The perfect 35mm adapter?

Toenis Liivamaegi · November 21st, 2006, 10:24 AM

I seriously doubt that JVC`s 16mm PL lens adaptor will be as good as even the DIY adaptors offering bigger than 16mm image circle.
JVC`s S16 lens adaptor is completely static and designed for Super16 lens image circle. I wonder how can image from such a small image plane be grainless and produce proper bokeh...
Also this adaptor is designed for HD200 that has vignette correction and image flipping capabilities built in so it doesn`t flip the image and will possibly vignette on other ProHD camcorders.
One interesting thing is that this adaptor opically converts 16mm image circle from GG directly to 1/3" CCDs thus allowing no secondary iris control.

Also the $4300 price isn`t that good.

T

Jim Lafferty · November 21st, 2006, 11:16 AM

For $4,300.00 I could spec out and have machined the "perfect adapter" in answer to the question :D

I think everyone's got good ideas here...

As for light loss, I think it has a direct corollary in bokeh quality, so while I understand the gripe (from a shooter's perspective), I accept the limitations as just part of the reality of designing a good diffuser - as light loss goes down, bokeh quality changes (often for the worse).

Phil Bloom · November 21st, 2006, 03:11 PM

Tony,

I have a 50mm f1.4 if you are interested. It's very clean etc...

Dave Perry · November 21st, 2006, 06:24 PM

Quote:

Originally Posted by Tony Relph

Cant seem to find a decent Nikon Nikkor 50mm f1.4 anywhere. Anyone got one to sell or know where to get a decent one? Tried eBay but no good (statches and dust).

Tony,

Go to www.keh.com. I picked one up while in Atlanta last week for around $100.

Bob Hart · November 21st, 2006, 07:06 PM

I may well be wrong as to the technology but in general terms at least, this would not be the first time JVC has visited this idea.

There were two cameras, heads only, not camera/recorders, Model KY-F50 which enabled a 1/3" CCD to see a "C-Mount" lens as if it was a 2/3" CCD, Model KY-F32 which enabled a 1/3" CCD to see a B3 mount lens as if it was a 1/2" CCD.

From the lens mount to CCD block there is a long metal tube about 100mm long. These cameras produce the correct fields of view of these lenses as if they are attached to 2/3" or 1/2" CCD cameras. On the surface at least, the system looks like it is an aerial image relay.

My imagining is that the 35mm system wll do something similar, offer a genuine 35mm motion picture camera field-of-view, but not the same shallow depth-of-field options of GG image relay or film imaging.

The lens focal plane co-incided almost with the front glass element of the tube.

I found dust and metal flakes from the mounts getting on the glass could be troubling when tight apertures were selected on Nikon SLR lenses mounted to the system via a Nikon to "C-Mount" adaptor.

By the way, these cameras were offering a flavour of 25P in 1996. with output options of component, RGB, S-Video, composite, selections of black levels, sharpness, gamma and many others.

Phil Bloom · November 23rd, 2006, 06:59 PM

I would love to know what Jim's "perfect" tailored made adaptor would be. Still cheaper than a mini 35!

Tony Relph · November 25th, 2006, 03:40 AM

I want to test the various focal lens with Nikon lenses. What would be the best all-in-one lens to buy that has all the focal lengths (eg: 28 - 100mm) or something close. There are many AF lenses out there but are there any suitable MF ones (new) available?? If so where?

Bob Hart · November 25th, 2006, 09:13 PM

Tony.

If you intend to use a wide-ranging zoom lens to test or make demos with your adaptor, you will be doing yourself and your project no favours.

Zooms are mostly softer than prime lenses and can have inferior contrast. If you use an inferior lens while developing the product, something may creep through which only surfaces when somebody puts a really sharp lens on it.

There is a straight boundary CA in my own adaptor, I think due to slight misalignment of prisms opposing faces. The only lens which shows it up is the Nikon f1.8 85mm prime at about f4.

In something destined to go to market it would be a shame for something like that to get by undetected because the humble public whilst eager for the bargain still bites unforgivingly when it doesn't measure up, expecting to get a Rolls Royce instead of a Bambino.

The zoom is desirable for quick testing to see if SLR to GG back-focus of the mount is correct, providing the zoom lens itself is good.

My personal preference is to have the SLR lens flange to GG distance adjustable to make that small alllowance for lenses wich are slightly off due to wear etc..

If you don't want to invest in a lens set, you might instead hire a good stills photographer in for the day to bring his professional kit with him, put your adaptor to the test in all the creative compositional and lighting situations he or she can imagine.

You may be an optical egineer so ignore my comments as I am not.

Many who develop their own GG based relay systems are going through two levels of learning, that of basic optical theory engineering on the run and the actual process of research and development.

In this regime, many more mistakes are going to be made and great results might be more serendipitous than planned.

Dennis Wood · November 27th, 2006, 08:27 PM

I'm not clear if the lens is imaged/captured, or just relayed through? If relayed, normally the DOF properties would be those of the CCD, not the lens.

Bob Hart · November 28th, 2006, 01:13 AM

When I first saw the KY-F50 I thought it was a groundglass based solution as there were fixed grain artifacts in the image. It turned out to be dust and stains on the glass.

Now if JVC could solve the problem of colloids cracking (breaking down) under pressure whilst inside a 3 micron or so space between two glass wafers, they would have the fluid groundglass nailed.

