Question Correction : aux lens adaption for video camcorders

W

William Estes

Member
Greetings,
The following question was stated wrong. (My appologies)
Has anyone developed a method for using a 35mm lens or other large format lens directly in front of a video camera without a unit such as the SGpro?
The question is, has anyone developed a lens adaption system for using 35mm and other large format lenses in front of a consumer/prosumer camcorder (std 8mm, Hi8, or digital ) with a unmountable or stationary lens ?. The aux lenses can range from 35's smallest to largest mm values. Would anyone be interested in a system of this nature ?.
William
 
Thank you for the reply,
My lens adapter does not have a ground glass or focus screen, or a motorized spinning disk. I use the lenses earlier mentioned without my images being upside down or reversed. All of the lenses produce a definable depth of field keeping the primary subject in focus.
Regards
William
 
I'm not sure how you can get the camera to "see" all of the lense due to the smaller chip size. There have been interchangable lense systems that allow for alternate lense mount such as the Canon XL adapter, but the result is a eight-fold magnification of the focal length. You'll get a very short DOF for sure with those, but it's not very useful because the FOV is so narrow.
 
jdajda said:
So you've actually made this or are thinking about making this?
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Greetings from William,
I have working prototypes and i will be posting still and video samples soon. I've been working on this idea for some years now, the formula and component research has been intense as everybody (experts alike) i've talked with tell me it cannot be done. The sgpro, brevis, m2, letus35, and many more 35mm adapters are very good, but i have to do things differently. My old video editor is down, but will have raw tape samples samples soon.
 
Greetings NOMADIC,

No sorry to say I do not have a degree in optical physics, I just like to do things the hard way, asking lots of questions, reading subject books and some specific journals, Backward engineering or taking things apart and seeing just how they work and what each element does gets the job done for me. I work in a specialized electronics field, thats about the limit of any information about myself for now. I will deliver what i have described.
Bill
 
Perhaps impolite, but I don't think he meant any disrespect.

The claims of an aerial image that can have shallow DOF, and full coverage sound too good to be true - in other words, a holy grail of sorts for us 35mmDIY geeks.

That's not to say it can't be done. Looking forward to the pics!
 
So no footage?


syncman said:
I don't think it can be done! In order for the camcorder Lens to "see" the Image it needs to be a "Real Image" The Image from the 35 mm lens is a Virtual Image. The only way to see a Vitual Image is to let it "shine" on a screen of some sort, and produce a REAL IMAGE that the Camcorder can SEE!!!
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Well I guess no one told JVC or Angenieux that it couldn't be done...because they both have released lens adapters that work with only optical elements and no 'ground glass'

:thumbsup:

Now whether nor not you can go from 35mm down to 1/3 inch using an optical relay....that I don't know.
 
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syncman said:
OK Luis you are much better read, than the rest of us. I notice you don't come up with any ideas. Looking back over your posts you only Criticise and make Sarcastic Comments. Perhaps you could give us the benefit of your knowledge?

By the way what is an optical relay?
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WOW.
Are you being serious?
I'm just going to move on pretending I didn't read that...

An optical relay is exactly what is being talked about in this thread.
An adapter which uses lens elements (and not a ground glass or something like that) which allows you to mount a lens of one frame size onto a camera of a different frame size while keeping the attributes of the original format (ie. 35mm dof on the Angineux adapter made for 2/3" cameras or 16mm dof on the JVC adapter made for 1/3" cameras).

Check out the link to the article about the JVC adapter that I posted above - it has a much more detailed explanation than I can possibly give.

The thing with the optical relay adapters that are out on the market is that they are taking either 35mm lenses down to a 2/3" chip or 16mm lenses down to a 1/3" chip. I don't know if it's possibly to build an adapter in this way to go from a 35mm lens down to a 1/3" chip and keep the attributes (mainly DOF) of a 35mm lens. It seems that there is something inherent in the optics which may not allow for it - but I'm not sure as I don't understand the intricacies of it.


Edited to add:
If you have any personal issue with me, feel free to PM me.
I will gladly discuss anything with you that way.
I'm not about to clog up the boards with that kind of thing, though.
Thanks.
 
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Whoa Luis that JVC adapter is pretty tricky. Says its for 1/3" CCD's and uses a virtual focal plane instead of ground glass. Now thats beyond my level of even wanting to understand. Images look nice though, now I'll have to find some time to read the entire article later.

Syncman - chill out.
 
Jeff - yeah, it's pretty wild - but like I was saying above, as far as I understand it it will only retain the DOF of 16mm, not 35mm. So while it's really nice - its not going to give people the 35mm dof they're looking for (and meanwhile it costs somewhere over $4K).

BUT - it's totally clean, no gg, no grain, no shutter speed limitations, etc etc.
Pretty amazing stuff.
 
For me 16mm DOF would be plenty, but 4k is a bit high. Guess I glossed over that part :) I wonder who their market is going to really be though - seems like people in that price bracket are more apt to shoot with a red or similiar.
 
I never doubted it was possible. I mean, it's 'just' light path modulation via optics, what every compound lens does anyway. This business of essentially 'copying' the image projected by a front lens system off of a screen is kinda yesteryear for me! It's how people converted films onto Video tape in the begining:grin: The information lost is large, even if the end effect is sorta acceptable. It's just a matter of time before a manual follow focusable HV20 formfactor camera comes out. Worth the wait IMHO:thumbup:

Luis Caffesse said:
Jeff - yeah, it's pretty wild - but like I was saying above, as far as I understand it it will only retain the DOF of 16mm, not 35mm. So while it's really nice - its not going to give people the 35mm dof they're looking for (and meanwhile it costs somewhere over $4K).

BUT - it's totally clean, no gg, no grain, no shutter speed limitations, etc etc.
Pretty amazing stuff.
Click to expand...
 
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