It can be difficult to understand the many different types of camera out there, and which is best for you. If you are looking for an analog system, chances are you are going for a SLR or TLR.
Both cameras work in different ways, and have different advantages and disadvantages. From working with both types of camera, I would like to breakdown a few differences between the two.
What is a TLR?
A Twin-lens Reflex is a camera with two lenses, each with the same focal length. Each lens has a different purpose; one lens is the viewfinder and the other captures the scene. The connected lenses move together, allowing the film to be as focused as the viewfinder.
These cameras aren’t used at eye level, yet rather held at the waist/hip level, viewing the scene by looking down. This is the reflex part, where the scene reflects on the interior mirror and to the viewfinder. This had an added stability benefit as opposed to only hand-held shooting. The Reflex refers to the 45-degree mirror inside the camera allowing the viewer to look down into the camera.
An example of a Twin Lens Reflex would be the Rolleiflex 2.8F.
The classic Rolleiflex TLR by Juhanson
What is an SLR?
A Single-lens reflex is a camera with only one lens - the photographer views and captures using the same one. This is possible by a prism and mirror system, reflecting the scene to the viewing window. The exception are rangefinder cameras as they use a viewfinder that doesn’t go through the capturing lens.
Since 1943, the SLR became a hand-held camera, used at eye level. Compared to TLR cameras, this requires thought and stability to get a well-focused image. When pressing the shutter, the mirror flips up, allowing light from the scene to hit the photographic film.
An example of a Single Lens Reflex would be the Canon AE-1.
Black model with 50 mm f/1.8 by Cburnett
What is the Difference Between an SLR and a TLR?
Both types of camera were developed around the same era - in 1884/5. For TLR cameras, The London Stereoscopic Co's "Carlton" model was an improvement on the plate cameras used at the time. The issue was that to capture an image, first the scene must be framed, which is then blocked by the film loader to capture. With two lenses, this was no longer a problem. For SLR cameras, C.R. Smith's Monocular Duplex was the first large format on the market, with Leica's PLOOT being the first 35mm SLR in 1935.
Most SLR and TLR cameras are film based, and although there were digital versions, each would be a DSLR and DTLR. Both cameras are present across all formats (small, medium and large) as having one or two lenses doesn’t denote the size of the machine. For example, a large format camera is by nature, an SLR. TLRs in any format tend to be bigger and thus weigh more. Most TLR cameras are medium format, requiring 120 film. When we refer to SLRs, we look towards the small format (35mm).
With TLR cameras, you encounter problems you wouldn’t with the SLR counterparts. The main problem, apart from being bigger and heavier, they encounter Parallax Error. Due to framing with a different lens than capturing, there is a discrepancy with subjects close to the camera. Most, such as the Mamiya C330, show a bar in the viewfinder to point out the top of the film, which lowers when focusing. Also, the viewfinder shows a flipped image, where the left-side of the frame shows the right side of the scene. A prism finder add-on regulates this, yet it adds more bulk to an already bulky system.
Personally, I prefer to capture street photography with TLR Medium Format cameras due to the way you use the viewfinder. With SLR 35mm cameras, you bring it to your eye, which is what most people look at on the street. Having a TLR camera is less obtrusive, allowing for more realistic shots. You also get a lower perspective from a more stable viewpoint. Due to this top/down view with TLRs, they are limiting their use on tall tripods.
Conclusion
From working with both types of camera, I am happy to have both for different reasons. SLRs are smaller, weigh less, and have more possibilities in lenses. The TLR medium format produces a bigger negative, and thus, more detail and a higher resolution (if scanned correctly). Due to the almost square negatives, TLR cameras are good for portrait images, as long as your subject isn’t too close. They work better for street photography as people have less time to shy away.
If you are looking into getting either an SLR or TLR film camera; don’t hesitate. Having any film camera will force you to slow down and think about the scene, improving your photography skills no end. TLR and SLR cameras are no longer being produced, so you'll have to buy second-hand. You can still buy both types online cheaply, based on what you are looking for.