The Leica SL Is Not A Perfect Camera (But It Could Be!)

Any frequent readers of should know that I am an avid user and big fan of the Leica SL Type 601, a mirrorless 24 megapixel camera introduced about a year and a half ago. The Leica SL was the first major production camera from Leica aimed at gaining audience with outdoor and landscape photographers who have traditionally used Nikon and Canon products.

To me knowledge, Leica has never stated that they are trying to explicitly sell the Leica SL to outdoor and landscape photographers, but a look at the specs sheet for the Leica SL and it's clear that is an audience they'd love to get. Just look at the amount of weather sealing and rubber gaskets in the camera!

Anyway, all of this is a long way of getting at the point, which is that Leica needs to issue a firmware update for the Leica SL to fix one of the (if not the) greatest pitfalls of the camera. This is the one thing that keeps the Leica SL from arguably being a contender for 'best outdoor photography' rig:

There is no way to disable the long exposure noise reduction (aka LENR).

LENR is a process that digital cameras use to remove sensor noise from a photograph, resulting in an overall better output image file. During long exposures, it is possible for hot pixels or pixels with bad information to appear, which would degrade the final image. To resolve that, engineers force the camera to take a second black "exposure" of equal length to the first image. Any bad or hot pixels will show up on the second image (which we, the user, never see) and the camera can process that bad information out of the final product. Basically it's a way of subtracting out bad data from an image, which sounds like a good thing.

A 2 minute exposure of Joshua Tree National Park - that took 4 minutes to get.

In practice, this means that if you take a 15 second exposure of waves crashing on a beach, you need to wait 30 seconds (15 seconds for original exposure + 15 seconds of LENR = 30 seconds) before you have that single photograph. 

So what's the problem? This is less of an issue for daytime photography, but most landscape and outdoor photographers also will point their camera to the night sky for star trails and galaxy shots, which is where LENR becomes a problem.

Here's why: Let's say I want to shoot some star trails, and I want to create an image where the stars curve and bend into a circle following the rotation of the earth. An image like this one.....

Star trails over Badwater Basin in Death Valley National Park, California

See those nice long star streaks in the sky? To get something like that, you need to photograph the nights sky for an extended period of time - upwards of 30 minutes. 

The traditional technique to take a photograph like this was to put it on a tripod, click the shutter open for 30 minutes or more, and wait. But what if a car drives past and puts some light into your image, or a strong breeze knocks the tripod, or a plane flies through the scene, creating a straight line of light? Your long exposure is ruined, and you have to start again. With the improvement of digital post-processing techniques, nighttime photographers now often shoot a series of shorter images (20-30 seconds on average) over a long period and stitch them together in Photoshop, creating the same star trail effect.

The technique of shooting a series of hundreds of images that get stitched together is becoming more popular, as it also lets you throw away any single exposure where a plane, car, or other light source disrupts the image without compromising the final result.

But here's where we get back to the issue with the Leica SL. Most other professional cameras let you disable LENR, and instead take a single "black" exposure with the lens cap in place during the shooting sequence. That file is imported into Photoshop with the rest of the series and Photoshop does the noise reduction processing, rather than the camera. The benefit to this approach is that the camera can spend more time shooting the stars, and you can get seamless star trails shots.

What do I mean by seamless? It doesn't take a very long exposure before a tiny bit of smearing (aka rotation) starts to show up in a star photograph. The exact time it takes before the rotation of the stars becomes visible in the image depends on a host of other factors, but the gist is that for a camera like the Leica SL with the 24-90mm f/2.8 lens, it's in the range of 20 seconds. Let's say I shoot 20 second exposures for 30 minutes and then process the files in Photoshop. Because of the LENR, I will really only have one exposure every 40 seconds, and only 15 minutes of rotation for that 30 minutes of imaging. In other words - half the star rotation would be missing!

Leica's engineers will argue that forcing LENR results in an overall cleaner image product, and as a company that expends considerable effort into creating the very best image quality, I appreciate their interest in preserving that; however, the inability to disable the LENR for nighttime shooting and do the processing in Photoshop means the Leica SL is ill suited for serious nighttime photography work.

I used some Photoshop magic to create this image- the files were all taken with the Leica SL, but I needed to be a little heavy handed with the edits to create the final product.

During the course of the Revolutions project, I photographed the sky and night at least a dozen separate occasions, and came to determine that, for now, getting star trails with the Leica SL requires a good amount of Photoshop Magic to fill in the gaps of star trails. While this cover-up technique creates some pleasing images, it's not the same as having the real thing - as having all the data.

So Leica, please publish a future firmware update and allow users to temporarily disable the LENR. Feel free to put a disclaimer in the menu warning people not to mess with the option unless they really understand the consequences. But if you make that firmware change, then the Leica SL really can compete for the title of 'best outdoor and landscape photography camera'.