Bronica Classic Cameras using 2x Telephoto Converters
Komura Teleconverter for Auto-Diaphragm Lenses
| Bronica Lens | 35mm equiv. largest square | telephoto 2x converter | 35mm equiv. with 2x |
|---|---|---|---|
| Small Bayonet Mount | |||
| 135 mm F3.5 Auto-Nikkor | =58 mm | 270 mm | =176 mm |
| 200 mm F4 Auto-Nikkor | =84 mm | 400 mm | =261 mm |
| 150 mm F3.5 Auto-Zenzanon | =65 mm | 300 mm | =195 mm |
| Large Bayonet Mount | |||
| 300 mm F4.5 Auto-Zenzanon | =130 mm | 600 mm | =391 mm |
| 400 mm Tele-Nikkor with focusing mount | =173 mm | 800 mm | =521 mm |
| 600 mm Tele-Nikkor with focusing mount | =260 mm | 1200 mm | =781 mm |
| 800 mm Tele-Nikkor with focusing mount | =346 mm | 1600 mm | =1,041 mm |
| 1200 mm Tele-Nikkor with focusing mount | =520 mm | 2400 mm | =1,562 mm |
| largest square: lens x .433 | 35mm equiv: lens x .651 | ||
| Thanks! to Ed Scott for Equivalent Lens Focal Lengths For Different Film Sizes | |||
Another interesting camera adapter is a behind the lens multiplier,
typically available in 1.4x, 2x and 3x varieties. These telephoto
adapters must be made to mount with your camera lens mount, such as the
Vivitar and Komura 2x telephoto lens adapters for the Bronica classic S2A
cameras. These telephoto adapters makes it possible to extend the reach
of your short telephoto lenses into the mid-to-long telephoto
range and even beyond into the extreme telephoto region.
Naturally, you will lose some light using these
magnifying adapters, i.e., 2 stops for 2x, 3 for 3x. Some sharpness and
contrast differences may be
noticeable compared to the equivalent full-size original manufacturer's
telephoto lenses. But the savings in weight and cost may make this another
attractive option for your use.
In effect, the purchase of a telephoto lens adapter multiplies the number
of lenses you have for your camera. Don't forget that you can use the
telephoto adapter with many lenses. Consider a camera bag carrying an
accessory 135mm and 200mm pair of lenses. Add a 2x teleconverter, and
you gain the equivalent of 270mm and 400mm lenses. You end
up filling the holes and extending your range to cover
135mm, 200mm, 270mm, and 400mm telephoto lengths with just one inexpensive
and lightweight accessory
(and your tripod!). Now you can see why telephoto converters are so popular.
Observe that your medium format moderate telephoto lens of
200mm f/4 mounted on a 2x teleconverter
becomes equivalent to a 400mm f/8 long telephoto lens. The lens and
telephoto
converter pair will have 2 stops less light if using the commonly
available 2x Komura/Vivitar teleconverter for Bronicas. Contrast and
image sharpness will probably be rather less with the combination than
with a prime 400mm lens. Compared to the prime 400mm f/6.3 lens, the f/8
combination of lens and teleconverters will be slightly darker too. Your
camera bag will be lighter with the teleconverter, and a 200mm lens and
teleconverter is a lot easier to pack around than the longer lens too.
On the other hand, buying the long telephoto lens may mean that it is
your wallet that ends up being a lot lighter, so the choice is yours!
With Bronica mount 2x Komura/vivitar teleconverter prices around $65US to
$125US, this approach becomes very attractive if you already have some
auto-nikkor telephoto lenses. Most of us would be hard pressed to justify
the extreme telephotos for the number of times we use them, even if they
weren't already quite rare. On the other hand, you may be able to build a
very sharp 500mm medium format telephoto lens for the standard 57mm screw
thread mount on the
later Bronica cameras for under $100. A companion
article on homebrew lenses gives some specifics and references to Tom
Fuller's original article in Shutterbug Ads.
You can use a similar
approach to build an inexpensive short telephoto lens, such as the
57mm screw thread mount 135mm f/4 nikkor shown in a companion article.
 Telephoto adapter |
Finally, there are
relatively inexpensive telephoto and wide angle
adapters that fit on the
front of your lenses using filter thread mounting rings (e.g., Series
VIII or 67mm adapter rings). These adapters are available very
inexpensively, often for $10US to $25US and up on the used market each.
Besides their low cost, their biggest advantage is they can be used with
many more lenses. These adapters are designed for use on the typical
normal lens (e.g., 75-80mm on Bronica). You can get a moderate telephoto
effect for very low cost by just screwing one of these onto the front of
your chosen lens. But yes, there is a catch. The quality of a $10-25US+
adapter lens won't match prime lenses costing twenty times as much. But
they are cheap, light, and easy to use for achieving a moderate telephoto
effect. Unlike a teleconverter, you don't lose several stops of light
too. For the price of buying and developing a roll of color
print film, you can have a lot of fun experimenting with these lenses.
See our companion article on front of the lens
adapters for some photos of sample telephoto adapters.
Use of telephoto adapters can help fill holes in your lens coverage in medium format work, at a cost that won't break the bank. Enjoy!
[Ed. note: related medium format (Hasselblad) 2x converter comments...]
Date: Tue, 29 Sep 1998
From: [email protected]
To: [email protected]
Subject: Re: Teleconverters
I own the Kenko 2x and an old 250mm silver f5.6 and a 150 CF. The 250 is
superior to the 150 with the 2x for several reasons: 1) one stop faster.
2) the 2x works best 2 or more stops down from max, making the f4-150 with
2x a decent lens at f16 real, so the 250 is effectively 3 stops faster.
3) the 2x Kenko costs $250, a used 250 (silver, 25 years old) can be had
for $800. I know that you will be happier with the old 250 than the 150 +
2x, and the difference is only $550, which we all know is chump change to
a Hasselblad owner, right?
I also have the feeling that a photo cropped out of the 150 will be as
sharp or sharper than one taken with the 2x and a 150mm, printed full
negative.
So what do I use the 2x for? Well, 250 times 2 is 500mm in a pinch,
stopped down, on a tripod, occasionally it is useful. Also, the 2x with
an 80mm backs me up at weddings should the 150 fail (which it never has,
YET).