The Exakta Varex IIa - the ideal 35mm SLR

Using Exakta SLR's for astrophotography

I have owned one of five Varex IIa's since 1973, simply because it is one of the best SLR's for either piggy back or focal plane or eyepiece projection astrophotography. My second was acquired as recently as 1994 from the now defunct Vienna based "Rare Camera Company" which flourished briefly in Pied Bull Yard, near Russell Square. I payed £25 for the first, and £300 for the second. Both have been subsequently serviced by fellow circler Tom Page whilst at his Bittacy Hill business premises. Both are fitted with metering heads, neither of which work, and even if they did so would not be of the slightest use at night, even on the Full Moon, but they look good! I have also acquired a type 8 Varex IIa from Campkins' King's Parade shop in Cambridge. Recently I purchased on-line a VX and a VXIIa from Miles Upton, and a fifth IIa body & prism from Andrews in Teddington for a mere £69!

Exakta cameras and accessories, many of them superbly designed and crafted are highly desirable in their own right, and if it weren't for collectors mopping them up, they would have long ago ended up on the proverbial skip. But I am not a collector, let that be clearly understood.

There is a distinction between wanting to learn about and understand cameras, those made by Ihagee in this instance, and acquisitively hoarding them. A camera sat in a display cabinet in my humble opinion best belongs in a museum. I particularly warmed to the idea for instance of a virtual museum on the Exakta Circle's website. One of the difficulties of small specialist museums is access. Getting your hands on precious and rare Exakta cameras merely to satisfy one's curiousity can prove very awkward.

I also fully appreciate that many older models are not really suited to even occasional use. What I like about my Varex IIa's is that they have remained my most stalwart workhorses. They have proved consistently reliable in cold and damp conditions, and stand up well to my indifferent treatment, usually in the dark, in my astronomical observatory. Over the three decades I have been interested in Exakta Varex IIa 35mm SLR cameras I have built up a serviceable and practical outfit.

But I digress. As a keen practical amateur astronomer and telescope maker, as well as an Exaktaphile, and a semiretired mechanical engineer with an admiration bordering on veneration for English Victorian craftsmanship, I am disposed to eschew modernity; for the most part.

I constructed my first telescope during my technical apprenticeship with English Electric almost 40 years ago. It was a 3-inch f/16 refractor on a German equatorial mounting supplied by Charles Frank's of Glasgow, equipped with drive, slow motions and setting circles. However it was not heavy enough to carry even an Exa1a. It was though enough to wet my appetite. The Exa's sector shutter vignetted the focal plane image of the Moon, so it had to go, despite being a 21st birthday present. In its place was substituted the Varex IIa, fitted with a new shutter. I had seen this model highly recommended in a German book on the subject of astrophotography written by Gunther D. Roth, and it didn't take long to find a suitable specimen or acquire the viewfinder accessories Roth extolled.

During the 70's I curated a public school observatory, The Assheton Observatory at Rossall, on the Fylde coast. Housed therein was a magnificent 6 Paris inch achromatic refractor manufactured by the celebrated York telescope maker, Thomas Cooke & Sons, circa 1870. It was horribly neglected, but my initial views of Jupiter and its four Galilean satellites had me in thrall. I dedicated 7 years to restoring this telescope to its original condition, during which time I developed my skills in Lunar, Solar & planetary photography, using the aforementioned Varex IIa, with an aerial focusing screen and Magnear finder.

Progression in my career necessitated leaving the Fylde for Southern California and later East Sussex. Yet despite having purchased a very modern and state of the art Quantum 6-inch Maksutov-Cassegrain telescope well suited to astrophotography, nothing about it felt anywhere near as good as the Cooke. But I quested for something better yet, a Calver. Cooke made achromatic refractors, whilst Calver, his contemporary made Newtonian reflectors. A Newtonian reflector is simplicity itself in terms of optics. A parabolic primary mirror as objective, whose purpose is to gather light and reflect it to a sharp focus, and a diagonal to divert it through the upper side of the tube where you can examine the image without your head obstructing the incoming beam.

Calver reflectors in any sort of condition rarely come on the market. I looked for a long while. Eventually my pertinacity was rewarded. Slough Astronomical Society had the remains of one in their chairman's garage at Farnham Royal. Originally housed in the grounds of Eton public school, it had been presented to the local society in a derelict state in the early 60's. Unable to afford to restore it, and lacking the technical knowhow, it had languished for two decades, slowing rusting away. Until that is I acquired it.

