OLPF-mod/fish-net/back-filter for Moire?

U

USLatin

Panamaniac
I hope this question will spark a discussion that will cover any possibilities of limiting the detail to about 720p (or where that may fall) to avoid moire.

Some may want it to be removable, but if it made it far easier or feasible I am also sure many wouldn't mind a permanent modification to a $1,700 body.

I know fishnets are/were used between the lens and the camera, and I believe it gives a softening effect... but I have never done it and that might not be the look it gives you.

What about some sort of internal modification, like a OLPF mod... I was wondering if there could be a spot in the optical path where a small purpose-built filter could be dropped in, screwed in, heck... glued in. ;)

What about some sort of adapter that could click in and somehow still allow the same back-focus distance?
 
That would be the ideal solution, but the problem is that it would change the focal point permanently. Not a big deal if you always focus by eye (which, given the accuracy of the markings on SLR lenses, you should be doing anyway).

The SLR already has an OLPF installed, suitable for still cameras. If someone wanted to make some real dough at modifying SLRs, they should just pop that filter out and replace it with an appropriately stronger one.
 
The problem with putting something in front of the lens is, the varying focal lengths will demand different degrees or patterns of diffusion to cancel out the frequencies that the moire happens at.

I've done extensive testing with the Caprock anti-moire filters, and found that some combinations work really well (such as 25mm with the 1.0) and some are completely useless (such as 85mm with the 1.0). The 2.8 works really well with the 85mm, but it's pointless with the 25mm.

The way to do it right would be behind the lens.
 
Would a small square cut out off a caprock or other filter shoved in there somewhere do any good?

Barry_Green said:
The SLR already has an OLPF installed, suitable for still cameras. If someone wanted to make some real dough at modifying SLRs, they should just pop that filter out and replace it with an appropriately stronger one.
Click to expand...

So would these be available from other cameras? I suppose not since it would be an abnormally strong filter, correct?

Once made how hard could it be to replace them...

...unfortunately I doubt enough people would understand how amazing this would be, and they would be fixated on having to pay for severe resolution loss.

Barry_Green said:
That would be the ideal solution, but the problem is that it would change the focal point permanently. Not a big deal if you always focus by eye (which, given the accuracy of the markings on SLR lenses, you should be doing anyway).
Click to expand...

I suppose you are referring to a click-in adapter. If so, would we also lose infinity focus capabilities?
 
dcloud said:
since these cams pixel bins.... those would just reduce it to lower resolution...
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The pixel binning is what has already reduced it to low resolution.

An optical filter would just cut out all the garbage that seeps through and contaminates the image.
 
USLatin said:
Would a small square cut out off a caprock or other filter shoved in there somewhere do any good?
Click to expand...
Doubtful. You'd want a normal diffusion filter, not something like a caprock.


So would these be available from other cameras? I suppose not since it would be an abnormally strong filter, correct?
Click to expand...
I wouldn't expect any other camera's filter to work. The only one that could possibly work would be one from a video camera, but that's not gonna happen because their sensors are too small.

...unfortunately I doubt enough people would understand how amazing this would be, and they would be fixated on having to pay for severe resolution loss.
Click to expand...
There's already sites out there advertising to *remove* the anti-alias filter from your SLR so that you get "sharper" images... sigh.



I suppose you are referring to a click-in adapter. If so, would we also lose infinity focus capabilities?
Click to expand...
Unless it was engineered to be a direct replacement for the existing filter, then that is a possibility, yes.
 
So, bottom line, any real hope on any of these fronts Barry?

An other diffusion filter shoved in there? A click-in? Even murdering those OLPF people, would it help my image at all? :)
 
Putting an OLPF behind the lens? That's a dedicated hardware fix. If somebody like Illya does it, then it becomes a reality. But without someone specifically like him or some other qualified hardware tech doing it, well, don't hold your breath -- I don't think any DIY solution is likely to produce consistent, reliable, better results.
 
There are IR conversion shops that deal with replacing the OLPFs and IR-cut filters on DSLRs all the time. I'm sure you could pay one of those shops to install a new OLPF directly on the sensor for a reasonable price. Of course, you'd have to source an appropriate OLPF for 1080p which I'm not sure where or how strong.
 
That sounds reasonable, yes... the big thing would be determining the appropriate strength, and 1080p would be the way wrong strength. You'd want something more like 720p to match up with what the camera actually resolves.
 
Would the perfect OLPF be one that allowed just under the maximum clean lines resolved in a 1080p shot with the best lens possible at its sweet spot?
 
It should pass exactly as much detail as the sensor can comfortably resolve, and no more. So having a perfect image sent to the filter is a fine way to test whether it's working, but it doesn't really matter what the image is, as long as it's as sharp or sharper than the imager can resolve.

I would love it if I could use my sharpest lenses at the sweet spot. Right now the results are absolutely sickening on any wide shot, and I purposefully have to blur them down to get acceptable results.
 
I find it strange that people are dropping large sums of money on SLR lenses for "absolute sharpness" when all they intend to do is shoot video and not stills. I can understand ergonomics, weight, color, bokeh, breathing but I don't get sharpness. SLR lenses have been out resolving 1080p on 35mm and APS-C for a long long time.
 
Scarlet and Epic will take their $500.- electronic Canon mount (and Nikon too). Add a RedMote Pro and you got wireless follow focus with your fav SLR lens a'la Birger mount. They plan to release Mostro, an FF35 sensor, and in the mean time you get to shoot pro stills, avoid CA and distortion, and enjoy their contrast. They are a solid investment. Unless you can afford better, like ZF's, Compact Primes, the upcoming 17-50mm RPZ, or RPPs... or MPs which would be swheeet on a 7D with a proper low pass... then blow your mind on an M-X sensor.
 
Barry_Green said:
Putting an OLPF behind the lens? That's a dedicated hardware fix. If somebody like Illya does it, then it becomes a reality. But without someone specifically like him or some other qualified hardware tech doing it, well, don't hold your breath -- I don't think any DIY solution is likely to produce consistent, reliable, better results.
Click to expand...

The EOS D2000/Kodak DCS520 had a 1,728 x 1,152 APS-C sensor, EOS D30 was 2160x1440 APS-C. Looks like a $100 or less experiment from ebay, discounting the risk of destroying your new sensor.

(Or wait 6-12 months for the readout bump that will make this irrelevant.)
 
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shaocaholica said:
I find it strange that people are dropping large sums of money on SLR lenses for "absolute sharpness" when all they intend to do is shoot video and not stills. I can understand ergonomics, weight, color, bokeh, breathing but I don't get sharpness. SLR lenses have been out resolving 1080p on 35mm and APS-C for a long long time.
Click to expand...

I can't see spending "LARGE SUMS OF MONEY", but I do find it desirable to get as much sharpness as you can within your price point.

It really does make a difference in the end, and you can always blur if need be.

What troubles me, is why someone would spend LARGE SUMS OF MONEY on Zeiss lenses that usually are always soft in corners wide open, while Canon "L" lenses are generally great wide open, and fit perfectly, and allow push auto focus in a pinch for less money. Sure Zeiss lenses look good at F8, but for video, most lenses do.
 
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