Are ALL manual focus primes soft on XTrans cameras?

Started Mar 13, 2014 | Questions thread
Jim King
Jim King Veteran Member • Posts: 8,345
Re: Are ALL manual focus primes soft on XTrans cameras?

R Neuschul wrote:

"About the only thing a bad adapter can do is cause a very slight 'tilt' effect on the focus, sort of like a tilt/shift lens."

You are assuming that the length of the tube - the adjusted registration distance - is correct: a variance as small as .001 mm out of spec can be sufficient to affect focus. Manufacturing tolerances are critical in optical equipment, as are the grades of the materials used to manufacture the adapter, especially the mounts at each end of the tube. Remember too that temperature can also affect materials: poorly selected materials will shrink/expand as ambient temperatures vary.

Good manufacturing tolerance with thermal stability is harder [more costly] to achieve, let alone achieving it consistently across a production run. There's almost always a reason why Novoflex and other similar "quality" adapters are more costly than something from Kippon or Fotodiox.

If the length of the adapter were slightly off, there would be no problem with manual focus except at infinity, as the MF process would take the actual length of the adapter into account.

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