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Pentax 30733 SMC -3 Diopter Correction Lens
Pentax 30733 SMC -3 Diopter Correction Lens
Pentax 30733 SMC -3 Diopter Correction Lens
Pentax

Pentax 30733 SMC -3 Diopter Correction Lens

★★★★★4.6 (17 reviews)

Correct your viewfinder to -3 diopters for sharp, glasses-free shooting on compatible Pentax cameras.

$22.01*
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*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

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Overview

The Pentax SMC -3 Diopter Correction Lens is a simple but valuable accessory for nearsighted photographers who want to ditch their glasses while looking through the viewfinder. It threads onto the eyepiece of compatible Pentax cameras via the included M adapter, shifting the viewfinder's focus point by -3 diopters so the focusing screen appears sharp to the unaided eye. Pentax's Super Multi Coating is applied to the optic, minimizing internal reflections and delivering a high-contrast, clear view.

Measuring just over an inch across and weighing very little, the lens adds no practical bulk to the camera body. Installation is tool-free — simply thread it into the eyepiece mount. Because it only modifies the viewfinder optics, it has zero impact on image quality, autofocus, or metering. The main consideration before buying is ensuring that -3 diopters is close to your actual prescription and that your specific Pentax body uses the M-type eyepiece system.

Key Features

Finder Accessories

Attach to the viewfinder eyepiece of a camera that is beyond the camera's aperture adjustment range or does not have a vision adjustment mechanism

Adjustable vision according to the photographer's vision Cannot be used with eyecup

Product Model Number: 30733

Brand: Pentax

Specifications

Brand
Pentax
Model
30733
Diopter Correction
-3
Coating
SMC (Super Multi Coating)
Adapter Type
M Adapter
Lens Design
Prime
Focus Type
Manual Focus
Dimensions
1.15 x 0.25 x 0.65 inches
Weight
1 pound

Pros & Cons

👍 Pros

  • SMC coating provides a clear, low-flare view through the viewfinder.
  • Lets nearsighted photographers shoot without wearing glasses.
  • Compact and lightweight design adds virtually no bulk to the camera.
  • Simple thread-on installation requires no tools.
  • Durable metal and glass construction built to Pentax OEM standards.

👎 Cons

  • Only corrects to -3 diopters, so it won't suit all vision prescriptions.
  • Limited to Pentax bodies that accept the M-type eyepiece adapter.
  • Small size makes it easy to misplace when not attached to the camera.
  • No storage case included for safe transport.

Frequently Asked Questions

This lens is designed for Pentax cameras that use the M-type viewfinder eyepiece adapter. Check your camera's manual to confirm it accepts M-mount diopter lenses.
The -3 diopter correction is intended to let nearsighted shooters use the viewfinder without glasses. If your prescription is approximately -3, this lens may allow you to shoot comfortably without eyewear.
No. The diopter correction lens only modifies the viewfinder optics so you can see the focusing screen more clearly. It has no effect on the image captured by the sensor or on metering.
Pentax's Super Multi Coating (SMC) reduces flare and reflections within the viewfinder optic, giving you a clearer, higher-contrast view through the eyepiece.
It threads into the viewfinder eyepiece using the included M adapter. Installation takes just a few seconds with no tools required.

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