My first prototype static adapter with pics
 

Just put together my first prototype static 35mm adapter. The adapter uses optosigma 1500 grit 50mm ground glass, a Knight Optical 50mm 63mm focal length plano-convex condenser and a nikon nikkor-S 1.4F 50mm lens.

Here are two test images:

http://homepage.ntlworld.com/wayne.kinney/cat01.jpg

http://homepage.ntlworld.com/wayne.kinney/cat02.jpg

2 Problems, you can see the grain, and some dust that needs cleaning off. Also the condensor creates a far bit of barrel distortion around the edges.

However I get NO vignetting or hotspot. so i think if i change my condensor to a longer focal length this will reduce or eliminate the distortion.

Setup is like this:

35mm lens----GG---|)condensor-----DV cam lens

I am not using any macro as my panasonic nv-ds30 has no problems with focusing. The condensor is right up against the ground glass.

Anyway, let me know what you think, ill post some pics of the adapter later today, and some video.

Cheers,
Wayne.

If you move the condenser back from the GG the distortion will reduce, but you will lose field of view/image size will get smaller (centre of image is magnified). A longer focal length condenser will have less distortion/aberration but will also have less hotspot correction. This can be improved a bit by moving the camcorder back and zooming in. I thought I had a solution with two 120mm FL PCX () between GG and camcorder (one on its own still had hotspot), but then I noticed something about the Optosigma GG that is really annoying me - you get a lot of diffusion on out of focus areas. With 2x 120mm I still have a small amount of hotspot in certain light, 2x 100mm would probably be better.

Another thing I noticed is you should put the ground side of the GG towards the camcorder or you get an internal reflection in bright light. I thought the grain on the Optosigma was acceptable for me, couldn't see it in most light. An air duster is a must for getting the dust out!

Thanks for your reply Andy,

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If you move the condenser back from the GG the distortion will reduce, but you will lose field of view/image size will get smaller (centre of image is magnified). A longer focal length condenser will have less distortion/aberration but will also have less hotspot correction
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I really dont want to loose any field of view, so changing condensor seems the way to go. I have no hotspot so feel i can increase the ocal length some more.


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An air duster is a must for getting the dust out!
-----
I must get myself one!!!

Wayne.

Those are very sharp images!
The 1.4F 50mm lens is the main reason you have such little vignetting. I'd keep the condenser close to the GG if I were you. I use two condensers (and a F1.4 58mm lens) with the 'ground' glass sandwiched in-between. No distortion.
If you want to get rid of the grain (as far as possible) take a look at the Microcrystalline wax thread or my web site http://members.chello.nl/a.schultzev...wax/index.html

Thanks for your reply, Oscar,

Can you tell me what the FL's are of the condensors you are using?

The Microwax maybe something ill look into in the future.

Cheers,
Wayne.

Try the sky. The cat pic is good but a tough call to prove. (yeahhh... right! prooove-shmoooove! She's-a-round! ....lol)

Dan, that's the third cat shot with an adapter...but you started it (with poor Felix).

Wayne, I can't tell much about the condensers, because I just took them from old lenses. One from the front lens of a telephoto and one from a super8 film camera zoomlens. Both are pretty weak and thin. Almost flat ,slightly concave on one side. I put them like this (|GG|)

"Dan, that's the third cat shot with an adapter...but you started it (with poor Felix)"
Ohhhh.... derz more than three, but the others got it soooooooo baaaaaad, they did not make it in the finals....
"Wayne, I can't tell much about the condensers, because ...." You can tell ME! I'm a doctor! (Leslie Nielsen-Airplane)
BTW: one's "contraption" is as good as the hair on the puss is showing... Dam' see what you made me say? Now, the cat's out of the bag! nough-all-ready.

Dan,
Ill try out some panning shots of sky as its nice sunny day today.

You can defenitly see the grain in this 2 images:

http://homepage.ntlworld.com/wayne.kinney/fan01.jpg

http://homepage.ntlworld.com/wayne.kinney/fan02.jpg


Ill get some video posted later.

Regards,
Wayne.

Diffusion
 

You can also see the diffusion I was talking about in the second shot around the window. :)

I spoke to POC last night about their diffusers and the guy said they were quite different to ground glass, I was going to order one cause I thought (also looking at Dan's shots) they might not suffer from the diffusion, but they are $120 and I think that's too much to take a pop on something that has a lot of light loss (but maybe that would be improved with condensers?)

Here is the adapter (please forgive the temp glue job;) mounted on the front of the cam.

http://homepage.ntlworld.com/wayne.kinney/adapter01.jpg

And here is what it looks like down the tube:

http://homepage.ntlworld.com/wayne.kinney/adapter02.jpg


I think maybe ill order another condensor, the same as the one i've got, which is a 50mm dia, 63mm FL. Then try this arrangement:

35mm lens----(|GG|)----DV Cam

I tried putting the condensor between 35mmlens and GG like this ---(|GG---

This had the same effect, no hotspot but distortion, however the distortion was the other way round. So im hoping 2 condensors will work to correct eachother.

Wayne.

Wayne,
Really sharp pics!

I have the same setup, except my 50mm condensor is 70fl.
I had distortion as well with this set up...

35mm lens - GG - |) - DV camera

So I switched to this...

35mm lens - GG - (| - DV camera

seems to have fixed my problem, I cant see any barrel distortion anymore. See if it works for you.

Donnie,
I tried what you sujested but did not seem to work with my particular condensor. Some more pics:

http://homepage.ntlworld.com/wayne.kinney/coin.jpg

http://homepage.ntlworld.com/wayne.kinney/clock.jpg

I have now recieved my second condensor and this seems to both correct the barrel distortion and brighten up the image even more. Not sure if im getting some chroma problems around the edges, there seems to be a sweet spot in the distances between the lenses.

Ill shoot some more today. My final step will be to rotate the ground glass using Nick Bartlett's method of using a larger bearing.

Wayne.

Here are two short clips i did today:

http://homepage.ntlworld.com/wayne.k...rack_focus.mov

http://homepage.ntlworld.com/wayne.kinney/candle.mov


Wayne.

Condensors and barrel distortion
 

Hi,
I have been playing with my condensor lens, its a 50mm diameter, 63FL. Problem is it gives loads of barrel distortion. I played with distances of the lens from GG and from the camcorder, and I can say, DISTANCE MATTERS!

Below show 2 images, first with condensor right up against GG, second with it 11mm away. Setup is like this: SLR lens--->GG---->|)condensor---->camcorder:

http://homepage.ntlworld.com/wayne.k...distortion.jpg

http://homepage.ntlworld.com/wayne.k...distortion.jpg

The camcorder was around 1 inch away from the condensor. I wonder if others with barrel distortion have tried this?

HTH,
Wayne.