I'll be sending out an email to everyone on the list in the next couple days.

Thanks!

<<<-- Originally posted by Jose di Cani : where is the link with the tutorials? I am lost in this million-dollar thread. I need shalower DOF now!

thanks

god bless the makers of selfmade adapters. I love you guys/girls..whatever. -->>>

ok heres all of the addresses i have saved so far for reference.

http://ideaspora.net/oldskool/

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

http://www.mediachance.com/dvdlab/dof/index.htm

http://www.gamecrafters.com/sillydaddy/Agus35_MarkIII.html

http://www.moorefilms.com/aldu35.htm

http://www.blindcat.de/index.php?page=dv35genglish&title=DV35g%20-%20A%2035m

http://www.de-interlaced.net/mini35/

http://www.dvinfo.net/conf/showthread.php?s=&threadid=30086

anybody know of local places you can buy fresnel lenses in dfw? or stores in general? like what aisle would they be on??

Cody, what kind of camera do you have?

well im looking for one for my mini35 since they are supposed to be cheap... im just looking for a cheap alternative to get rid of the "halo" bright spot on the GG.

You have a mini35? You don't have a camera? I can help you with the halo...

sorry, im using a panasonic pv-gs50... little consumer camera with 27mm thread size stepped up to 52mm

Cool.

my mini35 setup currently consists of, project box design with rotating GG. miranda mount for lenses. about 8 miranda lenses to choose from. plus a telephoto lens.

i was having a heck of a time getting the cd closer to the lens so the focus would be correct at infinity. i had my cd motor still mounted to the plastic thing that came out of the cd player...i found out my motor was already sandwiched against the wood i had it mounted to. cut a hole out and its just perfect.

i will post some pictures up when its totally finished. i still have to work on the GG, way to grainy. i have barely even tried though... that was a quick job to see if it works.

After the debacle of my Agus which fell and broke the glass disk and prisms,
I needed a gg fairly quickly and decided to try a DVD+D disk. I have plenty
of failed burns so there's plently of disks. I found you can split them.

Once you get the edge joint started, they come apart fairly easily. One face has traces of the burn or guide tracks on it. This is the face you dress. The
plastic seems to be a better material and is quite tough and takes longer
than the glass to dress in a tumbler. It seems to yield a finer finish for
the same grade of grit than glass but the same problems of variable density
flicker found with the CD-R spacers is still there in certain lighting
conditions. In operation the split DVD+R seems to be thinner and lighter,
spins up and shuts down faster and despite being thin, does not seem to move off the focal plane in pans and tilts as one might expect it would.

When mounting the disk to the hub, do not use contact cement. As this stuff
dries, it shrinks and whilst the disk sits flat when the glue is fresh,
after a while it will tilt one way or another and no longer run true. The
best glue remains the water cleanup white silicone bathroom sealer.

The new images at www.dvinfo.net/media/hart are tests from this disk whilst
it was not spinning, plus the very last image off the glass oharadisk. The
filesnames are "cdstrer2.JPG" "cdstrer3.JPG" and "0038b.JPG"

The optical path remains the same as for the oharadisk in the prism version - SLR lens >> groundglass disk >> 2 x 40mm x 40mm x 56mm x 40mm common thickness rightangle prisms in 90 degree opposition >> 7+ Century Optics Achromatic diopter >> camcorder.

Just a bit of an update on things AGUS. Recently I have been involved in a bit of aviation videography. I have been using the erecting prism version to enable attachment of my Nikon mount long lenses including 500mm and 1084mm mirrors. This was one of the objectives of building my AGUS35.

These are things the PD150 was never intended to see through, however provided your lenses are centred with the cam via the prisms you can get a good result.

I spent a few hours at the local airport today getting the method right.

A heavy fluid-head tripod like a Miller is essential once you start trying to aquire and pan in full frame, aircraft in flight or closer on the cabin windows or moving control surfaces.

A simple ringsight is also needed for aquisition, the right eye in the cam viewfinder, the left eye looking at the image au-natural, keeping your head level, getting the subject centred then it pops into the cam viewfinder and you track it from there.

My thinking on the AGUS is to perhaps use the smaller diameter disk in the larger housing and arrange the motor and disk in a swing-down arrangement so I can have 35mm emulation when I want it or shoot the aerial image when I want the telephotos, all in the one piece of sewer pipe.

