Homemade 35mm Adapter

[Bob Hart]

Looks like the clip has been taken down again for furthur polishing. I think there has been a couple of colour grades done on it since it first went up.

The Youtube user name for search is "johngeopix" It will be on the bottom of the list of clips. Have a look at the Wise Family with Andy Irvine music clip if you like old country music. It is not groundglass work but worth a listen regardless.

[Bob Hart]

The clip is back up again at the same address

http://www.youtube.com/watch?v=2eOPz08uLcI

Sorry for the confusions.

[Bob Hart]

At this address is a short behind the scenes of a short movie, "TEARS IN THE RAIN", in production with the JVC GY HD100/Mini35, Skater Dolly, filmed on Sony HVR Z1P with Agus35.

http://www.youtube.com/watch?v=XXBjmXkwec8

[Bob Hart]

I just spent the better part of today filming some stocks of the Red Bull Air Race - can't publish as IMG Entertainment will shut the clip down. They have a lot invested in bringing this event to the world so it is understandable if a little frustrating.

Instead of removing the GG I left it in place, too lazy to set up the backfocus and everything again. I mainly wanted the support events for local pilots involved. This version of the device is the 4+ achromatic dioptre long setback setup.

I also kept the GG in because with the 4+ there would have been a distinct vignette in aerial image.

Here's the conundrum. The groundglass images despite the f6.3 narrow end of the Sigma 50mm-500mm look better and sharper than aerial image. Because verything bent and warped through trying to follow very agile aircraft, I picked up the bottom corner of the disk when things shifted.

If the Red Bull Air Race comes your way next year, take a look.

[Bob Hart]

Agus.


If you are still out there somewhere, could you email me through dvinvo.

Do you have access to webcam for speaking to a forum about your first groundglass machine and how you made it? Would you want to talk about this?


Regards.

Bob Hart.

[Bob Hart]

For those with an interest, here is a link to a clip shot on the Agus35 with a Sigma f4-f63 50mm-500mm zoom lens of a recent aerobatic display. An aperture of f6.3 is in the red zone for most groundglass imaging.

http://www.youtube.com/watch?v=4gnLzWVxdnI

There are a few things wrong with the image, firstly the prism block got dusted and there are some marks in the image, secondly, the rods and bridgeplate arrangement I have fell in the vehicle and disrupted the Agus35 so the bottom left corner of the groundglass is also in the image as well as the edge falloff from the prism path on the left.

Although the edge of the disk, complete with fingerprints is in the frame and the disk running only at about 1500 rpm, there is very little flicker, which is one saving grace of large diameter disk adaptors which will tolerate higher shutter speeds.

Once IMG Entertainment get wind of this, they will probably block the clip so it may not be up for long.

[Bob Hart]

Here is a link to a later clip of behind the scenes of "Tears In The Rain", a short feature which has just wrapped.

http://www.youtube.com/watch?v=1KZayueFxcQ

The footage is of the second last day of the shoot, some well rehearsed enactment of gratuitous violence.

The production camera is a JVC GY-100 wearing a P+S Technik Mini35-400.

The behind-the-scenes footage was shot with a Sony HVRZ1P, some with AGUS35 with Nikon 35mm, some direct-to-camera.

[Sunny Singh]

I hope this is the proper place for me to post this question. I've recently started to learn more about enhancing the quality of my video and I decided to purchase this lens for my GL2:

http://www.schneideroptics.com/Ecomm...D=1462&IID=855

which will allow me to natively film in 16:9. I've been wanting to build a 35mm/DOF adapter and my question is as follows:

Is it possible to build such an adapter and use this lens at the same time? More importantly, does it even make sense to use this lens in conjunction with a 35 mm adapter?

I ultimately want to be able to both use the features of a DOF adapter AND film natively in 16:9. I guess I'm not experienced enough in this area to know if such a concoction is viable or logical.

[Bob Hart]

Diverting the subject probably is not good form but if it is limited to one question and one reply it should not hurt.

The wranglers will intervene if it becomes a problem. If you want to get into a more lengthy discourse of several posts then maybe it should be raised as a new topic.

Short answer to your question, the 16:9 adaptor will work with some caveats. I have tested with a PD150 and home made AGUS35 adaptor. The PD150 is optically very similar to the GL2. I think the same offset between CCD centre and optical centre exists.

The adaptor has to go on front of the still-camera lens which is attached to the 35mm adaptor.

The SLR must be one on which the front of the lens barrel does not rotate when being focussed because the 16:9 adaptor will turn with it.

A custom adaptor mount has to be made for each prime lens whcih has a different size filter thread diameter.

There were two styles to the 16:9 adaptor, one with custom PD150 bayonet mount, another with 58mm filter thread mount. Threaded mount is easier with only simple step-up rings required, however these must be parallel face type otherwise the 16:9 is set too far forward of the lens it fits to and the optical performance will go off.

The image area off the groundglass has to be about 22mm to 24mm wide, no larger.

It will work for the basic set of primes, 28mm, 50mm and 85mm with a little bit of vignette on the 28mm. These represent the zoom range for which the 16:9 adaptor was designed except for the wide end.

The sharpness starts to go off with the 85mm and the 135mm whilst it will work is unacceptably soft. There is a softer return on ther other lenses which you should expect when adding more glass and stretching the image.

