The Kowa SETR - an excursion into leaf-shutter 35mm SLRs

There are two predominant types of shutters in cameras - focal-plane shutters, and leaf shutters. Focal plane shutters typically are rubberized cloth and travel horizontally, or are Copal- square type shutters that are made of metal blades and travel vertically. The focal plane shutters are behind the lenses, right in front of the film plane.  Focal-plane shutters are found in most 35mm SLR cameras, some medium format SLRs (such at the Pentax 6x7 and Pentacon 6), in the large-format Graflex SLR RB cameras.

Leaf-shutters however, are usually located within the lens assembly and are comprised of a series of thin plates (leaves) that overlap and typically operate at a maximum 1/500 sec, and because of their mode of operation, are also able to be used with a flash at any shutter speed.  Some leaf shutters may be quite simple and consist of 2 blades. Leaf shutters are found in twin lens reflex cameras (TLRs), medium format SLRs such as the Hasselblad and Kowa 6, folding roll-film cameras, large-format cameras, as well as many 35mm rangefinder and zone-focus cameras (for example, Kodak Retina and Argus).  One advantage, albeit only a slight one, is that a leaf-shutter tends to have less vibration, and is also quieter than a focal plane shutter.  This comes at a cost, as the lens assemblies are more complex to accommodate any removable lenses.  Over time, as these 35mm cameras have aged, the leaf-shutters are not as reliable and usually need a good cleaning and lubrication to maintain any usability.

In 35mm cameras, the focal-plane shutter is the preferred type in SLRs and some rangefinders (Leica and Contax and the clones from Japan and the USSR).  The focal-plane shutter allows for much simpler lens systems, and thus, a far greater variety of focal lengths and mounts, as the shutter is independent of the lens being used.  In addition, a focal plane-shutter allows for much faster shutter speeds. In SLRs, focal plane shutters are behind the mirror.  The mirror flips up, the shutter fires, and the mirror returns (early SLRs required the shutter to be cocked to return the mirror). I'm not going to get into the exact mechanism of a focal-plane shutter, but there are some good online references should you want to know.

That 80mm f/4 lens looks great, huh?

However, there are always some camera manufacturers that do things differently. Kodak used leaf shutters in their Retina reflex cameras of the 1950s and 60s, and these are common finds.  Zeiss-Ikon used Compur leaf shutters in their Contaflex SLRs, too, and they are beautiful cameras.  Voigtlander's Bessamatic, which first appeared in 1959, featured a Compur shutter, and a built-in meter.  It had interchangeable lenses as well.  Other models of the Bessamatic were made until 1969.  All of these leaf-shutter SLRs are attractive, well-made, and collectible. 

The Nikkorex 35, Nikkorex Auto 35, and Nikkorex Zoom 35 are fixed-lens SLRs from 1960-1963 with leaf shutters. Not exactly up to the quality of a Nikon F,  and they are rare finds today.  They are also unlikely to be in working condition. 

Bought this for $5 in 2013

Topcon came out with a Topcon Uni SLR in 1964, which featured through the lens metering, and a behind the lens Seikosha SLV shutter. The camera has an interchangeable lens, and the 53mm f/2 was standard.  It was also sold as the Beseler Topcon Auto 100. The Topcon Unirex followed in 1969, and it had full-aperture spot and average metering.   I didn't use the Topcon Uni all that much, but I did like the bokeh from that lens.




KOWA!

A very clean, uncluttered look.

Now, I am finally getting around to the Japanese Kowa SLRs.  The Kowaflex first appeared in 1960, and was a pretty basic SLR with fixed 50mm lens and a Seikosha SLV shutter.  Shutter speeds were B, and 1- 1/500 sec -- pretty much the standard for leaf-shutter SLRs.  Later models had various improvements, such as meters, but still had the between the lens  Seikosha shutter  and fixed lenses.  In 1965, the Kowa SER appeared, and it featured a Seikosha leaf shutter behind the lens, a CdS metering system, and a suite of lenses that ranged from 28mm to 200mm. The Kowa SET followed in 1966, but it was a fixed lens SLR with TTL metering and Seikosha SLV shutter. 

