Aperture is not wide open during auto focus

[falcon123]

I switch from Canon DSLR and use Nikon ZF now.

When I use Canon DSLR, the lens is always wide open before I fire the shutter. It auto focus under wide open condition.

But for my Nikon Zf camera, I saw the aperture inside the lens is followed to my apperure setting.

So I though when I am using smaller apperture, there will be less light pass into the camera that may affect the performance of the auto focus.

Does Nikon Z camera can be set with aperture always wide open during auto focus?

Anybody can share some experience.

 

[PLShutterbug]

I switch from Canon DSLR and use Nikon ZF now.

When I use Canon DSLR, the lens is always wide open before I fire the shutter. It auto focus under wide open condition.

But for my Nikon Zf camera, I saw the aperture inside the lens is followed to my apperure setting.

So I though when I am using smaller apperture, there will be less light pass into the camera that may affect the performance of the auto focus.

Does Nikon Z camera can be set with aperture always wide open during auto focus?

Anybody can share some experience.

By default, Z-system cameras stop down to the actual shooting aperture until f/5.6. If you are using a narrower aperture than that, the camera stops down to f.5.6 for preview/focusing and then stops down to the shooting aperture for the shot.

In firmware version 3.00 for the Z8, they introduced a new system setting, “Maximum aperture Lv”, that if enabled keeps the aperture at its maximum until the shot. This is the setting you are looking for. I don’t know if it has been added yet for the Zf - check the manuals online and recent firmware updates.

If it hasn’t made it to Zf firmware yet, it is likely to get there eventually. Regardless, Z cameras do well in most shooting situations even at f/5.6 so the default behavior generally is not a concern.

 

[falcon123]

I switch from Canon DSLR and use Nikon ZF now.

When I use Canon DSLR, the lens is always wide open before I fire the shutter. It auto focus under wide open condition.

But for my Nikon Zf camera, I saw the aperture inside the lens is followed to my apperure setting.

So I though when I am using smaller apperture, there will be less light pass into the camera that may affect the performance of the auto focus.

Does Nikon Z camera can be set with aperture always wide open during auto focus?

Anybody can share some experience.

By default, Z-system cameras stop down to the actual shooting aperture until f/5.6. If you are using a narrower aperture than that, the camera stops down to f.5.6 for preview/focusing and then stops down to the shooting aperture for the shot.

In firmware version 3.00 for the Z8, they introduced a new system setting, “Maximum aperture Lv”, that if enabled keeps the aperture at its maximum until the shot. This is the setting you are looking for. I don’t know if it has been added yet for the Zf - check the manuals online and recent firmware updates.

If it hasn’t made it to Zf firmware yet, it is likely to get there eventually. Regardless, Z cameras do well in most shooting situations even at f/5.6 so the default behavior generally is not a concern.

Just search all around the camera menu, I cannot find any "Maximum aperure Lv" item in my ZF.

As Nikon add this feature to Z8, it should have its reason and advantage. Do you find any performance improve, such as auto focus.

Anyway thanks for your information.

 

[PLShutterbug]

I switch from Canon DSLR and use Nikon ZF now.

When I use Canon DSLR, the lens is always wide open before I fire the shutter. It auto focus under wide open condition.

But for my Nikon Zf camera, I saw the aperture inside the lens is followed to my apperure setting.

So I though when I am using smaller apperture, there will be less light pass into the camera that may affect the performance of the auto focus.

Does Nikon Z camera can be set with aperture always wide open during auto focus?

Anybody can share some experience.

By default, Z-system cameras stop down to the actual shooting aperture until f/5.6. If you are using a narrower aperture than that, the camera stops down to f.5.6 for preview/focusing and then stops down to the shooting aperture for the shot.

In firmware version 3.00 for the Z8, they introduced a new system setting, “Maximum aperture Lv”, that if enabled keeps the aperture at its maximum until the shot. This is the setting you are looking for. I don’t know if it has been added yet for the Zf - check the manuals online and recent firmware updates.

