False Colors With Removed Aa Filter With Large Apertures

To participate in the forum you must log in or register.

Author	Replies: 5 / Views: 1,349
rmpsrpms Pillar of the Community United States 4038 Posts	Posted 05/06/2013 1:05 pm I started another thread over on photomacrography.net that might be of interest to folks here. I'm seeing "false colors" on my T2i after removing the AA filter ("HRT2i"), and show some examples with discussion from others as well. This has some implications to the apertures I can use with the HRT2i. I had already realized there is little or no benefit to shooting wider than the DLA of the sensor, but now I see some serious drawbacks to it if you remove the AA filter. I also tested the idea of improving sharpness by doubling magnification using a 2x teleconverter. The result is ASTOUNDING. But before you get excited, this only works for a system that is not DLA limited. If you are already DLA limited, sharpness will actually degrade. For full effect, the effective aperture must be 2 stops larger than the sensor DLA. It's a tall order, especially for the smallest pixel pitches like the T2i. I used my 105PN to test the theory, and while it's not quite good enough (!!) for full effect, it did show a significant sharpening capability with the 2x teleconverter. A 1.4x teleconverter would only require 1 stop margin to DLA... Anyway, here is the discussion: http://www.photomacrography.net/for...28227#128227 Contact me for photographic equipment or visit my home page at: http://macrocoins.com Report this Post to the Staff

SsuperDdave Moderator United States 23522 Posts	Posted 05/06/2013 1:32 pm That's precisely what I saw from Day One with the 75ARD and unmodified T2i. The exact same phenomena, as discussed here before. Report this Post to the Staff
rmpsrpms Pillar of the Community United States 4038 Posts	Posted 05/06/2013 5:39 pm SD...wasn't that due to the LED's not being diffused, ie the "red and blue sparklies"? That phenomenon looks similar, but this thing I'm seeing now is independent of lighting. One of the PM forum members suggested I re-do the experiment with halogen or xenon, presumably because he expected the colors were due to the color spikes in the LEDs. I did take new shots and posted them, but the false colors are still there. It could be due to the same effect, but now is independent of lighting. That would be cool, but I still can't explain it. If my hypothesis is wrong, we need a new hypothesis... Contact me for photographic equipment or visit my home page at: http://macrocoins.com Report this Post to the Staff
SsuperDdave Moderator United States 23522 Posts	Posted 05/06/2013 8:18 pm I was getting the same thing with both diffused and non-diffused LED's and the halogens I'd used for years before. I didn't pursue an answer from that direction because I found such an easy correction in post. We may be looking at separate phenomenon anyway, even if the symptoms are so similar. Report this Post to the Staff
rmpsrpms Pillar of the Community United States 4038 Posts	Posted 05/07/2013 5:57 pm What is the correction you apply? From discussion on the other thread, "sparkles" as they call them is the consensus opinion. Larger apertures make the problem worse, as I found. Ray Contact me for photographic equipment or visit my home page at: http://macrocoins.com Report this Post to the Staff
SsuperDdave Moderator United States 23522 Posts	Posted 05/07/2013 6:13 pm Quote: What is the correction you apply? Reduction of chrominance noise (Canon's term) in RAW pp. Works like a charm. Report this Post to the Staff
	Replies: 5 / Views: 1,349

To participate in the forum you must log in or register.

All Forums Category: General Numismatic Forums Forum: Coin Photography, Image Editing, and Related Software

The First Dollar, your premier source for bullion and rare coins. See our bullion list on the site and the coin inventory on ebay.

Silver Gold Bull US is the United States leading bullion dealer. We deliver gold coins, gold bars, silver coins, silver bars and precious metals to your door. Order today!

View Last 100 New Topics

View Last 100 Active Topics

Disclaimer: While a tremendous amount of effort goes into ensuring the accuracy of the information contained in this site, Coin Community assumes no liability for errors. Copyright 2005 - 2026 Coin Community Family- all rights reserved worldwide. Use of any images or content on this website without prior written permission of Coin Community or the original lender is strictly prohibited.
Contact Us | Advertise Here | Privacy Policy / Terms of Use

Coin Community Forum

It took 0.27 seconds to rattle this change.