There is an artifact introduced to out-of-focus areas as you also observe with film anamorphic, soft foreground is stretched one way, soft background is stretched in another.

Have a look at this image :-

http://www.dvinfo.net/media/hart/agu...20filmlook.JPG

which is two grabs which were colour corrected by the process published here at dvinfo. - also

http://www.dvinfo.net/media/hart/aguscne1.JPG

done with a Proskar anamorphic projection lens for 16mm film - vignettes on wider than 50mm.

www.dvinfo.net/media/hart

is an undisciplined and random collection of images which go right back to my own first simple experiments with sanded microscope slides, pringles cans and rolled up socks jammed in the ends to hold the lenses and the camera together.

I abandoned this approach as it denied me too many lens choices.

If you still want to go this route there are two more files for you to look at :-

www.dvinfo.net/media/hart/agus3516.pdf

and

www.dvinfo.net/media/hart/agus3516b.pdf.

Both illustrate a way of building the PD150 adaptor for the Century Optics 16:9 for the Micro-Nikkor lens.

[Bob Hart]

Time to slide this historical icon of a thread back to the top of the heap and also to advise those who might vaguely recall, I shot some shadow footage of a feature project, The Eleventh Soldier and posted a clip on Brightcove in about January last year.

The trailer for The Eleventh Soldier has been updated and can be found at this address :-

http://www.cinemascorestudios.com/th...ldier/home.htm

The shadow footage can be seen at this address :-

http://www.brightcove.com/title.jsp?title=572028460

or at Youtube :-

http://www.youtube.com/watch?v=T-Kfupy53s0

[Bob Hart]

The home-made AGUS35 I built some time back, finally got its first serious gig on Wednesday on a local shoot of a small feature. It was third camera for an action scene.

It also showed its true contrary form and a hasty jerry-rig of gaffer tape, a thick pine stick harvested from the forest floor and part of the tripod mount was needed to deal with slump in the case which was causing a top edge of the prism path to vignette.

Maybe now I'll pull my finger out and rebuild the case as one piece instead of all the cuts and joins it now has due to trimming and rebuilding over time and experimentation

The main cam is a JVC GY-HD100/P+S Technik Mini35 combination. There was a second HD100 as back-up shooting direct-to-camera. There was also a pyro-guy who set things in the ground to explode and throw up debris.

An enjoyable day for all.

A Kinoptik 9.8mm f1.8 also got its first use here on the Mini35 for the same project. The lens is actually a rebarrelled and geared version by Century Optics, already fitted with a PL Mount.

As was the caution by a competent DoP here, this lens does have corner brightness falloff and requires careful lighting to light evenly. With that attended to, it works well in a confined space like a small office.

[Bob Hart]

For those with an interest in things both groundglass and aviation, this address leads to a rough and ready assembly of some footage shot this weekend at Serpentine in Western Australia.

http://www.youtube.com/watch?v=6-FrlHKsurs

The very first aircraft and last two aircraft were shot using the Mini35. All other footage was via the Agus35. The lens was a Sigma 50mm- 500mm f4 - f6.3 zoom with an optical doubler. Due to the possibility of clash of internal optics, the Sigma lens becomes locked into 200mm - 1000mm range when the doubler is fitted.

The available aperture range becomes tightened to the ballpark of f5.6 -f8, which is hostile territory for groundglass work against light bright overcast which prevailed on the day.

Artifacts were observable with both groundglass systems however did not impact adversely on the images. The Mini35 is observably sharper than my own device.

Except for the ability to reach furthur than the lens-in-camera Sony Z1 camera type used, there is limited amenity in using such a long lens except perhaps to beat the tub and say it can be done. Following a dynamic subject with 1000mm offers some challenges.

[Agus Casse]

Its amazing, how come over the past 5 years, this proyect have grow up that much, i recently read an article ina magazine and found out that there are many companies now making new adapters from what at the beginning just a proyect.

Thanks Bob, to still keep this thread growing, i would love to come back to the project again, with a new model, lets see whats happens this year.

[Bob Hart]

Agus.


Long time no see. Welcome back. Having you walk this thread is a bit like Francis Ford Coppola posting on Zoetrope's "The Virtual Studio" website.

My guess is that the days of groundglass image relay as a professional level production tool are probably numbered.

It's been an interesting ride. I'll bet you never imagined just how far people would pick up and go with what you started off.

The new Nikon and Canon digital stills cameras have become video capable. They have much room to improve but it will come. The RED and Kinor 4K fullframe sensor motion video cameras and others which come along wait for more capable computers and storage able to handle 4K images so for low-budget film makers, there is time for the groundglass relay adaptor yet.

[Bob Hart]

You may have recalled my previous posts on a local indie, then worktitled "The Cage", created on the JVC-GY-HD100 camera system.

The DVD version has found a home on Netflix as "Death Bet".

The feature was shot direct-to-camera. Some of the "behind-the-scenes" footage was shot
on a Sony HVR-Z1P with an early version home-made AGUS35 35mm adaptor.

How much of the adaptor footage was used in the featurette if any I don't know.

The revised trailer can be seen on YouTube at this web address :-

YouTube - Death Bet