35mm Adapter Static Aldu35

[David Kelvin]

Spent the day searching this thread, but I couldn't find a clear solution for a lens mount.

Anyone know if there's an alternative to using the lens mount of an old slr camera, such as a lens mount adapter perhaps, that would bridge a 35mm slr lens to (55mm, 58mm, etc.) filter threads? I don't mind if it increases the cost. I just don't know what to look for, and I'm starting to think I may be dreaming. I'd just like to avoid any gluing of parts on, drilling, etc., if at all possible, and attempt an all-screwed-in solution based on James Webb's using various empty uv filters as spacers:

http://homepage.mac.com/dvx100/.Pict...r_JWebb_03.jpg

I'm thinking there isn't, and I'll have to get an old slr camera, but it doesn't hurt to ask.

[Bob Hart]

The older Pentax cameras used a threaded mount for the lens rather than a quick-change bayonet style mount. So it may be possible to assemble enough different adaptors with this lens style to get what you want.

[John Cabrera]

The lens I'm using (vivtar) is threaded... from an old XC-3. But I still have to use the camera's own lens mount for the final design. Even though it's threaded, the threads aren't the same size as the threads on filter rings. I took it to a camera store to test it out. My only option now is to drill into a 55-46 step-down ring or glue it on (not my preference). I don't know if those Pentax lenses have the right threads either. My gut is that they don't since they make these standard threaded protective caps to be used on lenses with threads. So I think there is some degree of standardization on that.

John

[Brett Erskine]

If your following my basic design like the one James onlined in his pictures you might think about taking the mount off a junked camera and remount it to a filter stacker. Drill a large diameter hole in the center to let the light thru and your done. Make one for each different camera mount and you now have adapter with quick change mounts for any given make.

But if you want to keep it real simple and cheap go with the T-Mount lenses and a step down ring. The bonus here is that T-Mount lenses are generally the most inexpensive lenses (yet still high quality) due to the fact they normally dont mount to modern camera bodies and certainly dont have any of the automatic/electronic fuctions. This doesnt matter in our case so its a real smart way to go.

-Brett Erskine

[David Kelvin]

Thanks, guys.

After reviewing the options, I think I'll just go with drilling holes in the step-up ring to fasten the slr lens mount. I couldn't hardly find any T-Mount lenses anywhere, and I read somewhere else tonight that John is most likely correct about different threads on the Pentax screwmount.

[James Webb]

My plan was to eventually go the stacker route too. I do believe it would require a machine shop to do the job right, no? Those little buggers are sturdy!

[Damion Luaiye]

Howdy. First post - been following for awhile. Very impressed with what you've all done. Thank you.

I recently put together a test rig using a multi ring Nikon extension tube: standard Nikon lens mount on one side, 52mm thread for each of the separate rings. Sturdy and interchangeable - no drilling, gluing, etc...

[Nick Conti]

Hello All,

I've finally got some test shots up from my first attempts at the adapter. It's not really completely finished yet at all, I was holding the slr lens onto the front just so I could see where I was standing. I'm using a nikon 14mm extension tube as a spacer and as a way for the lens to mount without needing to permanently attach the actual lens.

Pretty much all of the footage would be unacceptable for shooting, but I wanted to put it up so people who aren't working on the adapter yet or are just starting can see the hurdles that have to be passed before this thing works at well as it possibly can. I really don't know what to do to fix some of the problems I'm having, so if anyone has any insight as to what I can do to improve my image quality I'd love to hear your comments.

The pcx condenser I used really did a lot for the hotspot, but the condenser ends up screwing around with the flange focal length and I couldn't just throw on another nikon lens of a different focal length without making adjustments to the adapter right? Is there any way to have one set adapter that can swap a specific lens type freely?

The movie is in mpeg-4 format so you'll need quicktime to be able to view it. And I spelled warping wrong in the one I uploaded yesterday so bear with me.

http://www.themotherofallshows.com/Mini_35/adapter_on_camera.JPG
http://www.themotherofallshows.com/Mini_35/Adapter.jpg
http://www.themotherofallshows.com/Mini_35/50x50mm_condenser.jpg
http://www.themotherofallshows.com/Mini_35/Nikon_Extension_Tube.jpg

<a href="http://www.themotherofallshows.com/Mini_35/Nick_Conti_adlu35_tests.mp4">Adapter Test Footage</a>

[Nick Conti]

Hey Damion,

That's pretty funny that you brought up the extension tube just as I was putting up some pics on the one I used as well, although our ideas may be a little different.

