James, that looks beautiful. What a nice record of the moment.

Hmm, it could be your Konica lens, but hopefully you can narrow down your problem, as the Hoyas seem to be the only way to go right now. Thanks for the reply.

For what it's worth to people researching different diopters, my first attempts were with a Sony VX2000E and a Century Optics +7 diopter (58mm). The Century Optics (Schneider) lens despite being an expensive piece of glass, still managed to show noticeable pincushion distortion when used in conjunction with my VX2000, though it stayed sharp even toward the edges.

I initially dropped the project because of the hotspot. I hadn't considered using a condenser before reading this thread. That seems to change this.

Anyone have any luck finding an Achromat PCX lens? Maybe an Achromat is overkill for the condenser, but might be worth it if they are out there.

Just had a thought about testing the cause of the smearing. James, if you try to shoot a relatively uniform image source (like a bleached out sky or a bright wall) and stop down your Konica lens a bit until you can clearly see the grain pattern of your GG, then take a frame grab of that, you might be able to ascertain if the smearing is caused before the image hits the GG (i.e. by your SLR lens) or after the image hits the GG (i.e. by your diopter combo). If it is caused by your Konica lens, the grain pattern around the edges of the frame will still be consistent with the grain pattern in the rest of the frame. If the smearing is caused by your diopters, then the grain pattern around the edges of the frame will be disturbed (i.e. smoothed out).

Anyhow, great work!

DAMN! Bad news. The Hoyas do appear to be causing the aberrations.
http://www.homepage.mac.com/dvx100/PhotoAlbum5.html

Although the test was less than exactly accurate, it does clearly show the problem.

Thanks for the push Joel and the compliment :)

Sorry to hear that, James. But at least you now know what's causing the blurring.

You could always try taking off one of the diopters. This would force you to zoom in more, which would also mean you'd be shooting through less of the diopter's edge area (i.e. through more of its sweet spot). The only hurdle could be that the DVX100 might not be able to zoom in enough to shoot a 24X36mm target full frame with only one diopter. You can certainly test this, though. You mentioned you were zoomed to about 60 as it is. I wonder if you have enough zoom left in the ol' camera to fill the frame.

On the downside, it would lengthen your adapter by 5cm, but might improve your results.

Hmm, by my pen and paper calculation you will probably not be able to zoom in down to 36mm across. If you are 60% zoomed in at +20, I think that with a +10, the tightest you can frame in will be around 40mm.

Though, I'm curious what the real world numbers are.

James,

I think the solution is simple. You need to get your hands on two 72mm +10 macros. Put those on first, then your 72-55 stepdown ring. That way the edges of the diopter would be covered by your stepdown and 55mm tube rig.

I just ordered two 72mm +10 macros off ebay for that specific reason. When they get here I'll let you know how it works.

John

One thing everybody might need to be mindful of is that when optical image erection into camcorder via prisms/mirrors is designed, things will change.

I haven't done it yet because I am too pre-occupied with more essential things right now.

Early experiments indicate that the current crop of close-up lenses, macros, etc., will shorten the camcorder to groundglass image path too much for a reflective erecting array to be inserted.

The longer path caused by the prisms/mirrors will require weaker lenses to be used. Co-incidentally, the deficits associated with strong lenses will be reduced though not avoided.

John -
I agree, the right 72mm Macros (could they be had) would likely resolve this issue. But you might want to go back and read up on the discussion about macros and why I went with the Hoya 55mm. You can start around here:
http://www.dvinfo.net/conf/showthread.php?s=&postid=144202#post144202

Then again, I haven't tested those eBay 10X 72mm macros. So they may work. Good luck and let us know!

In the light of a new day, I went back and tested various configurations (AGAIN!) of my adapter and found that with just a little more care taken on focusing I was able to reduce the smearing of the edges a little bit while staying close to the 36mm area of the GG.

