Field flattener back focus. , how far back the telescope+flattener will focus the image. Back focus is important because some accessories require a specific back focus distance to work properly and correct optical aberrations such as coma or field curvature. Dec 22, 2017 · Field flattener back focus - posted in Beginning Deep Sky Imaging: I am using an Orion EON 130mm ED Triplett refractor scope and Orion proprietary field flattener with a Canon EOS 70D for astrophotography. We adjust the back spacing of the field flattener to match your camera's back spacing using a series of extension tubes Apr 29, 2022 · Back focus is a term that causes much confusion among newcomers to astrophotography. I . This is a critical parameter in astrophotography. I have a LPS clip-in filter. The camera has a 6. My problem is the back focus of the field flattener is only 51. This is because when people talk about back focus, they often mean different things: the back focus on a telescope, the required back focus for accessories such as field flatteners, or the flange focal distance of DSLRs and astro cameras. This refers to a distance in millimeters and has nothing to do with focus per se. I just got my first refractor with field flattener and I image with a Canon DSLR. 6mm away from ideal 75mm isn't going to make things terrible. I Jan 8, 2024 · Determining the correct back focus for your telescope can be a daunting task for both beginners and experienced astrophotographers. Jan 17, 2022 · Like field flatteners, focal reducers require a specific amount of back spacing to work properly, so check the specifications of both the reducer and your telescope to ensure you will have enough back-focus to use the reducer. Nov 14, 2020 · The back focus is the distance between the back of the telescope and the focal plane, i. I currently use an Orion ED80 and Orion Field Flattener for Short Refractors. The FF has a required back focus of 55mm. Will the spacing between flattener and camera change with or without the clip-in filter? I noticed that the focus changes with and without the filter. Sep 23, 2016 · Field Flattener Back Focus - posted in Experienced Deep Sky Imaging: Hi there, Just purchased a ZWO ASI1600MM-Cool, the ZWO EFW-mini, and the respective ZWO LRGB filters for 1600mm. Mar 2, 2025 · Field Flattener back focus and clip-in filters - posted in Beginning Deep Sky Imaging: Hi everyone, I have a likely stupid question. 5 +/- 5 mm and the flange to sensor distance in the Canon dslr is 44 mm. With a 5mm thick T-EOS adapter, the back focus is SFFX1 FlattenerBack spacing is also referred to as back focus. To make sure the field flattener is spaced correctly from the camera, you need to know the distance from the camera's attachment thread to its sensor. In this article, we’ll discuss why back focus distance is so important, all the factors you need to consider for back focus distance, and how to use adapters and spacers to get the perfect back focus distance. Dec 28, 2023 · Back focus is the distance from the last optical element of your telescope or accessory (such as a field flattener or a focal reducer) to the focal plane. To get the sharpest correction out of your field flattener, it needs to be placed the proper distance from the camera's sensor. 5mm back focus, filter wheel is 20mm, T2-T2 is 1mm, so that is 27. Oct 30, 2022 · In this article, we’ll go over why back focus spacing is so important to get right, everything to consider for back focus spacing, and how to use adapters and spacers to get your back focus spacing perfect. 5mm. Dec 19, 2017 · If there is no power in the flattener (it doesn't alter telescope's f/ratio), back focus is not terribly critical. e. Jul 20, 2021 · This article explains the back focus of telescopes and optical accessories like field flatteners and focal reducers, and why back focus is important for visual observers and especially for astrophotographers. This distance, measured in millimeters, is known as the camera back focus. Sep 13, 2021 · In addition to reducing the focal length of the telescope and thereby increasing the photographic speed, these new Astro-Tech reducer/field flatteners flatten the normal field curvature inherent in refractors to provide images that are focused out to the very corners of a large format chip. azcts peuv apbdof edo gtka oabmj lovs rkbj qzjbc xas