10 minute made "70mm" adapter

[Postmaster]

Having a free afternoon I played arround with a Zeiss 6x6 lens and some plumbing equipment.

The GG is an focusing screen of an 1950s Exacta.

Plumbing tube and rubber grommets of the plumbing supply shelf keep everything in place.

In the back sits an Achromat (10 dioptr.)

No glue or other modifications, everything bolts right in.

Took me about 10 minutes including quick and dirty backfocusing.

I just clamped it betwen the HVX and the mattebox.

Have to find a way to make a solid support.

Frank

 

[Postmaster]

Here are some screengrabs.

First is a reference shot with the blank HVX.

Light was changing verry quick - thats the reason for the different look.
On number 3 and 4 I was throwing an 800 watt fresnel in - less noise.

No filtering - only resize to widescreen.

The grain is pretty visible but not as bad as I thougt for an static adapter.
You also can see dirt, spots and speckles on the GG. -
Got to clean that up and find a way to vibrate the GG.
It also looses about a stop and a half (on that vinatge 80mm 2.8 lens)

Not bad for a 10 Minute made static adapter for allmost nothing huh?

Frank

 

[Jason Adams]

Wow, I can't make coffee in 10 minutes and some people make static adapters. Very cool.

 

[puredrifting]

Frank:

Admit it, you took lesson from MacGyver, right? Very impressive for so little time put into it.

Best,

Dan

 

[USLatin]

dude... I wanna see clean ones!

mad props to ya, hehehe

keep tinkering and paint that 'thang black!

 

[Postmaster]

Yeah Dan, I confess it.

comming out mode on:

I was a big McGuiver fan back then.

comming out mode off:



Nah, I just wanted to see what difference 6x6 lenses make compared to the 35mm glas we usualy take for adapters.

Got to play arround some more to see if it is worth to go into that.

....and yeah, paint it black of course.

Frank

 

[Luis Caffesse]

Looks like something out of the 1930's
Just kidding.


Nice work - I'm with jason on this, I can't even make coffee in 10 minutes.
Hell, it took me almost 10 minutes to reply in this thread.

The ingenuity of the users on the forum constantly impresses me.

 

[Over Crank]

Having a free afternoon I played arround with a Zeiss 6x6 lens and some plumbing equipment.

The GG is an focusing screen of an 1950s Exacta.

Plumbing tube and rubber grommets of the plumbing supply shelf keep everything in place.

In the back sits an Achromat (10 dioptr.)

No glue or other modifications, everything bolts right in.

Took me about 10 minutes including quick and dirty backfocusing.

I just clamped it betwen the HVX and the mattebox.

Have to find a way to make a solid support.

Frank

My KOWA SIX is volunteering to be chopped up for a similar experiment. After telling him about the new life in Video Nirvana off course.
Could you share the shopping list for the plumbing goods ?
If you wanted to do it again , what would you do different ?

 

[Jing]

the responses are so funny xDD

nice job

 

[Dennis Wood]

The great thing about this design is that if you're at a gig and they suffer a major plumbing failure....

Seriously though, the first "Brevis" still runs (on our wall of shame) and is made essentially from two pieces of ABS plumbing pipe. Plumbing pipe is to DIYers what duct tape and WD40 is to the rest of the world

 

[davide]

Nah, I just wanted to see what difference 6x6 lenses make compared to the 35mm glas we usualy take for adapters.

Got to play arround some more to see if it is worth to go into that.

....and yeah, paint it black of course.

Frank

I used the medium-format adapter made by Winston Vargas once. It was amazing how much more light medium formats pick up at a given fstop than 35mm lenses, so I'm thinking that that would be a major plus. With an imaging circle that much bigger than the part of the ground glass you're recording one would think that vignetting would be less of a problem too.

