BebuLamar

Does the mirrorless camera aperture is at maximum aperture until it actually makes the exposure or is it always at the set aperture?

Largobob

The aperture happens in the lens (diaphragm).....not the camera.

BebuLamar

OK Thanks.

lamiaceae Loc: San Luis Obispo County, CA

If you mean as in like Live View on a DSLR, yes, the iris should stop down to selected f-stop. As another said the iris (diaphragm, f-stops) are in the lens.

Rich1939 Loc: Pike County Penna.

Generally speaking, for almost all modern cameras,the aperture stays open until the moment the picture is taken. Things like auto focus for instance would really struggle to operate with a lens stopped down. Not to mention the operator's struggle to frame the shot.

f8lee Loc: New Mexico

This is incorrect. For SLRs and DSLR, where you are viewing the actual light passing through the lens, the design is to keep the aperture fully open and sprung in such a way that when the shutter is tripped the aperture closes down to the desired f-stop.

However, for mirrorless cameras, this is not necessary, as the EVF (electronic viewfinder) can compensate for the lower light coming through the lens. Thus the lenses do not have the "always open" capability. When you stop the lens down to f11, the aperture gets smaller - you just cannot tell in the EVF since it looks the same. This makes the lenses less costly to manufacture, as there is far less mechanical complication.

Largobob

Soooo....how does this apply to those who use DSLR lenses (with adaptor) on their mirrorless camera?

f8lee Loc: New Mexico

Well as none of the adapters I have for my Nikkor lenses to work on the Fuji mirrorless have a lever to hold the aperture open - this tells me that stopping the lens down simply closes the aperture in the lens.

Rich1939 Loc: Pike County Penna.

Auto focus is affected by the light so, having roots in Missouri, I need to see that for myself. Do you have a link? or two

burkphoto Loc: High Point, NC

The lens is at max aperture if it is a native lens, and you're working in an automatic mode.

If you are in FULL manual mode (set ISO, set aperture, set shutter speed), some models will use the set aperture for viewing. That way, you can see the effects of your exposure (and depth of field) and JPEG processor settings in the EVF.

When working with adapters that do not support electronic coupling between the lens and camera, you have to set the aperture manually in most cases. So there is no automatic diaphragm control. Some adapters for Nikon lenses have a ring that you turn to set the aperture. So when you use these, the actual lens aperture is used for viewing and exposure. This limitation is why I never adapted my Nikkor lenses to Micro 4/3. Stop-down metering is a pain in the butt.

Largobob

Wow....a lever to hold the aperture open? They must be oldies...? More modern lenses (G = guilded, for instance) have no external aperture ring. The aperture is controlled electronically.

burkphoto Loc: High Point, NC

Adapters for Nikon lenses generally have no electronics. Hence, there is a lever to stop down the G lenses. Old pre-AI and AI Nikkors have aperture rings.

BebuLamar

For the G lenses to work the Nikon DSLR still have a level to hold the aperture open and stop them down when just before the shutter opens. Only the E type lens which has electronic diaphragm is fully electronic.

Largobob

Thanks BebuLamar. But, now I'm really confused. (Don't worry, it happens to me often).

Please explain to me, how the lens "knows" what aperture is selected if it does not have an external aperture ring.

BebuLamar

I can't speak of the mirrorless system which is why I asked the question but on the 35mm SLR and DSLR for the G lenses the lens knows nothing about the aperture. The camera does it all. When you mount the lens on the body a level push aperture stop down level on the lens and keep it wide open. The camera via electronic communication with the lens knows what is the maximum aperture of the lens. For example you have an f/1.4 lens when you mount the lens the camera knows that it's f/1.4 at it's widest with the level at normal position. So either by automatic or by you set the aperture to a certain aperture it knows just how many stops it has to close the diaphragm to get to the right aperture. It does it by moving the aperture control level the right amount at the time of the exposure.
With AF and AF-D lenses it works in similar way if you set the aperture ring to the smallest aperture. The level would makes the lens open fully and then moves to stop it down the right amount. When you elected to set the aperture by the aperture ring the camera level will move all the way and let the aperture ring stops the movement at the right aperture.
With AI/AI-S lenses the camera doesn't know the maximum aperture of the lens via communication with the lens so you have to tell the camera that the lens you attach the maximum aperture of the lens. Also the DSLR's requires you to set the aperture via the aperture ring and so it only works on A and M modes. At the time of exposure the camera aperture level simply moves all the way and let the aperture ring setting on the lens stops the movement at the right aperture.
Only on the E type lens that the camera via communication can tell the lens which aperture to stop down to without any mechanical couplings.