Q2 ISO 50 broken ?

[nicci78]

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First weird thing, ISO 50 is not included in Auto ISO settings

Second, it does not expose as a real 50, but something like 60 or 80. 

Third, what you see in live view is not what you get ! You cannot expose to the right. It will give you badly over exposed final image. But it is fine in live view !

Fourth it seems that you only get better dynamic range in the shadows, but less in the highlight. Overall dynamic is may be little bit better than ISO 100. But does worth the trouble ? 

Why so poor implementation? Is ISO 50 only a marketing tricks ? With no useful application? 

Edited August 23, 2019 by nicci78

[LexS]

Forget ISO 50, and go on.

[Alain88]

LOL! I wish you never work in after sale service! ^^

[Miltz]

Not sure what you’re talking about, but 50 ISO has a noticeable image quality advantage over 100 ISO. Both in dynamic range, color, and shadow recovery. The Q2 has poor highlight recovery at all ISO, not just 50.

[nicci78]

I gave up on ISO 50. Because I have to remember to switch back from ISO 50 to Auto ISO. 

And essentially because live view histogram is not reliable at all with ISO 50 ! It is with all other ISO settings. Metering algorithms seems wrong with 50. 

I never got blown out photos when exposing to the right with auto ISO. However with ISO 50 most of them are blown out when exposed to the right ! I cannot trust histogram. Crazy 

By the way I do not see real improvement over ISO 100. I think that Leica only shifts black point in 50. And that it is just a pull ISO setting with ISO 100 as the real floor. And that’s why it not included in Auto ISO. 

Edited August 24, 2019 by nicci78

[evikne]

I don't know the Q2, but this reminds me a lot of what we have with the M10. It goes down to ISO 100, but the base ISO is higher (reputedly about 160), and iso 100 is "pulled" from that base ISO, with easily blown highlights as a consequence. That's why ISO 100 was removed from the M10's auto ISO by a firmware update after a while. 

So I guess Q2's base ISO is somewhere around 100. And with Q2's very fast shutter speed I cannot see any good reason to use ISO 50. 

[nicci78]

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Yes that’s right, I remember when Leica downgrade M10 from ISO 100 to ISO 200 in auto ISO. Jono Slack even wrote an article about M10 blown highlights 

http://www.slack.co.uk/m10-highlights.html

Therefore after several blown out photos of landscapes. I am giving up for good ISO 50. 

Q2 should be advertised as a ISO 100-25000 not 50-50000 

Edited August 24, 2019 by nicci78

[Jared]

ISO 50 is not a “pull” on the Q2 (or at least not completely) since dynamic range definitely increases.  I hadn’t noticed a difference in how it meters, but I honestly hadn’t checked for that.  Since highlight recovery is fairly mediocre with this camera at all ISO’s I don’t tend to push very hard in terms of “expose to the right” technique.  Generally, I find myself only using ISO 50 for tripod work where I’m likely to either bracket exposures (for a little extra room in terms of dynamic range) or at least be very careful in checking my results on the histogram after the exposure.  The in-camera histogram of an actual image (not necessarily in Liveview) is generally a “worst case scenario” with respect to dynamic range since it uses the 8-bit JPG.

As far as not remembering to put it back to Auto ISO afterwards... I use user profiles pretty extensively for the basic camera settings for my most common scenarios, so that makes it pretty easy to both get to ISO 50 and remember to get back to a more flexible setting.

Don’t give up on ISO 50.  The times when it is most useful—landscape work, for example—usually give you ample time to get the exposure correct, and there definitely IS a bit more dynamic range at ISO 50.

[Jared]

19 hours ago, nicci78 said:

I gave up on ISO 50. Because I have to remember to switch back from ISO 50 to Auto ISO. 

And essentially because live view histogram is not reliable at all with ISO 50 ! It is with all other ISO settings. Metering algorithms seems wrong with 50. 

I never got blown out photos when exposing to the right with auto ISO. However with ISO 50 most of them are blown out when exposed to the right ! I cannot trust histogram. Crazy 

By the way I do not see real improvement over ISO 100. I think that Leica only shifts black point in 50. And that it is just a pull ISO setting with ISO 100 as the real floor. And that’s why it not included in Auto ISO. 

You can look at Photons to Photos as well as DXO Mark.  Actual measurements show about an extra half stop in dynamic range and a corresponding improvement in signal to noise ratio.  If it were just a “pull” ISO that wouldn’t be the case.  

[nicci78]

There is reality vs DXO and PTP. My pictures are burnt, something that do not happened for years  with my other mirrorless Leicas. 

Leica shifts black level at 50 for sure. It is not even a real 50. 60 at best or maybe only 75. 

You get more DR in the shadows but less in the highlights. Overall you got a bit more DR, but I think that it does not worth the trouble to trade  headroom in highlights for more headroom in shadows. 

 

One thing is sure. I’ve got many blurry photos. Because I forgot to switch back to auto ISO ! What a bummer. 