If it hasn’t made it to Zf firmware yet, it is likely to get there eventually. Regardless, Z cameras do well in most shooting situations even at f/5.6 so the default behavior generally is not a concern.

Just search all around the camera menu, I cannot find any "Maximum aperure Lv" item in my ZF.

As Nikon add this feature to Z8, it should have its reason and advantage. Do you find any performance improve, such as auto focus.

Anyway thanks for your information.

You’re welcome.

Several people here have commented about AF performance in very low light conditions with lenses stopped down below maximum aperture. The new setting was to allow maximum aperture focusing in those conditions.

 

[kenw]

I switch from Canon DSLR and use Nikon ZF now.

When I use Canon DSLR, the lens is always wide open before I fire the shutter. It auto focus under wide open condition.

But for my Nikon Zf camera, I saw the aperture inside the lens is followed to my apperure setting.

So I though when I am using smaller apperture, there will be less light pass into the camera that may affect the performance of the auto focus.

Does Nikon Z camera can be set with aperture always wide open during auto focus?

Anybody can share some experience.

By default, Z-system cameras stop down to the actual shooting aperture until f/5.6. If you are using a narrower aperture than that, the camera stops down to f.5.6 for preview/focusing and then stops down to the shooting aperture for the shot.

In firmware version 3.00 for the Z8, they introduced a new system setting, “Maximum aperture Lv”, that if enabled keeps the aperture at its maximum until the shot. This is the setting you are looking for. I don’t know if it has been added yet for the Zf - check the manuals online and recent firmware updates.

If it hasn’t made it to Zf firmware yet, it is likely to get there eventually. Regardless, Z cameras do well in most shooting situations even at f/5.6 so the default behavior generally is not a concern.

Just search all around the camera menu, I cannot find any "Maximum aperure Lv" item in my ZF.

As Nikon add this feature to Z8, it should have its reason and advantage. Do you find any performance improve, such as auto focus.

Anyway thanks for your information.

You’re welcome.

Several people here have commented about AF performance in very low light conditions with lenses stopped down below maximum aperture. The new setting was to allow maximum aperture focusing in those conditions.

Yep, somewhat better low light focusing performance with the trade off that then some faster lenses will suffer from focus shift when shot stopped down. Key point is that focusing wide open is in general less accurate than focusing stopped down to the shooting aperture. How much error depends on the lens (check reviews that test for focus shift with a lens to get an idea of home much).

Best of both worlds is to have a choice of course!

Since the OP is coming from DSLR, worth noting that DLSR dedicated PDAF sensors are significantly different from mirrorless on chip PDAF sensors. With DLSR it often made sense to accept the risk of focus shift while focusing wide open. With mirrorless that's less often the case.

 

[Bob A L]

Also with mirrorless cameras, you are viewing the scene as an electronic photo as on a computer screen so if the aperture was always wide open when focusing, the image would many times be too light to be distinguished. With mirrorless one of the differences is that you see the photo as it will be exposed when viewing the scene through the electronic viewfinder. You should have the option to not reflect settings in the viewfinder to partially get away from closed down focusing. I don't have a Canon mirrorless, but feel pretty sure that any brand of mirrorless operates like your Nikon with respect to the aperture size when focusing. Mirrorless= what you see is what you get.

 

[jthomas39]

Also with mirrorless cameras, you are viewing the scene as an electronic photo as on a computer screen so if the aperture was always wide open when focusing, the image would many times be too light to be distinguished. With mirrorless one of the differences is that you see the photo as it will be exposed when viewing the scene through the electronic viewfinder. You should have the option to not reflect settings in the viewfinder to partially get away from closed down focusing. I don't have a Canon mirrorless, but feel pretty sure that any brand of mirrorless operates like your Nikon with respect to the aperture size when focusing. Mirrorless= what you see is what you get.

"so if the aperture was always wide open when focusing, the image would many times be too light to be distinguished"

The Live View doesn't work that way in all scenes. Even though the lens set at f/11 is opened to f/5.6, the view is adjusted in brightness amplification to see the effects at f/11 (except for depth of field blurriness).