That link I have in my last post for the mp4 file needs to be a link so you can right click it and save it to your computers, but I guess my html was off so if you guys can get that file onto your computers you can see my test footage.

[Brett Erskine]

Nick Conti-
Are you saying you tried and had back focus problems when you switched to a different Nikon lens? Or are you saying you BELIEVE there MIGHT be a back focus problem when you try to switch to another Nikon lens? The reason why I ask is because you shouldnt have any problems with back focus between ANY Nikon lens with the same mount because they WILL have all the same back focal lengths. As far as your condenser screwing with that back focus distance ...well IF it does it does it too all nikon mount lenses by the same factor so readjustment of your adapter shouldnt be needed.

-Brett

[John Cabrera]

I just got my last set of parts for my Aldu35. I've been playing around with just the right combination of filter rings that I have for the parfect fit. I think, like James, I found the magic number. My focus marks seem to match up perfectly with what I'm shooting. The only thing I'm wondering about, is what seems like an excessive amount of zooming going on when I focus. Does any one know why this might be happening? I guess excessive is an overstatement... the image moves in or out slightly... but it is noticable enough to look strange when doing a rack.

John

[Brett Erskine]

I'll take this one guys.

This is called "breathing". It happens on some 35mm still lenses but not all. Techically speaking what your seeing is the effect of the elements inside of your lens as they shift forward and backwards as you find focus. This makes it look like your lens is zooming in and out a bit.

How do you get rid of it? You dont. That particular lens will always have that characteristic. But like I said before not all 35mm sill lenses do that and ALL 35mm CINE lenses are designed to never have that problem. So if it really bothers you then its time to buy or rent another lens.

If Im not mistaken (and somebody correct me on this if Im wrong) lenses with "internal focus" dont have this problem.

What are internal focus lenses? They are lenses that both dont physically get slightly longer or shorter as you search for focus AND the front element of glass doesnt rotate at all when your focusing. They are generally more expensive lenses.

That will be 5 dollars.

-Brett Erskine
Freelance Cine/Videographer
www.CinematographerReels.com

[John Cabrera]

You're a good man.

Well, this lens must be cheap as hell cause it breathes like it has emphysema.

Otherwise though, everything is working like a charm. No distortion. No Vignetting at all. I'm just barely able to zoom in to 36mm horz... I'm a happy guy. Now to find a good lens.

John

[Brett Erskine]

BTW nice idea with using a extension tube instead of taking the mount from a old SLR camera. Im curious how you ended up getting it to mount to through filter rings. Please show and or explain it to us all in detail. Thanks

-Brett Erskine

[Nick Conti]

<<<-- Originally posted by Brett Erskine :
Are you saying you tried and had back focus problems when you switched to a different Nikon lens? Or are you saying you BELIEVE there MIGHT be a back focus problem when you try to switch to another Nikon lens? -->>>

Brett,

You're totally right about the back focal length issue. When I wasn't using my condenser I had no problem at all switching between my other Nikon lenses (50mm,105mm,200mm). But as soon as I put my condenser in and readjusted with the 50mm and threw on the 105, I would have to lengthen my adapter to compensate. I'm under the impression that the condenser had to match the back focal length of the lenses to be able to make one adjustment that corrects for all lens types. That distance for my Nikon lenses is 46.5mm but my condenser is 50mm, I think thats why I'm having this problem. Do you think theres anything I can do to correct for it? Century Optics told me they could cut one to my specifications but it was way too expensive.

Has anyone been able to look at that footage I tried to put up or is it messed up? I've been experiencing that breathing effect also. I guess all my Nikon lenses are like that so I'll have to look for better ones as well.

I haven't mounted my extension tube to my adapter yet, for my tests I was holding it on. Damion, I'd also like to hear or see how you connected yours to your adapter.