Do you have any stills?

Shawn.

I haven't taken any captures of my test footage but stills can be arranged in about 24 hours. There is a .jpg of a comparable image shot through the 500mm Nikon, the very last before the AGUS fell to earth and broke my glass disk. IT was through the groundglass. The direct aerial images improve a little in sharpness and much more in contrast because the 500mm mirror is a f8 only lens and the MTO 1084mm is a f11 only lens. These apertures are tighter than the no more than f5.6 recommended in the Mini35 operating instructions for minimising the effect of grain effects from the groundglass (my recollection of them??)

That image is titled "0038b.JPG" and there are some images from recollection titled "agusmto.JPG" or similar which were shot through the MTO also with the groundglass. Those images are softer because it was a warm day.

As well as my particular need right now of ability to get to aircraft performing at safe height, long lenses are a seriously practical option for sports videography, which can be a difficulty with the PD150 zoom cutting out at about 70mm. You can use zooms but there is no reliable means of establishing a notional backfocus for the zoom lens when using the aerial image, so the focus will creep when zooming and you have to chase the focus with the front lens.

However, the beauty is that once you have framed and focussed and are following the action, you can use the camcorder's own focus for fine adjustment on the run. Aufocus on the PD150 also works in this mode with one small caveat. The achromat (close-up, macro or relay lens) and the rear glass element in your front lens can have no speck of dust on them. Best practice is to manually focus the camcorder to sharpness with the front lens set to infinity focus, then work your front lens to focus on the subject, then use the camcorder focus for fine adjustment on the fly with occasional switching to auto but switching mostly to manual to stop any drift to extreme close up of the rear glass of the front lens.

You will find those .jpg images at www.dvinfo.net/media/hart

Shawn.

I have emailed some images to Chris Hurd for his assistance in posting at www.dvinfo.net/media/hart

The images will have filenames something like "aerdem03.JPG" or similar.

The MTO 1084mm images are not as sharp as the 500mm but this is as much to do with heat shimmer, trying to pan and pull focus at the same time and a more critical depth of field as of any optical deficiency.

I am investigating the Sigma 50 - 500mm f4-6.3 zoom lens plus 1.4x converter as an option with this setup. Other than the reviews found on the web, does anyone here have experience with that lens.

Well, after weeks of drooling and lurking on this forum, I finally had some time to put one of these DOF boxes together. It's all come around pretty easily, but now I'm of course dealing with the optics and ground glass issues... you can view my first attempt today at the link below:

DOF Test 1 (http://f1.pg.briefcase.yahoo.com/bc/tif383335/lst?.dir=/DOF+Tests)

It's not completely untouched (Ran it through avisynth), but it's dark qualities is pretty much what I was seeing before treating it. I have a frosted CD, which I initially used, but it doesn't seem to work right. I get a very pleasent/unpleasent bright circle in the middle, and it's really small (the size of the 35mm lens opening), while the outside is VERY dark... I'm guessing my frosted CD is too transparent.

So I've been experimenting with a half CD disc (a dvd split in half), that I've sanded down on one side with fine sand paper, and then smoothed with comet. So far with my limited resources (No car), this yeilds the best results, but as seen in the video is also unacceptably very dark.

I tried using a fresnel like the one here (http://www.par-t-com.net/mini50_fresnel.JPG) that I bought from OfficeMax today, but it didn't seem to do anything. I should be receiving a PCX lens soon from Anchor Optics (http://www.anchoroptics.com/catalog/product.cfm?id=16) that I'm hoping will help.

As per Jonathon, I'll probably also be buying some single-ply architectural blueprint mylar film for the ground glass... I'm hoping it will help.

Once I get this thing the way I like (I'm on my first prototype), I'll post some pictures of it... My current lens is a no-name f1.9 49mm. I'm hoping the Canon AE-1 50mm 1.4 lens I purchased on eBay this weekend will help.

Thanks for all the great discussion and suggestions (in particular Jonathon Wilson), hopefully some student films will be made with this stuff in the near future.

Heh - funny how these things go. I'm just starting in on my third adapter :) Best of luck, Matthew! The footage looks pretty good, especially for the first stuff! I'll bet you see a big difference with the Canon lens. I have that same 1.4 50mm and it just seems to do much better in terms of hotspot than other lenses I've tried.

