Why choose UFC Quickchange-Frontfilters with DSLR-Cameras?

Info about using quickchange-frontfilters with the UFC in combination with DSLR-cameras

There are no monochrome DSLR-cameras on the market, so a filter holder (e.g. the Baader-UFC) may seem quite useless for DSLR imaging, but if you take a closer look, there are indeed some interesting use-cases.

Many owners of DSLR-cameras remove the complete UV/IR-blocking filter and use this simple way to improve the sensitivity especially for H-alpha – but because of the costs, they decide not to add a new blocking filter with increased H-alpha-transmission.
But as a result, you have to find another way to block the IR- and UV-parts of the spectrum so that they will not decrease the image quality. You can use the UFC to mount such a UV/IR-cut filter in front of the camera - and to quickly replace it with another filter, without touching the camera.

Narrowband filters are not perfectly suited for a DSLR because of the Bayer-matrix, but especially a 35 nm H-alpha filter will show the emission nebulae better.

Especially in light-polluted areas the UHC-S-filter is very helpful. You can use the Baader-UFC to switch between several filters fast and easy. This way you can see which filter is the best for your conditions.

A Fringekiller or other filters which decrease chromatic aberration can also easily be used with great effects on an achromatic lens telescope with the UFC. Nowadays, you can adjust for slight changes in the colours with the help of the white balance of modern cameras or software.

When a telescope – and the camera with it – faces upwards into the sky, the dust inside the telescope will fall towards the camera sensor. Pure CCD-astro-cameras have got an optical windows which also stops the dust, but inside of a DSLR, the dust will come much closer to the sensor, so that it will be visible as dark spots on the image. A filter held by a UFC is an effective protection against dust falling onto the sensor of your DSLR.

As a conclusion, an UFC filter changer gives you many new options also in combination with a DSLR, and as bonus, it offers additional protection from dust reaching the sensor of the camera.

Following are some Backfocus examples of UFC-System with DSLR-cameras on Celestron EdgeHD Tubes

Please take a look at the specifications given by Celestron about the backfocus. You can find them in the EdgeHD-Whitepaper on page 14:
www.celestron-deutschland.de/edge-hd-whitepaper
The shifting of the focus by ca. 0.66mm when using 2mm thick filters is already included in the overview above. As a rule of thumb, a filter moves the focus in the extrafocal direction for 1/3 of the filters thickness.

Please note the big advantage of 11" and 14" EdgeHD-telescopes when used with the 0.7x-reducer: The backfocus does not change, you can use the same setup with or without the reducer.

When using an 8" EdgeHD in combination with the 0,7x Reducer, the Backfocus changes from 133,35mm to 105mm - for this reason the adapters have to be changed as described below as well as visible in the images.

This setup demonstrates the shortest possible connection of one of our 2" diagonals at a Celestron SC/EdgeHD with an UFC. The shorter distance between telescope and eyepieces enables a better illumination, especially for eyepieces with longer focal lengths.

• 1x 2458270 Ring NexStar Locking Ring 2"
• 1x 2459128 UFC 2" Telescope-Adapter
• 1x 2459110 UFC Base (Filter holder)
• 1x 2459120 UFC 2" Camera-Adapter
• z.B. 1x 2956100 ClickLock mirror diagonal 2"
• z.B. 1x 2954217 Morpheus 17,5mm Widefield eyepiece
• Filter slider according to requirements (2" M48 Filter, unmounted D50,4mm or 50x50mm)