Explore Scientific 3" Field Flattener .7x Focal Reducer


Availability: More on the way

Explore Scientific’s 3” Field Flattener .7x Focal Reducer is a multi-faceted accessory designed to enhance your astrophotography experiences.

Our Product #: ES3FF
Explore Scientific Product #: FFFR507X-00
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Product Description

The Explore Scientific 3" Field Flattener/.7x Focal Reducer is designed to increase your photographic enjoyment of your Explore Scientific refractor.  Depending on which refractor you own, you might need an additional adapter.  Out of the box you will be able to attach it to the 3" Explore Scientific focuser.  However, you will need the #510366 adapter if you have the 2.5" Hex focuser, or the 510364 adapter if you have the 2" Explore Scientific focuser, to attach this piece of equipment to your scope.  

Once installed you should notice a few things.  1.  The stars are pinpoint out to the edge of your camera, no more curvature.  2. You will notice more sky in your field as you have reduced your f/ratio by .7x.  And finally 3.  Your exposoure times will  have decreased and your images will be brighter due to the faster optic.  

Explore Scientific has thought of everything.  The device is fully multi-coated to help maximize light transmission, and it also comes standard with adapters to help your camera/DSLR/CCD attach.

This piece really works well from f/8 to f/7.5.

Tech Details

Warranty 1 year, extendable to lifetime


Review by:
I’ve used the ES 3” field flattener / field reducer for astrophotography with my ED127 APO for the past year. With the reducer in place (666 mm fl @ f/5.25), stars are sharp to the edges with a Canon 70D / APS-C sensor; however, with Canon 6DM2 / FF sensor some vignetting is apparent in the corners. When using an APS-C camera, the Andromeda Galaxy (M31) literally fills the frame on the diagonal, while a FF camera will nicely frame both the Trifid (M20) and Lagoon (M8) nebulas. The FFFR is well made, performs very well and attaches easily to the ED127 APO.
(Posted on 7/22/2019)
Review by:
I use this reducer/corrector with my ES 127mm APO and APS-C sized sensors to get wider views and quicker exposure times. Stars are tight all the way to the edges, even on Full-Frame sensors. Light loss for APS-C is fairly minimal at around 15% in the extreme corners. Full-Frame is another story, with about 70% loss in the corners, so you'll probably want to stick with APS-C or smaller sensors. My only issue with this reducer/corrector is a lack of a place to mount a 2" filter. Other than that, it performs very well. (Posted on 1/5/2019)
Review by:
While a little pricier than others, it is definitely one of the best focal reducer/field flattners I've used and worth the extra expense. Images are crisp and flat all the way to the edge with my ES 127mm APO refractor. When doing astrophotography, I can cut my exposure time by 10-25% and get a wider FOV. The unit is fairly heavy at almost 1.5lbs and may require additional tube balancing when installed. But, this is a small price to pay for the gains you get . The 2" nosepiece adapter is also a handy accessory. (Posted on 12/20/2018)
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