Previous, if I wanted to change a filter when using a dedicated astro photography camera with my Samsung f2 135mm lens I had to remove the camera and part of the adaptor ring I was using, which was not exactly a fun task at one o'clock in the morning on a freezing winters night. This combined adapter and filter draw saves all the hassle without altering the length of the optical train significantly. By having a spare draw with the selected filter pre installed, it takes seconds to change a filter without any need to disturb the optical train or even switch off the camera.
FLO's service when ordering this item was again exemplary

I first used it with A Samyang 135mm f2 lens and was unable to reach focus and initially thought there was a problem with the specification of the drawer. Turns out the problem was the infinity stop on the lens. Apparently a common issue with this lens. After some fiddly adjustment, all good.

So pleased with my filter drawer. 100% happy. Fast delivery

I had two options for attaching a Samyang 135 Canon EOS fitting lens to my ASI 533MC-Pro; this ZWO filter drawer or the Astro Essentials Samyang to M48 Adapter.

My inital idea was to get the Astro Essentials adapter and then use my existing ZWO filter drawer with some additonal spacers (need to purchase those too) to get the correct back focus. My thanks goes out to Alex at FLO for sending me a really good explanation of what I would need to purchase to get everything working, as being new to astrophotography I still have trouble getting my head round back focus! The email was a fantastic explanation.

In the end I chose to get the ZWO filter drawer for Canon EOS Lenes for the simple reason of ease of use, as I wouldn't have to do a complete image train breakdown to move the 533 between my RedCat 51 and Samyang 135 len - just unscrew the camera.

The filter drawer looks a good bit of kit and connects to the lens really well and secure, and of course it just screws into the camera. Can't wait to use it now.

After reading about an ill fitting adapter the new product with filter slider is a welcome upgrade. The adapter fits my Samyang 135mm perfectly. It is odd that the existing ZWO 2" to 1.25" filter adapter does not fit, or so they tell me, however the adapter from my Starizona slider, for RASA 8, fits nicely. Sadly, importing issues now make FLO's prices less attractive for the future, I won't mention the 'b' word.

A well made adapter that is as tight as you want it to be. I haven't noticed any tilt with my Samyang 135 so well happy. FLO great service as usual and got it in time for 2 clear nights on the bounce!

I had reserves about buying this as another astro friend said their ZWO / EF adaptor was very questionable.

However, I believe ZWO recently re-designed their adaptors and this one is anything but questionable! The quality is perfect. It fits snug with the EF connection locking in place nicely and easy to unlock. The filter drawer is similar to starizona / Baader filter drawers withmagnets to hold the drawer in place securely.

This drawer holds my Astronomik UV and Narrowband filters and ZWO 533 with no problems. This drawer provides the perfect 44mm back focusing distance needed for EF lenses without any need for spacers or extras

This is just about the only way to have a Canon EF lens reach focus properly with a ZWO camera *and* be able to use filters. However... (no fault of FLO!) the filter drawer in this is completely different to the regular ZWO filter drawer for use with a ZWO camera and telescope. I was really hoping they'd be the same, but they're not - and not compatible. This means I have to unscrew my filter each time I want to swap back and forth. Why ZWO didn't make the drawer the same is beyond me, but there you go - something we have to live with to be able to take filtered images with EF lenses! Well made item, and a satisfying click when the lens attaches, with no wobble. Expensive, but of good quality.