Xjyuk

Most people use SLR because of the flexibility of using zoom/tele lenses. For some who willing to lose this flexibility, rangefinders are a good choice, because they are more compact and quite.

Now I wonder what is the design philosophy of TLRs. They share some similarities with rangefinders, though:

• More silent (because the mirror is fixed)


• Relativiely easier to shoot at slow speed while being handheld


• Not seeing the object directly via taking lens (which eventually causes the parallax error)

Compared to rangefinders, of course they are bigger, because of 1 extra lens and a space occupied for mirror. BTW, my main medium format camera is a Rolleiflex and a Rolleicord. My main reason of purchasing them is because they are such cool, retro-looking box which is a conversation starter. Of course, they fit my shooting preference: sometimes street photography, sometimes landscape, sometimes portrait, sometimes architecture, whatever not involving fast action.

My understanding is if you want a WYSWYIG camera with zoom/tele lens support, go for SLR. Or if you want a lighter/silent system, at the expense of only using prime lenses, go for rangefinder. But TLR? I still don't get it. The only advantage of using TLR to rangefinder I can think about is taking really low angle shots is easier. With a TLR, you simply put the camera on ground and pop the waist level viewfinder. Done. With a RF? I'm afraid you have to cram your face a bit on ground. Not that convenient.

The rangefinder only supports framing (with parallax), the dual-lens reflex also supports focussing. This assumes that both lenses move in tandem, and that the picture through the upper lens is viewed on ground glass.

You have to look at things in context. At the time (pre 1930's), photographic options were quite varied but all similar in design. You used some sort of external focusing aid not (Kodak pocket camera) or set up a rather large camera that projected the image onto ground glass, which would then be swapped for film.

The photographic industry has always been driven by consumers - not professionals. The design of the TLR, as Jeroen van Duyn points out, allowed the consumer to frame and focus the image. (side-note, I have a Canon SII [1940's] and can tell you that using it is very, very difficult and in bad lighting, nearly impossible. The viewfinder and parallax mechanism is very tiny and low contrast. I find myself still simply setting distance using the lens markings and only using the viewfinder to frame, not focus)

The TLR, in comparison, allows focusing for me even in terrible light - a huge win.

As you've rightly pointed out, time has made the TLR irrelevant. Rangefinder viewfinders got brighter, and SLR's took a huge chunk out of both of those markets - diminishing rangefinder producers essentially to 1 and decimating the TLR industry.

So, what are the advantages of using TLR vs. Rangefinder today? Not much - simply nostalgia and the joy of shooting them. (An argument could be made for them if you restrict your options...but leaving it open to all cameras ever made...there's a reason TLR's went out of production)

All cameras are a series of compromises, and while the TLR vs Rangefinder compromises appear small on the surface, they can actually add up to a few fairly [to some photographers] big differences.

As pointed out in the question one of the biggest advantages of TLRs and rangefinders (and scale-focus cameras) over SLRs is the lack of having to move the mirror to take a photo. But in addition to reducing sound and vibration, skipping out on the mirror in a camera design also skipped out on the engineering and reliability complexities that go with it. Much of those issues have been lessened after nearly a century engineering and manufacturing advancements, which has seen the TLR's advantages drop in importance compared to their disadvantages to the point that TLR's have effectively disappeared from the industry.

The Pro/Con list of TLRs over RF boils down along the lines of:

• TLRs can provide a larger and more detailed viewfinder than RF [Very useful for tripod work, as you can more carefully study the scene before pressing the shutter.]


• TLRs offer more flexibility in configuration with less redesign work [Consider the Mamiya C3 line of cameras: interchangeable lenses and viewfinders made for a very flexible system that could be configured for several types of photography. Reflex viewfinders, folding waist level finders, fixed chimney waist level view finders, etc.]


• TRLs naturally allow a very stable hand holding [You can tuck them in against your body, cradling it in your hand while it hangs from the strap, as opposed to holding the camera up by your face.]


• TLRs larger design nature translates into a natural robustness and stability with lower risk of elements getting out of alignment. [They're big boxes, and the moving parts they have tend to not be as small or delicate as what is required for a compact RF. And if you're not making them small and delicate, then your RF is giving up a lot of its advantages over the more easily designed TLR.]

But that then leads to their downsides...

• TLRs aren't as easy to carry around due to their larger weight and size [And designing one as a 'folder' is not only difficult, but also gives up much of the design's robustness.]


• Lenses are more difficult and expensive to produce to high quality [As long as angle of view matches, you can get away with a far cheaper Viewing Lens, but it still tends to be a larger lens than used on RFs if you want the TLR's viewing advantages.]

In the end, SLR tech caught up enough to limit a TLR's usefulness in the market to the point that they were edged out. The value of its advantages weren't strong enough to outweigh its disadvantages. [Which ironically were mostly its weight...]