Hello, I been going around this problem for a while. I am trying to attach the ASI 6200 with a canon lens. The camera comes with a M54M-M48F tube, the tube is good for the adaptation of the flange distance of the canon lenses. I have a canon adapter but it has 54mm in the internal screw. The box of the adapter says ZWO NEW EOS T2 adapter. So the tube fits in the camera and not in the canon adapter or viceversa. Would you please tell me what should I buy?
Thanks
nahuelv ZWO NEW EOS T2 adapter.
That adapter uses a T2 (i.e., M42x0.75) interface to a camera that has a flange-to-sensor distance of either 12.5 mm or 17.5 mm. Any adapter from M42 to the M54 thread of the camera will need to be either precisely 5 mm long, or zero mm long. If you add filter glass, you will need an additional spacer that is 1/3 the thickness of the filter glass.
The bigger problem, if you are using it with a ASI6200, is that you will get severe vignetting. The hole size of the T2 interface is only 37.3 mm (I just measured), while the diagonal of your full frame sensor is 44mm. The hole needs to be substantially larger than 44mm -- especially with an f/1.4 lens -- to prevent the hole from obstructing the light cone from the lens.
Even if you can use flat frames to reduce the light drop-off from vignetting, the aperture vignetting causes pretty severe ugly diffraction notches in bright stars that are only half way from the center of the ASI6200 frame (which cannot be corrected with flat frames).
Depending on the f-number of the lens, you could get vignetting even when used with a smaller APS-C sized sensor.
Caveat Emptor.
Chen
I have the same question as nahuelv. I too have the an ASI6200 MC pro that I successfully use with my newtonian astrograph, but would also now like to use it with my Canon EOS L-Series EF lenses. I understand why the ZWO New EOS T2 adapter will not work (though I cannot understand why ZWO describes it as being for all ASI cameras... clearly not true). But what we want to know is what WILL it work with?
I see that there is an EOS adapter (ZWO EFW-EOS-Ⅱ) described as "Short EOS adapter for EFW & Cooled camera (6.5mm backfocus version)." I already have a 20mm deep filter drawer (FD-M54) in front of the 17.5mm offset sensor so if the ZWO EFW-EOS-Ⅱ really has a 6.5mm backfocus, then I should get the exact 44mm backfocus required for the Canon EOS EF lenses. But unfortunately, neither the exact dimensions, nor the threads for this short EOS adapter are specified anywhere that I can find. I think that's because ZWO expects you to use it with the electronic filter wheel (which is 20mm deep according to the mechanical diagrams) but it is not possible to determine from the product description(s) what to use for the ASI 6200 cameras. See using-asi6200mc-pro-with-a-canon-eos-ef-l-series-lens
If anyone has solved this problem, please let us know.
laszloilyes the 6.5mm backfocus refers to some cameras where the sensor is at 6.5 mm (most of the cooled cameras will have the sensor at 17.5mm)
Flange distance for EF lenses is 44mm
Less 17.5mm camera
Less 20mm filter drawer
Leaves you with 6.5 mm total adapter length and I am pretty sure the EF adapter is much thicker. You will have to find a much thinner adapter and that might be tricky.
Additionaly, the lens you plan to use needs to be wide open when the lens is disconnected. If it isn't, there isn't anything you can do about that because it will be the equivalent of f22 or worse.