After almost 20 years it is now resurrected, Phoenix-like, to pristine glory. Weighing in at nearly half a ton, it is even man enough to carry a couple of Varexes (the IIa's of course), and two telephoto lenses, a 150mm /1.8 Astro-Berlin Pan Tachar and a 400mm /4.5 Tele Ennalyt.

What is it about the Varex IIa that makes it ideal for Lunar & planetary photography? Two principal difficulties afflict the would be amateur astrophotographer in his quest to capture on film what he sees through his telescope .

The first is "seeing". "Seeing" is the term astronomers give to undulations in the image caused by minute thermally induced variations in the air's refractive index. It manifests itself as scintillation, the telltale hall mark of stars viewed with the naked eye on crisp winter nights. Scintillation is magnified by the telescope as well as the image of the object itself. "Seeing" blurrs the image during even the briefest of exposures.

The only way round the blurring effects of seeing is to take lots of pictures and select the better frames. In average seeing you need to keep exposures short, so medium speed film is a must. Seeing tends to improve though during the night, particularly during spring and autumn. Exposures can be increased so slower fine grain films can be used to advantage. It helps if you can wind your own cassettes and change them in midstream. And we all know there's only one SLR that enables you to do this. And that is why I still use an Exakta Varex IIa.

The second is focus. If you think getting a sharp focus with a long telephoto on a bright sunlit object or scene is difficult try focusing Saturn through the same camera setup behind a telescope's eyepiece. The only way to obtain a crisp focus is to use an aerial screen and parallax technique [if you need to ask you're out of the loop so don't fret about it]. A magnified view of the central clear portion of the focusing screen is essential, and very few SLR's affect this without resorting to a reflex eyepiece extension which is extremely inconvenient and awkward. In fact non-system SLR's don't allow you to change screens in any case. Only the Exakta Varex, the older Nikon F series, original Canon F1, and the Pentax LX, offer such viewfinders and screens. The glass screens of the Varex are distinctly clearer and brighter than even the modern "Beattie" screens. One modification I did resort to though is to take a basic ground screen and using telescope mirror polishing techniques fine grind and semi-polish it on a pitch lap.

There is another problem most amateur astrophotographers encounter simply because their kit tends to be lightweight and therefore lacks inertial mass. The instant return mirror can induce a nasty little sharp jolt which has an irritating tendency to make the 'scope vibrate, and apart from using either the self timer device, or the mirror lift mechanism after focusing, neither of which are desirable because you loose sight of the image for so long, there is nothing effective you can do about it. What is perceived to be a technical limitation by most SLR users is actually one of the Varex's strengths. Not having an instant return mirror greatly reduces mirror slap.

And why spend almost two decades doggedly persuing a single goal? Simple; no currently manufactured telescope within the budget of a remotely sane amateur astronomer has anything like the performance characteristics of an English Victorian behemoth. And just because its antiquated and huge doesn't make it a dinosaur. There is no substitute for cast iron, steel, bronze, silver and brass. You can take your aluminium alloys and polycarbonate or PBS mouldings and shove them where the sun don't shine!

Before describing the telescope I would like to explain some of the other virtues of the Exakta Varex IIa for this line of photography and draw comparisons with modern 35mm or APS SLR cameras.

Coupling an SLR body to a telephoto lens mounted on a telescope or the telescope's rackmount adaptor, in either total darkness or dim red safelight conditions can prove awkward. If the SLR body is fitted with either an M42 universal screw or a complex bayonet, it proves nigh on impossible. The Varexes elementary bayonet is almost foolproof, nothing fiddly to align. Contrast this with the complex contemporary auto-everything SLR's so much in vogue. The Exakta Varex bayonet is also adjustable. The bayonet leaves are split and can be prized apart with a jewellers screwdriver to adjust tension and compensate for wear. You cannot do this with for instance a Canon FD or a Pentax K series bayonet.

Time exposures on modern SLR's are not mechanical and drain batteries rapidly. Battery performance in low temperatures is lowered. Combine the two limitations and imagine the mounting frustration of a failed exposure.

Liquid crystal displays require back illumination if they are to be of use at night. Even the dim back illumination of an LCD ruins dark adaptation. Dew forms on the upper part of a telescope tube where it is near the dome shutter opening. Condensates are not LCD friendly.

