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Camera User Test Report - Soligor TM

June 1975

by John Ward

 


 

Soligor, a firm well known for their lenses and accessories, have recently added a budget-priced SLR to their range of equipment.

Although discount buying considerably swells the number of cameras available for less than £100, genuine budget-priced SLRs are few and far between. It does seem that manufacturers have forgotten this important section of the market. The Soligor TM could well be the answer for those after a low-cost but reasonably advanced SLR.

The TM is a second-order SLR featuring stop-down through-the-lens metering. Undoubtedly the basic attraction of the camera results from the adoption of the extremely popular 42x1mm screw mount. Literally thousands of lenses at all quality and price levels can therefore be fitted ... not forgetting Soligor's own lenses in this mount.

General Features

External appearance of the TM indicates nothing more than what is now deemed to be conventional in terms of features and their layout. Top-plate controls consist of the combined ASA film speed/shutter speed dial, release button, additive frame counter and advance lever on the right hand side of the pentaprism, and the rewind knob assembly on the left.

The film advance lever spindle is unusually short and is located to the end of the body, thus the lever tip is well clear of the eye and this is useful for speedy eyelevel operation. There is no lever stand-off from the back; in operation the user's thumb catches the end of an uncomfortably styled plastic grip to commence the 180°-plus single stroke wind-on cycle. The winding stroke in itself is not smooth, the first part involved some considerable pressure (presumably necessary for the mirror raise/shutter cocking system employed) which suddenly eases, resulting in a rather lurching action that makes speedy eye-level operation a little uncomfortable to the thumb and forehead. Shutter release and subsequent wind-on home allows the latter to swing past the normal limit of its wind-on angle, to be brought to rest against the protruding frame counter window. Luckily no damage appears to result from this but it does mean the user can't use his thumb inside the lever to create the lever stand-off necessary for speedy eyelevel operation. As a whole, the lever wind mechanism is suspect to a point ... but remarkably tolerant to the rigours of testing, so should last well in practise.

Near to the pentaprism is the speed dial. It's small in size, and changing speeds with the camera at eye-level is not particularly easy to do. The dial is not fully rotating and movement between settings is regulated by the setting of the film speed, this corresponding to the meter coupling range. At the 25 ASA setting, the speed dial is free to move from B to 1/250; at the other extreme, the 1600 ASA setting, the lever (sic) is free to move from 1/8 to 1/1000. All speeds can only be set at 100 ASA.

ASA film speeds are set by lifting and rotating the dial's outer rim until the desired figure appears in the cut-out on the face of the dial. Individual shutter speeds are heavily click-stopped, and the black on chrome figures are very clear to read.

Immediately to the front of the dial is the shutter release button. The release action is a single-phase one that imparts little in terms of predictability. A slightly greater knob surface area could have improved matters, but at least one can make use of the adjacent speed dial as a finger platform to prevent release stabbing. The button positioning is comfortable, and is such that the user cannot avoid cupping the right hand side of the body in his hand, thus improving the handling stability of the camera.

The rewind knob assembly consists of the usual foldaway crank and, on a collar, a simple film type in use reminder. So simple, in fact, that you've got a choice between Black & White and Colour ... not too useful, methinks. Although the lever is not angled, there is comfortable finger room between its circle of turn and the pentaprism housing to enable speedy rewinding. A rim on the base collar serves as the lock release catch for the viewfinder This rim is turned clockwise to withdraw a small bar from the tracking groove of the 'finder assembly. Very simple ... very neat.

For flash photography, an accessory shoe bridge is mounted into the base of the rewind knob assembly, where it is held in place by anchor pins and a sprung stud. The accessory shoe is available as an extra.

The interchangeable viewfinder facility considerably increases the scope of what would otherwise be a fairly basic camera. Naturally this feature is an offshoot from existing Miranda designs, but nonetheless appealing for it. Versatility at budget prices is appealing. Two accessory 'finders are available: a waist-level hood, and a critical focus magnifier Focusing screens are not interchangeable however.

The standard focusing screen is composed of Fresnel-backed ground glass with a course central micro-prism aid. The latter is adequately large and performs its function very well with lenses of about standard focal length. With wide-angles and telephotos of around 200mm, its capabilities are stretched a little but one can make use of the surrounding ground-glass. The focusing image is clean but not particularly bright, about average for this type of camera.

To the left hand front of the camera one can see the depth of field preview button. This has a push in to lock, push in again to unlock action, which is necessary for the stopped-down metering function. Release of the shutter also releases any locked stop-down. The meter circuit itself is activated by winding-on the advance lever, and is switched off by releasing the shutter.

A pair of coaxial flash sockets (X and FP flash sync) are located on the other side of the front. Baseplate features consist of the expected battery compartment, a rewind button, and a particularly well reinforced tripod socket.

The back is released by a effective lock/release mechanism; this reveals a simple but extremely well finished film chamber featuring broad film guides and the now conventional slip-grip take-up spool. The pressure plate on the back of the camera is, I feel, on the small side but tests indicated that there was a particularly good relationship between the film and image plane.

Exposure System

The Soligor TM has a through-the-lens exposure measurement system reading at the taking aperture, a necessary restriction imposed by the adoption of the Pentax type mount and the low selling price of the camera. Nowadays it is extremely rare for new cameras to have this form of TTL metering, most - including many 42mm mount cameras - tend to provide full aperture systems, but then there have been few recent additions to the number of budget-priced SLRs.