Hey Jonathon, thanks for the encouragement... I've posted my second test just about 10 minutes ago using similar shots.

I received my macro lenses and bought some drafting film today. Both seem to help quite a bit, but it's still a little dark, and I've also noticed some barrel distortion in the leaves when they go out of focus. Will the condenser help with this? Currently I'm only running through the macro, so it's pretty much exactly what's seen on the disc.

Check it out:
DOF Test 2 (http://f1.pg.briefcase.yahoo.com/bc/tif383335/lst?.dir=/DOF+Tests)

P.S. For those of you with Macs (Like me), you'll have to wait for the 2mb file to load completely before it plays

Just got my PCX lens today and it seems to be working perfectly. There might be some barrel distortion here and there (or it could be my imagination), but overal, the light quality and and vignetting is improved dramatically... I don't even need to use macro lenses now.

You guys can go to the same link again for the added videos. I did one on campus before I was able to install the condenser lens, and then did one more video after I got home... it follows the same shots as the previous two... enjoy

DOF Test videos (http://f1.pg.briefcase.yahoo.com/bc/tif383335/lst?.dir=/DOF+Tests)

Looks good Matthew,
What camera did you use?

Thanks... on the first 2 DOF tests, I used a Panasonic GS120. Because I really wanted to be able to do widescreen, I upgraded to the GS150, which is the camera I used for the campus video, and the DOF test 3.

So far I'm really happy with the GS150. Both it and the GS120 seem to be excellent cameras, and for the price they're absolute steals!

In the next week I'm going to plan out a shooting session with a friend and use her as a guinea pig to really work this thing out (I'll post the results)... I want to get some practice with it before I do my first short. (^^)

Keep it up, you are doing good.

Mathew, I also had to deal with the barrel distortion that I found using different glass in front of the camera, most probably the PCX lens because it is concave. I found this especially annoying with poles and straight objects because they bend and make the image look rather fish-eyed. I am thinking that there is another way to get rid of this - maybe the photo-enlarger condenser lens?

BTW, good job, but I don't know what codec you used for the video and when I viewed it is was pixelated for the most part.

Thanks for the encouragement. You said you also had this problem with the barrel distortion... did you find a lens that fixed it? My PCX lens I think is too concave, and even though the distortion is minimal, it's very noticeable.

I'm not sure about the pixilation issue, but I think I'm going to switch codecs and start using the Sorenson codec for my later videos.

I have to switch to an achromat (ala Bob Hart's advice). I found a great one in a 100mm slide projector - broke it open and took it and it is nice - no barrel distortion at all.
I found a codec to walk the videos, they look great! The PCX is concave and that is why you are getting the barrel distortion - you need to find something else - try

www. surplusshed.com for achromats.

A PCX lens is not concave. It is flat on one side and curves out on the other. http://www.anchoroptics.com/images/products/a_L_pcx_a1.jpg.

A PCV (Plano-Concave) lens is the opposite -- flat on one side and curves in on the other. http://www.anchoroptics.com/images/products/a_L_pcv_a.jpg

Any concave lens will have the opposite effect that you want. You definitely want a lens with an outward curve for the proper correction.

If the focal length of the PCX lens is too short (bigger curve) it can certainly cause spherical distortion, at the expense of less correction to hotspot/corner darkening. The balance is difficult to find.

What was the F.L. and Diameter of the PCX lens you have, Matthew?

An achromat (a lens formed from two different types of glass, cemented together) will only solve chromatic abberation -- that's what they're designed for. The spherical distortion is only a factor of the focal length of the lens. (Which isn't saying you don't have chromatic distortion that an achromatic condensor would help. But generally, the condensor isn't that picky about achromats -- it's the macro, if you need one, where this is important).

Hey guys... ya, I'm definately using the lens that curves out on one side. It's DIA is 60mm, and FL is 83mm.

I've just posted my most recent video using it: Telegraph (http://f1.pg.briefcase.yahoo.com/bc/tif383335/lst?.dir=/DOF+Tests)

It's hard to really see the distortion at low res, and I've also noticed there's still a little bit of vignetting, but it may have been my fault (not completely centered maybe). One possible issue I also discovered with the lens today is that it has some of the same cons of a static GG. If there is ANY dust on it whatsoever, it shows up... my lens also has a couple tiny bubles in it :'( , which show up in some of my shots sometimes. I'm going to attempt to get it replaced, but in the meantime, tell me what you guys think...

