M42 to A Mount on A850/A900

[S k u n k]

Hi all! 

Did try searching but couldn't find much that specifically discussed this as a subject, so sorry if I'm duplicating a thread.

I have an A850 and would like to use M42 lenses (specifically Helios 44 series lenses, as I have several) but am unsure about the flange distance being safe with an adaptor. I really don't want to damage the mirror on my body, so I'm wondering if anyone can suggest an adaptor that will work, or if anyones had any experience with this? Tons of information out there about E mount of course but nothing on A mount! 

[Pieter]

Since the flange distance of M42 is only 1mm longer than A-mount (45.5mm vs 44.5mm) and the throat diameter of M42 is narrower than A-mount, technically it's possible with a 1mm shim where the M42 thread fits right into the A-mount. These adapters do exist, like this one:

https://fotodioxpro.com/products/m42-sna-p-v1?srsltid=AfmBOoo6xau1kk888K5aamsUS8vbGOf1REt3Owc418sWdEZtaGKRH55R

Edited December 13, 2024 by Pieter

[S k u n k]

4 hours ago, Pieter said:

Since the flange distance of M42 is only 1mm longer than A-mount (45.5mm vs 44.5mm) and the throat diameter of M42 is narrower than A-mount, technically it's possible with a 1mm shim where the M42 thread fits right into the A-mount. These adapters do exist, like this one:

https://fotodioxpro.com/products/m42-sna-p-v1?srsltid=AfmBOoo6xau1kk888K5aamsUS8vbGOf1REt3Owc418sWdEZtaGKRH55R

Ideal, thankyou Pieter! I did think this would be the case, not sure why I didn’t have a look for Fotodiox

[XKAES]

There are lots of M42 to a-mount adapters.  I use them on my a850, too.  But the different adapters have some differences.  You should check them out.  For example, I use a PIXCO adapter which is a "CHIPPED" adapter.  Having a computer chip on the adapter allows you to get the GREEN focus verification LED to operate in the viewfinder -- even though you are using a manual-focus lens.  If that is of interest to you -- the a850 does not have any manual-focusing aids in the viewfinder, such as a micro-prism -- the PIXCO adapters are about the same price as unchipped models.