The situation is (as Joel implied earlier), I'm so close to the macros that I'm unable to focus on the entire 24X36 image area. I can focus on the outer edge, but then the center area is slightly soft. For DVX100 users, the difference between the inner and outer focus point is around MF07 to MF04! So I decided to set the focus on MF05 @ Z57 which brought the outer portion of the image closer to focus while appearing to maintain focus in the center. It's not a fix but it's better. Along with letterboxing (which I almost always use for asthetic reasons), the image is somewhat more acceptable.
http://www.homepage.mac.com/dvx100/PhotoAlbum5.html
Note: This test (image) is not exact since I'm hand-holding the camera and also only approximating the distance between the macros and where the GG is ;)

Hi James, that looks a lot better. Thanks for posting the images. Those 72mm +10 diopters are the only ones I've seen anywhere, and there is no indication if they are achromats or not. It's worth a try though.

In the thread you posted a link to, Brett mentions that he heard Hoya came out with 58mm +10 diopters and was going to order a couple. Unfortunately, I haven't been able to find mention of those anywhere on the net.

So, is it safe to assume that this won't work with just one +10 diopter and the DVX100 (while still framing for 24x36mm)? I might have missed a post where someone verified that.

James, would you be able to verify that?

Bob, in my early designs, I considered a front face mirror and prism combo, but opted against it because of the associated light loss from the addition of those materials and the fact that this necessitated more zooming, which at a certain point, also made me lose 1.5 stops of light. Doing an LCD screen "erection" seemed like a better solution with regard to preventing light loss.

John, I hope those diopters give you good results, and if so, that they are available to the rest of us.

Good luck everyone.

I also didn't see anything in those auctions about those lenses being achromats. I'm really interested in seeing what kind of an image those macros will produce, can't wait to hear how they work John!

I posted something on the dvxuser messageboard and haven't gotten any responces yet so I figure I'll throw it up here and see if anyone has any thoughts that may help me out:

There's a few questions I wanted to ask you guys about the achromat diopters. _I'm shooting on a 100A and most likely won't need two 10x pieces. _If I used two 10x anyway would that hurt me in any way? _The reason I would just get two 10x instead of experimenting is at least I know I can work multiple lens type usage in there somehow and I don't have the time or money to try all different power levels. _But if I did take the easy way out would I have to just zoom in more and possibly deny myself of the ability to attain a lower f-stop? I've already started principle photography on a sketch comedy show I'm shooting and the sooner I can be running accurate tests the better!
_
I understand in full the purpose of the condensor, but am not completely sure what I should be looking for to use as one. _This would be a piece along the lines of a fresnel right? _If Brett or anyone out there can bear with my newbie-style questions I'd be all too thankful _
_
Since I was first thinking about Building the Agus my brain is still bent on thinking about a spinning ground glass, or at least one in some form of movement. This static adapter is much less bulky and easier to start out with, especially for the DVX, but can't there be some way we can incorporate the moving ground glass into this "barrell" style design
_
This was rolling around me head lastnight, so please try to follow my fragmented logic
_
Let's say we had a threaded filter that has the ability of its glass element to spin in its housing for adjustments to be made in its orientation. _I'm not sure if these really exist, but for some reason I feel like I've seen them before. _That would mean if it was used as the ground glass, there would be a way for it to spin already. _The motor would obviously have to spin the ground glass filter from the outside, and that is something a little tricky to figure out. _Maybe using the basic principle of a follow focus mount to spin the glass? _I'm sure I'm simplifying it, but mount a geared ring around the ground glass filter and place another gear to work with that one at 90 degrees and thats the one you can hook the motor to. _So the motor will spin the gears and in turn spin the ground glass. _Can someone shoot me down cause I know I have to me missing something and I bet its impossible!
_
And if this was even able to be employed, would we experience the "grain vortex" that I've read about with the older P+S mini35 models? _ Just a thought that maybe can get some of these great minds on this messageboard brewing some new innovations! _
_
Maybe we could get real fancy and figure out a way to make the glass oscillate so that vortex isn't an issue _
_
Hope to hear all your comments and opinions soon!
_
Nick

I thought of this a while back playing with a polarizer filter in my hand...it would be something like an extended middle section with a ball bearing assembly so it could be spun. I wasn't even thinking of gears, but more of a direct drive type where the motor would have a rubber wheel attached and this would spin the glass. I guess you could have a belt drive too, which would also probably be easier than gears.

I never really pushed this idea since I heard people talking of a...oh now I forget...how...ME! It was an effect of spinning the GG in a circle --the grain would create some weird effect where the image would appear as a...a...AHHH! sorry. The grain wouldn't be moving over the image area in the same way -- the grain at end of the gg would be always spinning and moving quicker than the grain near the centre.

someone PLEASE help me out with what i am trying to say...ugh sorry!

