35mmm adapters & in-camera ND filters?

C

cameralady

Member
Does anyone know why you're not supposed to use the in-camera ND filters with the 35 adapters? I've been doing it with no major complaints but I know i'm not supposed to... am i missing something? do other people do it?
 
sure thing Dan- i've just not had the chance to see the footage on a decent monitor yet & have been getting paranoid...
 
I think I remember reading this too at some point.
Tried to search for discussion on the topic when I got my adapter, but found nothing.
I've been using internal NDs and haven't noticed any negative effects.
 
Aside from some minor questions (specifically about the HVX200's ND's quality vis a vis a *very* slight color abberation, reddish IIRC) there's no reason not to use them if they're needed. Tim Naylor was the person who pointed out the HVX color thing to me.

There's been much discussion about how lenses on adapters might "blow out" or whatever if the ND was behind them rather than in front, but it seems that's been pretty well debunked by now.
 
Ted Spencer said:
There's been much discussion about how lenses on adapters might "blow out" or whatever if the ND was behind them rather than in front,.
Click to expand...

That was the story I had seen posted here and elsewhere, that you had to ND the front because the imaging element would show blooming or whatever with too much light coming in the front.

Maybe that was all just an excuse to sell some 4x4 matteboxes but I just use the built in NDs on the Canon XHA1 all the time.
 
Over at the redrock forums there was talk about the internal ND of the EX1 throwing off focus a little bit (so you would have to readjust on the ground glass).

I own the EX1 and have not experienced this. Neither did I have any problem on my HVX
 
The idea that the GG will blow out was really only being pushed by Dennis Wood about his brevis. I don't remember any other adapter maker telling users that they needed to nd in front of the lens to keep from having the image blowing out, nor am I even sure if Dennis is still making that argument.

There's an old thread around here discussing it. I haven't found it but this dvinfo.net thread references that thread I can't find and features some of the key players from it like Lenny and Dennis Wood.
http://dvinfo.net/conf/archive/index.php/t-101051.html

Here's a quote by Dennis from the dvinfo thread. Notice he doesn't mention the idea that the gg will overepose:

"The discussion of external vs internal ND's is always a lively one :-) Like Gene, I do use external ND's and nearly always shoot in this mode these days when shooting with the adapter. However, there's no question that I would (and do) use the internals in a pinch.

There are a few positives to using external NDs:

1. In many cases, they are used in matteboxes, which also shade the35mm or camera lens from non-image forming light. Lens flare, lens hazing and internal reflection are therefore minimized at the start of the optical chain. Nd's positioned downstream of the lens optics cannot help with this.

2. Reducing internal light levels (either in a set of lens elements, or a 35mm adapter) will coincidentally reduce internal reflection/flaring/hazing that may be introduced at the 35mm lens, imaging element, or achromat.

Add in some of the benefits of other filters (like polarizing filters to reduce glare) and the expense of an external mattebox/filter system becomes a bit more palatable."

In another thread on dvxuser someone quotes Dennis about the gg overeposing and he jumps in and clarifies with this:

"When a diffuser of any type is "bathed" in excessive light, you will end up with hazing and other image degradation. Our three diffuser options will behave differnently of course in terms of what constitutes overexposure."

http://www.dvxuser.com/V6/archive/index.php/t-82918.html

That doesn't seem to be the same as overexposure, but he still seems to be arguing that the light hitting the gg has to be controlled rather than simply just the light hitting the camera sensor.
 
Well that principal seems to make sense to me but the question is, is the effect dramatic enough to even matter 9/10 times?
 
Some may not experience this but I've found footage shot with the internal ND to be noticeably softer with considerable color aberrations as well than footage shot with good external glass ND's. Maybe my camera is a lemon because some people claim to have not experienced it. Which is great. With my camera it's not speculation but a sad reality. I discovered it on set when the director complained the image looked not as crisp as before. After eliminating all the variables, it came down to the internal ND's. As soon as we took them off and switched it for glass it was like night and day. Haven't used them since unless I'm in a hurry on a doc. I now have a set of screw ons and 4 x 4's. I with this wasn't the case as I use internal ND's without hesitation on Panny's high end cameras and they save a lot of time and hassle. Concerning flaring the ground glass theory - it only happens when you're shooting Bigfoot or the Loch Ness Monster.
 
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