It happens every time I am in reflection what should be the next camera I should purchase. Because I use to love to work with rangefinder film cameras (Leica M4-P & M6) and digital cameras with “off-center” viewfinder such as the Fujifilm X-E2 & X-E2s and the compact X-30. But in the same time over the years in many action photography situations I had like better to rely on SLR models (Nikon F1-2-3HP-4) or their actual digital counterparts such as my present Fujifilm X-T20.
So the dilemma will always be there: rangefinder style or utilitarian DSLR type? For sure it depends what kind of photography which are attempting to do and which photo equipment will better suited your tastes. It is meanly a personal endorsement of material. And it is also a profound love affair (Dont try to reject that subjective argument in your choice).
Technically both categories of these digital cameras can perform almost identically for their exposure abilities, for the quality and definition of theirs pictures, for their reactivity especially for focusing, for their functionalities and interface and even for their electronic viewfinder specifications. So it is not a matter of technical limitations but there is some design caracteristics that can definite more the strength of each viewfinder positioning category.
The rangefinder love affair
At first we must say that it was the classical way of designing a photo camera. The rangefinder has been brought to photography in order to solve the focusing task of the taking lens on which it has been eventually fully couple in order to facilitate and accelerate the work of the photographer. Off-center viewfinders were the technical respond to accommodate the two independent lenses required for the telemetric purpose and the device was incorporated with the optical viewfinder used for the framing purpose. Today such technical requirements are no longer part of the focusing system into our digital camera.
But the past contraints had influenced the architectural of these film rangefinder camera models for a very long period of time. Many photographers of that time have also appreciated the compactness of the design especially with the ones that are using 35mm films. Those rangefinder cameras were far from perfect. The final picture frame appreciation was very approximative and was variable with the change of the distance between you and your subject and even more with very near areas (parallax). The interchangeability of the different focal length lenses was severely limited by the framing ability of the optical viewfinder. There was no way to get a visual confirmation of the deep of field generated by the aperture selected on the taking lens. Because of the shutter curtain type introduce into the interchangeable lens models, the shutter speed limit for the use of electronic flashes was very low. And I am sure I have forgotten other annoyances of the past.
Almost all of those problematic rangefinder specifications of the traditonal film era have been adressed by the digital new technology in a very accurately manner with functional and efficient technical solutions. Today using a rangefinder style digital camera is simply charming with the advantage to be a less intrusing for your subject who is often associating a DSLR camera style with intimidating photojournalism. The viewfinder framing past problem with the different focal lenght is no more an issue with the new electronic viewfinder technology (EVF). You got the exact framing of the final picture. The flash shutter synchro speed limit is the same as for DSLR camera type. The deep of field can be fully evaluated through your viewfinder.
So there is no formal reasons to avoid the use of a rangefinder style digital camera. And many today photo professionals are true users of models such as the Fujifilm X-Pro2 to name one among others. And that can be apply to many others types of photographers that love and share the rangefinder style design.
The DSLR domination
So why to choose a DSLR type digital camera with the event of the new performing electronic viewfinders (EVF)? You have to remember the SLR film era with the avent of mystical reflex models such as the Nikon F to name one. At that time it was a revolution that have solved many rangefinder design flaws and facilitated greatly the work of photographers especially the action ones. Precise framing, full lens interchangeability, visual deep of field appreciation, fast flash synchro shutter speed limit, centered viewfinder architecture for easy follow-up of the movement of the subject, good ergonomic with motorized film advance optionality, etc, etc. At that time there was no way that film rangefinder cameras have been able to compete with their SLR counterparts.
The “Reflex” (named because of the mirror use to reflect the image through the prisme which is preventing the reversal of the subject seen through the viewfinder) film cameras were the kings of their era that last for more than four decades. Professional news or sports photography has been associated with the look of the SLR models and SLRs were present everywhere from the fully amateur to the more advanced photographers. Manufacturers have introduced many improvements to the basic concept over the years with a huge success.
Even with the advent of the digital camera era and the introduction of higher quality electronic viewfinder (EVF), the DSLR design have maintained its appeal among the photographic community. Why? Maybe because a centered viewfinder is still the best solution to follow a moving subject when it is combined with a long focal length lens. It is obvious that it is still a more confortable way of doing action photography. Maintaining the viewfinder in the same optical axe as the taking lens is unbeatable for panning the subject with accuracy and stability of a tripod or a monopod stand. There is no “parallax phenomena” induced by the optical lens
axe and your eye view such as it can be experimented with off-center viewfinder of the rangefinder style models.
At the end the different viewfinder design schools will kept its defending lovers and the ambivalence of the choice will stay in your hands. May be the best is have the two possibilities on your side and have some “rangefinder days” and other “DSLR subject day tasks”.