- Produced 1980s? Japan
- Mount Pentax K
- Focal length 2x
- Aperture range n/a
- Focal range n/a
- Filter thread n/a
- Elements 3(?)
- Aperture blades n/a
Nice multicoated doubler for Pentax K mount cameras by Vivitar. Construction is on a par with late model Pentax lenses. The big button on the side makes it easier to get your lens off than other 2x I’ve used. Nice addition to your travel kit!
Remember – a 2x converter doubles your focal length, and does so at a price: a loss of two stops.
What a 2x is good for: lightening your walking kit for close pics in a pinch. What a 2x is not good for: getting the best out of your best prime lenses. That’s it in a nutshell. I do think every SLR kit should have one. If your lens is good and your 2x is clean, your 8×10 print is not likely to have any noticeable difference.
Attach the converter to the camera, then the lens to the converter. To remove, do the reverse. It’s more difficult to take the 2x off the lens than to take the lens off the 2x. Besides the loss of two whole f-stops, the other thing to consider is that the handholding rule of thumb is to shoot at 1/focal-length as the slowest shutter speed, eg 1/60 if you’re handholding and shooting a normal 50mm lens. Add a 2x and your focal length becomes 100mm, suddenly you should be shooting at 1/125 or faster to avoid camera shake. Add the 2x to your 200mm and… get your travel tripod out!