Check this out. It's complicated to work with, but seems to achieve a nice look...

http://8mm.filmshooting.com/scripts/forum/viewtopic.php?t=1377&start=0&sid=b628e2a55787baa0dc9facb68367f1f4

Interesting, but this is really just a homebuilt version of the Mini 35. Same idea, lower tech.

This is something I've been experimenting for a while and which can be done fairly cheaply with an out of usage Kiev medium format camera with a clear matte ground glass as the viewfinder or on the back if you have one of these Hasselblad type cameras with removable back.

As the pictures show very clearly, the problem is that you tend to get vignetting as soon as you go wide and of course you see the grain from the ground glass (along with the hair&dust since it is almost impossible to keep it 100% clean).
With the mini35 the ground glass actually rotates at high speed making the grain and dust in effect (almost) invisible. You also lose more than a stop of light.

But it is very fun to experiment and I recommend it to anyone with one of these cameras lying around. You can get them fairly cheap on ebay, but you also need to find that clear matte ground glass (without the usual fresnel and split focusing aid in the middle).

I'm trying to construct a picture in my head of how this rig would
look... but having a hard time. Can anoyne explain to me how
this rig is looking and working?

Thanks.

Jeez, I have a bunch of that stuff sitting around here. I'd love to see some pictures, or a diagram on this setup too. This would be a great way to make a cheap "film like" rig for certain productions.
Mark

I would love to see pictures, but it seems like you would be limited to a certain focal length.

The results are really good though!

Of course, you could always overlight a room, zoom in, open wide, and slide on the ND for shallow DOF.

<<<-- Originally posted by John Threat : Of course, you could always overlight a room, zoom in, open wide, and slide on the ND for shallow DOF. -->>>

Perhaps I am misreading this. If you were shooting wide open, you wouldn't need to add light and then ND down.

You would also never be able to achieve this degree of shallowness with a standard DV lens at the same field of view, or even close to it. I can't recall the magnification characteristics of medium format but it's even greater than the 7x difference between DV and 35mm.

Sorry, I can't post any pictures right now because I don't have the camera on hand. I'll try to get it back a little later this week.
But it is really very simple. You just stick your camcorder lens as close as possible (depending on minimal focusing distance) to the groud glass, and that's about it. Just make sure that no light filters out between the two.
Basically you're filming what would normally be imprinted on the negative.
It's a little tricky in practice since the image is obviously inverted.
In fact you don't even need a medium format camera (or any camera at all). Just take a lens (from your SLR for example), a piece of fine and clear ground glass and place the two at the correct distance and film the image formed on the ground glass with your camcorder. You then just need to design some kind of box to keep all three elements together at the correct distance one from another, and to keep any light from filtering in or out.

Note however that the result looks a bit strange since the grain from the ground glass isn't "moving" as film grain or video noise would. But it is an interesting look and you can get *extremely* reduced DOF.

Excuse my ignorance... how does one go about getting a piece of 'clear ground glass'? I'm not sure exactly what that is, but I wanna give this a shot with my SLR lenses, since I have a couple of pretty good ones...

Well, that's the main problem ! ;-)

You can get some from camera shops that handle medium format cameras and accessories but they are expensive. Here are a couple of examples:

http://www.bhphotovideo.com/product/112276/HOGGSW/REG/971
(I'm not sure if this one is really without any markings or fresnel)

http://www.kievcamera.com/camera.php?ID=44
(This one seems to have a slight fresnel which could cause the sides to appear darker)

The best bet is to ask at a specialized shop or try to have one made to your specifications.

If you just want to try things out you can also build a makeshift ground glass by applying some Scotch tape (the "magic' type) to a clear piece of glass. ;-)

I need to correct something: the fresnel (which can be noticed on the Kiev ground glass) is actually necessary *NOT* to have dark vignetting at the edges...

you can fin your ground glas on a box (the ones with 25 or 50pcs) of CD-Rs. The CDs are place between two "faked" CDs. Offen they are clear but I found some that are like the "ground glas". The good think about thouse "fake" CDs is that they are... round. So you can make something out to rotate the "ground glass"! A small mortor from a toy or something...

where does the fresnel lens goes?

I'm curious about the fresnel, too. My understanding is that if the ground glass is in the film plane, then the crisp rectangular image that would be captured by the film would be on the ground glass.

The camera would be focused and fixed on the ground glass image, and all practical focusing would be done with the 35mm/med format lens.

A bit on the glass....

I just spoke with a camera technician who is renowned for his work with ground glass...he was nominated for an Oscar in '97 for his process.

He can brighten a piece of glass between 1-2 stops.


