Hi everyone

this is a list of parts to build the 35mm adapter:

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=116732&is=REG
http://www.thorlabs.com/ProductDetail.cfm?DID=6&ObjectGroup_ID=213&Product_ID=1481

(2)http://www.thorlabs.com/ProductDetail.cfm?DID=6&ObjectGroup_ID=848&Product_ID=1483


50mm 1500 grade : part number 099-0160http://www.optosigma.com/miva/merchant.mv?Screen=PROD&Store_Code=OS&Product_Code=pg211&Category_Code=Filters+%26+Apertures

50mm 70fl :part number 011-2870http://www.optosigma.com/miva/merchant.mv?Screen=PROD&Store_Code=OS&Product_Code=pg55-61&Category_Code=Spherical+Lenses
you will need two step rings the size will be determined by your camera and the size of the c-mount adapter thread.


this is an example of a step ring
http://www.bhphotovideo.com/bnh/controller/home?

O=productlist&A=details&Q=&sku=11925&is=REG

completed adapter http://www.dvinfo.net/media/mellor/35%20mm%20adapter%20thorlabs%20tube.jpg

Richard, I can't remember if you have used both the OptoSigma GG and Thorlabs GG but if you have which did you find to yield a brighter image?

I have used both. the opto sigma is better . the thorlabs glass even came with flaws.

I would like to see some video shot with this adaptor

EDIT: ^^^ beat me to it.

Do you have any test footage or even some stills from using this adapter?

Richard,

Congrats, That looks like a really pro unit and like the others some stills or footage would be great.

Is there any benefit to getting the coated 50mm 70fl?

Better contrast and light transmittance

Many thanks Richard, that's very usefull.

Can U please post some pictures of the parts inside the thorlabs tube (or just a bigger one like this already posted) ??

Tnx again for the infos.

I started thinking about this while I was cutting the grass....this is really an impressive design since its completely modular. No glueing or taping..everything screws in...it seems like it would be easy to change the GG to anything should someone come up with a new breakthrough idea .

And all in all it costs only $170 to $200 depending on the lens mount and step ring you go with. Extremely impressive.

Can't thank you enough for this post Richard

Richard, how did you connect the c-mount to the tubing?

this is a photo of the back of a c-mount you would just step from this thread to the 52mm tube . If you notice the back of the mount can be removed. the reason my adapter looks different is i removed the back and glued a step ring into the back.
I don,t want to recommend this I may have the alignment
to the lenses a little off . as the ring was a little smaller which may be causing some loss of focus.
If you build the tube. you could go to a camera shop and try all the rings you need to build this. the best part is the tube is 52mm
and standard camera parts will attach. http://www.adorama.com/VDCMCA.html

Wow. Most impressive. I'm a bit confused about the C-mount and C-mount adapter -- are both needed? Excuse my ignorance; I'm not knowledgable about still lenses. Also, any instructions on how to set up the lens and GG inside the tube, or is it just trial and error to get the focus correct?

Thanks,

Fox

Thanks for the info Richard. I wasn't aware that these mounts were threaded! I should have guessed!

The reason both the c-mount and c-mount adapter are used is because that's how you can buy them (I presume). I don't think it is possible to buy just (for instance) a nikon F mount with threads on the back.

when I was setting the focus with the ground glass I had
a failed attempt at making a homemade ground glass I used this to set the focus and then replaced with the opto sigma. maybe if you had a 50mm lens you could sand it good enough for focusing

Richard, I was completely confused by your last post. :-) I've been looking at other designs for static adapters and those use diopters to allow your video cam lens to focus on the GG. Yours, more eloquently I'm guessing, uses the convex lens. How are the GG and convex lens set up inside the tube in relation to each other and in relation to video lens? Or should I just send you a check and let you worry about that? Thanks.

Fox

If you were holding the tube in your hand the first part in would be retaining ring . next ground glass frosted side up then flatside of plcx on top then retaining ring

this is a picture of the first adapter I made with filter rings.
the plcx was a square cut . the thorlabs version will be even sharper than this. this is what your camera will see. the diopters will only come into play if your camera cannot focus on this image

http://www.dvinfo.net/media/mellor/35%20mm%20lens%20test%202.jpg

Richard, one thing I cannot fully determine from the images and description is whether we would need to provide a macro lens. I presume that would be necessary?

Richard, now I get it, thanks. I do mirror Aaron's question about the macro lens.

Fox

Let me reply to my own post -- you already answered my question about the diopters.

Say, what camera are you mounting this on?

Fox

this is a still from the first adapter . the problem was not getting the plcx directly on the ground glass . the thorlabs version is improved. with better opto sigma glass.

this was shot with only the adapter as you saw it my camera did not need a macro.

http://www.dvinfo.net/media/mellor/PDVD_540.BMP

the camera is a $50 pawn shop special one chipper.
the hope is to put this on a high def homemade camera.

I have some footage with this GG and Cnvx lens. I made the tube out of PVC.
http://hazardousproductions.com/films/chron_frd.mov
right click save link as.

I did have to use a macro on my gl-1.

