2009-10-29

Industar-69 28mm

This lens was made for the half-frame Belarussian "Chaika" ("Чайка" = "Seagull") half-frame cameras.  The 2nd and 3rd models of the Chaika were designed to have removable lenses.  No one is sure why this was done -the first Chaika model had a fixed, non-detachable lens-, but I think it was to allow the lens to be used in an Enlarger for printing. 

The lens has the standard Leica M39 thread (LTM39) mount,  but the working distance (the focal plane to lens mount flange distance the lens is positioned which allows infinity focus) is not the the same.  Leica's is 28,8mm.  Chaika used something like 29 or so mm.  This extra millimetre or so prevents infinity focusing when the I-69 28mm lens is mounted on the Leica.


the "Индустар-69" 2,8/28mm mounted on a Leica IIIc




As the reader will note later, infinity focus is not the only, nor is it the greatest concern here.  Coverage, or the ability to focus an image large enough to fill the frame.  "Frame" here is relative- the standard 24 X 36mm, 'half-frame'(a.k.a. "single frame") 18 X 24mm, and the 23.7 x 15.6 mm APS-C size CCD of the Epson whose 1,5X factor makes it 'see' like a 42mm on standard 35.

The lens was modified by altering its focus movement.  Portions of the inner barrel were filed away to make the lens move further in to allow infinity focus.  The focusing scale on the barrel was also reset to synchronise it with the lens' focus.  The aperture mark no longer coincided at the new positions, so a new mark was made by putting a drop of red paint on the aperture adjusting ring.

The lens too, being originally meant for a non-RF coupled camera, will focus only by scale since it has no means of engaging with the RF cams of the camera.  Scale focusing with a 28mm isn't that hard- its greater DOF more than compensates for focusing errors.  Plus, the I-69 has three "snapshot" focus settings on its barrel: "Portrait", "Group", and Landscape".  How is this used?  Look through the finder and set the focus against the figure which resembles closest what was seen through the finder:



Just line up the figure against the pink triangle which corresponds to "how much" is seen in the viewfinder.


Focusing is often a trivial matter.  In many instances, leaving the scale at the "group shot" mark (the 3 metre mark) and using f/8 will deliver DOF with a range of 1,6 metres to infinity.

Since the I-69 was designed to cover the 18X24 frame, the IMAGE CIRCLE it produces will be much smaller- smaller than what 'full frame' needs, but sufficient for the smaller 'half-frame'.

On an APS frame, the corners already vignette.  Aside from losing coverage, the edges of the image circle also dims.  Here is what it does with the Epson R-D1s digital rangefinder camera:




Scale-focused/distance 'guess-timated' at 0,9 metre.  Full 2,8 aperture. 
The I-69 is a Tessar type lens, and produces a swirly blur when used at full aperture, for closeups.
The corners of the picture show significant vignetting.



If the smaller APS-C frame already shows vignetting, a full 35mm frame shows TOTAL DARKENING at the corners of the frame.  This, as well as the significant loss of definition at the threshold areas indicate that its image circle is too small for the 35mm format, but more than sufficient for the half-frame picture.



Same subject as above, but on a 24X36mm Leica frame.
The blue tinge stems from the unfiltered exposure of tungsten movie film in daylight.







Conclusions:  The significant vignetting prevents further use of the lens for 'serious' work on full frame 35.  However, it can be useful for experimental or whimsical applications.  

On the Epson R-D1s, it can be used as a scale-focus snapshot lens, with a 42mm view.  Using it at f/8, the vignetting is not to apparent in many situations. 

The lens would be a perfect "normal" focal length for the micro 4/3s cameras.  No modification is even necessary to adjust the focus.




















