Making my diy 35mm adapter work
 

Hi,

I recently purchase a diy 35mm adapter to shoot a shortfilm. It's a static adapter for nikon lens to use with the hvx200, really cheap so I didn't expect wonders. The guy that sale it sent me some photos and a video shoot with the adapter:

[img=http://img49.imageshack.us/img49/904/adaptador2ax5.th.jpg]

There's the video:
http://es.youtube.com/watch?v=mzvyau1HXh4

So I got the adapter and as we didn't have the time to make tests we tried it with our nikon lens (55mm, 28mm and some 200 mm) with some step-down rings and our hvx200. The fact it's that we were impressed by the quality of the image but we were unable to focus properly, the only thing we got working was the telephoto lens, and it was really difficult to get the focus, and we had to zoom in a lot. So, the end of the story: we didn't shoot with it, too difficult and no time to test.

Now I'm trying to make the damn thing work with my mini DV (an old Sony PC120, 37mm filter diameter). But I need some help, becasue I don't know anything about these thigns :)

1) The adapter has NO ground glass, so I really wonder how the hell this works (I didn't know that when I purchase it....hmmm)... And now I understand the focal lenght problems we had when we tried it... I guess I can put a ground glass on it, following some tutorials I see here an on the net, but do I have to follow some distances/rules to place it?

2) In any case, i need some step-down rings to put it on a 37mm diameter (I can test it also o na DVCAM with a 55mm filter diameter a friend of me have). But do I need some extensions tubes, or I just have to attach it as I did with the hvx200?

Sorry if this sounds stupid, but I just want to make this thing works and try it with the camera I have (or the one that my friend have), even If I have to modify it (put a ground glass on it or use extensions tube). Any help/tips/links to follow i'll really be appretiated.

Thanks a lot!!

DP: I can supply photos of the adapter if needed.

If there is no groundglass 46.5mm rearwards of the front face of the Nikon lens mount, you will be getting aerial image relay only from the Nikon lens into your camcorder. The groundglass is what enables you to get the shallower depth-of-field and field-of-view characteristics of the 35mm camera lenses.

In other words, the groundglass causes your camera to be making a picture of a picture, the one projected onto the groundglass by the 35mm camera lens.

With the correct close-up lens on front of your camcorder and adjustments to the distance between close-up lens and focal plane of the 35mm camera lens, you would be able to get correct focus into the aerial image.

Creatively, without the groundglass, there is no advantage over using the camera's own lens except in being able to put long telephoto lenses on the camera and you have the added chore of dealing with an upside-down image.

Bob,

I'll get a ground glass from ebay or jetsetmodels and see if I can place it correctly in the adapter.

The adapter has a close-up lens in front of the camera lens. I'll try to follow the tutorials I found around here, in order to place correctly the GG.

So basically, without ground glass I just get the image quality of the nikon lens without shallow dof...

Thanks.

I know very little about the jetset option. What I have read here suggests that it may well be the best option for you.

As above, the textured surface of the groundglass needs to be 46.5mm rearwards of the front face of the Nikon mount.

I don't know what power close-up lens or dioptre you have. A very rough guess of workable lenses and distances from front of close-up lens to groundglass is :-

Dioptre power.------------Distance from groundglass.---------- Camcorder zoom for 24mm frame.

3+ -----------------------Approx 10 inches------------------- not known - may vignette

4+ -----------------------Approx 8 inches-------------------- 54mm for Sony FX1.

7+ -----------------------Approx 5 inches-------------------- Approx 40mm for Sony FX1

10+ --------------------- Approx 3 inches--------------------- not known - may go soft on edges.

Your close-up lens needs to be an achromatic dioptre which is a two pieces of glass often in a metal frame and glued together. A single element lens will cause chromatic abberation and image softness on the edges of the image.

You may find for your camcorder, that the dioptre has to be furthur back from the groundglass than it is right now.

Better brains than mine can tell your more. This is some info to start with.

Bob,

Thanks you very much for the info. It'll help me a lot :)

I'll take a look at the close-up lens to see what kind it is.

Hi Ivan,

I used to work with a diy static adapter. The images I got were not bad at all. Now I use a rotating adapter.

However if you are interested I think I still have 2x 52mm diameter GG that I bought from Optosigma! I won't use them anymore so I can sell them!

Simon