Fiber screens, the future of the 35mm adapters?

canon fd 24mm f2.8

canon fd 24mm f2.8

It would be great to see the performance of THIS fiber screen with the canon fd 24mm f2.8

and when you get the new fiber screen with the curved face you show another test in january
 
There is a compression on the AVC-Intra 100 codec ...
I thing this is noise because the set was underexposed by 1,5 stop as I see it in waveform... so to bring up the level I pushed it in Color... so that probably shown the noise as a pattern... This is a guess thought... Probably Monday I will shoot another TVC... and then we will see...
 
Apefos Adapter said:
It would be great to see the performance of THIS fiber screen with the canon fd 24mm f2.8

and when you get the new fiber screen with the curved face you show another test in january
Click to expand...

I will arrange it in couple of days... when the camera stay a bit in house... sorry to, much work... I shoot three TVC's this week and I have another two for next...
 
frobozz said:
Yes, I fear the cost too! Also, a spinning disc is incompatible with the idea of using a concave surface to help with vignetting. I hope the concave surface is not required. But maybe the ability to accept blemishes will help the cost?

If by "first image" you mean the third example image contained in the first image (non-vibrating fiber glass) then yes. It's hard to tell from a still, but that does look a bit like what I'm seeing in the example movie. So probably it wasn't vibrating.

The really weird effect is in the second image in that first image, with the CFXL GG vibrating! What is up with that weird swirly pattern on the edges of the highlights?!

Duncan
Click to expand...

also, doesn't this fiber screen pretty much negate the advatages a spinner has over a vibrator?
 
frobozz said:
Hang on, I thought he said the footage with the BlackMagic codec was uncompressed. How do you get jpeg artifacting in uncompressed footage?

Duncan
Click to expand...


I meant compression artifacts. oops:) In photoshop, under noise reduction,
there is a checkbox labeled "remove jpeg artifact."
 
Evangelos Achillopoulos said:
I don't use condenser lens in the above examples... the FiberScreen exhibits a static minimal vignette in all the range of the aperture, you can check out the stop down test...

In the next experiment, that is on the manufacturing state, I will try a slightly concave side to grab the steep angled rays from lenses like the FD 24mm F2.8 in order to minimize the vignette to zero... I will have the samples first weeks of January because they have to build the special aspheric tool to do it...
Click to expand...


The hv20/30 type cameras usually need a condensor lens. Have you had any tests done on this camera yet?
 
astigmatic said:
also, doesn't this fiber screen pretty much negate the advatages a spinner has over a vibrator?
Click to expand...

Probably yes, but I will know when I test the curve... In the edge of this screen there is a remaining of the old curve, to see the light correctly you have to be vertical on the curve... that makes me thing that If I follow the angle of rays I could possibly gain the minimization of the vignette in weird lenses...

But this is impossible with a spinner...
 
Inexistence said:
I meant compression artifacts. oops:) In photoshop, under noise reduction,
there is a checkbox labeled "remove jpeg artifact."
Click to expand...

OK, but my question stands: how do you get compression artifacting in uncompressed footage? (That was the whole point of him posting the uncompressed footage, to settle the question of whether it was artifacting.)

It's not surprising that the "remove jpeg artifact filter" cleans up the problem, even if it was screen texture not artifacting. That's what that kind of filter does: smooths over teeny-tiny features.

Duncan
 
astigmatic said:
also, doesn't this fiber screen pretty much negate the advatages a spinner has over a vibrator?
Click to expand...

My understanding of the movement of a ground glass screen is... to blur away any perception of the grit pattern on the glass. These fiber screens still have a pattern when standing still, though it's far less noticeable.

I think the big advantage of spinning over vibrating is that you can go faster. If your frame rate on the camera gets anywhere near the motion rate of the GG, you end up seeing the texture again, so faster motion means faster max frame rate.

Duncan
 
it would be completely pointless to use this as a spinner. the whole reason for a spinner is to get rid of grain and the ability to stop down. seeing how this screen has no to very little grain static, you would be wasting the money getting a big enough piece just to spin it. but whatever works...i say vibrate it. you can always try out the ones on surplusshed that are circular and have concave, but a bit small. only 5 bux if you want to do a DIY type 35 like this.
 
frobozz said:
OK, that did the trick! I still see the same issue, so that means it's not compression artifacting, right? I'm going to go with your theory that your batteries had run out and it wasn't actually moving.




Hey, but if it's spinning a few blemishes don't even matter, right? That's the whole point of spinning it. A bunch of blemishes that all happened to line up at the same distance from the center...well, that would be a problem. But a dozen or more randomly dark fiber "pixels" shouldn't be a problem at all.

