UV filters from Leica
Leica has been offering ultraviolet (UV) protection filters for its lenses since 1931. Initially these filters were intended for use in high-altitude areas, where intense UV light could cause haziness and a blue color cast in images recorded on film. UVa filters block the non-visible ultraviolet A-spectrum (wavelength of 400-315nm), and thus increase the contrast and color-fidelity of images in analog photography, while not affecting exposure otherwise. As film emulsions improved over time and with the emergence of digital cameras, which are not sensitive to ultraviolet light, the role of UV filters has increasingly shifted from being color-correction tools towards becoming devices to protect the front elements of expensive camera lenses.
The earliest Leica filters were produced with slip-on mounts, but soon screw-in filters became the norm. From the 1960s onwards, these filters were labelled with an "E" (after the German word for screw-in filter: "Einschraubfilter"), followed by the thread mount diameter in mm. In parallel, Leica used Series filters for lenses with a larger diameter. These filters have plain, unthreaded black metal rims and are held in place by the lens hood or attach to the lens through an adapter. However, since the 1980s, the use of Series filters has been phased out. In the current line-up of M-lenses, there is only one lens, the Summilux-M 21mm f/1.4 ASPH, that is designed to take Series filters (but through an adapter can also be used with E82 filters).
Leica no longer produces UVa filters itself, but commissions them from specialist-manufacturers (possibly Hoya). Yet, Leica-branded filters tend to command premium prices over comparable-quality offerings from B+W, Heliopan, or Rodenstock. In return for the extra expense, the photographer gets a filter that will be compatible with the associated Leica lens hood, is available in black or silver to match the design of the lens, and carries the prestige that comes with the Leica label.
Over the years, Leica has released 32 different UV filters, some of which have become highly sought after items at auction sites. Only a fraction of the total number of designs is today in use, though. Two-thirds of all M-lenses in Leica's current product catalog use E39 or E46 filters, and Leica presently sells only five UVa filter sizes (E39, E46, E49, E55, E60).
If you spot an error in the table above or can provide missing information, please get in touch, so that we can correct and amend the data. Also, if you have a particular tip or trick to share on the use of Leica lenses that could be added to the FAQ section below, please drop me a line. Thanks!
Leica UV filter FAQ
Are there any disadvantages of using UV filters attached to a lens?
An UV filter does not influence exposure, but it represents an additional glass to air surface. This can worsen lens flare in some critical situations, such as night scenes with street lights.
What is the advantage of using an UV filter on Leica lenses?
The expensive lenses will be protected from front tube and front element damage, and keep their (collector's) value better if they don't show any cleaning marks.
Are there any alternative ways to protect the front end of the lens?
Many photographers find it sufficient to use the lens hood and cap as protection.
Are the coatings on Leica filters as good as those on B+W MRC filters?
Judging from the reflections on the surface of the filters, the high-end B+W offerings appear to have a more sophisticated coating.
Are the mounting rings of Leica filters made of brass or aluminum?
Leica's filter rings seem to be made of aluminum, and hence are lighter but possibly less solid than brass mounts (as used on B+W's MRC filters).
For which lenses with reversible hoods do Leica filters provide a superior fit?
There are a number of Leica lenses with removable sun shades where the lens hood fits so tightly that the outside diameter of the filter is critical and non-Leica filters, such as those from B+W, do not fit. Examples include the Elmarit-M 21/2.8 ASPH, Elmarit-M 24/2.8 ASPH, Elmarit-M 28mm/2.8, Noctilux 50mm/1.0, and Summilux 75mm/1.4.
Which filters can be used with the Summilux-M 21mm f/1.4 ASPH?
This wideangle lens is designed to accept Series VIII filters in the lens hood. Alternatively, screw-in filters can be used with Leica's optional adapter ring 14481. This adapter will natively take E82 filters, but can also be used without vignetting with E77 filters in connection with step-down rings.
What does UVa mean compared with UV?
UVa refers to the long-wave, "black light" part of the ultraviolet spectrum with a wave-length of 400-315nm.
What are UVa/IR filters?
UVa/IR filters were offered by Leica (and other filter brands) for use with the M8 to address issues of a magenta cast in some images due to the sensitivity of the sensor to infrared light.
Why do some filters carry the name "Leitz" and others "Leica"?
The filter designations reflect the change of branding over time.
Are Leica's order numbers unique to a particular type and version of a filter?
In general, Leica order numbers are specific to individual products. However, there are exceptions (mistakes?), such as order number 13374, which has been used for the silver version of the E55-UVa filter and also for the Leitz E55-Polarizing filter.
Many older Leica M-lenses and R-lenses have front filter mounts for series filters. You can find more information on this legacy filter system and the different series filter sizes on a dedicated page on this site. For further discussion on the pros and cons of using UV filters, Tom Axford published a nice article on the subject on dpreview. Moreover, Steve Perry actually conducted a drop test to find out to what extent a front filter protects the lens.