[Jared]

It may well be a true ISO 60 or 70.  That is likely, in fact.  But some are assuming it’s simply a pull ISO.  It’s not.  

As far as forgetting to switch back... I haven’t had that problem, but I may just use the camera a little differently from you.  At the end of each photo taking situation—perhaps a particular event or scene—I switch back to my default profile.  This ensures any overrides to controls I may have made are “fixed”.  In fact, I have profiles for all my most common use cases.  One for studio (off camera strobe), one for tripod work, one for general shooting, one for action, etc.  The only one where I use ISO 50 is the “tripod” setting.  In addition it turns off OIS, turns on the rear screen, throws in a couple compositional aids, etc.  Then, when I’m done with the tripod I go back to default.  Everything gets reset.

In any event, if you don’t find ISO 50 worth the bother, I can understand that.  I hadn’t noticed any difference in metering, but I don’t push highlights that hard.  I try to leave a little headroom there.

[bags27]

I find the discussion linked below both helpful and sobering when it comes to the reality of ISO, among a number of digital issues on exposure. I am a complete dunce when it comes to the technical aspects of digital photography, but, as the below demonstrates, to get the best out of your digital camera, you really need to know this kind of stuff. Among other things, it helped me understand why I am still drawn more to film than to digital aesthetics.

http://wwwimages.adobe.com/www.adobe.com/content/dam/acom/en/products/photoshop/pdfs/linear_gamma.pdf

And nicci78, while I don't have a Q2 to discuss (still holding on to my Q), I appreciate what you say here and very much so in your discussion of a future SL2. Fingers crossed your information is correct!

[nicci78]

@Jared according to Jono Slack, in its M10 blown highlights issue.  Leica stops labelling ISO as pull and Push. Even if M10 ISO 100 is a pull setting ! 

After an early firmware update, Leica remove the possibility to chose ISO 100 in Auto ISO for the M10.  Just to avoid blown highlights. 

It strikes me, that it is so close to M10 situation. Q2 ISO 50 is not available in Auto ISO. In order to protect blown highlights? 

[nicci78]

@Jared I really liked the way you set up your profiles. I will make better use of them in CL and Q2. 

Edited August 26, 2019 by nicci78

[Jared]

43 minutes ago, bags27 said:

I find the discussion linked below both helpful and sobering when it comes to the reality of ISO, among a number of digital issues on exposure. I am a complete dunce when it comes to the technical aspects of digital photography, but, as the below demonstrates, to get the best out of your digital camera, you really need to know this kind of stuff. Among other things, it helped me understand why I am still drawn more to film than to digital aesthetics.

http://wwwimages.adobe.com/www.adobe.com/content/dam/acom/en/products/photoshop/pdfs/linear_gamma.pdf

And nicci78, while I don't have a Q2 to discuss (still holding on to my Q), I appreciate what you say here and very much so in your discussion of a future SL2. Fingers crossed your information is correct!

Well, I can certainly understand still liking film, but I wouldn’t let the complications of digital put you off.  Film has different challenges, but there are just as many and overall much less flexibility.  Things like reciprocity failure and lack of dynamic range, particularly with chromes, come to mind.  Most of all it was much harder to learn what did and didn’t work since you would have to wait for (typically) days to get any results.  As far as the aesthetics of film... Well, that’s a whole other can of worms.  I won’t go there for fear of derailing a generally productive thread.

[Jared]

1 hour ago, nicci78 said:

@Jared according to Jono Slack, in its M10 blown highlights issue.  Leica stops labelling ISO as pull and Push. Even if M10 ISO 100 is a pull setting ! 

After an early firmware update, Leica remove the possibility to chose ISO 100 in Auto ISO for the M10.  Just to avoid blown highlights. 

It strikes me, that it is so close to M10 situation. Q2 ISO 50 is not available in Auto ISO. In order to protect blown highlights? 

M10 ISO 100 may well be a pull.  I sold my M10 some time ago so I have no way of checking.

I just did a simple but real world test on my Q2, though.  It’s not “just” a pull.  I put “just” in quotes because there is certainly more room to recover highlights at ISO 100 than at ISO 50.  I would guess about half a stop more based on an admittedly limited data set. 

There is also clearly more dynamic range at ISO 50.  Even once you account for the lack of recoverable highlights.  The usable blacks go about a full stop deeper.  If I were to guess?  If you assume that ISO 100 is accurate (and there is no way to tell for sure since we know the f-stop on the lens but not the T-stop) then base ISO is actually somewhere around 70 and is “pulled” from there down to ISO 50. The light meter seems to be giving exactly the same results at ISO 50 as it would have at ISO 100.  That is, if the camera thinks 1/30s is the correct exposure at ISO 100 it also thinks 1/15s is correct at ISO 50, and the mid tones match almost identically after raw conversion, within a tenth of a stop or less.  

My best recommendation if you have a technique or experiences that let you accurately protect highlights at ISO 100 and want to maximize dynamic range/minimize shadow noise at ISO 50?  Set the camera to ISO 50, use your technique/experience to “expose to the right” as usual, then reduce the exposure by ½ stop.  

