stadtmkw Loc: Burlington, MA

Would appreciate feedback to help me understand what's happening.
I'm in the process of calibrating lenses to a D750 body. I've used both an angled focus chart and the DotTune method and found the DotTune method works better for me.

I noticed two things in this process..
1) I have the camera set to use the AE-L back button focus. If I manually defocus the lens and press the back focus button for less than a half second, the camera mis-focuses. If I press and hold the the back focus button for between 1 and 2 seconds, the camera focuses correctly. Not sure why this is happening.

2) I'm shooting at a target with the camera on a tripod and VR and AF are turned off. I manually focus to critical focus using LiveView. If I then shut LiveView off and take the picture, without refocusing, the actual image in the display is noticeably less sharp than the LiveView image was. Does LiveView apply any in-camera sharpening to the image and if so, is there a way to shut this sharpening off?

Thanks in advance for your responses.

Ken

jerryc41 Loc: Catskill Mts of NY

1. Even electronics need time to work.
2. I bet LiveView is doing some modifying, which you will not be able to turn off. The optical viewfinder is just that - optical. The image on LiveView is, by definition, manipulated. On the other hand, I've seen many videos and articles that recommend zooming in on the LCD to get sharp focus.

JD750 Loc: SoCal

You are turning live view off THEN taking the picture? What happens if you just snap the image with live view still active? What does that look like?

stadtmkw Loc: Burlington, MA

If I leave LV on and take the picture, I get the same result. I noticed that the difference between LV and actual pic is minimal with the 24-70 F2.8. In fact I'm not sure there is a difference. But with the 16-35 F4G there is a definite difference.

JD750 Loc: SoCal

This is a focus issue you are talking about right? Manual focus or auto? And this focus issue occurs only with live view not with using the viewfinder?

Live view and optical use different focusing systems, but what is odd is that it changes after you focus and take the pic. There is an autofocus fine tune function but I'm not sure how that helps in this case. If you have not already read the manual, recommend you take a look at pages 57..59 of the D750 Users Manual. Particularly page 59 where they provide a checklist for live view autofocus.

one more thought, and this is a WAG, ok, but my camera seems to make a lot of noise when I snap a live view pic. I know the mirror is up, but i'm not clear on what all that commotion is about. So maybe try the mirror up release mode and see if makes a difference?

Otherwise it may be time to consult a Nikon specialist.

stadtmkw Loc: Burlington, MA

Thanks for your insight. I've read the pages in the manual that you mentioned. What I took away is that there may be auto focus issues in LiveView depending on the scene. That is not the issue I'm having. The camera auto focuses in LiveView every time and produces sharp results when examining the LV image on the monitor while zoomed in. The problem occurs when I proceed to actually take the picture without refocusing from the focus setting in LV. The focus setting that produced a clear image in LiveView does not produce as clear an image in the actual picture when viewed on the monitor zoomed in to the same fov as when the scene was observed in LV. It's as if the camera is applying sharpening and contrast enhancement in LV that is not applied when the picture is taken and subsequently displayed on the monitor. As I mentioned this seems to happen with only one of my two lenses. Hopefully Santa is going to bring a third lens and I will have an opportunity to check that one as well.

The image in the VF appears clear but I'm not viewing the scene at any where near the magnification level that I'm viewing it while in LV on the monitor so I can't discern any difference from using the VF alone. I'll try mirror up release mode and see if it makes a difference.

Thanks again.

oldtigger Loc: Roanoke Virginia-USA

Perhaps your mirror is dropping to measure exposure and then reopening to take the shot.

JD750 Loc: SoCal

Hmmmm. Perhaps. It doesn't bother me I don't use Live View much. But OP has a problem with blurred images, and vibration could be the cause for that. If so, switching to Manual Exposure should eliminate that as a cause.

JD750 Loc: SoCal

Stadtmkw, you might want to post this question in one of the UHH Macro Photography categories, people there may be more familiar with the issue.

Close Up Photography
http://www.uglyhedgehog.com/s-113-1.html

True Macro Photography
http://www.uglyhedgehog.com/s-102-1.html

stadtmkw Loc: Burlington, MA

Thanks, I have posted on one of the other sites.

JD750 Loc: SoCal

I'm curious about how this turns out. Please let me know. Thank you.

stadtmkw Loc: Burlington, MA

I posted a question to Nikon about this on 12/27 and have not received any response. Is it normal for Nikon to take this long to respond to a question?

Thanks

stadtmkw Loc: Burlington, MA

Nikon finally responded and requested sample images to determine if there is something wrong with the camera. Further experimentation leads me to believe that the setting of the Picture control affects the Liveview image. If I set the control to Neutral, the Liveview image and the acquired image, as displayed on the camera monitor, are identical to my eyes. I was unable to find a reference in the manual to any connection between the Picture control and IQ of the Liveview image but there is a definite affect.