When photographing the Moon's terminator the dynamic range across it towards the bright limb confuses TTL centre weighted and spot metering, especially those using so called "fuzzy logic". Having a programmed aperture or shutter priority exposure control system is a hindrance, not a boon. I always calculate my own exposure times and bracket 1 & 2 stops either side. In fact I have designed and had manufactured my own circular slide rule style exposure calculator for all classes of astronomical objects and phenomenon.

Autofocus mechanisms on all 35mm & APS SLR's except the Contax are useless for astrophotography through a telescope. Because the autofocusing actuation takes place within the lens, rather than the SLR body, unless one uses the afocal method of projection photography, the essential element is removed from the setup! Light levels are typically too low for autofocus systems to respond reliably in any case. There is simply insufficient light for the system to react in time with the defocusing frequency (typically about 100Hz). Seeing compensation accessories are available for the amateur lunar & planetary astrophotographer, usually first order wavefront tilt compensation devices. They can make a difference, but they won't act as an autofocuser, and it is the placement of the filmgate at the focal plane that is of utmost significance.

Polycarbonate and polybutadenestyrene may be more resilient at room temperature, but in freezing temperatures they become less so. If perchance you fumble the withdrawal of the SLR from the rackmount, as it inevitably plummets three or four feet to the observing floor, the prognosis for the modern SLR body is not too good. Contrast this with my older Varex which bounces well, even off concrete!

So to summarise, every innovation in 35mm SLR technology post 1975 is completely and utterly superfluous to the needs of the lunar & planetary astrophotographer. SLR body composites; autoexposure systems; complex wide throat bayonet couplings; autofocusing lenses; LCD digital electronic displays; low inertial mass electronic carbon or boron fibre gate shutter mechanisms. All the necessary technology was already developed by 1957-58, and what innovations were subsequently made have not been in the least way beneficial. Indeed current trends are a nuisance, and nonsensical.

The telescope, for those interested in such details is a 10-inch aperture f/10.6 Newtonian reflector on an overhung German style equatorial mounting, manufactured originally by Geo. Calver c1894, and rebuilt by H.N. Irving & Son, Teddington. The prime focal length is 105.6 inches, and it is capable of resolving details as fine as 0.45 arcsecs [4565 line pairs per inch]. The mounting has worm and wheel drives on both axes, setting circles and slow motions, and is equipped with three finders and a 3.5-inch aperture f/11 achromatic guide 'scope. The tube is made of 16swg rolled steel, and is 12 inches dia. by 8 ft. long, and including all the tube furniture weighs approx. 400lbsf. The mounting and counterbalances weigh almost 800lbsf. It rests on a masonry pier which weighs 4.5 tons. I have replaced the original and missing falling weight clock drive with an electronic motor drive and I am currently awaiting delivery of a stepper motor slewing "GoTo" system from AWR Technologies. Clearly digital electronic controls can be married to Victorian engineering nouse. Pity the same cannot be said of plastic CCD cameras.

*Varex IIa version 3 1958 (Aguila & Rouah) with embossed escutcheon model #925909 with Ihagee meter head #136008 supplied by T.P Martin Ltd., 9, Castle Street, Cardiff.

Varex IIa version 1 1957 (Aguila & Rouah) with engraved escutcheon model #833481 with Travemat meter head #416081 supplied by Rare Camera Co.Ltd., 18-20 Bury Place, London WC1A 2JL .

Varex IIa version 3 1958 (Aguila & Rouah) with embossed escutcheon model #932529 with with Ihagee viewfinder prism version 4 #212608 supplied by Andrews Cameras, 17 Broad Street, TW11 8QZ .

Varex IIa version 8 1962 (Aguila & Rouah) with engraved escutcheon model #999115 with Ihagee waist level hooded viewfinder version 5 #184056 supplied by Campkins Camera Centre Ltd., King's Parade, Cambridge CB2.

Varex VXIIa version 1 1957 (Aguila & Rouah) with engraved escutcheon model #828079 chassis stamped "USSR OCCUPIED" with Ihagee viewfinder prism version 4 #137619 formerly owned by the late Lowell Hard.

Varex VX version 5 (Aguila & Rouah) with engraved escutcheon model #777405 with Ihagee waist level hooded viewfinder version 3 formerly owned by Miles Upton's father.

H.N. Irving & Son Ltd.,
258 Kingston Road
TW11 9JQ

If you require any specialist camera adaptors making to couple your Exakta kit to either antique telescopes or microscopes this is the place to go. Ron Irving is in his late 80's, and is the only man left in this country with the knowledge and machining skills needed for this type of work. However be prepared for a long wait, his services are in much demand.

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