Suggested feature to fix focus shift for Tamron 24-70 G2

Started 5 months ago | Discussions thread
QuietOC Veteran Member • Posts: 5,327
Re: Suggested feature to fix focus shift for Tamron 24-70 G2

calin wrote:

A reminder that focus shift is an issue specific with certain fast lenses and results in the focus plane not been the same at all apertures.

It more or less effects every lens if you check them carefully. SLRs could've implemented stop down focusing. Nothing necessarily ties it to mirrorless.

However, mounted on a mirrorless camera, the focusing processor is bypassed and the trick above can't be made.

EF to E-mount adapters with native emulation allow stopped down focusing with EF lenses and would probably work with that Tamron.

Someone could theoretically design a native emulation EF adapter for RF cameras. It would be a lot of work compared to simply passing through the EF support already supplied.

Tamron doesn't seem to have any interest in creating adapters for their lenses--probably since they are a big OEM for other brands.

The Sigma MC-11 adapter for E-mount allows their Art, Sport, and Contemporary lenses to emulate native lenses including stopped down focusing. I am not sure how their MC-21 works for L-mount.

Many Sony A-mount lenses have pretty large focus shifts, but like Canon, Sony only allows those lenses to focus wide-open. Sony SLTs do a form of stopped down focusing for video AF--stopping down lenses to F3.5.

I notice my A7RIV does more wide-open focusing with native lenses than my previous Sony mirrorless cameras. That change may have stemmed from complaints about stopped down AF performance. There are trade-offs for both methods. It would be nice to have user controls for these behaviors. There are settings that effect it on Sony, but they are not obvious.

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