This 4-stop FotodioX WonderPana 145 Core Unit for Sigma 12-24mm Lensfeatures a filter ring with 145mm front filter threads. With a 16x filter factor that provides a 4-stop exposure reduction. Its 1.2 optical density creates a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than normally required. By slowing your exposure time or increasing your aperture, you are able to control depth of field and convey movement more easily. Neutral density filters do not affect the coloration of the image and are ideal for pairing with other filters.

To prevent internal ghosting and reflections, this filter includes multiple layers of anti-reflection coating. These coatings also offer greater protection to the filter substrate and help it to stay clean for longer than with uncoated filters. This filter is constructed from optical glass for clarity as well as color fidelity and features an aluminum-alloy filter ring for durability while remaining lightweight.

For Sigma 12-24mm f/4.5-5.6 EX DG HSM    WonderPana 145 Core Unit    145mm Solid Neutral Density 1.2 Filter    16x Filter Factor, 4-Stop    Darkens Entire Image    145mm Solid Neutral Density 1.5 Filter    32x Filter Factor, 5-Stop    Darkens Entire Image    145mm Center-Pinch Snap-On Lens Cap    Use with WonderPana 6.6" Holder Bracket

1.2 optical density filter darkens the image, allowing you to photograph with a longer shutter speed or wider aperture than normally required.

Providing a 4-stop exposure reduction, this filter allows you to control depth of field and convey movement more easily.

Filter does not affect coloration of the image and is ideal for use with other filters.

Includes multiple layers of anti-reflection coating to prevent internal ghosting and reflections.

Constructed optical glass for clarity and color fidelity.

145mm front filter threads allow for use with other filters.

Durable, lightweight aluminum-alloy filter ring with one brass side knob allows the filter to be easily screwed on or off.

Filter pouch included for storage and transport.

Related Questions and Answers

Q: 1. Can focus and aperture be manually adjusted when mounted via a lens mount adapter that lacks electronic contacts?

A: The focus can be controlled manually on an adapter without electronic contacts. However, that adapter would need some type of aperture control built into it.

Q: 2. can a ND filter be attached to it?

A: Yes, Here is one system that is designed for the Sigma 12-24 f/4 Google nisi filters

Q: 3. Is this lens compatible with the Sony A9 camera?

A: Yes, the FE 12-24mm f/4 G Lens is fully compatible with Sony a9

Q: 4. Does this lens (FE 12-24) works well with Sony A7C?

A: Yes, it will be perfect for the a7C. It is designed for full frame mount cameras such as that one. The addition of the assignable button is also a welcome addition since the a7C has fewer buttons than some other Sony cameras.

Q: 5. Has anyone found a filter holder for this lens? The Haida holder for the Canon 12-24 is just barely too big.

A: Unfortunately, we do not have carry a filter adapter for the Sigma 12-24mm f/4 at this time. It might take some time for an option to hit the market.

Q: 6. Will this lens work with the A 7R lll

A: This is a terrific lens and I use it whenever appropriate. For landscape, fine art, real estate, and other applications it is flawless. Very light, and as sharp as the GM lenses I own. Can't recommend it more highly. I use it a lot.

Q: 7. Is this rectilinear or a fisheye? How much distortion is there at 12 mm?

A: It is rectilinear. Distortion is minor all lengths.

Q: 8. Can a person who is otherwise a die-hard Canon lens fan be satisfied with this Sigma lens? The comparable Canon 11-24mm seems just too expensive.

A: Buying a brand-new lens does not necessarily means you will get a good copy. You will need to test the lens out yourself. If you are lucky, then you will have a good copy. If not, you will need to calibrate it with the DSLR you are using to adjust the sharpness.Unfortunately, I did not get a good copy so I am waiting for USB Dock for Canon EF-Mount Lenses to arrive so that I can use it to calibrate my Sigma lens. I believe once it's calibrated correctly for your DSLR, the sharpness should be as good as the Canon 11-24mm.

Q: 9. What size is the image circle, will it cover a 33x44mm sensor?

A: This lens' image circle will not cover a 33x44mm sensor.

Q: 10. Does this lens have a rear gel slot?

A: There is no gel slot.