He also says that the #32 glass (ultrafine) will yield about 300dpi. This produces no visible grain in DV, but the contrast is a lot lower. He suggested testing #32 and #16 to see which yielded the best results.

He worked on Top Gun, and they ended up stepping one step back from the ultrafine, as the contrast wasn't where the steadicam operator needed it.

I'm getting a couple scrap pieces from a local camera repair shop. When I have some results, I'll post them. I'm looking at using a K-mount on a small box...my repair resources suggest about 4" long...that's not bad to put on rails in front of a camera.

Here's a goog link for understanding where the fresnel goes:

http://www.camerascreens.com/LFormat_Intenscreens/Large_Format.htm

I assume the person you're referring to is Bernie O'Doherty at http://www.laserbrighten.com (I've done my homework on this ;-) )

Please let us know of your results! What do the numbers you mention refer to exactly?

Steven-Marc,

Yeah, it's Bernie...:) I was just trying to stave off a bunch of emails to the guy...he's swamped with ACL repairs.

Thanks for posting the link...I'll check it out.

As far as the numerical stuff is concerned, apparently the #32 is ultra fine grain, #16 is one step back, then #8 and #4. I'm trying to find out which #'s represent how many dpi.

I found an optical company I that carries 5cm diameter discs that are measured as 240, 400, 600, 800, 1000 and 1500. I'm not sure what that means...I've requested more info. They are at optosigma.com.

I found a company that touts its product as being far superior to intenscreen...go to www.brightscreen.com. Similar product concept, but they claim that they don't suffer from hotspots, falloff problems or manufacturing errors in the optical alignment.

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?

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?

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...

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!

Charles:

A very enlightened view as always. BUT I'd have to say that I am way too happy with my mini35 for words. Yes, it has its own operating quirks, but nothing an experienced and willing DP couldn't work with.

It is a fanciful notion to "rephotograph" an image off of a piece of spinning ground glass. Crazy for sure. Though, with the right lenses your image resolution will be BETTER than any other lens you can plop onto the XL1. Don't fear the technology ;)

I will always want to shoot with the mini35 over the vanilla XL1 (or even the DVX100) in almost EVERY instance (unless, of course, the project demanded the video look). There is no other miniDV set up I like.

Going to HD is, well, a step up, and productions are demanding that kind of resolution and quality. It's the obvious move. But again, with any of the HD tests and shoots I've done, I've always come away with not loving the "crisp" image. It's still video. Even at 24p.

So again, I turn to what I like, shallow depth of field. Again, that's just my preference. Every gig I've shot, has benefited from it, people have been floored at the quality and beauty of the images.

Charles, I'll be down in LA sometime soon for some HD testing. I'd be happy to bring my rig down if you want to have a real look see. Or, I'll actually have some sort of reel in the next few months (finally) and I'll post that on my site.

P.S. it was nice to finally meet you at NAB.

Charles, You mentioned "breathing" in still camera lenses as a detriment to their use in a motion picture situation. Could you
explain a bit about how this artifact happens and how the
design of a motion picture lens improves this situation. Thanks

Sure, Richard, I'll give it a try...

When you turn the focus ring on a still camera lens, you may see a slight zoom in the size of the image. This is not considered a problem for still photography, but obviously that is a detriment for motion picture work. This is the phenmenon known as "breathing". Many video lenses suffer from this, as well as older cine zooms. In recent years computer-aided design has allowed for very sophisticated systems with multiple glass elements moving in precise formations to combat the problem. Naturally, this is expensive, and part of the reason why a good cine prime lens costs $10,000 and up.

I remember seeing a post with something like this before in the DVX100 forum.

http://owyheesound.com/Motion_Pictures/DV-SCOPE/dv-scope.html

This whole homemade mini35 stuff has me interested.

Ok, i am making some test with some 50mm lenses... now... i heard that you can make a ground glass from one of those fake cds that comes in the 50pcs packs... but how can i make one face translucent ?

Hi Agus.
I mentioned the fake CD. I was doing some tests and it looked OK. With the CD spinning...
You don't do anything with the fake CD to make it translucent. They come in two models: some of them are just clear plastic. But the ones I was talking about have one side exactly like a ground glass... So, look for them when you buy writable CDs! :-) You could buy a 50pcs box, throw the CDs, get the fake CD and walk out of the store! :-)

How about paper? Here we have a kind of paper known as 'diamond paper' which is like that semi trasnparent scotch tape. Don't know what it is called in other parts of the world. You can get it here in most graphic design or art shops, were you would buy other kinds of paper, aerographs, technical drawing pens and the like.