Variable ND weirdness

[LoriGBermuda]

I recently purchased a 9 stop ND filter and took it out for a test run. I was shooting in 3 different locations and many of my images had strange shadows (see attachment). Can anyone tell me why this is happening? Is there a way to make this filter work properly?

Thanks,

Lori

[dem]

Do you also use a polariser?

A variable ND filter is made of two linear polarisers sitting close to each other. If you use an additional CPL filter with your variable ND filter, you are technically looking at the world through three polarisers and very weird things can happen.

[IzzieK]

Welcome to CiC...Please refer to this before uploading an image....We are a friendly lot in this site and we will appreciate it very much if you fill in your profile so we will get to know how to refer to you in the future. Also, please do not forget to comment on other members' post too. We will truly appreciate your input and thoughts and observations and in the process you get to know us through our photos too as we will on yours.

Enjoy your stay while you are here.

[chauncey]

Read and/or watch...http://www.redbubble.com/people/pete...ensity-filters
https://www.youtube.com/results?sear...density+filter

[LoriGBermuda]

Welcome to CiC...Please refer to this before uploading an image....We are a friendly lot in this site and we will appreciate it very much if you fill in your profile so we will get to know how to refer to you in the future. Also, please do not forget to comment on other members' post too. We will truly appreciate your input and thoughts and observations and in the process you get to know us through our photos too as we will on yours.

Enjoy your stay while you are here.

[Dave Humphries]

Hi Lori,

It would also be useful to know the focal length of the lens(es) in use.

I suspect Dem may be on the right track, it may be exacerbated at wider angles of scene being captured.

Could you do me a favour please?
Could you click Settings (right at the top),
then Edit Profile (on left)
and put your first name (Lori) in the Real Name field
and where you are (roughly) in the Location field?
this helps everyone give you more personal and relevant answers - thanks in advance.

Welcome to the CiC forums from, Dave

[dubaiphil]

A silly question, but in broad daylight did you cover the viewfinder???

[LoriGBermuda]

Hi Dave,

I was using a 28 - 70 at F20 I didn't have a lens shade on or any other filters. I had this same result in three other locations. All were at different angles to the sun.

Incidentally, I've entered some profile information. Should have done that from the onset.

I'm relatively new to using ND's, so I appreciate very much all of the input.

[LoriGBermuda]

No, I didn't. The view finder was useless. When using the ND the view finder was so dark I couldn't see anything. I focused and set to manual focus to stop searching and then tripped the shutter.

[LoriGBermuda]

Hello Chauncey,

Thanks so much for referring me to such a great site. Super information.

[Stagecoach]

Lori,

This cross pattern affect is a very common problem when using Vari NDs at their closer to max settings with wider FL lenses.

It seems to vary between makes and is much reported on the web as I found out whilst undertaking research prior to purchasing one a while ago (that I'm still waiting to receive).

Perhaps the answer is to determine max amounts that can be used with certain FLs by test.

[Polar01]

Lori just a couple of questions to help better understand, what stop setting were you dialed into and the make of the variable ND filter. I think that may help some of us.

Cheers: Allan

[rpcrowe]

PHIL ASKED, "A silly question, but in broad daylight did you cover the viewfinder???"

LORI ANSWERED, "No, I didn't. The view finder was useless. When using the ND the view finder was so dark I couldn't see anything."

What Phil was referring to is that often when you have a very long exposure, especially in the daylight, light can enter from the viewfinder and hit the sensor. That is why, for Canon and Nikon DSLR cameras at least, plastic covers for the viewfinder are supplied with the camera.
http://www.pclix.com/blog/151-the-eyepiece-cover
These fit on the camera strap. Most folks either throw them away or lose them but, they are valuable for those long exposures, espcially in the sunlight...

[dubaiphil]

Well I don't know if that's the issue here necessarily but that will mess with exposure and bounce stay light around all over the place. Broad daylight, camera on tripod, eye not looking through viewfinder = cover it!!

[IzzieK]

Well I don't know if that's the issue here necessarily but that will mess with exposure and bounce stay light around all over the place. Broad daylight, camera on tripod, eye not looking through viewfinder = cover it!!

Thanks for reminding me where I put mine last time I put it down...

[dubaiphil]

The built in viewfinder shutter - why other bodies and brands other than the Nikon D700/800/810/D3 and onwards don't have this, I don't know. Patented?

One of the big downers of the DF, for me.

[Mark von Kanel]

I think youll find out its somthing to do with your Apeture focal length combination , have a read of this . http://havecamerawilltravel.com/phot...ter-field-test

[dubaiphil]

I think youll find out its somthing to do with your Apeture focal length combination , have a read of this . http://havecamerawilltravel.com/phot...ter-field-test

LOL! All hail the vario ND! Don't get that with a 10 stop, do you now?!?! I do seem to remember a certain member of CiC lauding the vario ND at every oppo

[LoriGBermuda]

Hello everyone, My camera settings were, F20 ISO 200 (not sure what the speed was). The filter doesn't have a brand name on it. I bought it from Scott Robert Lim's company. I actually e mailed him last night about this. He said some vignetting isn't unusual, but this goes well beyond that. He immediately offered to replace the filter. So I'm very pleased with his prompt response and service. We'll see how the next one is. In the meantime, I'll make some images and as suggested will see how many stops I can successful achieve. I'll also try covering the viewfinder. That hadn't occurred to me. Great input from all. Will keep you posted. Many thanks!

[LoriGBermuda]

Hi Mark,
Good article, thank you. Admittedly one of the reasons I bought this filter was it was inexpensive. Perhaps that should have tipped me off. I think I'll put the filter on my 70 - 200 and see what sort of results I get.