There's a new setting on the Z6 iii, just added. a13: Maximum aperture LV= On/Off.

With this a13 off, or with cameras without this setting:

Apertures smaller than f/5.6 will open the lens to f/5.6 for focusing, then close it when the shutter is pressed to take the photo. Apertures wider than f/5.6 will use that aperture for focusing and live view. It's easy to see this looking into the lens when it's set to something like f/11, or to f/2.8.

With a13 =On, the lens is opened to it's max aperture for viewing, no matter what aperture the camera is set to. I know that wedding photographers that work in dim rooms have been waiting for this Z8 feature to be added to other Nikon cameras.

From what I've read, the PDAF autofocus pixels built into the sensor works optimally at f/5.6, using the light rays coming in at opposite angles to the sensor. Do very wide apertures improve the autofocus speed or accuracy, or is it for improved subject detection and an improved scene view, with more light on the sensor?

The downsides to using wide open:

The "i" description in the a13 menu says:

"Maximum aperture is used for live view. Shooting with a smaller aperture may extend release time lag. When "Silent mode" is ON, lag may be further extended".

(In silent mode, the camera turns off sound effects, and minimizes focusing noises coming from the lens, probably by slowing the aperture changing speeds.)

 

[monte12345]

In Low Light. Because I have seen this in my Z7 II and it can be bad enough that it's not possible to see if the camera is in focus. Oddly enough with my 50mm f1.4 set to f1.4 this is not much of an issue at all. The only thing I can figure out is that Gee, the f1.4 aperture lets in a lot more light than f4 and thus the image in the viewfinder is a lot less noisy.

BTW a noisy viewfinder is NOT an issue with my Zf in low light. However with my Z50II it is apparent at a 100% zoom and higher but it's not bad enough to interfere with focusing. I suspect that on the Z50II the noise seen at high magnification is an artifact of the high pixel density of the image sensor in this camera.

 

[Leonard Shepherd]

In the background, a few lenses have either slight or occasionally even significant focus shift when changing the aperture; primarily with the aperture near wide open.

When using a lens of this type, focus is more accurate when made at the shooting aperture.

 

[monte12345]

Also with mirrorless cameras, you are viewing the scene as an electronic photo as on a computer screen so if the aperture was always wide open when focusing, the image would many times be too light to be distinguished.

Huh ? ? ? Cameras in 1959 to the last DSLR's focused the lens with the aperture wide open and then closed the aperture as the mirror swung up before the shutter was tripped. The latest Firmware for the Z8 uses the same process and it was an oversight on Nikon's part that their mirrorless cameras failed to do this from the start. Because using the widest aperture for focusing increases Accuracy, allows more light for the image sensor, and allows accurate metering at lower light levels. In addition it's simply a matter of programming the camera to close the aperture before initiating exposure. So I have no idea at all where you came up with this statement about the image being "many times too bright".

With mirrorless one of the differences is that you see the photo as it will be exposed when viewing the scene through the electronic viewfinder. You should have the option to not reflect settings in the viewfinder to partially get away from closed down focusing. I don't have a Canon mirrorless, but feel pretty sure that any brand of mirrorless operates like your Nikon with respect to the aperture size when focusing. Mirrorless= what you see is what you get.

If the camera closes to the working aperture prior to operating the shutter What you See is What you get can still be employed, it's simply a matter of adjusting the brightness of the image in the EVF to match what the aperture setting would produce. This is the same as what the camera does when you change the shutter speed.

 

[monte12345]

A design that can be considered as Antique and approaching Ancient. With the Image Quality produced by modern mirrorless lenses I expect it will approach impossible to actually find a lens that has aperture related Focus Shift because the cause for that particular defect was found and eliminated many years ago.

 

[Leonard Shepherd]

A design that can be considered as Antique and approaching Ancient.

Maybe yes – maybe no. I have seen reports I consider reliable that at least one Z Nikon zoom has distinct focus shift.

You can use old and many ancient F mount lenses on Z bodies.

--
Leonard Shepherd
In lots of ways good photography is similar to learning to play a piano - it takes practice to develop skill in either activity.