The two shots where the distortion seem to show most is just after the first cut in the out of focus tie die shirt past the tea pots, and the last shot before the fade out. Do you think I need to get a more curved, or less curved lens? Is the distortion different with different 35mm lenses (As in different brands, and also focal legnths)? Also, since the distortion is comming from the lens, and being projected onto the CD, can a correction after the projection even take place? I don't really undertsnad optics that well, but my first assumption was that the PCX would go between the CD and Lens, until I saw all the posts talking about it going between the GG and camera (which after more reading does make sense now)

Just FYI... my current setup looks like this:
Lens - GG - (| Condenser - +5 Macro - Camcroder

Thanks...

P.S. You may notice flickering in the video... the batteries for my CD motor were going dead :P

Ok... it may be a little early to celebrate, but I think I fixed my distortion issues. I just received my Canon FD 50mm lens yesterday, and while messing around with my setup came across Mandy's thread about a homemade achromat lens. I played around with my macros, trying to see if I could get better results, and then starting playing around with my PCX lens... I turned it around so the curved portion faces the ground glass, and even though it looked REALLY distorted to my eyes, when I placed my camcorder in front of it, everything looked normal.

So far, I don't see any kind of distortion, so this may be what I've been needing to do from the beginning. Sorry Jonathon if I misunderstood your instructions.

Anyways, I've made another DOF test at this link (same as before) called DOF_Test_4.mov. (http://f1.pg.briefcase.yahoo.com/bc/tif383335/lst?.dir=/DOF+Tests)

I'm hoping this solves my distortion issues... I'm going to go out and shoot some more with it in the next couple days, and will make an update on how it looks...

Thanks everyone!

Mathew, the image is gorgeous. No vigneting (that I could tell) and as crisp as possible (for the frame size ;...spider web in 720/480....? That is as good as it gets). I think I will make myself one!!! (I was planning anyway, but this time I got inspired) hehehe. You still have to do another one for that right corner spot, but that's nothing! The pic is good. Get the footage in a retail store and watch it on a lage screen, let us know how it looked.What is the frame size?

Bravo!!!

Thanks Dan,

So far I'm pretty happy with it... for those of you who can view H.264, I've posted a full resolution clip of the video there (720x405).

Can anyone tell me how to use Brett's chart with a 50mm lens? His instructions say to fill the screen with the 24mm x 18mm printout, but even with macro lenses I can't seem to get close enough. Should I print it larger?

Thanks

P.S. it seems heavy traffic knocks the link to my files down every so often... sorry. Anyone got space/bandwidth to spare?

I do have space to share.
Drop me an e-mail at eric-ohmanATtelia.com and we continue from there...

AT = @

// eric

Matthew,

Do you have a picture of your setup? Congrats on getting so far so soon! I has taken me a good 6-7 months and I am nowhere near you as far as quality!

What are you using for a condenser and where did you purchase it? Are you still using the Macro lens - or did you get an achromat?

hi
first. english dont's my born language. excuseme
i'm making a 35mm-dv converter with static groundglass
i have a problem. on the GG apear a circle more lighting. do how can resolve it.
i think to use a old +4 filter used however condenser lens. it's ok?
* the cam lenses take focus on GG without close-up lenses. it's ok?
* the cam record the images inverted. do i rotate 180d after?
thank you

saludos

Yes Mathew! You have done an amazing job. I'm in the process of building a spinner, but yours takes the cake. Would you please let us know your design and what gg, condensor, etc. you used? I'm very impressed!

A bit of an update on the AGUS35 plumber's version.

After the Cunderdin Airshow debacle when the heat softened the glue and the appliance fell off the front of the camera like a melted candle, I finally got around to fitting another glass groundglass for two student single scene shoots.

I am also getting in some more prisms, this time with coatings on the reflective surfaces. In the meantime, I found I could just get the image through past the chips in the damaged prism if I positioned it the right way.

I had rejected this particular glass disk because it ran out and shook the camera too much and had forgotten it still existed.

This time, I took the time and trouble to remake the front lens mount cap and bring it closer to camera lens centreline and to set the backfocus sharp across the whole frame.

This is apparently very important for the wide angle lenses 28mm or similar. Whilst these have a greater depth of field than a zoom, it seems they are less tolerant of backfocus being off.