2008-07-14

DIY Takeup Spool for Kiev Rangefinder Cameras

An Easy, Do-It-Yourself, Fall-proof (almost), Non-Wobbling, Takeup Spool for the Kiev Rangefinder Cameras  
Many Kiev RF are found without takeup spools These cameras (except models "5" and "4M/4aM" with fixed takeups) were designed to accept either cassette to cassette loading or else an accessory removable takeup. Being removable makes this spool easy to lose. The usual DIY spools use the discarded spools from standard 35mm film cassettes. The usual design calls for a slit of some sort, to catch the film leader tip, to be cut diagonally into the spool spindle. Kodak cassettes, with solid spool cores are often used. Spools from Fuji and others have split cores (with hooks to catch the end of the film) are not often recommended. Using the 35mm spool as is makes them wobbly and loose. They will fall out easily (that's why the second step in Contax/Kiev loading is to hit the floor, crouch on all fours, and look for the wayward spool! ).
 
This design uses 35mm spools too. But unlike the usual DIY's, this modified spool does not fall out easily. The key here is to use the cassette's metal caps. Sticking these to the plastic spool's ends makes the flanges wider. The idea behind this is that the takeup side was designed to accommodate a 35mm cassette- so making the takeup spool as wide as the cassette would make it fit nicely without wobbling.  
Wider flanges will keep the spools from falling out. The flanges will be retained by the spring flanges on the camera's film chambers. Wider flanges also prevent the spools from wobbling, and make locking the camera's back easier.  
The first step is to cut a lengthwise (not angled) slot on the spool shaft. A copping-saw blade (with its ends snapped off) will fit through the central slot. Cut all the way to the spool's flange. This will be the slot which will hold the film.  
Apply rubber contact cement ("Rugby") on the spool's flanges and the cassette metal caps. Use 'snap cap' cassettes, rather than the crimped ones. Metal flanges from crimped cassettes usually become warped and distorted when removed from the cassette shell. When the rubber cement becomes tacky dry, stick the metal caps and hammer a bit for a firm fit. Once stuck, they will be almost impossible to remove.
 
The film tip goes through the cut slot. Fold the tip a bit to prevent it from slipping out.
The spool in action. That's all that is to it!.  
*Compatible with Contax RF too.

2008-05-09

RESTORING A 1937 FED-1

This FED (#34961) is from 1937. Made when Stalin was at the helm of the USSR. Two years before WW2 started... It was found non-working, with a broken shutter. Everything else appeared to be in order. The viewfinder is very clear, the rangefinder equally clear and contrasty. Its lens is an Industar-10 3,5/50mm, uncoated. Some features are different from later FED-1. The platform under the shutter speed dial is oval, rather than tapered and cornered. The shutter button is small and unthreaded, almost similar to the Leica's. Its top engraving translates to "FED, Labour Commune NKVD U(krainian) SSR, Factory named after F.E. Dzerzhinsky, Kharkov" The shutter wasn't working when it was found. The cloth blinds have become fossilised and crumbled. For a 71 year old camera, this isn't at all unusual. The focal plane curtains of FED, like the Leica it was copied from, were made of rubberised silk cloth. Repairing the shutter required major disassembly. This is the FED, partially disassembled: Removed from the shutter crate, the shutter parts looked like this. The drum, spring-loaded rollers, and metal shutter laths (spines) are still serviceable. They only need to be cleaned of all the remnants of the old shutter cloth. The two thin rollers contain the springs which power the shutter: New shutter blinds are cut from new shutter cloth. This shutter cloth is a DIY material from Fotofabrik/TKP-RF ( Smiley !). the cloth is cut to proper size and length. Then glued and sewn to the lath. New ribbons are also made and fit to the laths. The new shutter curtains installed in the shutter crate: After reassembly, the 1937 FED is ready to shoot again. Its dulled vulcanite finish was prepped by a thin layer of black paint. I now realise that it should have been left in its original reddish brown finish. This may have been its original colour. The lens, which was originally soiled, was also disassembled and cleaned. The dirty lens elements were soaked in dishwashing liquid overnight. For a more complete and detailed description of the FED-1/Zorki-1 shutter, go to the FED/Zorki Survival Site.