The Kowa SETR and the subject of this review, was manufactured from 1968-1971.  It features TTL full-aperture metering and the Seikosha behind-the lens leaf shutter, accepts interchangeable lenses, and with the 50mm f/1.9 lens sold for about $100 in 1969.  I do not know if the lens mounts of the SER and the SETR are the same, but I am assuming that they are. 

My example of this camera is in very good cosmetic and mechanical condition. The serial no. is 906004.  There is no flash shoe, but I can see how one might have clipped on via the eyepiece flange.  The PC flash socket is on the front of the camera, and the top deck has only the film advance lever, shutter button, frame counter, and rewind lever.   All of the exposure controls are on the lens barrel and at the base of the lens.  This makes sense, as the shutter is behind the lens itself, but in front of the mirror, of course.  This is unlike the Retina SLRs, which have the shutter between the lenses. There is a set of rear elements that remain in place, and the front elements are the only ones that change with the lens system.  That means that the lenses can never be very fast, especially with longer focal lengths.  In the Kowa SLRs, that's not the case, as the lens unit is self-contained, and while the focal lengths are not as varied as "normal" SLRs, the size of the rear element is constrained by the throat diameter through the shutter assembly, so you won't see 50mm f/1.4 lenses.  The f/1.9 is pretty fast by leaf-shutter SLR standards. The filter ring takes 49mm filters.

control rings

To set the ISO, you move the ASA dial (range 10-800)
to match the film speed with the maximum aperture of the lens. There is a small chrome knob on the aperture ring that is pulled out slightly to set the ISO.  Everything is nicely marked in colored paint, and is easy to see. The meter is visible in the viewfinder, and while it originally required a mercury 1.35V cell, I just used a 1.5V alkaline SR44 and the meter sprang to life.  The needle centers when you have a proper exposure, and under-exposure makes the needle go towards the top, over-exposure makes the needle go to the bottom.  No aperture or shutter speeds are visible in the viewfinder. The viewfinder is therefore, quite uncluttered and easy to use and focus. There is a microprism spot at the center to get critical focus. 

press in that lever on the chrome ring to remove lens

Looking at the front of the camera, there is a small silver button on the lower right which is pushed in to switch to M, X, and V for flashbulb (M), Xenon strobe (X), and self-timer (V).  At the the 7 o'clock position, there is a small angled lever that when pressed, allows you to remove the lens from the body.  The ring closest to the body controls the shutter speed, and the ring above that controls the aperture.  The outer-most ring is for focus.  Overall, all are very well implemented and the camera is easy to use.  Because this is a leaf-shutter, you can fire the flash at any shutter speed, from B to 1/500 sec.  That certainly has its advantages over the focal-plane SLRs of the day which usually had a flash sync of 1/60th sec.

Lens removed from the body. 

The camera is easy to use overall. There is a satisfying sound when the shutter is fired, and its different sounding than that of an SLR with a focal plane shutter.  I shot a test roll of Ultrafine Xtreme 400 in the Kowa SETR, and developed it in Rodinal at 1:25 dilution for 7.5 minutes.  I am quite pleased with the results. The Seikosha shutter works fine at all settings, and the exposures were well within the acceptable range. 

Perhaps I ended up with an exemplary example of this camera.  Using it has certainly changed my opinion on leaf-shutter SLRs a bit. My previous experience with leaf-shutter SLRs has been limited to Kodak Retinas and a Topcon Uni.  I would say that anyone considering using a Retina SLR make sure that the shutter gets a CLA, as more often than not, the shutter will need service to make the camera usable.  I'll keep using the Kowa on occasion, as it works fine, and certainly has a clean and very retro look to it.  I'll also keep my eye on eBay for additional lenses.  A working, clean, Kowa SER or SETR will probably cost you around $100.  Finding one with a full set of lenses will cost you far more.