The results in bright daylight with the prime lenses are better. In poor light, there still is softness in the image. The glass gg does not flicker.

Despite being a f4 to f6.3 aperture, the Sigma 50 - 500mm zoom lens confers a satisfactory image via the groundglass in good lighting. The 2x doubler is a little softer. This lens must be supported otherwise it will pull the lens mount out of a plastic pipe cap.

Bob,
Thats great to hear you have a spinning glass adapter.

Could we possibly have some pictures? How was the disk created and centred?

I only read the first 50 pages of this thread so excuse me if this is a re post. I'm wondering about the setup they used for www.marlathemovie.com. It's a static ground glass setup. Well actually it's not even ground glass I believe it's a focusing screen of some kind for a slr. I assume you'd still get the 35mm dof with this setup. If you had a good enough screen grain probably wouldn't be a factor. No noise, no moving parts. alot smaller, and if built correctly you wouldn't have to mount the dv camera at a 90 degree angle to the slr body. If anyone is familiar with the adapter they used on that movie could you please explain why this adapter is undesirable. It seems to me that it should work perfectly, I must be missing something.

If you had a good enough screen grain probably wouldn't be a factor

That is usually the factor!

Most peope following this type of design have had luck from the 'Nikon D' screens or the more expensive 'Beatie Screens'

Bob has had a spinning glass unit for a couple of years now, if I am not mistaken - it isn't anything new for him.

Rob,
I experimented heavily early on with using the Nikon D static screen. This setup is undesireable because as soon as you start closing the iris of the lens (no matter how fast it is) the grain becomes alarmingly apparent. If you have a 1.2 of 1.4 lens you would certainly want to close the aperture somewhat at certain times because the DOF will be almost too shallow. If you have a static setup, however, closing the iris instantly creates serious grain problems. I'm sure that if you talked to the creator(s) of Marla they'd confirm that they never closed the iris. If you want aperture control, you need to go either wax or moving gg, bottom line.

Also, having your $2,000+ camera mounted vertically into a 35mm SLR camera on a spraypainted wooden board is simply unprofessional and awkward. Who would want to steadicam that thing?

Finally, I encourage you to look at the stills of the movie on the site www.marlathemovie.com. Even when the aperture seems to be wide open, the "translucent waviness" characteristic of a static adapter is always there in areas of shots that are out of focus. To many of us (including lazy old me) that's simply unacceptable. Also it looks like they didn't flip the image the right way (the name tags and letters in the stills are backwards?) Anyway, look at the media on that website and ask yourself if you could really live with the results of that adapter. I should add that they had to go through each individual frame of that movie and manually remove the grain from each shot.

Well, with all that, it still looks great and is a very entertaining movie. The artifacts kinda contributed to the look and style of the movie.

Wayne.

My version is old news. The original glass disk was broken last March. With a number of distracting things going on I did not get around to making another. I experimented with split DVD+R disks and these looked promising but actually take as long as glass to dress in the machine I made to do it.

Glass disks with holes in them can be ordered from Ohara in Japan. That's the good bit. The bad bit is you have to figure and polish them yourself, then after you have a clear disk, then apply the 5 micron finish to one surface.

The other bad bit is you have to order about 10 of them to make it worthwhile for Ohara to do the job. They are otherwise courteous and turn the order around in good time. The disks are thin 1.3mm slices off a 5" approx optical glass round. After dressing they come down to 0.9mm.

It's not a task for the faint-hearted. I broke 6 getting the process right and also attempting to make wax composite disks. I broke another one because I did not see it attached to the dressing platen which had been stored away. Then the good one got broke at Cunderdin.

They arrive in Australia raw at approx $50 each which is also not for the faint-hearted.

I have one remaining raw disk and one remaining clear finished disk and one other gg which has to be repolished on the front face.

As for fixed groundglasses, they can be made to work well but have to be more closely managed for acceptable results, which is another piece of workload to get in the way of inspired creativity.

Even the combination of spinning groundglass erecting versions and permanent non-detachable lens style camcorders still challenges spontaneous camera work. - For the camera operator familiar with the camera type, the first instinct is to go for the camera's own lens controls, rather than the objective lens on front.

