can U use inexpensive Rodensack HD lenses on F900?

[Guest Pete Wright]

http://www.1394imaging.com/products/optics...uring/linos.htm

 

Could someopne explain to me what is a C-mount? Are there different C-mounts? Can you fit an industrial high definition lens to Varicam or F900? Can someone make a custom adapter or a lens mount? Can someone click on one of those lenses that are in the above website and tell me if the lenses appear to be sharp enough, etc. based on the included graphs?

 

Thank you.

[Nate Downes]

A C-mount is essentially a 1" screw-mount for lenses. There are several forms of C-mounts, and for the most part they are interchangeable. A few cameras (Bolex Rex, for example) require custom C-mount lenses due to the location of their reflex prisms, but otherwise, they are similar. Some are designed with a focal length of 16mm, others for 8mm, and yet others for CCD's. You can intermix these to varying results. (I used a TV-camera C-mount on my 16mm camera once to good effect)

[Mitch Gross]

While it is possible to purchase from Century Precision Optics adapters for these lenses to fit your B4 mount camera such as the F900, by the included charts and other information I would consider them fully inferior in optical and mechanical design for the task you wish. These lenses are fine for technical and medical use, but if it were really that easy to use $500 lenses instead of $15,000 lenses, don't you think more people would be doing so?

[Guest Pete Wright]

Thank you for answering so quickly.

 

More questions:

 

I checked the Century Optics site. They don't have any adapters like that.

 

They have several 35 mm SLR lenses with different mounts that are many times higher priced than the non-modified lenses sell for. Too bad. It's too expensive for me. Does any company make cheaper modifications of still camera lenses?

 

I am looking at buying the Varicam. Maybe the Rodensack fixed focal length HD lenses would be enough for now on. The light fallout is high but the resolution appears to be OK. Other lenses they have there are a crap. The Rodensacks are German manufactured. They may not have the mechanical precision of the Zeiss primes, but the sharpness may be OK. Can you please look at the lens graphs again. Even the fallout is not as bad once you stop them down a little bit.

 

Really appreciate the help,

 

Pete

[GeorgeSelinsky]

Also just wanted to mention that the C-mount is prone to more problems than the bayonette mount, so if you invest seriously into lenses it's probably a good idea to use a bayonette system or have them rehoused if you've got that money.

 

-G.

[Mitch Gross]

Check with Optex for adapters if Century no longer carries them.

 

I've always felt that the glass is the most important part of the camera. Don't make it the Maginot Line of your imaging. I think you'd be far better off buying a good starter HD zoom from Canon or Fuji that goes for around $18k-$20k then investing in offbeat primes such as these.

[Guest Pete Wright]

Thank you all very much. Meanwhile I came to some new information so I may not be buying the Varicam. There were a lot of post in various forums, including this one, about new HD cameras. I just found out some more specific info and have posted it in another thread. There is also info on other cheap primes.

 

If I would buy one of the new cameras with C-mount, is there a 2/3" to C-mount adapter, if I would buy the Nikon or the Fuji lens?

 

Pete

[Guest J Jukuzami]

I think that if your budget is limited, the industrial HD prime lenses are fine. When it comes to zooms, it is a different story. Lenses are nowadays designed on compuers and are machine assembled. The resolution should be fine. Zooms are a different soty. HD cine and broadcast lenses are made in such low quantities that they use hand assembly and the price is ridiculous.

 

You see the ridiculous pricing at the Century Optics site, where you have a modified Minolta lens and they have the balls to increase the price 50x after minor modification. it's a crime!

[Valeriu Campan]

is there a 2/3" to C-mount adapter, if I would buy the Nikon or the Fuji lens?

 

Pete,

There are F > C mount adapters. F stands for Nikon camera lenses.

Also, there should be PL > C mount, so you can use cine zooms and primes (16-35mm).

[Guest Pete Wright]

Thanks for the info.

 

I have another question. In the post I made on the 3 new cameras, there is a link to Edmunds. They have many different kinds of lenses for industrial cameras. Some 2/3" lenses are high contrast, high resolution with and resolve 100 or more lines per mm. This is even wide open. Would this kind of lens be enough for 1080p? If not, how about for 720p? They cost a lot less than HD primes. I realize that they may not be as smooth and well constructed as the Zeiss and other primes.

 

Right now I would like to know about resolution only. I am on a limited budget and so I'm considering all options.

 

Are there also any adapters to use Nikon or other SLR lenses on F900 and Varicam?

[Valeriu Campan]

Pete,

The Rodenstock lenses are some of the best around, though they are targeted to special applications. Someone mentioned in a previous post here about the overinflated prices for cine or HD lenses. It is known that some reputable manufacturers convert ordinary stills camera lenses from Canon, Leica or Nikon to cine lenses and sell them for 10-20x their street value. Not all stills camera lenses are equal, they pick the best ones and and the modifications are done very well for a different working environement... but the price is still questionable unless you are prepared to do the work yourself.

