Ben, as you zoom in, the minimum f-stop you can use on the GL2 goes up. If you zoom out you will get back the 1.6. It's just how it normally changes as you change the focal length.

Yes, it’s the grain of the Beattie. It’s also apparent in some of Dan’s candle pics, even when the screen is moving.

I actually like the look...

I don't mind it, but I wouldn't mind getting rid of it either. All I would need to make it go away is a larger motor. Giving it more voltage will only increase the speed of the motion and decrease the radius of the oscillation. Less voltage does the opposite. It's a trade-off, and getting a larger radius without sacrificing speed just plain requires a bigger piece of hardware.

I've found the grain induced by the Beattie screen is most apparent on really bright lights that are out of focus. I'm learning how to make sure not to have that a distraction in my shots.

I've found that footage shown on a TV doesn't show the grain at all. But with us looking at it "under the microscope" looking for *any* imperfection, on our high resolution monitors inches from our eyes, and yeah, you'll see it.

As soon as the HVX200 arrives, I'll be able to test whether it can be significantly seen on HD.

But, in short, Ben, and anyone else using a moving Beattie element, to answer that age old question, "Are we there yet?" Yes! We are! Close enough! :)

I was about to mention that. On my CRT prod. monitor it's clear as day.

Thank goodness. We've spent enough money and time to get there...whew.

I enquired with a technical man about noise in small video camcorders.

Apparently noise occurs at a constant level. In bright conditions it is not readily noticeable. Apparently at lower light levels when some gain is applied, it still stays buried in the detail of the image, but is there.

When we create large areas of softness in an image with a narrow depth of field, we are leaving a space for any noise to make itself visible where it might otherwise be hidden by textural detail which would be in the image.

The "grain" you are getting may not be entirely from the groundglass.

There is reference above to aperture on the GL1 being set as wide as it will go. Is this necessary because of a gain problem with the GL1. If it is not and the GL1 is over-riding and using a higher shutter speed to limit the brightness, then the groundglass texture is going to get frozen and visible in the image.

My understanding of the Letus is that the excursion of the groundglass is small. Give there may be a stop and start cycle or a slow and fast cycle if the movement tends to be more linear than orbital, then with a higher shutter speed, groundglass texture may become visible.

All this may be very irrelevent in your situation however there are the thoughts.

If you are adding power in order to speed up or increase the excursion of the groundglass, would there be any future in adding some weight ballast to the groundglass frame.

Steve/Ben when you say "not visible on a TV" what TV are we talking about? I've found most everything unpleasant ends up visible on the my 51" HDTV. Worse when projected from an LCD projector onto larger screens. From my point of view, the microscope comes out, we post up footage, analyze, correct, then move on.

I guess after seeing the footage, I'm wondering if I should be abandoning my spinner for 1/2 stop gain over a spinner. The beattie should be perfect if rotated faster, but then you have the whole noise/vibration issue. I'll confess that this "noise", where ever it's coming from, is very distracting to me...and I noticed it right away. I'll also confess that noise/grain in general drives me crazy. Steve is right though in that we are much more critical of these aspects than the average observer.

Hmmm. Food for discourse. And just another reminder that as Scottie says "Ya cannot defeat the laws of physics Captain".

Well, it's a GL2--and all of the test footage has been shot completely in manual mode at 1/60 shutter, so there's no overriding going on. Grain becomes apparent pretty fast as soon as you start getting up into the higher shutter speeds.

Yes, there's inherent noise that comes with video, and party that's why most people are willing to accept noise that comes with shaking the Beattie. I guess I am.

And not to change subjects, but I just finished filming a scene of a movie I'm doing and I realized that it has very little to do with what you record with, but rather who you're recording. Acting draws people into the story, not depth of field. Good acting and shallow depth of field is quite a dynamite combination though. :)

Exactly! I was entirely excited when I saw my first adapter footage. Video obviously doesn't give nearly the same opportunity to draw the viewers interest to the "focal" point of your frame. I actually grabbed a few stills from the GS400 while the adapter was attached and got the old familiar SLR look, albeit at 4MB (well, really closer to 2.5MB). Very cool...a digital SLR, minus the 8MB quality.