There are occasions when you forget to turn on the disk motor and the grain is not initially noticeable until a change of light occurs or you pan across a dark area. A moving groundglass takes away one layer of unpredictability. Using an erecting path takes away another and eliminates extra post work.

A bit of re-grading of colour and contrast in something like After-Effects or similar is all that is needed.

When you can handhold the device and walkabout with it, then it is of practical use.

If I can find somebody with fast broadband, I'll send a demo .avi DVD+R by post for upload. Unfortunately it is in PAL. I have also written a rough user guide but have not published as I don't want to get sued. Any volunteers to convert and upload the vision for me?

I've just been doing 2 small single scene shoots for the PAC Screen workshop and one more to go. I have been doing them all with the AGUS/PD150/Nikon combination. From a directorial viewpoint they are not good, but do demonstrate the desirability of using film fomat lenses.

Thanks guys. Spinning ground glass it is!

Wow Matthew's stuff ROCKS!! Would u be able to post the configuration?

1. SLR>PCX>GG>Camcorder ?
2. SLR>GG>PCX>x7Macro>Camcorder ?

Recommended GG thickness=0.9mm? (Optical Glass)
Recommened PCX size=24mmx18mm

Sean.

I can only speak for my own version of the appliance.

Optical path is :-

SLR Lens (Nikon Primes - 28mm 50mm 85mm, all f1.8) >> +46.5mm from lens mount flange face to rear face of glass disk which is the groundglass side, >> two right-angle prisms 40mm x 40mm x 52mm all 40mm common thickness, in 90 degree opposition (like binocular prisms) >> Century Optics 7+ Achromatic Dioptre, 58mm thread mount type >> PD150 camcorder.

There is no PCX or other condenser arrangement in my device as there is not enough space within to fit added optics. A lesser power dioptre would enable this but would result in a longer device.

The GG finish is 5 micron, with a slight backpolish with cerium oxide to get a trace of aerial image through for sharpness and less light loss. This comes at the cost of an image which is more like video than film and in certain lighting conditions, where there are strong overlit sharp edged highlights, there will be seen a fairly distinct shape surrounded by a halo effect. If normal lighting methods are used, the creative depth-of-field effects can be realised without artifacts most of the time.

This arrangement suits my need to be able to intercut AGUS origination with normal video.

HDV and the AGUS35

I managed to get my greasy hands upon a Sony HDV for long enough to examine if the 58mm filter mount Century Optics 7+ Achromatic Dioptre will work as a relay lens into this camera.

The good news is that it does with some limitations. The lens obviously is going to vignette in a cruel way on this camera. However, by the time you zoom in to frame a groundglass image about 24mm wide, the vignette has gone from the TV safe area at least. Zoom in appears to be about the same as for the PD150 in practical terms. The HDV camera has a zoom lens of shorter focal length, but the CCD set may be smaller also as the framing seems about the same for a similar setting.

The bad news is you have to make up an adaptor with 72mm filter thread on outside and 58mm filter thread on inside to mount this lens and the making of it is a bit awkward.

The Tamron lens I used as a pattern for the 72mm filter mount has a different flavour of 72mm diameter. The plastic Sony case with its molded thread was a bit snug by about 0.2mm for a smooth fit on the Tamron.

It seems on my enquiries so far that there is no 72mm filter mount 7+ Achromatic dioptre available from anybody yet.

The appliance was offered up to the front of the camera by hand after the lens was mounted. The image seemed sharp across the width of the TV safe area viewable in the LCD. I did not have access to an underscanning HD monitor.

After I have made up the rear mount to the pattern I have taken from the camera, I'll see if I can get hold of it again and do some tests. This camera was the Sony HDR-FX1E. I understand there is a semi-professional camera based on this one.

If anyone has the computer hardware which can digest HDV for PAL and is willing to offer to capture the tape to HDV standard, I will send the test tape to a postal address.

Regards and all the best for the Christmas just past and for the coming New Year.

For HD via Sony's HDR-FX1E via the AGUS35 principle, certainly with the CD-R sized spinner versions, there appear likely two issues.


Steadyness of the image. -

Apparently HD broadcast compression cannot continuously deal with change of the whole image from one frame to the next frame, only partial changes in the image. (I have already observed the artifact of the far wall of a valley, framed by edges of a roadside forest, staying put when the camera view moves very slightly.)