Rob

Joel -
I can assure you the DVX100 won't work with just one 10X. Brett Erskine estimated that you'll need at the minimum +17 (again for the DVX100). I just went ahead and got (2) 10x Hoyas because I thought the extra power would help and that's what Brett was planning to use.

Oh, and if memory serves me I think if you read a little further from the mention of the 58mm macros, he recants. As far as I know the Hoya 10X only come in 55mm.

Nick, maybe you could try the Century Optics 72mm +3.5 diopter in conjunction with a Hoya 55mm +10. Though, bear in mind that the Century Optics lens costs $325 at B&H. I don't have the ability to test it myself, but +13.5 might be a good number.

Focussing at a very short distance (such as the distance dictated by a +20 diopter i.e. 5cm), as James has seen, causes some edge blurring if the diameters of the diopters you are relying on are significantly smaller than 72mm. In addition, focussing on anything with the DVX at 5cm ( in this case the GG), causes a fair amount of barrel distortion. The barrel distortion is unrelated to
the diopters you might have on the camera at the time. That's something inherent to the DVX100's own lenses when focussing so close.

Something like +13.5 diopter combination would put your focussing distance to 7.4cm (regardless of whether you have a DVX100 or DVX100A or even a Sony XYZ) and should improve the barrel distortion a bit, since the focussing distance is now a bit longer. But the main fact that one of the diopters has a 72mm diamter might give you less edge blurring.

Although, James's newest zoom/focus tests look to be pretty good on their own.

If you have the ability to test a Century Optics +3.5 72mm diopter and a Hoya without purchasing them, then you might want to do that and please tell us what you find).

Good luck on your show.

James

Yeah, I actually read that original post about the hoya +10s. The second webaddress does confirm that those hoyas are 2 element macros. But the first address where you purchased it doesn't... and as a matter of fact, it goes out of the way to separate them from the 2 element macros they're selling. And since I wasn't absolutely sure who was telling me what, and didn't want to spend $120 to experiment with two macros (especially since I knew they would at best give me the problem you're seeing), I went with the 72mms on ebay. They may not be good enough, I have no idea, but they're cheap enough for me to experiment with. Here's to hoping they work... for everyone's sake.

By the way, I just want to commend you on such a fantastic design. When I first saw it I had a mixed reaction of "YES!!", and "Man why didn't I think of that!" I can't stand the look of PVC or tape anywhere in the design. I know that's sounds base, but what can I say? I'm trying to come up with a really clean, fully metal, version of what you've made, but with an adjustable tube. I'm experimenting with filter rings of varing sizes that slide over the the top of the 55mm section snugly... I'm gonna use little plumbing O-rings to furthur seal off light, and a screw (similar to the one used with the DVX's plastic mattebox) to lock it in place. Any thoughts? Ideas? Wish me luck.

Thanks for the response, James. Based on my own estimates as well, I figured a +10 probably would not be sufficient, but would be pretty close. I just wanted to make sure. I don't want to start a big debate here about Brett's estimates, but I'm not as convinced that you will need a +17. Brett, I believe, also wanted to be able to focus down to a 16x22 target, which is not my intension. I think a +13.5 should be sufficient for framing 36mm across, but it should be tested, and in fact, I would have thought a +10 would have been just a few mm shy of being able to frame 36mm across. I'm using some visualizaton software to do the calculations, but they still aren't real world.

John-
Well according to B&H they are 2 element: http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=94233&is=REG

Here's the actual link that convinced me to buy them in the 1st place (although the samples don't show them stacked): http://www.lensmateonline.com/A80macrocomp.html

Concerning the design, I really went for the simpliest way to make the adapter. I wasn't too concerned with versatility and compatibility with different types of lens as much as I just wanted to make one that worked with the lens I had ;)

Joel-
Allow me to clarify. I misquoted Brett. This is actually what he said: "... +16 diopter(s) or stronger is whats needed if you plan on using cine lenses. Still lenses work with +13 maybe +12". Sorry about the misquote - just trying to pass along information :)

Oh hey, James, don't worry about the misquote. Thanks very much for clearing it up. That does seem to line up with my own calculations.

