DIY micro35 kit (New Footage!)

Re: DIY micro35 kit

Re: DIY micro35 kit

rpster,
I'm sure plenty of people will fund you if you build them one as well. Thanks for the info.
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Rpster-
Are you making a static or oscillated GG adapter? If its a oscillating adapter can you give me a direct link to the model of offset rod your going to use?

P.S. About the pentaprism. You wont be able to use one out of a 35mm SLR because their exit face is too small. You will have to either get a much larger pentaprism (good luck/$$$) or use the different style prisms (2) that the P+S Technik uses. Let me know about the link.

Brett Erskine
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Given that I am in the Optics business and have been for 40 years, I find this thread and similar ones interesting. It is relatively easy to make something that sorta works, much harder to make something that will be acceptable to customers.

A prism erecting system introduces a whole new set of problems that will not be easily or inexpensively solved.

I think the best bet is to make a system that records upside down, use a small monitor (upside down) during production and flip the image in post if you want to make something inexpensive that has a chance of having the necessary optical quality.

Having said all that, good luck and I will follow the thread with interest.

Bill Turner
Century Division
Schneider Optics
 
Re: DIY micro35 kit

Re: DIY micro35 kit

im not sure if this has been done before, but i would actually classify my ground glass as rotating, but on its center point. im using an ultra-thin precision ball bearing and mounting the ground glass into the bore. then rotating the ground glass by use of a collar and pulley. my design can easily be converted to oscillating version by simply reducing the diameter of the ground glass. its one hell of a ball bearing to use, but boy it's silent.

as for the penta prism idea, once i get this thing built, ill get back to you guys on it.

being the job-less high school student that i am, im going to use old minolta md lenses. for the sole reason that i already have a minolta x-700, and the plethora of cheap(but somewhat good) lenses availible on ebay.
 
Re: DIY micro35 kit

Re: DIY micro35 kit

rpster


Keep up posted and hook it up with some screen shots of your design. peace
 
Re: DIY micro35 kit

Re: DIY micro35 kit

here are some paper mock-ups of my design
computer models are great, but the physical mock-ups are better. the minidv tape is there for reference.

front
mini35mockup1.jpg


rear
mini35mockup2.jpg


you can see how dinky my design is compared to the usual cdr design. the reason for the small 37mm mount at the back is because i have a canon optura 10, but you can easily hook up a dvx100 using a stepdown ring or two.
 
Re: DIY micro35 kit

Re: DIY micro35 kit

It looks like a solid SLR design concept. I can tell by the shape that your thinking about using a pentaprism/mirror combo. While this obviously will work fine for 35mm cameras it may not work for your video camera. I alraedy went down this road and despite all my efforts I wasnt able to zoom in close enough with my video camera to look thru the eye piece end of the pentaprism. Its extremely tiny. But then again I was using a DVX. Perhaps your camera will be able to. I recomend you test this issue out before you put too much money and time into this design. If it doesnt work check out the prisms used in the P+S Technik for a alternative solution or simply flip in post. Good luck.
 
Re: DIY micro35 kit

Re: DIY micro35 kit

I already ran some tests with close-up lenses (tiffen +7 +10) and they achieve the close focusing needed (about 22 cm focal distance from the 37mm mount to the ground glass).

The pentaprism is not from an slr, it will be purchased from http://www.thorlabs.com  ;D
it will be pretty massive, but it provides a 38x38mm square apreture (large enough for the 36x24mm still image projection)
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Ripster,

On the off chance you have over looked the fact:

Penta Prisms do nothing to the image except deviate 90 degrees. I believe you will find that the Penta Prism used in a 35mm SLR is a roof type which is different than the standard Penta Prism in the catalog you list.

Most SLR's these days use mirrors arranged to mimick the result of a roof penta because it is much cheaper in massproduction. I assume from the layout that you intend to use a mirror at 45 degrees (like the mirror in an SLR) to bounce the light up into the Penta Prism.

Without a roof the resulting image (in the camera)will be right side up but reversed left to right , I think you will find. Adding a roof to the prism is a big deal as it needs to be VERY accurate to avoid a double image - far more accurate than the finder system of an SLR that is just used for viewing by the eye.