There has been mention of certain Super16 capable film cameras being unsuitable because of lateral weave due to no positive pressure applied to the film edge in the gate.

AGUS versions using the CD sized disk seem to be prone to a little flicker in the image from plastic disks or slight shiver of movement of the whole image due to run-out of these disks or the glass disks I have so far attempted to make.


Resolution limits.

A 24mm x 18mm movie frame appears to require too much magnification to permit HD quality detail from my combination of 5 micron AO finished glass disk prisms and dioptre. My erecting version does not permit a larger frame to be used due to the prism size (28mm width limit).

Subjectively, the resolution seems to fall somewhere between SD and HD. Some of this might be in the prism/dioptre/camcorder lens combination, as it seems difficult to get a really sharp focus on the grain of the stationary groundglass. It rests within the focal range of the lens.


Another issue appears with the widescreen (16:9) view. The camera zoom hits its limit just on the point where the edges of the farmost prism move outside the frame in the viewfinder which means they will be there in underscan.

The 40mm x 40mm x 56mm prism pair only supports an image width of 28mm at best (ie., half of 56mm). They require about 120mm distance in the image path disk-to-lens by the time you make up mounts etc.. and the front prism is within 8mm of the disk, the apex of the rear within 3mm of the rim of the dioptre lens on the camcorder.

You could get a shorter path by glueing the prisms together and clamping them from the sides, but then the construction gets really complex.

Bigger prisms to allow a bigger image frame on the groundglass (assuming you can fit in a condenser as well to deal with the hotspot) require a longer path which means a lower power dioptre which means a furthur zoom-in which is not available on the HDR-FX1 except by the doubler function.

I guess this is why P+S Technik seem to have gone with a hybrid prism and mirror arrangement and have a 21mm frame off the groundglass as I understand their design to be from their website. I guess it took them a lot of R&D to arrive there.

So, the simple home-build erecting version may have hit the resolution wall in terms of how far it can go. The only saviour that I can see may be the wax groundglass which may confer a higher resolution off the available 24mm wide frame. Except for the flickering I know how good these can be.

I did some tests in Kings Park in Perth city today. I can send SD .jpg images to be posted but these are probably pointless except for demonstrating the framing/fields of view/depths of field.

I've sent three jpg images to Chris Hurd with a request if he can kindly place them at www.dvinfo.net/media/hart. These are from the Sony HDR-FX1.

These will have filenames like FX1 TESTS MERGE 01.JPG or similar. This will depend on whether my webmail provider can actually send them on. They are not representative of true resolution as they are frame grabs off downconverted feed out to MiniDV from the camera's HD recording.

Since my wailings about not being able to frame within the prism boundaries at full zoom on this camera on my appliance, I have found that I might just be able to get more than the 24mm frame width if I mount the prisms differently. Presently the frame area is enclosed by support structure.

I can't see them Bob on the site.

Chris advises he is away and will post them after he returns.

Furthur adjustments and tests determine that there is just enough space in the 40mm x 40mm x 56mm 40mm common thickness right angle prism to place a 24mm wide image off the groundglass through a Century Optics 58mm filter mount achromatic dioptre into a HDR-FX1.

The image off the groundglass is effectively cropped top and bottom as the widescreen feature of the FX1 actually sees less of the groundglass than the PD150 at this magnification. You can creep about another millimetre width if you zoom back a fraction but at risk of picking up an edge.

The frame has to be slightly higher and right of centre to clear the apex of the rearmost prism which intrudes into the left edge when the camera is zoomed in. It was this and not a poorly centred lens which created the edge defect.

With the PD150 and its trait of walking across the image towards the right edge when you zoom in, this problem had never become apparent.

If anyone in Australia is making image tubes containing prisms, using PVC 100mm sewer pipe as a case and mounting to camera via a pipe cap, there is another cap which is of a thinner wall thickness than the Iplex caps. They are Ausplastics 100mm dust cap 31.100. The barcode is 9 323745 005552.

These caps are not as robust as the Iplex but are the exact wall thickness to match the channel behind the bayonet lugs on the PD150 and HDRFX1.

If you choose to mount the appliance to the camcorder via the lens hood bayonet fitting, then all you have to do is cut out the matching hole and reliefs for the lugs out of this cap and it will go on snugly without need for filing or scraping the face of the cap.

The dioptre still needs to be attached direct to the camcorder via the filter mount.