I wonder if you've noticed any barrel distortion with the +20? I suppose as you start to shoot a larger variety of subjects, such as poles or wall edges, etc, that might start becoming apparent. However, probably the best test would be to shoot some grid paper with your macros, much as you have shot the newspapers.

Great effort everyone!

Here are the numbers I've come up with for the DVX100:

36X24mm = Just over +10 power diopter (+13.5 will be enough)

24X16mm = aprox +17 power diopter or stronger



Here are the numbers I've come up with for the DVX100A:

36x24mm = I've HEARD you dont need any diopter at all due to it better minimum focus specs

24X16mm = If the above statement is true then logic tells us a +7 or stronger diopter should work


I've based my numbers on real world test with the diopters.

If you plan to use a anamorphic field lens for your GG then then your target numbers are going to be even smaller which means a stronger diopter.

Unless Hoya JUST came out with a new version of 72mm diopter in the last few months your ebay diopter is going to be a single element.

55mm is a big as anyone they make them when it comes achromats.

58mm dont exist. It was a misprint on a web site.

EVEN the 55mm Hoyas are two element achromats, they have the slightest amount of chroma abberation. Its much less than anything else out there of the same power and it becomes slightly more noticeable when you stack two. Using larger ones would be better but they dont seem to exist.

When focusing extremely close to a flat object like the GG when using two diopters you'll notice that the center is in focus while the outside of the image is not. This is due to the minor distance between the two points and the lens. Increasing the distance between the GG and the first diopter is the simplest way to fix this problem.

Glad you guys are still keeping this project alive. It just goes to show you that their are plenty videographers out there that truely understand and appreciate the subtle characteristics of a film image. Unfortunately I've been too busy lately to do much work on it but last time I screwed around with it I was working on incorporating a synced 180 degree rotating shutter with the GG. This achieves smoother, more natural film motion blur that even some of the most expensive HD 24p cameras lack and defeats the problem with apparent grain in the GG at the same. Anamorphic GG, tilt shift movements the possibilities seem endless. The goal: a adapter that allows small, light weight, inexpensive cameras such as the DVX100 to step up and produce the images that dont compromise our creativity and do it at a price where ownership makes sense in this progessively fast moving digital market.

-Brett Erskine
www.CinematographerReels.com

<<<-- Originally posted by Brett Erskine : The goal: a adapter that allows small, light weight, inexpensive cameras such as the DVX100 to step up and produce the images that dont compromise our creativity and do it at a price where ownership makes sense in this progessively fast moving digital market. -->>>

Here, here, Brett. Thanks for all the info. But, wouldn't an anamorphic pcx increase your target area? You aren't planning to squeeze the image in width, but actually stretch it in height. Unless, you're doing it the other way around for some reason.

Joel

Hmmm..... how could a second shutter on the GG (in addition to the existing shutter on the camera) help? The motion blur is going to be determined by only one thing - the time the shutter is open for the CCD on your camera. I must be missing something... I saw the word 'synced' but doesn't that just eliminate the need for the second shutter (making it exactly the same as the first shutter)? Help me to understand this...

Hello all,

Just wanted to say thanks again and great work to brett, james, jon, joel and everyone who is putting their minds to this project. I'm still in the baby stages, but I'll be grinding my ground glass this week and I'll be shooting tests with the 100A to see if I can really fill the 36x24 frame while in sharp focus without diopters. I'll fill you guys in as soon as I can.

Hopefully I will be able to achieve a nice frame in focus without any help from additional achromats. But even if its real close maybe just the 72mm +3.5 will do the trick, in which case I'll let you guys know how it works cause I'll most likely end up buying it.

Be back soon,

Nick

A physical mechanical shutter like the ones found in a cine camera and electronic shutter speeds in a digital video camera work towards the same basic end but a mechanical shutter creates a different look. Its slightly less jittery motion. I've talked to other people about this and have come to the conclusion that its due to how a mechanical shutter exposes film (in this case its a CCD) to light. For thoughs of us that dont shoot film a 180 degree mechanical shutter generally looks like a half circle that rotates. When it rotates it basically exposes the CCD half of the time and then blocks the light the other half of the time - 24 times a second. But if you slow down the process and think about it you'll realise that the whole CCD isn't being either all exposed or all not expose like someone switched on and off a light. Instead that half circle is progressively exposing the CCD to more then less light as it makes its circular path across the CCD. If you used the example of a light switch again the you could say its more like if someone dimmed up, held and then dimmed down the light. If Im right this should take the hard edge off of the motion blur on progessive digital cameras. On top of that your only one step away from having rotating GG which makes the whole idea much more attractive. Anyways I hope that answered your question.