Nice shot. Can't wait to assemble one and mount in on my DVX.

One question more: Would you get even more light into your camera if you didn't use the convex lens and just flipped the image in post?

Fox

The convex does't flip it.... To be honest i'm not really sure what it does, besides cost $30.00. I haven't experimented without it.

Here's a pic of the rig http://hazardousproductions.com/images/lens.gif

when the time is right. many people have found ways to flip the image on the viewfinder. the dvx100 just requires a small magnet placed near the lcd and it flips the image. then transform in after effects will do it in post.

Richard, I've seen the magnet trick and it works well. My question then is, what does the convex lens do? Thanks.

Fox

not being an expert on optics . the diffuser starts to scatter the light the plcx brings it back

http://www.edmundoptics.com/techSupport/DisplayArticle.cfm?articleid=267

I think I actually understood some stuff on that lens theory site. Another question just occured to me: where at in the tube do you place the lenses? Also, I'm assuming this whole thing requires step rings to go from camera lens down to 55mm and the 55mm to 58mm on the still lens side, correct?

Fox

Ignore this.

the distance from the end of the c-mount to the focal point of the ground glass is about 1 1/2"this is were you would start your first retaing ring . If you wanted you could use glass etching on a blank 50mm glass in fifteen minutes you would have a focusing ground glass
assemble the lens c-mout and tubes . just keep adjusting the thread with your fingernail untill it,s in focus . blow out the lens with compressed air and insert ground glass not touching the surface . blow dust out and place plcx on top thread down ring with fingernail . I bought the compressed air after I trapped dust in between. both the glass and the lens came dust free this was my error in assembling . the cool thing if you get the groundglass sealed with the plcx dust free It will stay that way. the tube and retaing rings solve the focusing and the dust problem of the
filter ring version


link to glass etching http://www.misterart.com/store/view/003/group_id/978/Armour-Etch.htm

Cool. I think I can figure this thing out now. The etched glass is a great idea. I'll post some shots when I get mine up and running, probably in a couple of weeks as I'm out of town at the moment.

Fox

Richard -- what size step-down/up rings do I need on the tube end? 52mm or 55mm? And the tube to still lens goes up to 58mm, correct? Thanks.

Jason

the thorlabs tube is 52mm thread

Good thing I asked. I haven't been able for find a 72 to 52 step-down. I'll have use a 72 to 58, then 58 to 52 if I can't. Probably not an issue though.

Do you think it is possible that this could be used with a microcrystalline screen? Obviously, it would be hard to make your microcrystalline screen round...but say if you made a square screen...is their some sort of round holder that you could put it on/in?

I made a few attempts at a microcrystline wax diffuser with a 50mm glass blank. It is not good enough yet .
and if you did the plcx has to fit directly on the wax diffuser
somehow

I found a52 to 77 this company seems to have a wide range of adapters I did a search under the term lens adapter

http://www.adorama.com/FLU5277.html?searchinfo=52%20%20ADAPTER&item_no=25

I need a t 72 to 52. I can find 52 to 72, but not the other. Weird. Someone must make one somewhere.

I found a great site for step rings.

this should fit just about every camera.

great prices too


http://www.2filter.com/prices/products/rings.html

Nope, no go on that site, either. Thanks for looking. I just don't think that size adapter is made. Is there any real issue in using two step rings?

Jason I've never seen a 72 to 52 anywhere. It's always been done with a 72 to 58 to 52. I don't know why, but the step ring guys just overlooked that one entirely. Probably never entered their heads that someone with a 72mm front would to put something smaller on it. What are you putting this on? A DVX? A Canon?

Joshua, it's going on a DVX. I figured the double step rings wouldn't be a problem, it'd just be nice to a) have one less part and b) save 10 bucks.

Fox

Another question: what size step ring do I need to go from the tube to the c-mount adapter? I can find the adapter's diameter anywhere. Thanks.

Jason

Found this on Schneider Optics site:

C-Mount

Mounting Thread = 1 inch x 32 tpi UN 2A
Length of Lens Thread = 3.8mm
Lens Flange Focal Distance = 17.52mm
Camera Depth (C-Mount Face to Image) = 17.52mm

I have a funny feeling that the size, and especially the thread configuration, is going to be hard to match with step-down rings (going from metric to inches). And what is UN 2A?

Anybody know for sure?

That appears to be for the C-mount itself; what about the C-mount adapter? I'm assuming Richard has this info; he just hasn't been on for a couple of days.

Anyone here know how powerful an macro adapter I will need to use one of these things with a DVX? Will +3 be fine or will I need to go higher?

One more question: How many retaining rings did you end up using Richard?

Do T-mount adapters have the same type of threads? The only problem with the C-mount is that it limits the light that can pass through.

Aaron, don't know the answer to your macro question yet -- I ordered a set of +1, +2 and +4 off eBay, so I'll let you know after I get this thing built (hopefully next weekend; still waiting on answers about the c-mount adapter before ordering the stuff from B&H). I ordered 2 retaining rings along with the tube from ThorLabs per Richard's instructions.

Fox