When you get immersed in this subject, it's easy to forget until your wife walks over, looks at the footage, then makes the comment: "You did all of this to get that???" Lugging the 100lbs of blast media in five different grades into my shop (GG tuning), I wonder myself sometimes!

I severly doubt that any casual observer would pick out the grain Ben. My thanks for all the work you've shared.

Yes, this is more of what I like to hear around here, in addition to all the tech talk. In addition to "acting" I'd say "performance" is key, whether that's captured reality, abstraction of reality, or scripted work. But I think production talk only happens when we're finished with hardcore R&D mode.

Congratulations Ben. Be sure to post more footage of your work.

"When you get immersed in this subject, it's easy to forget until your wife walks over, looks at the footage, then makes the comment: "You did all of this to get that???" Lugging the 100lbs of blast media in five different grades into my shop (GG tuning), I wonder myself sometimes!"

or when your girlfriend finds all the melted wax on her things .. or her hairdryer overheats and burns out, and destroy every cellphone in you house trying to find a vibrator that will work, or you cut your fingers wide open trying to get glass out of a filter and she looks at you and your bleeding hands in horror as you hold your fancy looking frankenstein adapter.. taped together for quick changes sake.. and "ALL" you have to show her for your efforts is "a blurry background :P "

g35 vs. Ben's Modified Letus
 

G35 footage by Matthew Wauhkonen :
http://csxinfo.net/mattw/g35.mov

Modified Letus footage by Ben Winter:
http://www.frozenphoenixproductions....estoutside.mov

Both have the buzzy grain. Both have very similiar results. I think I prefer Bens footage over the g35. Hmmmmm

Grain Question
 

Ok if the grain is there with both the old and new GG. Should one still consider replacing the GG with a new one? Or is what we are after is the Crispness of the image that is in focus?

Craig, by replacing the GG with a Beattie there is an increase in clarity as well as a decrease in light loss, which are the main reasons for the switch.
Don't forget that the G35 is built to be much more durable than the Letus, as well as the fact that the G35 is apparently static...but then again, is it worth the extra $$$?

Removed duplicate

I think I prefer Ben's to the G35 as well. I wouldn't even complain about that amount of grain, since it gives it kind of a film-y look. Since the G35 is static, I suppose you could concievably get almost zero grain out of it by making a grain filter in post (since there's so little as it is), but for my part, I like prefer the very slightly grainy look of Ben's.

Ben, did you have any luck with the EIA1956s with and without the adapter? For my tests, I left the tripod in place, just removed the adapter and reframed with the same f/stop settings (increased shutter speed after removing adapter). I'm very curious! It would be great to try this with the letus GG too, but that's a lot of work.

Well, for another day yet again I have been unable to do the EIA1956 test. But I did try quickly shooting a grid and I noticed that there is some slight barrel distortion, which makes me sad. It's probably the Century Optics macro acting up in this situation, which makes me wonder if my previous "shortened" design is still a better way to go. Still, I have a lot of footage to shoot tomorrow for an actual TV class project so we'll see how the footage looks, I'll post some tests. And yes, I promise I'll get around to the EIA1956, it's sitting on my desk right now :)

Ben, I am noticing this too with my rig, and it is bothersome. I think Wayne was saying there is a sweet spot for the macro to be in so that there is no barrel distortion? Maybe it was him?

The distortion is most likely coming from the PCX lens in the letus. The SG35 also suffers slight distortion.

So how the Mini35 works? No PCX, cause I haven't seem complains of distortions.

Not sure about the mini35, not sure many people know the optical setup of that, but i know the m2 does not use a PCX, but i have heard some have had trouble with vignetting.

Wayne, didn';t you say there was a sweet spot though?

Leo,
Its a trade off. You can move the PCX away from the ground glass, which will remove the distortion but start to give you more chromatic aberration.

Ben,

Did you notice the barreling before the Century optics?

Yes. I guess that makes it the the macro.

So your saying you had the distortion before and after the century optics macro?

Well the PCX on the letus mostly cancelled it out, but depending on the distance it would get better or worse.

Where is everyone getting their 120mm PCX lenses from these days?