Once again, good luck

Bill Turner
Century Division
Schneider Optics
 
Re: DIY micro35 kit

Re: DIY micro35 kit

[quote author=Bill__Turner link=board=Links;num=1097454631;start=45#48 date=11/16/04 at 07:16:03]Penta Prisms do nothing to the image except deviate 90 degrees.[/quote]

Here's the design I have been playing with which sounds just like the design being discussed here. Do you believe this won't work?

320144142.jpg
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Yes, if you read my post, the image will be reversed left to right (like looking into a mirror) lettering will read backwards etc---but it will be right side up in your video camera. I do not see the image plane location for camera lens (and the ground glass focusing screen but assume it either right before or right after the 45 degree mirror).

I believe another potential problem is trying to get the proper magnification of the 35mm SLR image at the working distance dictated by the prism's long (4x the aperature? not positive from memory) optical path length.

I am not trying to discourage anyone or be a party pooper, this is a difficult problem to overcome properly, especially when you add the problem of inverting and reverting the image so that it is recorded in the correct orientation.

Bill Turner
Century Division
Schneider Optics
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Ripster, you are correct, if you are making an erecting system using a 45 degree mirror and a penta prism(or a mirror box equivalent), you need a roof type which is type b on the site you referenced.

Just as a note, you probably need at least a 5 second accuracy on the 90 degree roof to insure good images.

Bill Turner
Century Division
Schneider Optics
 
Re: DIY micro35 kit

Re: DIY micro35 kit

I just realized something.
If i put a roof prism in place of the mirror, then just use a regular pentaprism, the image will be perfect!
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Keep in mind as you work thru this problem that there is a way you can "trick" your DVX LCD monitor to display the image correctly by doing both:

1)Select "mirror" image in the DVX menu and...
2)Place small magnet next to LCD pivot point.

The magnet triggers the camera into thinking that the whole camera is upside down when it fact it isnt. The resulting image is corrected perfectly, up and down AND side to side.

Personally I've given up on fliping the image optically for this reason and so many others ($$$, weight, size, quality, complex) but at the same time if you have hopes to sell your adapter you'll most likely need to figure out a way to do it so you can offer a complete solution.

Bill-
Hows the optical quality difference between a roof pentaprism and one made of mirrors? How about cost and size differences for one off pieces?

Thanks
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Here's another variation on the previous design. Any thoughts on using the ground glass surface as the mirror? Or, would this be a problem for the focusing?

321100243.jpg

Thanks!
 
Re: DIY micro35 kit

Re: DIY micro35 kit

Definetly problems with focusing, the focal plane has to be parallel to the lens or else focusing problems will ensue!

so far, i've found alot of roof prisms, but most arent the right size. a roof prism from a telescope eyepiece has a big enough apreture as well as a high enough quality (<5 arc sec. deviation) for this project (cost is about $200)
so that will kick it up to almost $700

the price breaks down as follows:
$180 - Machined Body
$60 - Pentaprism
$200 - Roofprism
$30 - Diopters
$200 - Hardware (bearing, rods, etc, motor)

keep in mind that this option is extremely similar to what the mini35 does, and far more complex than the blank cdr design.
id pull that little trick brett talked about IF i had a dvx100 and save a ton of money.
 
Re: DIY micro35 kit

Re: DIY micro35 kit

geez, I hear all this talk, I want to see a complete one for once. Too much talk guys. I know it takes time but its been a week. :)
 
Re: DIY micro35 kit

Re: DIY micro35 kit

You should check out the threads at DVi then ;) A month is nothing compared with those threads!
 
Re: DIY micro35 kit

Re: DIY micro35 kit

[quote author=rpster link=board=Links;num=1097454631;start=45#56 date=11/17/04 at 21:26:53]Definetly problems with focusing, the focal plane has to be parallel to the lens or else focusing problems will ensue![/quote]

Yup, that's what I figured. Oh well.

i've found alot of roof prisms
Click to expand...

A roof prism will flip the image but it also redirects the light path 180 deg, back towards the direction it came. How would the roof prism be used, for example in the design above, so that the light path would continue in the same direction? By direction, I mean from left (the source) to right (the camera) in the diagram.
 
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