electronic), and the signal to noise ratio is measurably better with the mechanical shutter, so theoretically one would get a higher quality image with a neutral density filter than with the electronic shutter.  I doubt the difference is enough to be visible unless you are pushing the exposure pretty hard in post processing, but it's easily enough to measure, so if you want to shoot wide open at base ISO with your Noctilux under bright daylight and want to preserve the best possible technical image quality in terms of SNR, you are, indeed, better off using an ND filter rather than the electronic shutter.

 

I'll create a new thread for anyone who is interested in reading more.

 

- Jared

 

Great test!

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