M9 intermediate ISO settings

[edwardkaraa]

Does anyone have any information about the intermediate ISO settings on the M9?

Are they real hardware steps like in pro cameras from Canon and Nikon, or just pushed in the camera processor?

Any info would be greatly appreciated.

 

[edwardkaraa]

To make it clearer, I am talking about the 1/3 stop values that are in between the full stops, 160-320-640-1250-2500. If I shoot at iso 400 for instance, is it in reality iso 320 pushed 1/3 stop, in which case it would be better to stick to full stop values?

 

[arild]

Seeing as every ISO setting above base ISO 160 is pushed, then yes. It´s just that it would suck marketing wise for all the big names to say that, like ISO 80 is a pulled stop on the M9, that 200,360,400,500,640, etc, etc, are just pushed stops (with software massaging the output files).

This applies to every pro Canikon sensor out there, too. Applies to both CCD and CMOS chips from any manufacturer.

 

[jaapv]

All ISO settings above base ISO are just amplification factors - in any digital camera. It is like the volume control on an hifi. In that sense every digicam has only one "real" ISO setting and even that is in reality indeterminate. The ISO norm refers to comparability to Film ISO value, leaving the camera maker to interprete..

 

[edwardkaraa]

Thank you very much for your answers, but that was not exactly my question. I am aware that sensors have a base iso, and anything above that is signal amplification.

My question is that signal amplification in most cameras happens only at full stop iso, and intermediate steps are just interpolated by software. There were studies on the 1Ds3 and D3X that showed that these cameras do signal amplification also on intermediate iso steps, but not the lower spec models. I was wondering to which group belongs the M9.

 

[douglasf13]

I've been meaning to check this out myself at some point. Either way, I normally only use one ISO in good light and one in lowlight, and I push in Lightroom from there, so sticking to the full ISOs is fine for me.

 

[edwardkaraa]

Absolutely, Douglas. In fact it is not an important issue as I believe most people stick to full iso values as well. It is more out of curiosity than anything else. I guess a simple test can show the truth. But if the M9 does amplification at all values, it would be nice sometimes to use iso 1600 instead of 2500 for slightly less noise, knowing that it is not iso 1250 brightened with the camera software, as I'm sure LR4 would do it better.

 

[douglasf13]

From what I've seen, I wouldn't be surprised if ISO 640 pushed in LR is better than 1250, 1600, or 2500. Unless I really need a good image review on the LCD screen, I usually stick to ISO 640 and push in LR past that.

There were some examples on the Leica forum a few weeks ago that showed that pushing ISO 160 three stops in LR was a little cleaner than using ISO 1250, FWIW.

 

[edwardkaraa]

I haven't done any testing myself, but I am shocked at how well the files of the M9 push. I had to fix some grossly underexposed shots, up to 2 stops, without any visible increase in noise. However, I noticed some weird effects on the colors.

 

[jaapv]

Absolutely, Douglas. In fact it is not an important issue as I believe most people stick to full iso values as well. It is more out of curiosity than anything else. I guess a simple test can show the truth. But if the M9 does amplification at all values, it would be nice sometimes to use iso 1600 instead of 2500 for slightly less noise, knowing that it is not iso 1250 brightened with the camera software, as I'm sure LR4 would do it better.

That I can answer. 1600 has clearly less noise than 2500, the difference between 1250 and 1600 appears to be slight. That range seems to be a bit of a sweet spot.

 

[edwardkaraa]

That I can answer. 1600 has clearly less noise than 2500, the difference between 1250 and 1600 appears to be slight. That range seems to be a bit of a sweet spot.

Thank you Jaap! That's actually very interesting because sometimes an extra 1/3 stop in shutter speed can save a photo, while pushing a full stop to 2500 can make the shot unusable in color.

 

[MirekE]

Does anyone have any information about the intermediate ISO settings on the M9?

Are they real hardware steps like in pro cameras from Canon and Nikon, or just pushed in the camera processor?

Any info would be greatly appreciated.

No info; I just assume they are full stop hardware steps and so I use only multiples of 160.
The author of rawnalyze app and great community contributor known as Gabor or panopeeper was able to figure it out from a series of raw files, but he is no longer among us. Does anybody know how to do it?

 

[edwardkaraa]

No info; I just assume they are full stop hardware steps and so I use only multiples of 160.
The author of rawnalyze app and great community contributor known as Gabor or panopeeper was able to figure it out from a series of raw files, but he is no longer among us. Does anybody know how to do it?

Well, it is not easy. Most cheaper cameras will push 1/3 stop from the lower full stop iso, and pull 1/3 stop from the higher full stop iso, which makes it easy to check from the histograms of a series of shots at different iso settings.

Definitely the M9 doesn't seem to do that, so it is either pushing both 1/3 and 2/3 settings (I tend to believe that) or it is using analog gain on all intermediate settings (unlikely imho).

 

[douglasf13]

Thank you Jaap! That's actually very interesting because sometimes an extra 1/3 stop in shutter speed can save a photo, while pushing a full stop to 2500 can make the shot unusable in color.

I probably wouldn't bother. I'd just shoot ISO 1250 and boost past there in LR. Your results should be as good or better, and you won't risk blowing out highlights.

The M9 is essentially an "ISO-less" camera, in that you could just leave the camera at base ISO and boost in LR, leaving you to only focus on shutter and aperture when the light goes down.

As I mentioned above, I usually only use 2 ISOs, 160 in most light and 640 (sometimes 1250) in bad light and boost from there.

Leica does apply a little bit of noise reduction on raws above ISO 160, so I would just always leave it at 160 all of the time, but I do occasionally want to review the images that I take in lowlight on the camera's LCD, so using a higher ISO allows that.

p.s. of course, this is assuming that you shoot raw. if you shoot jpeg, ISO is more important.