-Brett Erskine
www.CinematographerReels.com

Brett,

You shutter idea does sound interesting. Although I have a feeling that the instantaneous nature of progressive capture (basically the same as the electronic shutter in the sense that it just snaps a photo for an exact period of time, then instantly starts on to the next), versus the pricipal of a film strip moving across the lens contributes, at least partially, to the more natural fluid motion blur. But I don't doubt that having the light fade on an then off in that very rigid 1/24/second progressive scan will help out. It's a pretty simple experiment that can be done without the aldu35 or any adapter. Just take a dremmel and attach a 180 degree shutter to the front of it that 's exactly wide enough to cover the lens completely at the 0 degree mark. Set the DVX to 1/24 electronic shutter which is equivalent to no shutter or a completely open shutter and see what it does. You'll have to get just the right speed on the dremmel (1440rpm) and I'm not sure if there's a way to tell. But a Ground glass adapter shouldn't have anything to do with getting the smooth kind of blur you're talking about from the experiment. It would be a good starting place to test out this theory before combining it with the Aldu35 or Agus35. We should start another post about it.

If you glue a half circle of paper on a rotating AGUS groundglass you get some weird stuff. Interesting things might happen if the rotary groundglass could be driven by a syncable electric motor.

As to the image erector. With other committments and an AGUS arrangement which works well enough for the time being I haven't pushed the erector for much the same reasons - light loss and degraded image which will require a whole lot more time and effort in development to get right.
There's also a sort of white sheer with mirrors which is also a bit of a spoiler.

Brett as to creative effects, controlled artificial light onto the groundglass for a faked fogging effect might be worth examining.

Ah... that helps. Thanks.

CCDs work conceptually just like film - the photosensitive diodes measure an increase in voltage over a certain period of time (1/48th of a second, for example) before dumping that number out as its (the diodes) 'exposure.' If you were to 'wave' a moving shutter over the diode during this time period, it would have the same effect that putting a mechanical shutter over film has.

It would have to be either very-well secured, or very light (or both) to not introduce vibration. Remember that virtually all 'vibrating motors' work on this principle - spin a half-circle off-axis very very fast. You'd need to create a vibrating motor without the vibration :)

To erect image dont use mirror because you have a lose of light use 90° prism in a posso configurations..

I was testing double-weave mylar architectural drafting film as a ground glass and I came across some interesting information.

I was specifically looking at the diffusion and grain characteristics of the mylar, so I removed my condensor for testing. My camcorder has a built-in macro feature, so I can focus on something that's very close to the lens (1.5 cm). I have always attached my adapter right onto the end of the camcorder because I could and hadn't built any additional tubing. This created a situation with the condensor where the ground glass is about 3.25 cm from the camcorder lens which acts as my macro. I had always had to zoom in a bit past the edges of the hotspot, but thought this was normal.

Once I removed the condensor, I had the ground glass right up against the camcorder lens - about 1.75 cm. With the camcorder zoomed all the way out, the image completely fills the frame, but there's a big fat hotspot with literally a hard-ringed edge the same size as the aperture of the 35. As I open and close the aperture I can see the hotspot change size.

I took the adapter off the camcorder and looked through it directly... zero hotpot - I mean none. Perfectly flat even image across the entire 52mm gg surface. (?!). What the heck?!

So I tried taking some of my leftover PVC tubing (I think we all have buckets full of the stuff), and built a short extension tube such that I could manually hold the adapter at a longer distance from the camcorder - in this case, the pvc was about 5.5 cm long.

This time, when viewing zoomed all the way out, I (of course) could see the tube. However - at the end of the tube was a circle of almost completely even hotspotless image. I zoomed in just past the edge of the circle of the tube and was left with a very very nice image with a slight darkening in the corners... remember though - there's no condensor!

