Leica engineers their default Auto-ISO in the M240 to go from ISO 200-800. You can change it but will you endure brutal noise? Let's find out.

 

One can generally assume that a camera maker knows its products better than....well... anyone else. When I mention the M240 to some photographers they generally tell me that it's a good camera, overall, but I should not expect to use ISO settings above 1600; max. I take most people's advice with a grain of salt. Some people's advice with a whole shaker of salt...

The scene above was shot on the streets at night. I wanted to make sure camera shake didn't mess up my images so I set the shutter speed to 1/125th of a second. Seemed to make good sense when using a 50mm lens on a camera that does not feature image stabilization. My exposure setting for this image was 1/125th of a second, f2.8 and ISO 2500. I thought the exposure was just right since the most important things in the frame are the two images in the center. I didn't want the whites to blow out into no detail land so I metered them carefully and proceeded with the exposure. 

If you enlarge the image you'll see that the main subjects, the two prints, are well exposed --- with detail in the white areas and good color overall. And you'll see that everything else falls into the shadow zones. My experience is that if you have made a competent exposure you won't be plagued by noise; at least not in anything above middle gray. The noise you will see will be in the shadow areas and will be more prominent if you try to use the shadow slider to pull up the shadows. But why would you? The shadows are there because...there were areas that fell into the deep shadow area of the exposure curve. 

If I don't make big adjustments in terms of shadow recovery the files look good. The highlight areas look really good and well saturated. The frame looks natural. But if I try to pull up the shadows by, say a stop, it's the equivalent of using an ISO in those areas equal to double the set ISO. It means the shadow areas are being exposed at ISO 5000. It's a dangerous area for an older sensor. If you push beyond a certain point; say one to one and a half stops, you will start to see chromatic noise and, eventually, banding in the shadows. 

A year or so ago this would have been a tough hurdle for an image. Too much noise in the shadows, coupled with banding is a lot to overcome when it comes to projecting technical competence of the overall system to viewers. Now, with the inclusion of A.I. driven "Denoise" in Lightroom, you have a fighting chance of saving the file even if  you do need to "lift" the shadows. But you can only go so far. 

I think Leica is far too cautious with their default Auto-ISO setting in the M240. I would feel safe in most situations with ISO 1600. Or ISO 3200 with perfect exposure and a reliance on the powers of the Denoise feature. 

Each camera is different. Each photographer has different tolerances for how much noise is too much noise in a file. I like clean files but I also like shutter speeds I can handhold. It's almost always a compromise. 

But in this case I suggesting that you try out the different upper ISOs to see where your personal tolerances lie and also that you nail exposure well enough so that you don't burn out highlights but you don't underexposure them by more than half a stop either. The less you need to increase exposure, obviously, the cleaner your files are going to look. 

This is one of a number of reasons that the older Leica M cameras (and maybe M digital cameras in general) are not a camera I'd recommend to anyone who is new to the all manual, rangefinder operating process. There's just too much pre-knowledge and testing to make it logical for everyone. 

If I shot in the dark all the time this would not be among my top choices for a camera system. Nikon, Sony and Panasonic all make full frame mirrorless cameras with much better high ISO noise profiles. Sure, they are eleven years more recent. But there it is...

ISO 200 is great for sun drenched scenes. ISOs 400-640 are great all around, general settings, ISO 800-1600 are very usable but you do head into the territory with more rewards for perfect exposures. And 3200 is surely usable with some noise reduction. Beyond that you are in Seurat Pointillism Mode. Venture there at your own risk. 

Almost all noise looks a lot less offensive in black and white. Or monochrome. Or Monochrom.