Autofocus when on manual focus?

[BenJN]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

 

[ghostfox_1]

Probably high thin clouds moving around.

 

[Wahrsager]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

You sure it wasn't the distance limiter switch?

 

[Andy Lucy]

I think that you are seeing the result of atmospheric turbulence. The image isn't going in and out of focus, but the details, and even shape, of the moon swirl around continuously as the turbulence occurs. It's very evident if you look at a high resolution video of the moon, as here:

 

[PLShutterbug]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

A few things …

Why 600mm to photograph a reflection in a puddle, unless the puddle is 50 meters away? Maybe you wanted the extreme flattening 600mm gives to the image …

Try “Exposure delay mode” rather than the self-timer. Investigate the differences, but I prefer EDM.

I have noticed weird artifacts in the EVF and monitor in low-light situations.

Are the resulting photos in focus?

 

[BenJN]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

You sure it wasn't the distance limiter switch?

Haha, yes. But even if it wasn't, with BBF, it shouldn't be trying to focus though?

 

[BenJN]

I think that you are seeing the result of atmospheric turbulence. The image isn't going in and out of focus, but the details, and even shape, of the moon swirl around continuously as the turbulence occurs. It's very evident if you look at a high resolution video of the moon, as here:

 

[BenJN]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

A few things …

Why 600mm to photograph a reflection in a puddle, unless the puddle is 50 meters away? Maybe you wanted the extreme flattening 600mm gives to the image …

Try “Exposure delay mode” rather than the self-timer. Investigate the differences, but I prefer EDM.

I have noticed weird artifacts in the EVF and monitor in low-light situations.

Are the resulting photos in focus?

The moon was pretty small even at 600mm with the puddle 6 feet away. But I guess being closer than with a shorter lens is worth trying.

I will investigate EDM thanks.

Some of them were in focus, yes. Others not, but given how difficult focusing on the subject was, that might have been down to my skills.

Thanks for your reply

 

[Wahrsager]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

You sure it wasn't the distance limiter switch?

Haha, yes. But even if it wasn't, with BBF, it shouldn't be trying to focus though?

What's your setting for a6?

 

[BenJN]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

You sure it wasn't the distance limiter switch?

Haha, yes. But even if it wasn't, with BBF, it shouldn't be trying to focus though?

What's your setting for a6?

Off

 

[briggart]

I don't have the 180-600 so don't know how quiet it is, but can you hear the lens motors? That should definitely tell if the camera is trying to shift focus or if something else is in play.

On top of atmospheric turbulence, the puddle is not a rigid body. Its surface will ripple, shift and generally move due to wind, ground vibration, etc.

Have you tried photographing the moon directly and check whether you still see the same issue?

Hope this helps, just thinking out loud.

 

[BenJN]

I don't have the 180-600 so don't know how quiet it is, but can you hear the lens motors? That should definitely tell if the camera is trying to shift focus or if something else is in play.

On top of atmospheric turbulence, the puddle is not a rigid body. Its surface will ripple, shift and generally move due to wind, ground vibration, etc.

Have you tried photographing the moon directly and check whether you still see the same issue?

Hope this helps, just thinking out loud.

Good ideas, thanks

 

[BenJN]

Thanks for all the replies. I will do some experimenting to try and work out under what conditions this is happening

 

[Bill Ferris]

Hi,

Z8 with 180-600 Nikon on tripod.

Slightly odd circumstances; trying to take a photo of the moon reflected in a puddle. Camera set to Manual mode on camera. Using BBF. Focus on the moon (quite a struggle!), change lens to manual focus via switch on side of lens. Focal length 600. Set timer to 10 seconds so that the camera isn't shaking from me pressing buttons.

When I watch the viewfinder, while the 10 seconds is counting down, it appears to be trying to re-focus on the moon. The image gets softer, sharper, little bit smaller, bit bigger as you might expect when focussing. Resulting image inconsistent and often not in focus.

I've tried looking at all the settings, but can't find anything that would suggest that auto focussing could be happening. What else could it be?!

Thanks!

You sure it wasn't the distance limiter switch?

Haha, yes. But even if it wasn't, with BBF, it shouldn't be trying to focus though?

What's your setting for a6?

Off

"Off" isn't an option. It should be set to "AF-ON only". In Nikon's great wisdom, a6 displays "Off" when AF-ON only is selected, but it's worth double- checking.

--
Bill Ferris Photography
Flagstaff, AZ

 

[Bill Ferris]

If the AF-ON button is set to AF-ON and the shutter release button setting (a6) is set to "AF-ON only," the lens can be set to autofocus (A) and focus won't be altered when the shutter release button is pressed to initiate a shutter actuation.

If you're using the rear LCD, are touch controls enabled? If so, it's possible touch autofocus may be active.

And just to cover all the bases, of you switch the lens to manual (M) focus and press the camera's focus mode button & also select manual focus (MF), does pressing the shutter release still initiate focus acquisition?

 

[jthomas39]

Maybe the wind was distorting the surface of this shallow puddle? With a 600mm view, the surface curves could be very minor and still alter the reflections.