November 21st, 2006, 10:24 AM	#16
Toenis Liivamaegi Major Player Join Date: Nov 2005 Location: Tartu, Estonia Posts: 579	About JVC PL lens adaptor I seriously doubt that JVC`s 16mm PL lens adaptor will be as good as even the DIY adaptors offering bigger than 16mm image circle. JVC`s S16 lens adaptor is completely static and designed for Super16 lens image circle. I wonder how can image from such a small image plane be grainless and produce proper bokeh... Also this adaptor is designed for HD200 that has vignette correction and image flipping capabilities built in so it doesn`t flip the image and will possibly vignette on other ProHD camcorders. One interesting thing is that this adaptor opically converts 16mm image circle from GG directly to 1/3" CCDs thus allowing no secondary iris control. Also the $4300 price isn`t that good. T

November 21st, 2006, 11:16 AM	#17
Jim Lafferty Major Player Join Date: Dec 2003 Location: Brooklyn, NY Posts: 636	For $4,300.00 I could spec out and have machined the "perfect adapter" in answer to the question :D I think everyone's got good ideas here... As for light loss, I think it has a direct corollary in bokeh quality, so while I understand the gripe (from a shooter's perspective), I accept the limitations as just part of the reality of designing a good diffuser - as light loss goes down, bokeh quality changes (often for the worse). __________________ Realism, anyway, is never exactly the same as reality, and in the cinema it is of necessity faked. -- J-L G

November 21st, 2006, 03:11 PM	#18
Phil Bloom Trustee Join Date: Aug 2006 Location: London UK Posts: 1,939	Tony, I have a 50mm f1.4 if you are interested. It's very clean etc... __________________ Philip Bloom Cinematographer, Director, Filmmaker www.philipbloom.net

November 23rd, 2006, 06:59 PM	#21
Phil Bloom Trustee Join Date: Aug 2006 Location: London UK Posts: 1,939	I would love to know what Jim's "perfect" tailored made adaptor would be. Still cheaper than a mini 35! __________________ Philip Bloom Cinematographer, Director, Filmmaker www.philipbloom.net

November 25th, 2006, 03:40 AM	#22
Tony Relph Regular Crew Join Date: Jun 2006 Location: Canary Wharf, London E14 Posts: 166	I want to test the various focal lens with Nikon lenses. What would be the best all-in-one lens to buy that has all the focal lengths (eg: 28 - 100mm) or something close. There are many AF lenses out there but are there any suitable MF ones (new) available?? If so where? __________________ Tony Relph. anthonyjohnrelph@hotmail.com

November 21st, 2006, 07:06 PM	#20
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	I may well be wrong as to the technology but in general terms at least, this would not be the first time JVC has visited this idea. There were two cameras, heads only, not camera/recorders, Model KY-F50 which enabled a 1/3" CCD to see a "C-Mount" lens as if it was a 2/3" CCD, Model KY-F32 which enabled a 1/3" CCD to see a B3 mount lens as if it was a 1/2" CCD. From the lens mount to CCD block there is a long metal tube about 100mm long. These cameras produce the correct fields of view of these lenses as if they are attached to 2/3" or 1/2" CCD cameras. On the surface at least, the system looks like it is an aerial image relay. My imagining is that the 35mm system wll do something similar, offer a genuine 35mm motion picture camera field-of-view, but not the same shallow depth-of-field options of GG image relay or film imaging. The lens focal plane co-incided almost with the front glass element of the tube. I found dust and metal flakes from the mounts getting on the glass could be troubling when tight apertures were selected on Nikon SLR lenses mounted to the system via a Nikon to "C-Mount" adaptor. By the way, these cameras were offering a flavour of 25P in 1996. with output options of component, RGB, S-Video, composite, selections of black levels, sharpness, gamma and many others.

November 25th, 2006, 09:13 PM	#23
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	Tony. If you intend to use a wide-ranging zoom lens to test or make demos with your adaptor, you will be doing yourself and your project no favours. Zooms are mostly softer than prime lenses and can have inferior contrast. If you use an inferior lens while developing the product, something may creep through which only surfaces when somebody puts a really sharp lens on it. There is a straight boundary CA in my own adaptor, I think due to slight misalignment of prisms opposing faces. The only lens which shows it up is the Nikon f1.8 85mm prime at about f4. In something destined to go to market it would be a shame for something like that to get by undetected because the humble public whilst eager for the bargain still bites unforgivingly when it doesn't measure up, expecting to get a Rolls Royce instead of a Bambino. The zoom is desirable for quick testing to see if SLR to GG back-focus of the mount is correct, providing the zoom lens itself is good. My personal preference is to have the SLR lens flange to GG distance adjustable to make that small alllowance for lenses wich are slightly off due to wear etc.. If you don't want to invest in a lens set, you might instead hire a good stills photographer in for the day to bring his professional kit with him, put your adaptor to the test in all the creative compositional and lighting situations he or she can imagine. You may be an optical egineer so ignore my comments as I am not. Many who develop their own GG based relay systems are going through two levels of learning, that of basic optical theory engineering on the run and the actual process of research and development. In this regime, many more mistakes are going to be made and great results might be more serendipitous than planned.

November 27th, 2006, 08:27 PM	#24
Dennis Wood Major Player Join Date: Mar 2005 Location: Ontario, Canada Posts: 916	I'm not clear if the lens is imaged/captured, or just relayed through? If relayed, normally the DOF properties would be those of the CCD, not the lens.

November 28th, 2006, 01:13 AM	#25
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	When I first saw the KY-F50 I thought it was a groundglass based solution as there were fixed grain artifacts in the image. It turned out to be dust and stains on the glass. Now if JVC could solve the problem of colloids cracking (breaking down) under pressure whilst inside a 3 micron or so space between two glass wafers, they would have the fluid groundglass nailed.