DIY lens adapter for 35mm and rb645 lenses compared

Ted Ramasola

Ted Ramasola

Veteran
Just want to share my results after making a 35mm lens adapter.
I first made the mid format adapter for rb645 lenses, and after using it in some corporate videos and a TVC i decided to fabricate one for 35mm lens.

For the pros and cons.

The mid format adapter cast a bigger gg image at 42mm x 24mm, this is much easier to capture and theoritically a less grainier image.

But other than this i began to encounter its limitations.

The adapter is bigger, due to bigger gg at deeper flange distance.

Limited availability of a variety of lenses not to mention more expensive than 35mm lenses.

I found another source of gg other than a frosted cd and began fabricating a 35mm lens adapter using an extension tube as a mount.

Since the image i am capturing is 29.6mm x 16.6mm on the GG i can use a smaller diameter gg and smaller housing. (see attached pic of size comparison).

The 35mm set up is less forgiving in alignment tolerances. Its really more difficult in getting everything centered and aligned as compared to the mid format.

In the end, the efforts are well worth it.

It aint perfect yet but i found it usable.

I also made a DIY rod system to support the rig and allow it to be used on different cameras, currently using it with hd100.


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Car3o

Yes i had them machined. I made the design in a 3d CAD for the machineshop to accurately do the blocks and camera mount plate.
I found those stainless steel rods at a homefurnishing store.
I cut small steel "strips" and spot welded them to the head of bolts for block tightener.

The camera mount has 4 elongated holes where bolts go through to attach them to the blocks and allow play to adjust for centering left and right.
The washers act as shims for vertical adjustment.

I attached a pic of the a 3d render and the assembled parts. I hope that helps.

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Would you happen to have the cost of it machined? and would you be generous to send me the cad file? i have a plastic shop up the road that can maybe do it as well.
 
Very nice job teddy bear!!



We're just about done with our large format adapter along with ten other things, working out the last bit of kinks.




"and would you be generous to send me the cad file?"



Not every controller program has the same G & M codes.




:)
 
twocik23

Thanks, which make of large format lens are you designing your adapter for?

Car3o,

I think it cost $67 more than a month ago but at the way the dollar nosedived and our currency appreciating due to OFW inflows its now $77.

The machine shop doesnt have computer control with their machines. I just gave them CAD print outs plus the isometric render to better aid their operators as to what the thing looks like when its done.

Also, regarding the specs, its quite proprietary because i don't intend to buy stuffs with industry dictated dimensions. So my rods arent 15mm but 13.5mm.

Its for a shower curtain.

The center to center distance though is 60mm with enough space in my blocks to expand the holes to 15mm in case the need arises to shift to industry sized rods.
 
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teddybear said:
Just want to share my results after making a 35mm lens adapter.
I first made the mid format adapter for rb645 lenses, and after using it in some corporate videos and a TVC i decided to fabricate one for 35mm lens.

For the pros and cons.

The mid format adapter cast a bigger gg image at 36mm x 24mm, this is much easier to capture and theoritically a less grainier image.

But other than this i began to encounter its limitations.

The adapter is bigger, due to bigger gg at deeper flange distance.

Limited availability of a variety of lenses not to mention more expensive than 35mm lenses.

I found another source of gg other than a frosted cd and began fabricating a 35mm lens adapter using an extension tube as a mount.

Since the image i am capturing is 32mm x 18mm on the GG i can use a smaller diameter gg and smaller housing. (see attached pic of size comparison).

The 35mm set up is less forgiving in alignment tolerances. Its really more difficult in getting everything centered and aligned as compared to the mid format.

In the end, the efforts are well worth it.

It aint perfect yet but i found it usable.

I also made a DIY rod system to support the rig and allow it to be used on different cameras, currently using it with hd100.


1197394959.jpg
Click to expand...

Ka-taka-taka!

Matalinong ka!

Maganda na Maganda.

Magkano?
 
Walang Anuman Ted.

Hindi, hindi ako sa Filipinas.

Taga San Francisco, California ako.

Maputing Kano ako. Aking asawa ay inpininganak sa Samar sa Visaya.

Taga-saan ka ba?


What kind of work do you guys do? What are you filming?

I like the look of the adapters you have done.

Do you have footage of them in action?
 
Hahaha!

Your tagalog is good for a Kano! As my location states I'm also from the visayas region. Our facilities is based on bohol island but our client base is on Cebu and Metro manila.
I handle our corporate division and do Corporate videos and TVC's. Our work involve a lot of CGI, greenscreen and location shooting.
Its a 45 year old studio, will be celebrating that next year.
Thats why i got a lot of old35mm and mid format lenses lyin around! LOL
I don't have a site to host a footage, just grabs.
 
Salamat Ted...

O.K. lang ang Tagalog ko.

Bahala na.

Paumahin sa huli sumagot.



I am sure that someone here could host your footage.

It would be worth asking so we could all see.
 
2 lens formats in one adapter

2 lens formats in one adapter

After finishing the 35 adapter i felt not using the brighter bigger mid format lenses is such a waste. I felt i had to utilize the large image of mid format while still allowing me the flexibility of diff 35mm lenses, without carrying 2 different adapters.

Then i came up to making a 645-to-35 mount for the mamiya 645 lenses.
Respecting proper 645 flange distance i can now attach the 645 lenses to the fixed nikon mount lens adapter.

The mount has a locking pin to prevent the lens from falling.

Though the 35 adapter cant produce the same image size as my dedicated 645 adapter, which gives a 42mm x 24mm image on the GG, the 35 adapter can still give a bigger image on the gg when using mid format lenses.

Im attaching photos below and a chart showing the difference in gg image size.

Ted

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Nikon 80-200 ED +adapter

Nikon 80-200 ED +adapter

I just acquired a nikon 80-200 ED and did some tests with the adapter.

This lens is heavy BUT its really bright and I think I'll be using this often than primes. I also think this will make me leave behind 3 lenses. my 85mm f 2, 105mm f2.8 and 200mm f3.5. the zoom will be very useful in quickly adjusting framing and composition especially in outdoor set ups.

Heres a pic of the lens on the adapter i posted at the other cameras/JVC forums. its a monster at 31 inches long.

http://www.dvxuser6.com/uploaded/6699/1201612645.jpg


Here are some grabs from some test shots today.

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short shot with diy adapter

short shot with diy adapter

This piece was suppose to be an audition reel. We got a bit carried away.. -we did the shoot in around 2 hours.
Lighting was just two sources. Both DIY too. A spiral flou array and a MH lamp to illuminate the outside of the balusters.

Shot with DIY 35mm adapter with nikon mount.
Lenses used; 50mm, 80-200mm.

The script is an adaptation from an Edgar Allan Poe short done by a friend of mine in L.A.


Here's a link to the clip. its very short, just 3 min.
http://exposureroom.com/members/teddybear.aspx/assets/fd2b5ba9619944f4a803656a272e09e7/

Heres a frame using the 80-200 lens;

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