Saturday, September 24, 2011

Three types of Byron conversion

Byron has been developed for about 6 years, during the period, concluding clients' feedback and some more request, the conversion service now had been categorized  into three types, according to client's lens selected.

Lenses' focal range are limited in 75~150mm, any lens with focal length lesser or greater are not feasible for Byron. 75mm lens is the widest lens Byron can bear, and even in this lens, there is some 4~5mm on side will be blocked by rail, please read the related post. But the situation has been improved, I managed to move the lens a bit higher, to bypass the barrier, so 75mm lens is the set.

Type A, Byron as snap shooter
Snap shoots on streets with a 4x5 format rangefolder is what the original idea when I developed Byron system, and the purpose needs a camera with speed on operation and as lightweight as possible.

Lens board for type A is in circular shape, about 60mm in diameter, when lens board threaded with #0 shutter, it is so tiny that you bare notice there exist a board with the lens, it takes no space, has advantages when traveling light, and stored in bag, that is important for street snaps.



Lenses selected based on the criteria mentioned above, we need lens could be stayed in camera when folded, so it could be ready to shoot whenever fold out, so lens should be tiny, shutter limited in #0 or even smaller, and the rear element should be no bigger than 44.8mm in diameter.


What the lenses I recommend for this type of conversion are:

Schneider Angulon 6.8/90mm
*Schneider Symmar-S 5.6/100mm
Carl Zeiss Tessar 4.5/105mm
Carl Zeiss Tessar 4.5/120mm
Rodenstock Ysarex 4.7/127mm (original lens on 110B camera)
*Fujinon W 5.6/135mm
**Rodenstock Geronar 6.3/150mm (or Caltar II-E 6.3/150mm)

They are all small enough to stay in camera when fold, and the image coverage is just enough for 4x5 format.


(*Lens must be taken off before camera folded.)

(**In type A conversion, 150mm lenses are limited in Geronar or Caltar II-E only, for they have shorter flange to focal image distance, which just great for type A conversion, other 150mm lenses such as Apo-Symmar 5.6/150, Apo-Ronar 9/150mm or Nikkor/Fuji lenses, their flange-focal image distance just exceed rail end, so they all fall into type B conversion, which has different front standard, can solve the longer f-f distance problem.)

Type B, Byron for those big rear lenses
Many modern design and better optical performance lenses have big front or rear elements, or with bigger aperture, bigger shutter.

Clients want to use them, and don't really care of the carrying issue or lens exchanging on field problem, they own these lenses already, and hope to migrant them onto Byron.



In this type, a new front standard and lens board system were developed to fulfill the purpose, any lens in #0 or #1 shutter is acceptable, and if the rear element is within 60mm in diameter, the lens could be mounted directly, no need to screw off the rear first. Due to the size, lens must be taken off before camera is folded.



What the lenses most situation I encounter, and they are able to be mounted directly without problems,

Rodenstock Grandagon-n 4.5/75mm (rear dia. 59.8mm)
Sinaron W 4.5/75mm (rear dia. 59.8mm)
Schneider Super Angulon 8/90mm (rear dia. 56.8mm)
Schneider symmar 5.6/100mm
Carl Zeiss Planar 2.8/100mm (in #1 shutter)
Schneider Angulon 6.8/120mm (in #1 shutter)
Schneider Xenotar 3.5/135mm (in #1 shutter, rear dia. 47.7mm)
Voigtlander Apo-Lanthar 4.5/150mm (in #1 shutter)
Voigtlander Heliar 4.5/150mm (in #1 shutter)
Schneider Apo Symmar 5.6/150mm
Rodenstock Apo Ronar 9/150mm
Nikkor/ Fuji 150mm lens

Type X, only for Xenotar 2.8/150mm 
This is a big, heavy lens that many photographers want to use it on portrait for its bokeh, for this special lens, I have developed a variety from type B, exclusive for this lens.


Xenotar 2.8/150mm lens must be mounted on a #2 shutter, I know it is hard to find for such a shutter, but  Byron just can not take normal #3 shutter anymore, too big in size.

The rear element is 62.85mm in diameter, Xenotar must first screw off the rear element, mount onto the standard, then screw back the rear.


Not only front standard needs to be enforced, rail and many other parts need to be re-adjust to allocate this big boy, the cam curve needs greater precision for its super shallow DOF too.

Oh, recently I saw other conversion service on ebay, also for Xenotar 2.8/150, although I did not see any image about the converted camera for Xenotar 2.8/150 yet, but the service charge do really THUNDERSTRUCK me a bit!



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