Cylindrical A-Lens Owner's Thread - Page 13

Not a shootout per say. I did demonstrate astigmatism adjustment using an ISCO III at a GTG in Melbourne. I found that it resolved single line 1080 display pixel lines the same as my MK4 can. Therefore I'd say my with confidence that the Aussiemorphic Lens MK4 is as good as the ISCO III for resolution.

What I find good is when calibrating the projector without the lens and then with the lens and there is no change in results that's a good indication in the quality of the lens.

The name cylindrical is given to the shape of the optics when viewed in plan IE - they appear as if a cylinder has been taken out of them (front lens) or appear to be part of a cylinder (rear lens). In essence, for a HE lens, these lenses curve in just one direction (horizontal) and are flat in the other (vertically). Spherical lenses curve in both directions.

This is an interesting comment as I read on a UK forum recently about a HD950 (RS25) owner who had an ISF calibration done (very well respected calibrator over on the UK forums). The owner has a cineslide and a Mk4 lens. The calibrations for both modes was quite different. He is extremely happy with the calibrated results (after being unsure as to the worth of getting it done). Apart from a small issue with a 'shadow' in one corner due to the cineslide being slightly too far to one side, he is very pleased with the lens. I understand he is moving the cineslide position this weekend to resolve the shadow isse.

Results below for those interested.

ISF 16x9 "WITHOUT LENS" SETTINGS

CONTRAST = 4
BRIGHTNESS = -6
GAMMA CUSTOM 1 CORRECTION VALUE 2.5
COLOUR TEMP CUSTOM 1

Custom Colour Temp 1
GAIN RED = 0
GAIN GREEN = -8
GAIN BLUE = -25

OFFSET RED = -3
OFFSET GREEN = 0
OFFSET BLUE = 2

CMS SETTINGS : HUE, SATURATION, BRIGHTNESS
RED : H = 12, S = -18, B = 1
YELLOW : H = 0, S = -41, B = 27
GREEN : H = -20, S = -42, B = 28
CYAN : H = 5, S = -47, B = 35
BLUE : H = -27, S = -9, B = 4
MAGENTA : H = 0, S = -26, B = 12


ISF "2.40:1 USING LENS" SETTINGS

CONTRAST = 4
BRIGHTNESS = -6
GAMMA CUSTOM 2 CORRECTION VALUE 2.5
COLOUR TEMP CUSTOM 2

Custom Colour Temp 2
GAIN RED = 0
GAIN GREEN = -3
GAIN BLUE = -12

OFFSET RED = -1
OFFSET GREEN = 0
OFFSET BLUE = 2

CMS SETTINGS : HUE, SATURATION, BRIGHTNESS
RED : H = 0, S = -20, B = 40
YELLOW : H = 0, S = -38, B = 60
GREEN : H = -15, S = -34, B = 60
CYAN : H = 0, S = -28, B = 55
BLUE : H = 0, S = -20, B = 50
MAGENTA : H = 0, S = -20, B = 48

I'm planing on renting an i1 Pro soon to redo my HD350/IscoII/VideoEQ Pro calibration and I plan on taking two sets of readings with and without the lens to see what results I get. I will likely only calibrate with the lens in place though as this is the vast majority of my viewing (unless I have enough time to adjust a spare memory). I would expect there to be some difference between results, though whether they are big enough to be noticable with the naked eye is another matter.

Could you place your current probe in front of your pj and lens and take a reading for white, and then move the lens to see if it changes? You could then see if the lens was introducing any colour shift (assuming you still have your old probe).

Gary

He is coming in Oct again to do another ISF calibration again because I have know moved it back from it original position. When he originally did it he showed me the results without the lens and then with the lens it didn't change( he was actually quite impressed ).

Yes I could, but I haven't had much chance to mess about with the calibration lately. I'll see if I can get round to it in the meantime (assuming you were directing your comments at me Gary ).

If its directed at me Gary I don't have the equipment I have to leave it to the experts which would be in OCT.

Oops, sorry, I was asking Kelvin

Gary

Gary. I don't have the equipment but if your interested will be happy to share OCT results with and without the lens if any of you like. Just curious whats everyone using because Im interested to ask him when I see him what he is using and the comparison between the two.

