35mm lenses

W

wagnermunhe

Member
I'm new to DVX world and I've learned a lot with this forum, which I follow every day whenever possible. I've seen here a lot about 35mm lenses and I'm intrrigued wether that is an alternative lens to DVX which needs an adapter or refers to some other equipment. I followed the threads but no cue at all.
Can anybody help?
Thanls
Wagner
 
35mm lenses

Thanks Tony for your reply. I did a search before posting this thread, but could not understand what the problem with original Leica lens is. Why change it to a 35mm lens? Isn't Leica also 35mm someplace cause the manual says it goes from 4.5 to 45, 35mm equivalent 32.5 to 325mm? What is finally the difference between Leica and a 35mm lens?
Today I did a search on Google. It looks like MiniDV lenses don't give a 35mm film look - especially when it comes to depth of field. And again my question is: since depth of field comes from focus length and iris opening, why do I need a different lens and its adaptors to have a film look?
Couldn't see any of these answers on what I read.
It might be silly questions, but again, thanks for any help.
Wagner
 
The issue has to do with depth of focus. There is a relationship between the size of the sensors inside the video camera and when things start to blur out in the background or foreground of an image. The 1/3" (about 16mm) sensors in most video cameras make everything in focus from about six feet to maybe 30 feet depending on the lighting, zoom, and so forth. In some cases, everything is in focus back to infiinty. The lenses on these cameras are great. They just don't provide the kind of depth-of-focus control that you might see in a movie. Part of that has to do with the fact that the movie film frame is 35mm.

If you want to isolate your subject against a blurred background, as a storytelling mechanism, or to use rack focus where the image shifts from sharp focus on one element in the frame to another, the video camera lens and 1/3" sensor really don't offer that kind of control.

A 35mm lens adapter is placed in front of the Leica (or native) camera lens. In most cases the way this works is that a strong magnifying lens is placed in front which allows the camera to focus on an image only a few inches in front of it.

Then a 35mm SLR (still camera lens) is positioned so that it focuses onto some kind of screen. The image on that screen is about 35mm in size. So it has the depth of focus characteristics of movie film. And the video camera can now record the image on that screen.

The result is video that looks like it was shot on film and then transferred to video, which is a very expensive process. So.... expensive looks and image control for a lot less than film.

There are a lot of things to consider if you are thinking about using a 35mm lens adapter. The screen that is used isn't going to be like film, which has a texture to it called grain that is caused by the chemical film process, and changes from frame to frame. The 35mm lens is much smaller than the native lens on most video cameras and will reduce the amount of light reaching the camera. The 35mm lens inverts the image, so it is recorded upside down and has to be flipped over in post. The upside down image is difficult to frame and work with in the camera. You lose autofocus (the "back" focus of the video camera is now focused on the screen). And with 35mm depth of focus the focus of that front 35mm lens becomes critical. So there are a lot of tradeoffs for the "35mm film look". But for many purposes and styles, the trouble is worth it. There are various solutions you can read about in the forums.
 
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35mm lenses

Thank you very much for such a clear explanation, Andy. It now explains everything. Thanks for your time. I relly appreciated it.
Wagner
 
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