Stopped-down and full-aperture systems each have their advantages and good points. If anything, the former are a little more inconvenient to use, but are as equally reliable and a good deal more economical to design a camera around. Also, equipping a camera with additional lenses is far less of a problem.

The system adopted for the TM differs slightly from normal. Instead of using an in-pentaprism cell arrangement, the meter cell of the TM is to be found on the viewing mirror, under a U-shaped grille of un-silvered slits. The sensing area is shaped to exclude the effect of the upper third of the subject seen in the viewfinder. Thus the sky area in a landscape shot would have little adverse effect in metering. The sensing area is defined and although readings are integrated the skilful user should be able to take partially selective measurements when this is necessary.

A cell on the mirror is also better located than ones in a pentaprism. It receives direct light (as opposed to transmitted and reflected light) and therefore is less influenced by stray eyepiece light and light scatter induced by the viewfinder optical system. It also enables designers to provide an interchangeable viewfinder system without the complications - and eventual expense - that one associates with sophisticated system cameras.

The claimed sensitivity range is from EV1 to EV18. Couple this with a film speed range of ASA 25 to ASA 1600 and the TM is capable of metering a wider range of subject brightness levels than would normally be attempted with this type of camera. At the very low light levels metering is difficult ... it's the usual difficulty with this type of camera: being able to see the needle.

The meter was found to perform very well over its range, with the needle moving quickly, positively and consistently throughout correlated exposure settings. Only at the lowest light levels did the needle exhibit a tendency to creep but metering under these conditions is difficult in any case.

In use the meter needle is aligned within a comparatively large +/- gate, conspicuously on the right hand side of the screen. With experience, users should be able to gauge up to two stops intentional under or over-exposure as this is the range covered by the gate arms, though the leeway for precise setting in the gap is less that half a stop.

This zero-needle readout is quick and efficient to use, and familiarity with the exposure measurement system should give the user a very high proportion of correctly exposed pictures. The incorporation of a shutter speed range limiting device when one exceeds the meter coupling range prevents any errors of this nature, and is a particularly endearing feature of what is a simple but good TTL metering system.

A conventional type cloth two-blind focal-plane shutter is used, with a speed range from 1/1000 sec to 1 sec and B in the usual progression. These appeared to be correct as marked to within accepted standards, if anything running slightly slow with the faster speeds and a little faster with the slower speeds. There was no evidence of blind drag or other lack of uniformity in the blind travel. Operational noise of the shutter mechanism is minimal, although the mirror's return does produce a distinct clack. A red X between 30 and 60 on the shutter speed dial indicates the setting for electronic flash sync, corresponding to a shutter speed of around 1/45 sec. There is no self-timer/delay mechanism.

 

Optical Performance

There's a choice from two standard lenses; an f/2.8 or f/1.8 Auto Soligor 50mm. With the former the TM's full price is less than £100, with the latter option the price is just over £100; discount buying reduces these to about £77 and £87 respectively.

The test camera was provided with the f/1.8 version. Soligor are no slouches when it comes to making quality lenses at budget prices so it was not particularly surprising that this f/1.8 50mm turned out to be a very good performer for the money.

I used the Patterson test chart and loaded the camera with Panatomic-X, which was subsequently developed in Aculux. At full aperture the centre was registering at just under 50 cycles/mm ... close to the chart maximum and an excellent standard of performance that was not significantly improved by stopping down. This would indicate that the lens resolving capability at the centre is around this figure. Optimum centre performance was at f/5.6 with a gradual fall-off as the lens was stopped down, reaching an equivalent figure at minimum aperture (f/16 as obtained ta full aperture).

A surprising degree of barrel curvilinear distortion was noticed. This and the presence of tangential astigmatism seemed to have considerable affect on performance at the extreme corners of the frame. At full aperture readings of 25 cycles/mm was registered. Subsequent stopping down improved this to between 27.5 and 30 cycles/mm at f/16. Two-thirds out from the centre performance followed the same pattern although improvements on stopping down were more noticeable. There was some indication of a focus shift between f/2.8 and f/4 but this wasn't considered severe. The tangential astigmatism was present through the entire aperture range, but only just noticeable at the two minimum apertures.

Despite all this, the Auto Soligor f/1.8 can be considered a good lens for the camera it accompanies. Image micro-contrast and tonal separation are very good and this indicates that the purple/blue/yellow coating is effective. On the flare test the lens came out very well. The inclusion of point light sources within the picture area does not produce severe diaphragm patterning, and there was no evidence of overall ghosting. The recessed front element and efficient mirror-box may have helped here.

 

Deserves Consideration

My final impressions of the camera are based on several weeks of field use that confirmed the bench test results. This was particularly true of the lens and meter performance, the results of which were most favourable.

Certainly I feel that this camera deserves to be a success. It is a simple design, versatile for the price, and good enough to appease the many whose circumstances dictate the purchase of a budget-priced SLR. As such it should appeal to newcomer and old hand alike. As always, one must point out that a budget camera is necessarily limited in scope and quality from an absolute point of view. Thus the Soligor TM should not be regarded as a poor man's Nikon (or whatever), but rather as a long overdue addition to the ranks of budget-priced SLRs.