Pentax K SLR / DSLR 2" UltraWide True-2 Prime Focus Adapter


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Fits all Pentax K DSLR Cameras. Our True-2™ UltraWide Adapter is a true 2" Prime Focus adapter that takes you directly from the Camera Bayonet mount to a 2" Barrel with as few wasted photons as possible, adding as much as 10mm additional clear aperture over legacy T-Ring adapters!

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2" UltraWide Prime Focus Adapter
for Pentax "K" Mount DSLR

As seen in Sky & Telescope Magazine

As the Imagers in our cameras grow larger it is more important to have an unobstructed light path to prevent vignetting. Most telescopes now have 2" Eyepiece ports and Camera Mounts are getting wider and wider. Why are we still putting a 1.5" bottleneck between them?

Our True-2™ UltraWide Adapter is a true 2" Prime Focus adapter that takes you directly from the Camera Bayonet mount to a 2" Barrel with as few wasted photons as possible, adding as much as 10mm more clear aperture over legacy adapters! The largest clear aperture of any adapter on the market. Fully baffled to reduce reflections and threaded for 2" eyepiece filters. 


Pentax K Mount Adapter
The True-2™ adapter goes directly from Bayonet mount to 2" barrel.
Bypassing the restrictive threaded T-Ring connection.

This increases the clear aperture from 1.5" to 1.85"
There is zero shading of the Sensor.


View Enlarged Setup Diagram


Never let a good photon go to waste! 

Why not just use a T-Ring?

Simply put todays equipment has outgrown the T-Ring. The "T2" T-Ring standard was developed by Tamron in 1957. It's purpose was to specify a common focus point when connecting 35mm Film Cameras to aftermarket camera lenses. In the 1950s the standard telescope port size was .96" and the Nikon F Mount was 40mm. Now telescope Port Size is 2" and the Nikon Z mount is over 49mm! The Clear Aperture of a T-Adapter is about 1.5" (38mm). Depending on your setup you can expect at least some vignetting when using a T-Ring.

What is Vignetting?

Vignetting is simply shading of the camera sensor. Since the light rays in a telescope are not parallel a restriction in the clear aperture can have more serious consequences than expected. Even if the restriction is larger than the sensor it can be at a place where the light rays will still be clipped by the angle. The shorter the Focal Ratio of the scope the steeper this angle and the worse it can be. The shaded area of the sensor will be dark and essentially wasted. The result in your images will vary depending on the degree of vignetting. Minor vignetting may clip the corners off the image, whereas more significant vignetting will give you a circular image in a dark field. Sure you could do extra work to enlarge and crop your images in a pc. But that can mean accepting a lot of loss in both image quality and overall value. Especially if you have an expensive camera. After all, what did 15% of that sensor cost?

Q: I have a Meade (or Celestron) SCT telescope and would like to have the benefits of this adapter but my scope only accepts 1.25" eyepieces. Is there any way I can use this adapter?
A: If your SCT is not already setup to accept 2" eyepieces and accessories you will need a 2" Rear Port Adapter, this item threads onto the large "SCT" thread on the rear cell of your scope and converts it to a standard 2" eyepiece port. The True-2 will slide directly into this port. Please see the setup diagram for details.

Q: I have a Meade (or Celestron) SCT telescope. Will this adapter thread directly on to the rear cell of my scope?
A: The True-2 adapter will not thread directly onto the rear "SCT" thread. It has a 2" barrel just like a 2" eyepiece and inserts into a 2" eyepiece port. If your SCT is not setup to accept 2" eyepieces you will need a 2" Rear Port Adapter. This is actually better than if it threaded on to the scope directly as it allows you to very quickly and easily install and remove the camera during a session. It also gives you absolute freedom in positioning the camera radially for the best framing of your shot.

Q: Will this adapter fit my spotting scope (or microscope)?
A: The True-2 adapter is for astronomical type telescopes equipped with 2" eyepiece ports only. It will not fit spotting scopes or microscopes.

Fits all Pentax "K" Mount SLR/DSLR Cameras including: Pentax K, KA, KAF and KAF2 mount Series SLR & DSLR Cameras including models K-01, K-x, K-m, K-r, K5, K5II, K5Ds, K7, K10D, K20D, K30, K50, K100D, K110D, K200D, K500, K1000, K2000 and All Pentax *ist D, DS, DL, DS2, DL2 models.

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