Another option (depending on the scene) that would do even better but is quite a bit more time consuming?  You could leave the camera at ISO 100, expose to the right as usual, and capture six or more exposures rather than one.  Then perform a median combine on the images.  This will get you even more usable dynamic range than the camera is normally capable of.  It also allows you to drop the color noise reduction in raw conversion to zero rather than leaving a little in place.  You’ll end up dropping your noise floor significantly, reduce moiré, maintain color details better, and won’t lose any highlight recovery.  Only downsides?  First, your scene must be static.  Second, it adds a fair amount of processing time (and drive storage space).  Third, your resolution will take a very slight hit compared to the sharpest image in your stack, though there are ways of compensating for this via appropriate up-scaling, alignment algorithms, down-sampling, and sharpening.

[Jared]

1 hour ago, nicci78 said:

@Jared I really liked the way you set up your profiles. I will make better use of them in CL and Q2. 

Yes, I have tried to set mine consistently between CL, SL, and Q2.  Very effective way to get the camera “close” for any given scenario and to keep me from having to remember what I changed and resetting when I am done.  Otherwise, for example, I would never remember to re-enable OIS when I take the camera off the tripod.  

On the Q2 I use the “default” profile as a dummy mode when I want to hand the camera to someone.  Then I have a general use profile that is appropriate for street shooting, more casual landscapes, slower-moving people and events, etc.  My next profile is for action shots.  Then I have one for studio/flash photos (where the exposure preview is disabled for “M” exposure).  Next comes the tripod profile that disables OIS and enables the real screen for composition.  Finally, I have a profile for when I want to stack images for maximum dynamic range/minimal chrominance noise.  Depending on how you use your cameras and how you think about your photography you may have a completely different set of presets.  You get the idea, though.  Fewer things to adjust as you move from one picture taking scenario to the next and (even more importantly) fewer things to remember to put back to “normal”.

[nicci78]

Thanks @Jared for the detailed answer and your insight about ISO 50 

I have also noticed the best shadow recovery. 

I will try to use ISO 50 only for certain landscape only. With compulsory chimping  

 

[Jared]

28 minutes ago, nicci78 said:

Thanks @Jared for the detailed answer and your insight about ISO 50 

I have also noticed the best shadow recovery. 

I will try to use ISO 50 only for certain landscape only. With compulsory chimping  

 

I only ever use it for landscapes myself (at least so far—I can imagine another couple uses).  And, honestly, in places where I am really trying to maximize dynamic range I would be likely to stack images anyway.  A single exposure at ISO 50 vs 100 is going to have less than one additional stop of dynamic range.  I could probably push that to two or two and a half stops and significantly drop the color noise without losing color detail by stacking images.  

Give me an hour or so and I’ll post an example...

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Hallo,

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[Jared]

1 hour ago, Jared said:

I only ever use it for landscapes myself (at least so far—I can imagine another couple uses).  And, honestly, in places where I am really trying to maximize dynamic range I would be likely to stack images anyway.  A single exposure at ISO 50 vs 100 is going to have less than one additional stop of dynamic range.  I could probably push that to two or two and a half stops and significantly drop the color noise without losing color detail by stacking images.  

Give me an hour or so and I’ll post an example...

OK, here is the example I promised... This is a quick snapshot from my backyard.  Not a dynamic image, I know, but it will illustrate the benefits (and limitations) of shooting at ISO 50 vs. ISO 100 when the dynamic range of the scene exceeds that of the camera. 

I captured and processed this image three ways.

1) I took the shot at ISO 100, f/4, 1/250s.  This was underexposed by about one full stop from what the meter was recommending.  That was just enough to avoid clipping the highlights (according to the in-camera histogram).

2) I took the shot again at ISO 50, f/3.2 (so two thirds of a stop below what I had used at ISO 100 to preserve approximately the same highlights), 1/250s.  

3) I took a dozen shots on high-speed drive mode, ISO 50, f/4, 1/250s, indicated as two stops underexposed for the scene (same exposure I used with the ISO 100 shot).

The first two pictures, the single exposures at ISO 100 and 50 respectively, were brought into Lightroom.  I sharpened them the same amount.  I added 100% shadow adjustment.  I reduced highlights just enough to indicate no clipping in Lightroom.  I brought up the exposure on the ISO 50 shot to the same middle gray as the ISO 100 shot by adding 2/3 of a stop.  Obviously, this does not give you a picture that is at all attractive, but it does maximize the visible dynamic range in the image and lets you see whether any noise is creeping into the shadows.

At web resolutions, the pictures are indistinguishable.  Here is the entire frame.

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Please bear in mind I am not trying to make an attractive image here--I'm trying to make whatever differences there are between ISO 50 and ISO 100 visible.  

Because  of my exposure adjustment between the ISO 100 shot and the ISO 50 shot, the highlights are virtually indistinguishable.  Any difference is in the shadows.

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