BTW -- if someone wants a Beattie screen (the smaller one, clear matte finish for the Contax), let me know. I've got an entirely unused screen here I just bought from B&H and have decided to use something else. Cost to me was $93 plus shipping, so I'd sell it for the same to anyone interested. Ordering it from B&H took a while -- I'd send it off w/in one day of ordering.

consider it sold....pmail me.

consider you pmailed.

Any new developments Ben? Seems like maybe you ran into trouble. I ordered a beattie screen, and also pre-ordered G35. I want to buy the high-lux version, so I'm hoping that the Letus can serve as my low-lux with the beattie installed. So I'm curious to see how it's going for you. Have you had to clean the beattie yet?

Testing the Beattie Intenscreen on the Letus35
 

I would suggest the following test:

TEST I

1) Before changing the Letus' focusing screen to the Intenscreen, shoot a good color chart with the original Letus GG and a line and pattern chart taking care not to pass the upper 80 IRE limit. Note the f value of the 35mm objective and the f value of the camera objective (e.g. objective).

Keep track of distance and angles and magnification, in order to ensure quasi-identical pictures.

2) After installing the Beattie Intenscreen repeat the same operation, conforming to the same upper 80 IRE limit.

Post the results as TIFF pictures (no further compression !).

TEST II

Create shooting conditions allowing to evaluate bokeh, CA and other artefacts.

Post the results.


Until then, the superiority of the Beattie solution remains an unsubstantiated claim.

Hey guys, sorry I haven't posted here in a while, I've been busy with a TV project that's due Tuesday--and we haven't even finished filming yet. So I apologize if I seem a little busy, because I am.

Daniel, I agree with the degree of thoroughness that you're demanding but you're not going to get those tests from me, sorry. I'm simply not willing to switch out my GG again after putting in the Beattie which was, I must say, a trying exercise. If Quyen's willing to ship me another vibration unit maybe I'd reconsider.

And unsubstantiated? Any fellow Letus owner would agree that the results I've posted are much sharper than that of the stock GG.

I do understand the strength of your curiousity but I'm sorry that I'm not able to satisfy it.

I will post res charts with the Beattie screen and more tests soon, after this nightmare of a project wraps up.

Testing again
 

Ben, I did not meant to say that your claims were unsubstantiated. Actually, the Beattie ground glass appears to be substantially better in term of (1) clarity, (2) sharpness. However, final judgement must be postponed until comparative tests taking into consideration all relevant parameters which constitute overall optical quality have been carried out .
It would much easier for people such as Quyen, the "Father" of the Letus35 to carry out such tests. I own a Letus35A Flip and I'm wondering whether Quyen has improved the GG in this version.

Daniel, being that you already have a letus flip, and you have a detailed methodology worked out....why not spend the $92, grab a beattie, and post em up? My thinking is that a random holographic diffussion surface combined with a light directing fresnel, and Dan D's exhaustive tests, would indicate that Ben's results are indeed valid.

From what I've seen of letus footage, I would theorize that the squirmy grain I pointed out is DV compression's response to low frequency vibrating GG's...regardless of surface.

Ben, those EIA1956 with and without your adapter would be easy though.....Steve Dinkins? MPIC test? Now if I could just find Jim with that beattie he's selling.....

Dennis, this sound interesting and potentially important, could you elaborate on this point (compression response) ? Thanks.

Another issue, which needs to be tested, and is potentially much more complicated, is evaluating the diffusion/spread pattern of colours through the focusing screen. And I'm not referring to "aberrations" or "artefacts" but to "the spatial interpretation of the color spectrum/colour space". As most of us have noticed, the overall colorimetry of a picture shot on a focusing screen afffected. Additionally, any filmmaker will develop a subjective experience of the "distinctive colouring" of the picture generated but any 35mm adapter. E.g., using the Letus35A Flip on a DVX100A with original Canon optics and shooting progressive, I get a much more saturated, more 16mm-like colouring. It's not a problem or a deficiency, just a characteristic of my adapter.

Well said, Daniel.

g35 no longer static
 

Actually, I just read in their FAQ that they will no longer be making the g35 static. Something to do with the requirements of HD cameras.

Suddenly, I'm much less excited about the G35