 

[Godfrey]

The problem with pushing in Lightroom and other software is the available range and camera calibration. Leica and others do some good translations when amplifying the sensor gain, at the expense of some dynamic range.

There are limits to any particular process. I normally have the M9 set to either 160 or 1250 as well, but I'm not above setting it to Auto ISO and letting the camera push the sensor around for me. There's not a whole lot different in the image quality that I've seen, and it keeps my adjustment range maximized to use an ISO that nets me proper exposure.

Biggest thing I've had to learn to do differently on the M9 is set the white balance to a fixed value, particularly under any complex lighting with more than one light source. Any fixed setting will do ... correct in LR afterwards. The Auto WB setting wanders all over the place and makes adjusting a group of photos in LR a true pain if I don't.

 

[edwardkaraa]

I will have to fully agree with Godfrey. I too believe that analog gain has a few advantages over software interpolation.

Also if you believe this graph, there is a significant increase in noise even between 1/3 iso stops at high values, except strangely between 1250 and 1600 where there is practically no difference. That is why, I too tend to use the excellent combination of auto iso and minimum shutter speed settings, as they give me the optimal iso in changing conditions, unless I am shooting something specific that requires a certain iso value.

 

[douglasf13]

I was involved in a very long thread on the Leica forum, and there were several examples showing pushing in LR vs. pushing ISO in camera. One member measured the noise of ISO 160 pushed 3 stops in LR to actually be lower than using ISO 1250. I also posted example test pics unlabeled, and they were so similar that no one could definitively tell which was which.

Most newer cameras with Sony sensors behave the same way. Pushing ISO in camera is mostly only advantageous in getting a good jpeg/LCD preview with these cameras (Canon cameras and Nikon cameras without Sony sensors are usually the opposite.)

Granted, I only shoot in M mode, because I don't find A mode useful without an AEL button to lock exposure for more than one shot without recomposing, so I'm not using autoISO. I essentially shoot this camera as I would with two film speeds, but with the advantage of being able to push exposure differently for each picture, rather than needing to push the whole film role.

In using only 2 ISOs and sticking to one set WB (at least as a starting point,) it sounds like Godfrey and I shoot similarly.

p.s. For a long time, most MFDBs, which had similar Kodak sensor technology, relied on converter pushing. You could set higher ISOs, but it didn't actually raise the camera gain, but, rather, told the raw converter to boost exposure at import under the hood.

 

[edwardkaraa]

Hi Douglas,

Definitely agreed about pushing in LR, as we have previously discussed. I did push an underexposed shot 2 stops without any visible increase in noise. That was really surprising. However I noticed some shift in color balance that I wasn't very keen on.

I'm very interested in reading the thread you're mentioning. Can you please give us the link?

 

[douglasf13]

That's interesting about the color shift, Edward. Overexposing midtones has been the only evidence of shifting color that I've seen in the past (here is one little article about it ChromaSoft,) but I'll keep an eye on it.

Here are a few posts in a long thread about this and exposure in general.

Expose to the right (ETTR) or underexpose? - Seite 7 - Leica User Forum

Expose to the right (ETTR) or underexpose? - Seite 9 - Leica User Forum

Expose to the right (ETTR) or underexpose? - Seite 9 - Leica User Forum

I've really not seen any technical or visually tangible reason to use the camera's ISO boost over boosting exposure in LR4. Of course, there are certainly practical reasons, like getting a usable review image on the LCD, and that's why I don't just use ISO 160 all of the time.

One thing to also consider is that using LR4 to boost exposure, rather than the camera, may be more future proof, as raw software does improve more and more as time passes, but the camera's hardware does not. So, in the future, we may get even better performance by boosting in the converter. Right now, it seems pretty close between the two.

p.s. I'm not sure why "Jaybob" on those threads was so keen on attacking me. He doesn't seem to understand that our cameras have a single, base ISO, and boosting comes after the fact, whether it be in-camera analogue boost, in-camera digital boost, or in-converter digital boost. They're all different methods of doing the same thing.

 

[Godfrey]

... Granted, I only shoot in M mode, because I don't find A mode useful without an AEL button to lock exposure for more than one shot without recomposing, so I'm not using autoISO. I essentially shoot this camera as I would with two film speeds, but with the advantage of being able to push exposure differently for each picture, rather than needing to push the whole film role.

In using only 2 ISOs and sticking to one set WB (at least as a starting point,) it sounds like Godfrey and I shoot similarly. ...

Yes and no. I use both M and AE modes ... I'm very comfortable with tweaking the EV compensation*in AE mode based on what my eye says ... so I often set AutoISO options and work fluidly that way. I set fixed ISOs and Manual exposure mode when I know the lighting situation will confuse the metering system, or I'm shooting a bunch of frames and I want them to all be close and reflect the way the light changes in the session. When I set fixed ISOs, I just tend to find myself at the limits of either 160 or 1250 most of the time (but I've gotten some good results even at ISO 2500 with the M9, which surprised me given the amount of "miserable high iso" bleating I've read on some forums).

I'd have to look at my LR catalog to see what ISO settings were used most of the time. Normally, I don't care much once I've learned the sensor's dynamic range at different settings, and just let it float on AutoISO unless I KNOW it needs a particular setting due to scene conditions.

Since the in-camera sensitivity amplification control is a firmware control function, it can be updated just as much as raw converters can update how they process the data. How much it is updated is the question mark ... The evidence isn't conclusive that it is substantively improved any more frequently with raw conversion sw than it is with firmware updates.