Using built in NDs with adaptor

[Gogu]

Hello guys,

Want to know if it's wise to use the camera's built in NDs (SONY Ex1) when using a 35mm adapter (Ultimate). Does it shift the focal plane ? I haven't done extensive test with this but it seemed like i was losing focus a bit when engaging the internal NDs.

And why is there no IR light contamination when using the internal NDs as opposed to NDs on the mattebox, which at .06 start to make the camera see IR.

Thanks,
Mike

 

[Lenilenapi]

Want to know if it's wise to use the camera's built in NDs (SONY Ex1) when using a 35mm adapter (Ultimate). Does it shift the focal plane ? I haven't done extensive test with this but it seemed like i was losing focus a bit when engaging the internal NDs.

If you are having a problem with shifting back focus with the EX-1 then perhaps you have early firmware that had this problem, or you have never done the back focus routine for the Ex-1. For both questions do a search on DVInfo.net on the EX-1 board.

It should not effect an adapter.

And why is there no IR light contamination when using the internal NDs as opposed to NDs on the mattebox, which at .06 start to make the camera see IR.

This is new to me and I have looked into the IR issue a great deal. I have never seen a specific IR problem due to any brand of ND. On the EX-1 in my own tests it showed up just as much on tungstun as any amount of ND though in theory it should be worse with ND.

If you can demonstrate these affects with stills please do that and post them here and/or privately email me if its hard for you to post . Also please name the type of external NDs.

I am working with Tiffen on trying to develop a dye based IR filter that won't vignette. We'll be meeting with the Tiffen rep on Thursday and if there is any unusual information you have I would very much like to see it before then if possible.

Lenny Levy

 

[Gogu]

Leni,

I shot with .09 NDs if i remember correctly plus some addtional ND grads. I forgot all about the ND IR problem that the camera has and when I viewed my footage it all had a sick pinkish hue on it.
A friend who has been shooting a documentary for the past few months with an EX1 said that he is using the internal NDs on the camera and hasn't noticed anything out of the ordinary.

My NDs and grads are from Formatt.

 

[Lenilenapi]

You have to do the tests yourself. Most people using the Ex-1 have not noticed IR problems until they are pointed out. I hadn't until i read about it on DVInfo.net.
Yesterday I worked with a guy who has used his EX-1 far more than i do, almost continuously on different projects . He has always said "what IR problem- I've never seen it. "So i pointed out that all of the people we had sitting in front of ur shot including the gaffer's shirt and the talents deep navy suit had bad IR.

Your problem with an overall tint however might have just been ND's that aren't perfectly neutral. That is surprisingly common with heavy ND's and Grads - and it usually leans toward a murky pinkish magenta or maroon tint.
IR will usually only be seen on black material not an overall hue. Did you white balance through the ND?

 

[Lenilenapi]

Gogu, After shooting tests with a variety of ND's today with a protoype Tiffen filter that solves the IR problem I discovered some interesting things.
We looked at a number of ND's just by eye and were surprised to see what we've been calling an IR problem obvious to the naked eye. Some ND filters that looked a bit warm to me were not only warm in general but also made some black materials very red. The so-called IR problem was actually visible to the naked eye and thus not just IR but also far red into the visible spectrum. Different ND filters had this affect to completely different degrees and some had virtually none.
I saw it plenty on format and scheider NDs BTW.

Thus your problem could have been a combination of IR, Far Red overall red tint and who knows what other contamination. The new Tiffen filter BTW fixed all those problems.

So perhaps what you saw