So... I'm wondering if a bit of space (at least a few cm) between the GG/Condensor and Macro is actually mandatory to allow the diffusion to happen. If you're too close (like I was), I think you still get the hotspot because there's no room for any diffusing to happen.

Just thinking out loud - thought it was interesting. By the way, the Mylar is a pretty good ground glass substitute. I don't think it will be quite fine enough for final product but for those getting started who haven't ground a real glass - it's super cheap and works awfully well. It's better than the focusing screen that came on my Canon AE-1. It would be awesome for a spinning ground glass version.

Jonathon-
The reason that your getting a hotspot on your GG when its real close to your macro is because all of that stray/diffused light near the outter side of the frame isnt being redirected towards the lens. The closer you are to the GG the more the angle of the stray light will need to be corrected. This is why you need a condenser -particularly at short distances.


Mechanical shutter-
A simple/even weighted example would be to simple spray paint half of the CD if your using a design with a rotating CD. Use flat black paint. Also the motor would need to be synced. The camera already sends out a electronic pulse to do this automatically.


-Brett Erskine
www.CinematographerReels.com

"If Im right this should take the hard edge off of the motion blur on progessive digital cameras."

Brett, you should ask Dan Vance about this.
He built his 1/2" Progressive scan camera with a mechanical shutter, I'm sure he'd have some insights on it.

http://home.teleport.com/~gdi/vancecam.htm

Luis-
Already done. ;-)

I met Dan Vance at NAB. We talked briefly on the subject. He's a incredible guy. I mean jez the guy MADE his own progressive scan video camera before any of us knew what the DVX100 was. I hope hops in this thread and helps us out.

Damn I really have to slow down and proof read my post. Hope you guys can understand me.

Joel,

Your question about an anamorphic lens can probably best be answered by checking out this thread:

http://www.dvinfo.net/conf/showthread.php?s=&threadid=23076&perpage=15&pagenumber=1

Check out the pictures. I think they make it pretty clear what the options are for an anamorphic lens within the adaptor.

Justin

Hi Justin, thanks for the link. I read through everything on that thread, but still don't understand why you wouldn't want to place a cylinder lens in front of your GG that expands your image vertically. The benefit of this is that you spread the same image out over a larger area of ground glass. This has two nice repurcussions for the final image since the weaknesses of the GG are limited resolving power and visible grain.

I haven't seen a real reason not to take advantage of a larger projection area.

Joel-
Heres why. When you stretch it out you create a image that may be 2.35 in aspect ratio but the image is also distorted as well. Correcting for this will only take you back to a 4:3 image. Now you are right about the fact that by using a larger area of the GG your going to have smaller/less noticeable grain in the picture which may be all that your looking for. What Im doing is squeezing a 2.35 image to fit into a 4:3 aspect ratio full frame on the GG so I can use ALL of my CCD. This will give you a higher res.

So to sum up your idea gives you less grain and my idea gives more electronic resolution.

-Brett

Hi Brett, thanks for the response. But, perhaps one of us is missing something in this equation. I'm talking about less grain AND more electronic resolution.

My assumption is that, of the nikkor/canon/etc. lens's image circle, you will be using only the center 15.3x36mm (2.35:1) portion, as though you were shooting something with a stills camera and then cropped the resulting image.

That 2.35:1 image would be stretched only vertically, so that when it appears on the GG for the video camera to record, it will occupy a 27x36mm (1.33:1) area of the glass, allowing your video camera to shoot it using all of its CCD's pixels.

Are you trying to do something more complicated than this, because unless you need some different sort of functionality, what I have outlined seems to be relatively easy to do with good benefits on image quality (i.e. more benefits than shrinking the image on the GG)? Please tell me what specifically I'm missing about what you're trying to do.

Thanks a lot.

I see what your saying now and your right. It will give you less grain and more electronic resolution (full CCD). The reason why I wanted to squeeze the image horizontally (which is more of a traditional anamorphic technique) is because it allows you to do 16X9 enhanced DVD's with a image that is 2.35. In case your scratching your head I'll explain.

Most DVD players can unsqueeze a image on the fly but only by a factor of 1.78 (16X9) so what the pros usually do when they are encoding a film that was shoot in a 2.35 anamorphic ratio (ie Panavision) is create a DVD with a image that is only partially unsqueezed to 16X9. The DVD player then takes care of the rest of the unsqueeze when it palys the DVD. This brings the image back to 2.35 and makes the most of the resolution that NTSC DVD's allow.

