Hi, a newb 35 adapter question, any help greatly appreciated

[Ivan Egorov]

Hi everyone, I got some questions regarding THE adapter:

I would like to make one myself (duh).
What I got is:
-Sony vx2100e
-Marumi macro +10
-empty rings (like 10 of them)
-lenses (canon, nikon etc etc)
-cd-motor and a frosted cd
-about $300

questions:
-how can I get the best quality+shallowest DOF using these parts?
-or what could I buy to achieve the "best quality+shallowest DOF" result?
-the frosted CD doesn't give me the quality I want, maybe I'm doing something wrong? (I'm using the mediachance.com DOF machine technique)

would be better to not spend money at all, as I'm paying for my computer

thanks everyone!

[Carl Jakobsson]

I also started with the legendary mediachance guide. I've used that recipe with major modifications on my own machine. What i've learnt is that the mediachance recipe lacks certain things that cannot be overlooked.

First, you need a good SLR lens. Preferably a Nikon, Canon or similar. Get one with a low f-value, 1.4 or 1.2 is preferred. The lower value, the lower depth-of-field and the brighter image. 1.2 might be overkill though (and they're very expensive), some say you get a too short DOF (a couple of inches in focus). I started with a cheap brand 1.9 lens and got horrible vignetting (dark edges). Buying me a F1.4 Canon certainly solved some of the issues.

Secondly, you'll probably need a condenser lens to avoid vignetting. Even though I'm using a Canon F1.4 I still get vignetting. I've solved this with a condenser and the image is now fine.

I would advise you to build quick and dirty prototypes of the machine, testing different approaches. I built my first machines with milk cartons and wood from a messageboard.

To get even more familiar you can also start by testing the latest approach for STATIC DOF-machines - plastic bags. Get a plastic bag that is diffusive (called "freeze-bags" in Sweden), stretch it and point the lens on it. Maybe you won't need a spinning ground glass.

But as I stated earlier, my first advise is to get a lens and do some experimenting.

[Ben Winter]

Originally Posted by Carl Jakobsson

1.2 might be overkill though (and they're very expensive), some say you get a too short DOF (a couple of inches in focus).

You can never have too fast a lens. If the DOF is too shallow it is suggested you stop down the aperture to deepen it, as most lenses produce their best picture at a slightly stopped-down aperture anyway. And a stopped-down 1.2 brings in more light than a 1.4, and with light loss being a very prevalant problem with these adapters, you need to take as much as you can get.

[Ivan Egorov]

Thanks alot, guys
I have a canon 1.8 lens, going to get a 1.4 a bit later

Now: what exactly IS a condenser lens?
and: what does the bag look like? a screenshot maybe?
and: what about quality?


thanks

[Carl Jakobsson]

Originally Posted by Ben Winter

You can never have too fast a lens. If the DOF is too shallow it is suggested you stop down the aperture to deepen it, as most lenses produce their best picture at a slightly stopped-down aperture anyway. And a stopped-down 1.2 brings in more light than a 1.4, and with light loss being a very prevalant problem with these adapters, you need to take as much as you can get.

Yes of course, stepping down is always an option. But considering his budget is $300 he would run into trouble buying a $300 F1.2 lens.

A roll of "fryspåsar" (freeze bags) is a the upper right of the photo below.
http://c4hvbat.origo.net/images/knltin0019.jpg

[Ben Winter]

Haha...true. But I was just saying buy the fastest lens available in your budget.

And, don't kill me, but I did manage to swipe a Canon FD 1.2 off ebay for $70. You just gotta keep an eye out for good deals :)

[Carl Jakobsson]

I got my Canon FD 1.4 for 10 Euros (~$10) :) off eBay Germany.

With a little bit of luck and patience, you might find a bargain.

[Ivan Egorov]

what exactly IS a condenser lens?
and what about quality?

thanks

[Joel Kreisel]

A condenser lens is a general term for a couple different varieties of lenses, the chief purpose of which is to gather and focus light. (It "condenses" it.) Most people around here use PCX (technically known as plano-convex) lenses. They are curved outward on one side and flat on the other. In general, shorter focal lengths are better because they focus the light more.

As for quality, that's going to change with practically every piece you put in your adapter. Condenser, ground glass, 35mm lens and macro are all going to affect what kind of picture you get in the end. Like Carl mentioned, the rage around here right now is the use of alternate-material diffusers (instead of traditional ground glasses) like plastic bags. Some people have gotten very good results with these, and others not so good. If you decide to go with a ground glass instead, the higher the grind (larger grit number), the less grain you're going to see in the final picture.

As for myself, I'm building a static adapter rather than a moving one. I'm shooting on HD so it's yet to be determined if I'm going to be able to get rid of enough of the grain in a static design, but some people have been getting extremely good results on DV with static designs, and in general they're cheaper and easier to build, so if you're not fixed on a moving design, you might want to check out the "Working DIY Adapter" thread, which describes Jimmy Hedberg's take on Richard Mellor's design and is relatively easy to understand.

Hope this helps!

[Ivan Egorov]

Thanks Joel,

I don't care about the GG (static/moving), I just need good results.
Now, where could I get a condenser lens? What does it look like?
I mean, do I take it out of an old camera lens, or what?

[Giroud Francois]

you could try to build a gg/condenser in one piece.
find a lense of about 55-60mm of diameter.
one side of this lense must be flat , the other one is convex (slightly).
the difference of thickness between the center of the lens and its borders sould be no more than few milimeters (about 5)
ideally the lens is very thin (border are 2 or 3 milimeters thick).
put some wax (or contact glue or scotch tape) on the convex side to protect it.
then you pass the flat side on different sand paper. starting with 600.
Always move the lense on the paper fixed to a really flat surface (marble or thick glass)
if your lens is really flat, it will become scratched on all surface immediately.
if not (most probable), it will scratch only the center of the lens.
So go back to 200 sand paper and make it flat. (you can even use electrical tools for this at slow speed)
when it is really flat, go back to 600 then 800 then 1200 sand paper and finish with 1500 aluminim oxid.(glass to glass)
When using sand paper, alway us a lot of water, to avoid deep scratch.
use special wet sand paper.
this way you will get (with a lot of effort) the best GG/condenser you could ever dream. (but is not ok for HDV).
This can be managed over a quiet week-end (no wife, no children).

[Ivan Egorov]

Thanks Giroud,
where could I find such a lens? a magnifying glass? or dismantle some photo lens?
I don't care about HDV right now, so I hope this will do.

[Ben Winter]

Originally Posted by Ivan Egorov

or dismantle some photo lens?

Yes, an aspherical lens assembly like an SLR lens has a plano-convex lens at the end of it (the front side). SLR lenses are notably tricky to take apart though.

[Joel Kreisel]

It looks like most people on here get their lenses from Optosigma, which cheaper and easier than trying to dismantle an SLR lens.

[Ben Winter]

Ivan, I'll sell you mine for $25, shipping included. I used it for my adapter and it worked great. It's an Optosigma FL70mm plano-convex lens, then same used in Richard Mellor's design. The size is 52mm.