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-   -   Real 35mm DOF with a Cheap sony TRV18 (https://www.dvinfo.net/forum/open-dv-discussion/16932-real-35mm-dof-cheap-sony-trv18.html)

Agus Casse November 11th, 2003 01:28 AM

Real 35mm DOF with a Cheap sony TRV18
Hello there folks... well.. first of all view a sample before putting anything...


Now... what i did is to grab a SLR 35mm minolta photo Camera.. and i put the sony video camera in the viewfinder...

the image was clear.. but you will see it with a lot of grain, cause i shoot it in the midnight with really low light...

the DOF is the one from the Photo camera..

I cannot open an readapt the photo camera..(its not mine :) ) but i could buy an old one and perfect the system.. anyone know how i could remove the focusing tool in the photo camera ?

Cosmin Rotaru November 11th, 2003 08:10 AM


The "focusing tool" you see is embeded in the ground glass. If you realy want to go that way, see if you can find a replacement ground glass with no marks and no "focusing tool" (I'll go with "focusing tool" because I don't remember its name also! :-) )on it.
The mini35 adapter works like you've experimented, but the ground glass rotates (or oscilates - in the new version) to blur the grain on the ground glass.

Jeff Donald November 11th, 2003 08:31 AM

It's called a focusing screen and the circle in the center is the focusing aid. Focusing screens are referred to as a ground glass in large format photography.

Ignacio Rodriguez November 11th, 2003 10:36 AM

This is very intersting. The Mini35, a little gadget that does the same thing, costs several thousand US$. I wonder why nobody has made a cheap version yet. We would ALL buy something in the sub US$200 that could let us use 35mm photo lenses. Anybody here up to it? I'll be a very happy beta tester <grin>

Agus Casse November 11th, 2003 10:56 AM

I am up for it... now i am hunting a cheap old SLR camera that doesnt work.. so i can try up more about this experiment... i really didnt have too much grain... but even if the grain is there... remember that i have a cheap Dv camera... even if the image isnt that great.. for really no money at all i will have a 35mm focusing tool,. and the image quality level that i have now will be really awesome compared to before...

Alex Taylor November 11th, 2003 12:39 PM


That's an interesting idea Agus! Let us know your progress.

John Hudson November 12th, 2003 11:49 AM

Great ideas! We all know the 'industry' is not kind to our $hobby$ and with this kind of resoursefulness I get really excited!

Agus Casse November 12th, 2003 07:11 PM

Here is another test... now


Ignacio Rodriguez November 12th, 2003 07:25 PM

Nice. The vignetting is quite significant though or is it on purpose?

Agus Casse November 12th, 2003 07:36 PM

Remember that i am capturingthis image from the photo camera's viewfinder... so the vigneting is from the black pastic... also the grain comes up since there was low light and i edited teh curves and levels in the post.

Agus Casse November 12th, 2003 08:09 PM

If anyone knows how to build the box where i can mount the SLR lens, and i can get the image in a homemade ground glass... post a link or here..

Ignacio Rodriguez November 12th, 2003 08:44 PM

I really know nothing about this kind of thing, but I guess an adapter, any kind with the right bayonet, could be the basis for a home-made mini35-like trick. You would need to build some kind of barrel and add a semitransparent surface like what we call 'diamond paper' here, and then the right mount for the camera, possibly with a bellows so as to be able to control the distance... hmmm perhaps a macro lens would come in handy...

... in my dreams, there is a photo store where you can buy all the stuff required and assemble it yourself for less than US$300 <grin>

Agus Casse November 17th, 2003 11:51 AM

Ok.. here is an update,

Now that i test the system. i started to make my own box...

I use a 50mm lens, witch it is calibrated to a homemade ground glass (which i will improve now) from there i was getting the image ... but the light coming from the lens was forming a big circle of bright light that ruin the image projected in the ground glass...

to correct this i noticed that the ground glass from the camera is not quite flat, so it acts like a magnifying glass, that makes the ground circle to disappear.. so i took a wide conversion lens that i had (x0.6) and disarm it, i found that the last piece of the lens acted like the magnifying glass that i needed in the ground glass...

All armed it looks pretty cool, now i am having too much grain from the homemade ground glass, so i will make the ground glass to vibrate... now...

What do you think, if it vibrates could work, or i have to rotate it to give me better results ?

Cosmin Rotaru November 18th, 2003 07:59 AM

there was an old topic... maybe you've already seen it:

Jon Yurek November 19th, 2003 02:17 PM


What do you think, if it vibrates could work, or i have to rotate it to give me better results ?
Well, the real Mini35 rotates the ground glass. I think vibrating it might make still shots difficult.

Agus Casse November 19th, 2003 06:23 PM

I put a new topic with the adapter finished and working.. there are some shoots as well


this is the first version of this homemade adapter... i think i can solve the problems of them later.. but the most importan thing is that now i can use the 35 lenses....

anyone that have a mini 35 could open it and show me a picture of how it works ?

Cosmin Rotaru November 20th, 2003 05:06 AM

"Well, the real Mini35 rotates the ground glass. I think vibrating it might make still shots difficult"
Well, the latest adapter has a vibrating GG...

"anyone that have a mini 35 could open it and show me a picture of how it works ?"

I can't think of anyone riping a 8k USD equipment to take pics!
Anyway, you already know how it works!

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