Open-aperture TTL metering was pretty standard when I started using 35mm SLRs in the Eighties, but back in the Sixties it was a Big New Thing. These two cameras, the Topcon RE Super and Miranda Sensorex, were pioneers of the genre.
Their specifications are very similar, so they’re worthy of comparison. The key to that is the interchangeable viewfinders – which remained a rare feature and is unheard-of on DSLRs. Apart from that they both have an instant-return mirror, front-mounted shutter release, shutter speeds from 1s to 1/1000s, and a self-timer.
Topcon RE Super
The first to market was the Topcon in 1963. This is a big, square-cornered camera, and oozes quality. The feel of the wind-on action is the most exquisitely smooth I’ve experienced on any SLR. No wonder it was the camera of choice for the US Navy, who ordered special editions by the thousand.
The killer feature of TTL metering was achieved by placing a CdS photocell behind the mirror. A criss-cross pattern of lines cut into the silvering allowed just enough light through to the cell, while remaining unnoticeable in the viewfinder. The meter needle is a swinging T-bar, moving across a circular target. It’s directly visible through a window in the top plate.
Looking into the eye-level pentaprism viewfinder, you realise that the same T-bar needle is visible below the image. Eh? How can that work? The answer can be found in a complicated series of prisms in the finder that look sideways, through a little window into the left side of the top plate. From there, the light is bounced through even more prisms that enable you to see the meter from underneath. Clever.
The Topcon uses an enhanced version of the Exakta bayonet mount. It has a small diameter, so the additional mechanical connections that enable open-aperture metering are outside the bayonet and aren’t covered by the lens cap.
Launched three years after the Topcon, this is a more rounded and stylish design, perhaps making it more consumer-friendly. Again, the TTL photocell is behind the mirror – but this time it sees the world through an oval of horizontal slits. The match-needle meter is above the focusing screen, but to use it you first have to dial in the maximum aperture of the lens on a knob on the left front plate. After that you’re chasing the big orange meter needle with a circle-on-a-stick controlled by the shutter / aperture combination. All very familiar.
The lens mount is an external bayonet, a bit like the Canon FD design. Despite a decent size and four lugs, it never really feels secure and lenses can rattle around a bit. The aperture coupling is very external — both the body and the lens have a long arm sprouting out, with sprung pin at the end to snap them together.
This is a dual mount though, because inside the bayonet is Miranda’s proprietary M44 screw thread. There are no control couplings, so it’s for pre-set lenses only (if you can find any).
Both cameras were designed to take the now-discontinued PX625 1.35V mercury oxide battery. There are various workarounds available, and my preferred option is to solder a BAT43 Schottky diode into the wire from the battery compartment. It conveniently absorbs 0.20V, allowing you to use a 1.55V silver oxide SR44. There’s plenty of space for the diode inside both cameras. Job done.
As with a lot of consumer choices, it’s the little things that make all the difference. Here’s a run-down of the main three things that impress / annoy me:
Original equipment is split-image on the Topcon, and microprism spot on the Miranda. Personally I can’t stand microprism focusing and for me it’s a complete deal-breaker. That doesn’t put the Miranda out of contention for anyone who’s handy with a screwdriver. The great access provided by the interchangeable viewfinders means it’s a relatively simple job to swap out the focusing screen for a different one. I chose a nice ‘period’ split-image screen salvaged from a Ricoh 35 Flex, calibrated with shims so it matches the focus at the film plane.
Meter on/off switch
On the Miranda, this is very sensibly placed around the rewind knob and can be quickly operated by your left thumb. The Topcon is a bit of a pain in this respect. The meter switch is recessed into the base plate, and is a bit fiddly. I keep forgetting to switch it off.
An optional waist-level finder is available for both cameras, and in both cases takes mere seconds to fit. It’s really just a hinged cover for the bare focusing screen, plus a fold-out magnifier so you can put your eye right up (down?) to it and focus accurately.
There’s an issue with metering though. A TTL meter is affected by light coming in through the viewfinder, which doesn’t matter for eye-level pentaprism finders because your head blocks out the light. With waist-level finders, you can’t block the light as effectively, even when using the magnifier.
Here’s where we can really differentiate these two SLRs. With the Miranda, waist-level metering is always going to be miles off. Perhaps only a stop with the magnifier, but a good 2 or 3 stops without it. The Topcon has an ace up its sleeve. Just close the waist-level finder, and you can still see the meter needle through the window in the top plate. Meter, open the finder, focus, compose, and shoot. Brilliant.
I love the looks of the Miranda, but the angularity of the Topcon makes it just as much of a head-turner. As a camera to take out and use, I’d go for the Topcon. Being able to use the meter with the waist-level finder fitted is a wonderful bit of well-thought-out design. Just remember to take a spare battery for when you forget to switch off the meter.
Oh – and good luck finding rear lens caps for either of them. Thanks for reading.
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