Bare in mind that cinematographers like Greg Toland, Gordon Willis, held in high regard by our comunity, worked only with their own lens kits. Storaro is using his camera/lens kit as he sees fit. Stanley Kubrick got special lenses from outside the mainstream industry when needed. I wonder what some would have said if they knew before seeing the results. They are all classics now, up on the pedestal, but wouldn't be there if they didn't push the boundaries and conventions at every level, not only technical.

[Max Jacoby]

Stanley Kubrick got special lenses from outside the mainstream industry when needed.

And he paid a lot of money for his custom build equipment:

 

On Barry Lyndon he used an f0.7 lens of which only 2 where ever build. NASA got the other one. On top of that he had to have the lens and his Mitchell camera modified and recalibtated by Cinema Products before he could shoot with it. Even then this was a lens that you could not pull focus with during a shot, so it's application was extremely limited.

 

I don't really understand the point of all these threats about buying your own cheap equipment and hoping that it will perform as good as professional custom build equipment. I mean, what is wrong with RENTING equipment???

[David Mullen ASC]

The main problem with putting cine lenses or still camera lenses directly onto an HD camera is if it is a 3 CCD design with a prism block, then HD lenses have been designed to focus each color sharply through the block and onto the CCD. So you won't get the same optical performance of the still camera lens if you just stick it onto a 3-chip HD camera. Of course, I may just be repeating the advertizing hype of Zeiss when talking about their Digi-Primes and why they won't work as well if just stuck onto a Super-16 camera.

[Valeriu Campan]

Hello David,

Pete referred in his posts at a single HD chip CMOS or CCD similar to ones used in Viper or Dalsa. They are Bayer pattern chips and for sure need postprocessing as the signal is sometimes captured in a RAW format. One of the cameras, though outputs RGB, sRGB, YUv...

As for lenses in regards with single chip systems, they work very well with the exception of wide and extreme wide lenses that tend to produce color fringing or how is called "chromatic aberration" of the chip!? Because of the shape of the sensor plane, the light is deflected and on the edges you see sometimes a narrow purple or green fringe around high contrast subjects. This is overcome with microlenses that cover the more expenses chips and/or with software that in the RAW > RGB conversion corrects this to a certain extent.

The links Pete put out are used in some project cameras on DVinfo forums that would probably use a home made (another!) mini35 adapter using direct to disk recording. Most people on those forums have NO or almost no film experience; even someone was surprised why should he bother of making a HD progressive camera for 24 fps !!!???

But help or suggestions are almost welcome, and who knows, this developments will make the market more innovative and competitive. It will be sometime before something like this will filter through to $1000K+ productions, but sometimes we all shoot in strange conditions. Just to say that for a HD production someone needs a crash camera or to rig something in an unusual place.

[Phil Rhodes]

Hi,

 

> Pete referred in his posts at a single HD chip CMOS or CCD similar to ones used

> in Viper or Dalsa. They are Bayer pattern chips and for sure...

 

Just a point of order - Viper is a 3CCD full-resolution RGB device, actually just one of Thompson's pre-existing hi-def studio camera heads.

 

Interestingly, that low-cost machine-vision-style HD camera that was mentioned in another thread used a Kodak CCD with microlenses. Perhaps Mr. Pytlak can look into that from his end and give us some more interesting information on the colorimitery and luminance response we can expect from small HD cameras such as those made by Redlake.

 

Phil

[Mitch Gross]

People have to remember that resolution is not the only measure of performance both in optics and in cameras. I've seen super-sharp lenses with terrible color , poor corner drop off, chromatic abberations and lousy contrast. I've seen high res. cameras with terrible vertical smearing, incredible image lag, severely limited color response and almost no contrast range. I would much rather use a decent SD camera and lens than such inferior HD counterparts.

[Valeriu Campan]

Rodenstock lenses are "notorious" for their macro range and being some of the best around used in large format photography. Ask some photographers if you want to hear that they wouldn't touch anything else. And by far, they are not from the cheap and nasty lot. The ones mentioned at EdmundOptics are highly specialised lenses for mainly close up work, flat field corrected and their coverage is larger than 1". So, the 2/3 format will fall within some sweet spot anyway. Also you should look at them as kit with various focal lenghts that have matching characteristics for colour rendition, contrast, resolving power... It's all in the end about the look you want to achieve and not to get the sharpest or the most contrasty of all.

[Phil Rhodes]

Hi,

 

I wouldn't want to use one of these as the actual taking lens - even using normal stills lenses for this can be a pain because of the way the focus is set up - but it might be a workable component of a homebrew groundglass system. It'd still be a pretty critical piece of engineering, though.

 

Phil