I thought I'd stepped on Franin's toes there. I'll get back to you with some results at some point (only an i1 LT sensor though for now).

I'd be interested in all results, though especially Kelvins, since we both have the same ISCO II lens. I can't remember if I measured my lens when I had a pj, but as I didn't move mine for 16:9, I probably didn't do the comparison.

Gary

Dont worry about that mate

I'd be interested to see the results from a probe like SENCOR

I don't know what probe was used in the above measurements, but it wouldn't have been a budget model. However, if I take two readings using the i1 LT within minutes of each other even if the absolute readings aren't @D65 it should still show if there is a difference with my Isco II in and out of the light path.

Thinking about it, there may well be differences not specifically related to any colour tint in the glass (if any?) but more to do with the uniformity of the projector in question. I know if I move the sensor even a small amount I can get variations in the readings (it was worse with my previous AE3000 for sure). Putting the lens in place may mean that a different sample of pixels ends up in front of the sensor perhaps?

Ultimately it doesn't really matter if the calibration is done with the lens in place (in my case as that's the majority of viewing anyway). If there is a requirement for non lens ARs then a separate calibration could be saved if it was felt to be that important.

No, sorry. It was cylindrical.

So where is the adjustment for astigmatism correction? And am I left to think the owner didn't know the difference between a prism and cylindrical lens? Hey maybe he is the same guy that typed that "review" about the MK4 when he actually had an MK3 in his possession

I'll see if I can find the review he did and link it for you to read

When you guys n' gals are doing your with lens and without lens measurements, could you also do CR, both On/Off and ANSI.

Would be most interesting to see the difference among the available lenses.

Don't know that it had one. Don't think it did. It was definately not a prism lens. And yes, would not surprise me one bit if some reviewer didn't know the difference.

Here's a good image of it.

Which reviewer was that Mark?

Here is the thread.
And here is a picture of his set up

You do mean lens in vs lens out + zoomed image of the same size? just to ensure one would be comparing apples with apples and not an image that's 78% smaller...

Josh has a nice setup. Does he still have the marantz? I know marantz is out of the projector game.

I believe he sold the lot a while ago.

Square anamorphic lenses are nothing particularly new. Here's the old Professor himself, Jean Chretien, showing off the original square lens in 1951...



It was mainstream technology, even by then, being what is regarded now as an old-fashioned, bare-basics, 4-element design, from 1927. Not quite as ancient as prism systems, but close.

Chretien's design didn't last long because it was so simple and there was too much distortion, as well as some ghost imaging, but it was good enough to get Cinemascope off the ground. It seems there are advantages to be gained by buying other people's designs whole, especially if you let others think it was your own brilliant invention...



Here it is on the first Cinemascope camera. 20th Century bought it right out of Chretien's desk drawer...



I even found this mysterious example (sorry bumped up from a lower res thumbnail)... squared lens in a round barrel... easier to rotate for lineup purposes, I'd think...



So, I guess square anamorphic cinema lenses have been around for, oh, at least 90 years (and the 4-element design form, about the same)

Seems there really is nothing new under the sun. "World Firsts" are rarer than some would like you to think.

That post about the Marantz lens...

http://www.dtvforum.info/index.php?s...namorphic+lens

...is wrong on at least one major count. From the post:


Prism lenses have a GREATER need for a curved screen. They distort the image even MORE than simple cylindrical systems do. Prism lenses have no curved air-glass surfaces to compensate for distortion. As a general rule the more curved surfaces you have, the better. Less curved surfaces mean you have less to play with in anamorposing the image. A prisms systems have ZERO curvature, then they can do nothing to fix the kinds of distortion a curved screen ameliorates.

Some prism systems have a "corrector" lens. The curvature on these corrector lenses is virtually nothing. It is a very weak lens that does a very subtle job. Corrector lenses are almost (but not quite) equivalent to a sheet of flat glass. They don't really count as a "curved surface" for distortion-correction purposes.

Sheesh...

Maybe world first for astigmatism correction for that design

Is it just me or does the bottom left corner where the elements are look plastic? Either the holders were plastic or the elements were? Looks a little odd and probably too hard to tell from one photo anyway.

So this lens is not being made anymore? Was awfully tiny for the price don't you think?

Hi Frank, what design do you mean?