Haida ND 3.0 (10 stops) filter issue or normal blur?

Question

Yesterday I had a chance to try for the first time the Haida ND 3.0 filter I bought on Amazon with my filter holder. This is this filter:

Haida ND 3.0 HD2505D: http://www.amazon.com/gp/product/B00JAKQ3K2

Sadly all photos I took were not sharp at all when zooming at 100%. I am wondering if I did something wrong or if it might be caused by a defective filter. Here is what I tested:

STEP 1:

First I do as if I take a normal shot. It is during the day. I take a test shot in manual mode, auto focus: it is super sharp when zooming 100%. I use a remote shutter release with electronic front curtain and mirror up, just to be sure to exclude all possible cause of blur. There is no wind.

Here is the photo 1: http://i.imgur.com/JXUAnta.jpg

Exposure time: 1/6 sec

STEP 2:

Then I switch from Auto Focus to Manual Focus on my D810 body. I place the filter holder on the ring. The Haida filter was already installed on the filter holder. I do this carefully to be sure the camera does not move at all. I run another test shot this time more than 1 min. as you can see, the photo is blurred as if something moved during the shot when you look at the rocks.

Here is the photo 2: https://i.sstatic.net/LirnK.jpg

Exposure time: 49 sec

STEP 3:

Then I just remove the filter holder, and do not touch to any other button or settings. So my focus is still manual. I take another shot (same time as in step 1) with my remote shutter release. The photo is 100% sharp when looking at the rocks.

Here is the photo 3: http://i.imgur.com/flEtDPp.jpg

Exposure time: 1/6 sec

ISSUE:

What I do not understand is that all my photos taken with the Haida filter (as in step 2) are all blurred as if the tripod moved during the shot. When zooming to 100%, both photos from test 1 and 3 are sharp but not the ones from step 2. So it is not an issue on the camera or the focus since with the test 3 I am sure that the camera and its focus did not moved / changed. Also, there was no wind at all.

Do you think I do something wrong ? Or it might be a defective filter ? It is the first time I am using it.

Thanks a lot for your help!

Mathieu.

Gear: Nikon D810 with Tamron 24-70 at 70mm

NB: sorry for not including photos directly and better links: Stack Exchange does not allowed me to :-(

UPDATE 1:

All photos have been taken at F8.0 / ISO 100.

UPDATE 2:

Added exposure times for each shot.

Answer 1

When doing long exposures, you usually stop down to a small aperture to be able to lengthen the exposure. If you were at f/16 or f/22 you can get blur due to the diffraction limit of your lens.

If you look at twigs in the background, you can see they look almost double. Unless there is some sort of internal reflection due to the filter, it looks like camera shake. Sounds like you did everything right (remote release, mirror up etc). Are you sure your tripod was well set up and locked down? How long was the long exposure?

So to troubleshoot this, I would do another experiment but keep the lens at f/5.6 or f/8 to reduce softness due to diffraction. Also set up the tripod securely and try a range of shutter speeds from long (10+ seconds to eliminate anything that might be caused by releasing the shutter) to short (1/30 or 1/60 if you can, to reduce the opportunity for wind or tripod movement.

You can put a filthy UV filter with fingerprints all over it on a lens and not see much difference in image quality, I would doubt a filter would directly cause blurriness. But I know from experience that diffraction can cause a lot of softness, and in your case it really does look like camera movement.

Answer 2

I am quite happy! After doing some other tests at home (no wind, solid wood floor), I've found that the following settings enabled me to get sharp pictures with Haida filter when zooming at 100% :-)

1. Set the VR Switch to OFF when on tripod. When set to ON, some blur could be seen.

2. Keep Auto Focus ON but set the AF-S Priority Selection option to RELEASE, so that the camera does not try to focus and block the shutter if it cannot focus. When trying to switch to manual focus, the camera could be shaken a little so this option enables to keep AF ON all the time but when the camera cannot focus (i.e. when the ND 3.0 filter is on), then the shutter is not blocked and the previous focus not changed. This combination does not enables me to get a better sharpness, but it can avoid making some mistakes ;-)

3. Do not forget to close the Viewfinder Eyepiece Shutter

4. Use the Electronic front-curtain shutter and Exposure Delay Mode to 1 sec.

5. The Haida filter has a protective foam tape onto it. By placing the ND 3.0 filter first on the filter holder, this protection will block a lot of incoming light.

I hope it will help some other people!