Safeguard the rear element of your Pentax K-mount lenses when they're not in use with this IRIX Rear Cap. Simply put it on the back end of the lens once you're done shooting to prevent scratches and shield the glass from dust, debris, and impact. The cap serves as a spare or replacement for the original one you received.

Protects Rear Element When Not in Use    Spare or Replacement Item

Related Questions and Answers

Q: 1. Does the Pentax 1.4x HD Converter work with the K-1 Camera? If so, does it work using FA (full-frame) lenses under the camera's full-frame mode?

A: Yes, the Pentax 1.4x HD PENTAX-DA AF Rear Converter AW for K-Mount Lenses will work with the K-1 camera, and with Pentax FA "full frame " lenses. It is important to connect the converter to the lens first, then attach the lens to the camera .

Q: 2. I own a Pentax K20D dSLR. How is this Pentax 1.4x teleconverter better than the Tamron 1.4x teleconverter I already own for this (older) camera?

A: I don't know anything about the Tamron 1.4x, but I too had an earlier 1.4x for which I paid $99. I forget the brand off the top of my head. In comparison, the Pentax is vastly superior (with my K-3; I'm not sure about how well it will work with a K20D). The picture quality is superb (while the cheaper device produced images that were no better than what Photoshop could do in post-processing). The in-lens auto-focus is supported in both my Pentax 300 and Sigma 150-500 and it works well and quickly with both. It does not work so well with my Sigma 18-250 lens (tends to overshoot and flip back and forth while trying to focus -- this can be overcome by using Live View). Also, with the Pentax lens, but not the Sigmas, the presence of the teleconverter is detected and included in the metadata, so, for example, the 300mm lens is shown as shooting at 420mm.

Q: 3. Will this work on the BMPCC4K with a Metabones Speedbooster (MFT to EF) ? Will there be vignetting?

A: Both the 0.71 and the 0.64 Metabones Speedbooster, show little to no vignetting.

Q: 4. Judging from the pictures of this lens it does not have a DOF scale. Do I see that right?

A: The IRIX 45mm f/1.4 Lens for Canon EF does not have a depth of field scale.

Q: 5. I own a Pentax K-3 with several lenses. Two of them are Sigma's. I am planning to use this coverter on my Sigma 70-300mm F4-5.6 APO DG Macro. Is this a viable choice to extend my capabilities? Sharpness? Loss of stops? Thank you!

A: I use the converter with a K-3 & a Pentax 300 mm F4 lens. As everything is Pentax all the lens functions are maintained and the camera recognizes the set up as a 420 lens. The set up dropped 1.6 F stops. Images are tac sharp!

Q: 6. Has anyone tried this teleconverter with the K3ii and the Pentax 150-450mm zoom lens?

A: Yes, users say the teleconvertor will magnify any positive or negative issues with the lens. One reviewer says "I was still very impressed, based on my experience with my K1 plus DFA 150-450 mm". Knowing that this teleconvertor is made for crop sensor cameras, using the K3ii, the results will be even better.

Q: 7. Hi, will this convert my MF lenses to AF lenses? I understand the older Pentax SMC-F 1.7x will allow me to AF my manual lenses? Thanks for your time and advice!

A: No it does not. Only the older Pentax-F 1.7x does that. It was designed to work with Pentax-A manual focus lenses as a transition to auto-focus. No other TC I know of does that.

Q: 8. Will this lens work on a Pentax 55-300 lens? Thanks. Steve

A: You may or may not be happy with the results. Bear in mind that teleconverters are designed to work properly with prime (fixed) fast lenses...f4 or faster. On zooms, even on fast zooms like 70-200f2.8, the results will not be that great. 55-300mm.... Probably not worth spending $$500 for a TC since the performance and quality will be marginal. I don't like it in my 70-200 f4 or f2.8

Q: 9. THIS SHOULD WORK WELL WITH MY NEW PENTAX SMC DA 18X270 SDM LENS F3.5-6.3 ED, CORRECT ?

A: Checked the compatibility list that came with my DA 1.4x and it does not list this lens as either compatible or Not compatible. To be sure you might want to check with Ricoh, though it does work with the 50-135 and 55-300 so I don't see why it wouldn't. You also may have to update your camera to the latest software for autofocus function.

Q: 10. What mm size UV protective filter fits this Irix 11mm Blackstone Lens?

A: Due the shape of the front element on the IRIX 11mm f/4 Blackstone Lens for Canon EF, it doesn't accept screw in UV protective filters.