DIY groundglass:
http://rmp.opusis.com/pipermail/cameramakers/1999-July/002072.html

Dear Jami,
the footage is quite interesting!! Like alot of the current people replying, I too would like to know how this was achieved and how you get it together :) Anyways, great work and don't quit! Maybe a little tweaking could get ya an even better mini35 look for a fraction of the price!

Kev

edit- just found a pic of the setup... click on the image to enlarge it
http://www.kopfrauschen.de/view_de.php?page=dv35m

where does the fresnell go?
is it between the (35mm) lens and ground glass? Or between the ground glass and camcorders lens? Is there any space between the ground glass and the fresnell?

Fresnel and moire
 

Has anyone who's tried this seen any moire problems when using a fresnel in front of the video lens? I would think that there would be a noticable pattern.

Does anyone know of optical lenses that meet the same dimensional and focal length requirements that would avoid this moire pattern?

source of ground glass
 

I have used Edmund Scientifics of Tonowanda,NY as a source
of a ground glass screen when I was adjusting the optics of my
Bell & Howell Eyemo movie camera. Their industrial catalog is :
www.edmundoptics.com . They have listings, for example, for
100 mm X 100 mm thin piece of ground glass for $31.50 .

Can someone explain to me what "ground glass" is?

Basically, could you adapt a 35mm lens onto the front of your DV camera, to get a shallow DOF? I don't have any 35mm lenses to try this with, though...

An even better question would be, why doesn't Sony, Canon, or Panasonic build a DV camera that could use 35mm lenses?

Wow, is Edmund in Tonowanda also? They are based in Barrington, NJ across the river from Philadelphia. As a kid in the 1950's they ran ads in the comic books. You could send away for this great catalog, and I used to order all kinds of strange things from them.

Then a couple years ago I made the connection that Barrington was actually very near to where I lived, so I made a pilgrimage to the factory store. It's a fascinating place, especially the back room which is full of surplus bins with all manner of interesting things. Definitely worth a visit if you're ever in the area....

Guys,

Te P+S mini 35 picture looks pretty bad when the screen is not spinning and the one they just developed for HD is not very usable for HD even with the screen spinning --- because of the increased resolution it looks bad -- at least that is what I heard.

Are you sure that what you're doing is possible? I am sure the German P+S engineers tried all of that.


Alex,

Here's basic explanation. 50 mm lens is a 50 mm lens. It will have the same depth of field on 35 mm photo camera as on a video camera with a 6 mm (1/4") CCD. On the still camera it will be a normal lens, on the video camera a long telephoto.

Ground glass is a glass with a mate surface on one side. SLR cameras use it. It is the 1st thing that the light hits after it comes through the lens and reflects from the mirror up. An image is created on the ground glass as it would e.g. on a piece of paper. But with the ground glass you are able to see the image on the other side too, and that is what you see when you're looking through the viewfinder and its prism. You're not looking through the lens but instead at image created on the ground glass.

Now if you aim your video camera at the glass, you will be able to take video of that glass. Or you can install the ground glass at the film plane. You keep your camera in macro and include the whole image with the video camera. It does not matter at what focal length is it set; you'll have to play with it for best results and possibly add a diopter adapter. You leave it set in that setting and do not change it.

To change focal length, you change focal length of the lens of the 35 mm camera. That will allow you to get the same depth of field as you would if you would use the 35 mm camera for stills with 35 mm film. The depth of field becomes shallow which gives you the film look.

Joseph, I pretty much knew most of that, and I could imagine what ground glass is, just by it's name, but I wanted a further explaination to clearify, thanks.

So basically you take a 35mm lens, and put a piece of "ground glass" between it and your camera, and tweak it for pefection, and you are suddenly shooting with a 35mm lens, essentially? Pretty cool, i'd give it a shot if I had a 35mm lens...

35 mm lens for experiments
 

Alex, 35 mm used lenses from older still cameras are not very
expensive. I bought a 35mm still lens of 50 mm focal length
(which is the most common still camera lens) from a now defunct
Japanese camera system for $19.00 . Try some of the New York
camera stores in the back of "Popular Photography" for listings .
The lens works reasonably well on my Eyemo movie camera .

I'd be interested in making something like this, for sure, since I am big on ghettoness -- of course, as long as it works, :D.

<<<-- Originally posted by Joseph George :

Te P+S mini 35 picture looks pretty bad when the screen is not spinning and the one they just developed for HD is not very usable for HD even with the screen spinning --- because of the increased resolution it looks bad -- at least that is what I heard.

-->>>

I just wanted to comment on what Joseph is saying and to make sure that there isn't any misinformation out there.

Yes, the image looks "bad" when the glass isn't spinning. That's why you need to make sure the unit is on. Not a hard thing to do. I usually tape down the switches and keep the mini35 on all day.

As for the HD version (the Pro35) it is absolutely the most remarkable thing I've seen on the HD cam. At NAB we played around with the Pro35 on a Varicam for nearly an hour and I was very very impressed. With the increased resolution it looked fantastic. The Pro35 has better ground glass and it's powered off of the cameras 12v relay. It's always on when you roll camera. I was even able to get 1 to 1 lighting with some adjustments on the Varicam. What you saw on set was exactly what you'd get on screen. Truly cool.

So I don't know what you've heard, but I've been hearing great things on top of my experiments with it. Soon enough that rig is going to be in my family of available equipment. Too psyched for words...

Thanks to everyone for an extremely interesting idea. I'll have to get out my old still camera and try this with my GL1.

Does anyone know if P+S is planning on building a mini35 unit that will work with the new JVC Hi-Def camera (JYHD-10U)?

Thanks,

JT Hall

I have been talking to the guys over at P+S and they are someone reluctant to make mini35 adaptors for cameras with fixed lenses. This isn't to say that they aren't doing it (they are working on a DVX100 mod right now based on some testing that I've done). But the problem is getting an acceptable image out of a fixed lens system. We found that there are chromatic aberrations with using diopters that would send the image properly through a fixed lens system. They are very slight but they are present. Better glass has minimized this, but it remains to be seen if it's really useful for production work.

I am not whole-heartedly endorsing it for projects (even though I had a working rig). I'm looking for other options hence my foray into the Varicam and the Pro35.

This is very interesting, I've been following Justin's progress with the Mini 35 for a while since I have not had the chance to use it in an actual production application myself. I've spent plenty of time at trade shows, eschewing the high-key, flat lit set consisting of a bored model and bunch of flowers and instead swinging it around to look at "real world" situations and imperfect lighting, and have drawn my conclusions from that.

The very notion that it is a good idea to force an image through relay lenses and ground glasses is somewhat alien to me, in that the idea is usually to maintain as pristine an optical path as possible. That's why cine prime lenses cost as much as they do (I cannot fathom using still camera lenses on this setup, with their inherent breathing, lack of compatability with follow focus mechanisms and useless barrel markings. It may work for some, but for me that would be like trading in my G4 for an Apple IIC or something).

Even under the best of circumstances, and I'm not denying that the setup is capable of great imagery, you are essentially putting a Porsche engine into an economy car. I'll take a shot in the dark and presume that's why Justin is moving beyond the DV format into HD...I hear you, daddy.

I'm still not a fan of the re-photographing the aerial image concept, but I can see the obvious advantages of a 2/3" setup over the 1/3", let alone the increased resolution. Let us know what it's looking like, Justin!