Preset lens adapters?

[Red735i]

The "problem" with most adapters is that they are really slow to use.  My way of doing things is to open th elens up to maximum aperture for focusing; Focus with A& to maximum magnification, focus using a ground glass approach : shut lens down to working opening: Shoot.  Repeat.  It is not the speed that is the issue, it is the requirement to open the lens up and then close it down..... which currently requires the user to take the camera from the eye to set the aperture.

In the old days (1960's)  lenses were made with preset apertures... you set one ring for working aperture, then use a second ring to open up to max aperture, and it locked you to working aperture without further examination.... it was like a limit stop that worked wide open and again at working aperture.

An adapter could be easily made to work with t he lens aperture as a preset one..... ( see the Novoflex Nikon to Canon mount semi permanent adapter which has this feature) but others, in general , do not.

Nikon lenses, Leica R lenses, Minolta, and others all work with a moving auto aperture pin that could be easily used in this mode....

Does anyone know what adapters have this feature? 

[howgus]

I'm sorry I'm not familiar with most adapters, as I use Sony lenses which the camera controls, often using manual focus.  If it's any consolation, Sony does not open lenses wide automatically when using MF Assist, an odd oversight, so for good focus, one has to open the lenses by twisting the little dial on the camera to open wide, focus, then twist again for the shot. 

[petrochemist]

I don't know of any adapters with this feature (there are some that control the aperture linkage but these are designed for lenses without aperture rings at all. The good news is you can usually focus perfectly well with the lens stopped down using magnified view & peaking - if focusing at wide apertures is needed there are a few lenses that will work for you.

OM mount lenses have a DOF preview button on the mount that will shut down the lens.

Many M42 lenses have an auto/manual switch or a separate pre-set ring too.

[Red735i]

I realize the stopped down focusing using magnified view with or without focus peaking is available.  However, this is hardly optimum for really good, accurate focus discrimination.  There is a Novoflex and Fotodiox Nikon G lens to Canon adapter that has the right feature. And right now, I use those adapters.  Yes, the Pentax M42 lenses, some of them, offer a preset feature, and I use that as well.  But I really want a Leica R lens solution, which does not seem to exist.  Mind you, each of the solutions noted requires a something to NeX adapter anyway.... why not include preset adapter in the final solution?

 

Note that this same problem also exists fo anyone with the new Canon -M or Nikon Z cameras.

[Koenr]

K&F concept has several mount adapters providing aperture control on the adapter. That way you can even use lenses without aperture ring. But when used with lenses with aperture ring you can preset your aperture on the lens and use the aperture control on the adapter to close to the preset aperture after focusing. I use my pentax-K lenses on a Sony A 7 II that way.