The only problem I could think of is that I hear that medium and large format lenses are usually less sharp overall than 35mm lenses. Medium format systems can capture very high resolution images with less grain due to the size of the lenses and the imaging sensor. But if you take the same size are on both a medium format and a 35mm lens, I hear that you are usually going to get the sharper image from the 35mm. I wonder if this would be a problem on something like a 35mm adapter on an HVX, or if it'd only show up on a 10mp still camera.

davide

 

[dadoboy]

I was thinking of adapting a Mamiya RB67 with a 6x7 polaroid back (now rendered pretty useless by Polaroid bankruptcy) - by basically replacing the film plane on the polaroid back with an etched ground glass. And using mirror lock up. A "cheap" static adapter and a terrible use for a Mamiya. But it won't take me 10 minutes, it will probably take me 10 months as I have no machining tools and I'm just slow and inept at do it yourself things. Just a project, not for real movie making.

Yes you're right davide, 35mm lenses are sharper per mm, but the ground glass-image circle on medium format SHOULD be much larger, so the effective resolution is the same or better plus or minus depending on the specific qualities of the lens.

I think medium format lenses, being longer focal lengths for equivalent FOV to 35mm, can afford even shallower Depth of Field. I've never seen a movie shot with MF lenses, but I've seen Anamorphic lenses used on 35mm movies of course (3:10 to Yuma for example, Memoris of a Geisha, etc) which tend to be longer and a have a very very special, often magical, look.

Of course pulling focus on anamorphic (as would Medium Format) is a real challenge for even the most experienced.

 

[Ryan Patrick O'Hara]

I used the medium-format adapter made by Winston Vargas once. It was amazing how much more light medium formats pick up at a given fstop than 35mm lenses, so I'm thinking that that would be a major plus.
davide

Unless I am hugely mistaken, if two lenses are set at the same F-stop, despite the format, they are accepting the exact (as exact as f-stops come versus t-stops) SAME amount of light. The formula and f-stop number is referring to the amount of light allowed to pass through, not reliant on format.

yes?

 

[dadoboy]

Yes, you're right Ryan. The optical formula applies to all the lenses regardless of format.
What the difference in format brings about applies to circles of confusion, but that is a focus issue, not amount of light per sq mm.

I guess what the original post referred to was a difference in PERCEPTUAL light since the ground glass was so much bigger?? Ground glasses do strange things to bokeh, light transmission, etc. so I wouldn't know without firsthand experience but I am curious too.

Having a quality medium format adapter would be an amazing tool to help distinguish the look of a piece. There is none out there I think.

 

[Ryan Patrick O'Hara]

I've seen Anamorphic lenses used on 35mm movies of course (3:10 to Yuma for example, Memoris of a Geisha, etc) which tend to be longer and a have a very very special, often magical, look.

Of course pulling focus on anamorphic (as would Medium Format) is a real challenge for even the most experienced.

What makes anamorphic extra difficult to pull focus for is because, if the anamorphic lens is opened to a wide aperture, the plane of focus on anamorphic lenses is slightly bent and it will start to show! :huh: Gotta stop those suckers down to get the depth of field to hide the imperfection.

 

[davide]

Yes, you're right Ryan. The optical formula applies to all the lenses regardless of format.
What the difference in format brings about applies to circles of confusion, but that is a focus issue, not amount of light per sq mm.

I guess what the original post referred to was a difference in PERCEPTUAL light since the ground glass was so much bigger?? Ground glasses do strange things to bokeh, light transmission, etc. so I wouldn't know without firsthand experience but I am curious too.

Maybe that was the case but i thought that Vargas' used a 35mm sized gg. Maybe he could comment on this thread to clarify.

 

[Postmaster]

I could not get the optic quality out of that experiment I need for my projects because of GG and lousy Achromat. But it was only for fun anyway.

But I religiously use the Zeiss medium format lenses on my LEX and love the results.
My Timefest entry was shot with that setup. And I like what I got out of it.
Not as sharp as the 35mm Nikon 50/1.2 I got but pretty filmic in my book.

Have a look:

http://exposureroom.com/members/FrankGlen.aspx/assets/878cd65038c5431c9fb60e6b6858efc5/

Frank

 

[Chris Light]

that was a VERY cool film Frank...i didn't even notice the use of adapter (...i thought i was watching an extended big-budget trailer the whole time)...awesome.

 

[Postmaster]

Actualy it was a ZERO budget production.

Thanks,

Frank

 

[bwwd]

Wow this was very very nice , i dont know is it because of the zeiss lens ? What kind of lens it is exactly ? Could you give some website with more info with it?