Do I Need One?
You might benefit from a viewfinder magnifier if you can answer yes to any of the following;
- Is your eyesight not quite what it used to be?
- Do you prefer longer focal lengths over wider ones?
- Is your focusing accuracy left wanting?
- Do you find it hard to frame with the smaller framelines?
- Do you shoot with glasses and/or wider lenses?
Rangefinders, unlike SLRs, have a fixed view of the world regardless of the lens you're shooting with and you must rely on the framelines and focus patch. This isn't so much of a problem with wider lenses as the framelines in the viewfinder are larger and the depth of field inherent in such lenses is more likely to make up for slight errors in focusing. Once you pass the 50mm focal length, things get progressively harder. The framelines get smaller and more tedious to frame with and the narrower depth of field as well as limitations in the mechanics of rangefinders limit focus accuracy.
Enter the viewfinder magnifier. They come in a variety of magnification strengths, from negative to positive - and are available from several vendors. Magnifiers are primarily available from Leica Camera, Japan Exposures (formerly MegaPearls) and Match Technical. They all function in the same way, and that's to screw into the M12 × 0.5 viewfinder thread (which all models from the Leica M9 back to the Leica M3 have). That's where the similarities end, however. Below, we'll get into the specifics of each brand.
The base magnification of your viewfinder plays a large part in the effect a magnifier will have. The "standard" magnification on most Leica bodies is .72x (with a diopter of -0.5) but you can also go wider at .58x and narrower at .85x. You'd go with a .58x magnification if you prefer wider lenses, and .85x for longer. On the digital bodies, the M8 and M9, the magnification is .68x - so, a little wider than the typical Leica film body. Some consider the ultimate long-lens body to be the Leica M3, with its native .91x magnification. Understanding that, let's see what a magnifier will do.
Say you're shooting with a .72x magnification body, but you prefer shooting with a 90mm lens. The framelines are relatively small and focusing accuracy depends a great deal on your eyesight (we'll assume that the rangefinder mechanism is tuned and within specification). Depending on your general preference in focal lengths (wider or longer), you'll want a magnifier that caters to your preferences and makes shooting with those lenses a better experience... So the exact magnification needed might take a little trial and error.
Let's assume the maximum magnification available - the Leica 1.4x magnifier. This will magnify your .72x finder by 1.4x to give you a 1x (or 1:1) finder. This is considered especially useful for the aforementioned reasons (larger framelines, magnified focus patch) but also another. A 1:1 finder allows you to shoot with both eyes open as what each eye sees is identical. This is the ultimate setup for "anticipating the action," a hallmark of rangefinder photography. Conversely, if you prefer wider lenses or shoot with eyeglasses and have problems seeing the framelines near the edges - you can use a negative magnification, something like the Match Technical .85x magnifier. This would take that same .72x finder and make it a .62x.
Subtle Differences in Brands
The Leica magnifiers are arguably the best as far as optical quality. They are small and bright, come with a leash and a leather pouch that attaches to your camera strap (so it's always handy and doesn't get lost) and can accept screw-in diopter correction lenses, much like the stock viewfinder. They come in 1.25x and 1.4x strengths. Perhaps not surprisingly, they're the most expensive option - but for what it's worth, they also offer the best image quality in terms of brightness and clarity and are built robustly.
The Japan Exposures magnifiers are quite popular as they're much cheaper alternatives to the Leica Camera ones. The optical quality is good, but there is some dimming. One of the best features perhaps is the built-in diopter correction (-3.0 ~ +1.0), which allows you to dial in the correction to your exact eyesight needs. They come in 1.15x, 1.25x and 1.35x strengths. The 1.15x magnifier is quite popular as it magnifies the view just the slightest bit while still allowing you to see all but the widest framelines - but perhaps more importantly, allows for a variable diopter adjustment. These magnifiers do not come with a leash or a pouch - so storing it when removed is left up to you. These are a great combination of price, performance and options.
The newest player on the block, Match Technical - makes high quality accessories (such as the Thumbs Up! device) as well as magnifiers with integrated rubber eyecups. The eyecups come in 34mm and 42mm widths, and the magnification .85x or 1.25x. You can even get just the eyecups without a magnifier but not the other way around - all magnifiers have the integrated eyecup. Like the Leica magnifiers, these accept Leica screw-in diopter correction lenses. The downside of this brand is if you use a half-case on your camera - as it may interfere with proper fitment. Like the Japan Exposures magnifiers, these do not come with a leash or pouch either.
Phottix offers both .85x and 1.25x magnifiers, and come in both back - and silver - something no one else seems to offer. They're reasonably priced - in fact, they're the lowest cost option. They're sourced from Japan and offer multicoated optics, a camera strap friendly pouch (like the Leica version) and can also accept Leica screw-in diopter correction lenses.
On digital bodies, one additional benefit to magnifiers is that it extends the finder backwards by about 5mm or so, depending on magnifier strength. This helps keep your nose off of the LCD just a little bit.
To clean the optics of magnifiers, as well as the built-in finder - one handy tool to always have in your camera bag is a cotton swab (a.k.a. Q-Tip). Touch one end to your tongue to moisten it and clean the surface, and the other end to dry and polish. You can use lens cleaning solution as well, but the benefit of using saliva is that much like with diving masks, it helps prevent fogging to a degree.