Now is your idea better or not...Hmm thats a good question. I wonder now. I think if you have static GG I would say yes. But if you have moving GG I would go with a horizontal squeeze instead.

Hope that explains it all.

Great thinking by the way.

-Brett Erskine
www.CinematographerReels.com

Thanks for the response. I think the biggest obstacle either way is finding a quality cylindrical lens with the proper characteristics, and that sounds like a cutom job to me. I would love to have this in a static adapter, since it would be so much simpler to make and the tolerances would be relatively looser.

A while ago I asked a lensmaker about having them make a cylindrical lens to my specifications based on an explanation of my overall intended device. We didn't get into prices at that point, but they did say the major problem would be about 1-1.5 stops of light loss first because of the magnification of the image and second because of the added optical "roadblock" to the device. Every piece of glass you put into your system will contribute to a loss of light that at some point will become unacceptable for your needs. The light loss, hotspot and accumulating costs were the three reasons I halted my own work on this project over a year ago. Things will hopefully work out this time because of this community of people working together.

The perfect cylinder lens will project the desired squeezed image on the back side of itself. Meaning the plano (flat) side of the cylinder lens, which would be ground to create a GG surface, would be a the perfect focal length for the right magnification. This will help cut down on the amount of elements in you adapter and increase the optical quality.

Joel.

Some time back, I shot a test into the AGUS35-PD150, through a Proskar Anamorphic projector lens into a 55mm Micro Nikkor. I can't remember the filename now but if you have a look at www.dvinfo.net/media/hart, and look for something like widescreen or cinemascope with .jpg after it on the list you'll find two 4:3 and 2.35:1 images composed together as single files.

There's also a couple of tests I did with the Century Optics 16:9 on front of the Micro-Nikkor.

Cinemascope was fine for MiniDV/DVCAM resolution in close to about 40ft but fell apart for sharp focus beyond that. I don't think it would hold up for HDCAM.

There's also a few early fixed groundlgass tests titled something like "fixed groundglass" or "agusday1" & "2" In those early tests I used a microscope slide dressed with aluminium oxide and enclosed in a Pringles can. The prime lens was retained in the can with a rolled up toeless woollen sock. (I suppose you could call that evolution the Pringlecam or SPUD35??)

Quality Statement:
I have made gg numerous times with mechanical abrasives up to 1000 grit AO. I consider myself somewhat good at this. The Acid etched gg is far easier to produce, costs less for materials and I feel is of far superior quality to mechanically produced gg.

Needed:
Soft bristle toothbrush (throw away when finished)
Armour Etch Glass Etching Cream 3 oz. or larger (available online and at Hobby Lobby for those in larger US cities.)
UV (Haze Filter) of appropriate diameter. LEAVE in its mount.
Soft paper towels and or toilet tissue
Windex or other alcohol or ammonia based glass cleaner.

½ hour !!!!!!!!!!!!!!!!!!!

Access to running water. This material when diluted and treated in a modern waste treatment plant will not harm the environment.

Precautions:
Follow the mfg. safety precautions printed on the bottle label.

You’ll need:

Rubber Gloves
Goggles (not safety glasses as the material can get past)
Long Sleeve protective garment (that you don’t mind holes eaten in)

Good ventilation.

Hold the work at a distance from your face when applying cream, brushing, rinsing, or working with the piece.

Technique Discussion:
With this etching method you’ll find technique is everything! Please re-read the previous sentence. Others have tried this and found that the results are blotchy. The label itself says that the material is not meant to treat large areas.

What you’ll notice is that if you apply the paste in a blotchy pattern, the glass seems to be etched in a matching pattern. If you use a toothbrush to apply the paste applying it with horizontally aligned strokes then the pattern of blotches seems to be horizontally aligned. This observation and others lead to the technique I use to produce a surface that is free of blotches.

I would say that the grain is finer than anything I’ve been able to produce mechanically.

