Just bought the A7 IV (33 meg) and also the LA-EA5 adapter. I already had the Alpha A65 A mount plus the SAL 2470Z Full Frame prime lens which cost a fortune then and is much more now, (hence the adapter). It works great but does add a little length. But then I can put up with that with saving nearly £1900 on buying the new E mount lens. Trying to find out whether everything would be compatible was a pain, the Sony site is poor & not easy to glean info. But a visit to the "Ken Rockwell" review site made things far easier to understand, search the LA-EA5 adapter, enter your camera body (A7-IV) etc, then have a look at the compatible lenses. Full frame should work, others will have limitations. I've found my particulay combination works great.