GEAR TALK - Why The Leica M10 Needs EFCS, Part 2

Building on last week's post, today's installment lays out another use case where Electronic First Curtain Shutter would improve image quality. This case is mostly unique to the Leica M10 Monochrom and colored filters. Yellow, orange and red filters are used to alter (boost) contrast. Green and blue filters are generally for foliage and fog. For more information on using color filters with the Leica M Monochroms, I first wrote about this in March 2016.

COLOR FILTERS AND LIGHT LOSS

Placing a color filter ahead of the lens fundamentally changes the incoming light captured by the sensor (or film). On the Leica M Monochroms, yellow and orange filers do not alter contrast much, so I generally use light red and dark red, and sometimes stack a polarizer. The red filter reduces the amount of incoming cyan / blue light and boosts the amount of yellow / red light.

The result are whites that really pop, and blue skies that are comparatively dark, potentially very dark if the conditions are right. The trade off with color filters is light loss, and there can be alot of light lost -

• -2 EC with light red
• -3 EC with dark red
• -1 EC with a polarizer (high transmission type)

If stacking a dark red filter with a polarizer, 4+ stops of light will be lost. If trying to keep shutter speeds up due to wind and/or because of shutter vibrations, more ISO is needed. If shooting with 28mm or 35mm lenses, all this light loss is not too dire. But as the focal lengths go up, keeping shutter speeds in check is increasingly important, thus ISO creeps into the 1600-8000 range depending on the focal length.

Also, color filters are generally acrylic, so there is going to be some sharpness lost. Stacking a polarizer atop will further reduce sharpness. To counteract the lost sharpness, maybe the lens gets an extra stop of aperture (eg. - shooting F8 instead of F5.6). What might be a F5.6 1/250th ISO 100 late afternoon shot can quickly escalate to ISO 4000-8000. That means more noise and less dynamic range.

HOW EFCS WOULD HELP

Electronic First Curtain Shutter is not a universal "fix" in this case. If shutter speeds are needed due to wind and/or freezing motion, then EFCS is moot or would offer minimal improvements. However, if the scene does not require a high(er) shutter speed, then we could use a lower ISO and drag out the shutter time.

Even in the case of wind, there might be some betterment. If shooting a 200mm lens and keeping the shutter speed at 1/400th to keep vibrations in check (which is what I do today), maybe 1/180th would be sufficient to freeze motion caused by the wind. If wind or motion is a non issue, then EFCS would bring a dramatic improvement. Instead of ISO 1600-8000, now it could be ISO 160 with the Leica M10 Monochrom.

B+W MRC Dark Red Filters and B+W MRC Light Red Filters

I want EFCS added to the M10 Monochrom's firmware so I can tamp down the ISO speeds as close to ISO 160 as possible. The M10 Monochrom's tones are silky smooth at ISO 160 and I want to get that file quality as often as possible. It is addictive.

Fortunately with wider lenses, like 28mm and 35mm, I can get away with dragging the shutter (nearly all my images with filters are shot with a tripod) and keep ISO at 160 or very close to 160. But there is a tipping point around 75mm where the shutter speeds have to increase.

Hopefully the firmware wizards in Wetzlar are at hard work :)