Procedure:
Rough etching. Always hold the glass horizontally.
1. Thoroughly clean the glass, front and back with alcohol or ammonia based glass cleaner and dry.
2. Apply a generous amount of etching paste to one side of your glass. Be sure to note the side you wish to etch so that subsequent treatments will be to this same side. Wait about 5 minutes.
3. Scrape the paste off the glass and back into the Armour Etch container.
4. Rinse thoroughly and dry.
5. Repeat steps 1 thru 4.
6. If any smooth glass remains spot treat them with paste until the entire surface has been etched and no smooth places remain.
Fine etching. Always hold the glass horizontally. At this point you’ll probably be very disappointed with the appearance of the gg. It’s all etched but hardly uniform in appearance.
7. Add a generous amount of paste (but don’t overflow the mount) to the glass surface.
8. Using short strokes (about ½ inch 13 cm) gently scrub the glass surface all over. Still with short strokes brush the glass horizontally all across the surface of the glass.
9. Now gently stroke with shorter strokes and at the end of each stroke pull the brush up away from the glass. Do this all over the glass. At the end of this step you’ll end up with a fairly uniform thickness of paste covering the glass (about 1/8 inch, 3 or 4 mm thick).
10. Let sit for 4 minutes, then repeat steps 8 and 9
11. Let sit for 3 minutes, then repeat steps 8 and 9
12. Let sit for 2 minutes, then repeat steps 8 and 9
13. Brush the excess paste back into your Armour Etch containerRinse thoroughly and dry.
14. Inspect the gg.

That should do it. If not try it one more time. Developing technique does require a little perseverance, experimentation, and practice.

James the Chemist

Thanks for the detailed procedure, James! I've been following this thread for a while now, and am very interested in starting up my own Aldu35. I've been extremely impressed with the samples on your website.

Have you tried the GG made with acid etching in your setup already? How do the images look? Let us know if it's better than your previous GG (which seemed to produce great results!).

James, I know this is going to sound crazy...but since we do have these dv cameras...hehe..would it be possible for you to give us a video tutorial of your method with audio narration of the steps? You don't need to show the full 30 min. Just so we can see the toothbrush 'stroke' technique, and how we're supposed to do this?

I read your post twice now, and I still have a fuzzy mental image of how I should do this. I would love to see this done by you on video.

-Dana

Very cool! Thanks James!!

-Dana-
Love to but time and hosting situation will prevent me from doing a video tutorial. Also my camera (a DVCPro 25) doesn't have firewire out and it's a pain for me to get it out into my PC at present my deck is away for repairs.

It's easy though and fairly inexpensive. About $5 for the paste. It will become more self evident if you just try it. I figured it out in a few hours just playing around here and there. Plus if you don't get it right just add more paste and start over till you get it right.

If you have more specific questions I'll try to answer. The key to the whole thing is that if you just glob it on the paste the glass is etched in an uneven way; but it's not random the pattern matches the "globbiness". I soon found that if you applied the paste with horizontal strokes all oriented in a single direction that the pattern of etching nicely matched the brush strokes.

Last I found that if you did a short horizontal stroke and at the end of the stroke pulled the brush away from the glass it left a finer grain.

I've only begun my Aldu35. So I have no means of final comparison. However it'll only be a few days off as I have a few 35mm cine primes and my Fujinon lens has a macro lens that will allow me to focus on the gg screwed onto the front of my video lens.

I have a microscope that I've been using for comparison purposes.

I can send 200X microscope pics of the grain from a 1000 grit AO and etched gg if someone will host them.

James, send the pics to me, one pic at the time.

Just reply to the email I sent you privately earlier today.

I'll gladly host them on my site, FancyFlix.com.

<<<-- Originally posted by James Ball : I've only begun my Aldu35. So I have no means of final comparison... -->>>

My mistake... I thought you were James WEBB, not James BALL. Sorry ;)

Anyways, the info was great! I can't wait to see pics once you put together an adapter!

James (Ball),

Is the thoothbrushing simply done to even out the cream on the surface of the glass, or is the toothbrushing actually done to help the corosive process.

The reson I ask is that if it's only used to help create a uniform spread of the cream, then couldn't you also just put a bunch of cream on the surface of the glass and then lightly press another piece of glass (uv filter of the same size without the ring) over the top of that till the cream speads between them both evenly like a sandwich?

John

Alex,

Thanks for offering to host James' pix. I'm really looking forward to seeing them.