I came up with the 4 inch diameter because I am convinced that one of the big vignetting problems with all the adapters is how close they cut all the dimensions. Even something like the M2, which has a seemingly big ground glass disc, is actually cutting it *very* close on fitting the image rectangle on the glass while avoiding the outer edge arc, the shadow of the motor, etc. Optics get weird near edges, so I would prefer to have a very generous area around the main image area, clear of all edges. This would also help when trying to cure misalignment of things. With an HVX200 and its misaligned CCD, you don't have any leeway on the M2 before running into an edge of something. The only choice is to zoom in closer on the GG. With a 4 inch diameter disc you could even project the lens image onto it in the other orientation (to left or right of center instead of above or below) if that made sense for some reason.

Duncan
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You've convinced yourself wrong. The reason for vignetting is not due to the size of the screen, but how well the screen evenly spreads light. Sure, a big enough screen means you can zoom all the way in to the hotspot, getting rid of vignetting, but trouble is, the bigger the screen, the more your housing will cost and the more expensive your screen will be. Take for example, light shaping diffusers, are fantastic at spreading light evenly having no vignetting effect. Problem with those, lots of grain, and lots of diffusion. But, nevertheless, great screen if you can spin it or vibrate it. I'd go with vibrate because they are light and can be found in cell phones. If you take apart a monitor you can find it in them too.
 
Car3o said:
You've convinced yourself wrong. The reason for vignetting is not due to the size of the screen, but how well the screen evenly spreads light. Sure, a big enough screen means you can zoom all the way in to the hotspot, getting rid of vignetting, but trouble is, the bigger the screen, the more your housing will cost and the more expensive your screen will be.
Click to expand...

Oh, I know about the obvious vignette/hotspot causes, with ground glass, which this fiber stuff seems to fix quite nicely. But after many many many MANY hours of screwing with my M2 trying to eliminate all the edge darkening problems, I came to the conclusion it wasn't going to be possible while using a setup with everything cut so close to the edge. Especially with that 24x36mm tunnel through the Micro-X, yikes. (You'll note that the "special EX-1 version" they are coming out with is significantly larger, and I bet this is one of the reasons.) Combined with the off-center CCD in the HVX200, it was just darkened edges everywhere.

Lens manufacturers don't get anywhere near the edge of the image circle - it lies generously outside the expected image area for the camera in question. I want to have just as much excess room on my ground glass/fiber screen.

It wouldn't bother me in the slightest to have the housing be bigger, if I could just completely eliminate the *(&*&%$&^%&**&( vignetting. I am trying to use my ultra-wide lenses, so admittedly I'm onto the worst-case end of the problem, but I want there to be a way. It's easy to get an 85mm lens to look good through an adapter. I want to use my 14, 15, 17, 20, and 24!

Duncan
 
frobozz said:
OK, but my question stands: how do you get compression artifacting in uncompressed footage? (That was the whole point of him posting the uncompressed footage, to settle the question of whether it was artifacting.)

Duncan
Click to expand...

Well, see it's AVC-intra 100 originally from the Varicam and not uncompressed.
Usually that stuff looks pretty hot. I work with Varicam footage everyday and
have not seen this issue (DVCPRO HD), so maybe it has something to do with
the output settings to Blackmagic. Not sure +3db gain would cause pattern
noise like that.

Either way what we need to examine is an unmolested avc-intra clip. Goodluck
trying to play that back without an avc-intra hardware converter or a super
sweet machine. One would have to use an intermediate clip for playback.
Although, he can export a 1second qt mov uncompressed. That should suffice.
 
Has this thing been tested with the dreaded EX1? How is the edge to edge on that adapter nightmare camera??
 
Car3o said:
with lens that wide you'll get vignetting on an slr camera.
Click to expand...

Is that in reference to the lenses I want to use? Not true at all. I've shot with those lenses for years and the Canon FD lens designers worked their magic to make them perform very well on SLR cameras onto film. I'm just hoping to get that look onto digital video, that's all.

I'm actually getting set up to prove to myself once and for all what's *really* coming out of the back of my lenses. I did a couple of tests onto B&W film but will do the real thing under more stringent conditions, onto color film. Here are my 24/2.8 and 24/1.4 lenses, captured onto 4x5 film so you can see *everything* coming out of the lens. For reference purposes I've drawn a to-scale 24x36mm rectangle on them.

http://www.betlikeduncan.com/duncan/redrock/lenscharts/canon_fd/lenscircles/24_14_boxed.jpg

http://www.betlikeduncan.com/duncan/redrock/lenscharts/canon_fd/lenscircles/24_28_boxed.jpg

Note that the 2.8 has much worse vignetting at the edges of the lens itself... but neither one of them has vignetting anywhere near the area that gets put onto film. And yet, when you mount the 2.8 onto an M2, the resulting image is *awful* due to the portholing caused by the ground glass interacting with the small exit pupil of the lens. These fiber screens should take care of that (I eagerly await the results of the impending 24/2.8 test!) but I'm also looking to avoid introducing any new edges that cause shadowing, in the adapter rig itself.

Duncan
 
with the brevis + brevis flip, you get no vignetting on the fd 28 f2.0 and 24 f2.8. Without the flip, the 24mm sucks.
 
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