terrycioni Posted April 5, 2007 Share #1 Â Posted April 5, 2007 Advertisement (gone after registration) Absorption versus interference, etc. Does this mean all that cash I spent on B+W filters was a waste of money? I know need rush out and get the far more expensive Leica (interference) filters. My head hurts. Where are we at here with filters, sorry Guy but I am tempted at this point to take them all off and not worry about it Has anybody done a definitive test that clearly demonstrates the superiority of over the other. Â Sigh...so much fun, I can't stand it! Â Terry. Link to post Share on other sites More sharing options...
Advertisement Posted April 5, 2007 Posted April 5, 2007 Hi terrycioni, Take a look here Leica/B+W/Heliopan/Rodenstock Filters. I'm sure you'll find what you were looking for!
DaveEP Posted April 5, 2007 Share #2 Â Posted April 5, 2007 I have not yet done a test, but I have one Leica E39 and one B&W E39. Â If people can agree on what the test subject and methodology should be, I would be happy to go for it, but alas I fear that what ever I do, *someone* will shout from the roof tops that the test is totally invalid.... Link to post Share on other sites More sharing options...
Guest guy_mancuso Posted April 5, 2007 Share #3 Â Posted April 5, 2007 I would probably wait until the new version is out just because certain parameters may change in the firmware so it may be good this week but different after the next firmware. Even though they maybe slightly different for the majority of things you may see no difference or very slight difference. Leica is still fine tuning things also. Link to post Share on other sites More sharing options...
wparsonsgisnet Posted April 5, 2007 Share #4 Â Posted April 5, 2007 Terry, I believe all three of the IR-cut filters work with interference (B-W, Leica, and Heliopan). Â Sean Reid was expecting that the Leica's would be made by B-W. The required volume of these difficult-to-manufacture filters may mean that Leica has used multiple sources. Link to post Share on other sites More sharing options...
scott kirkpatrick Posted April 5, 2007 Share #5  Posted April 5, 2007 Absorption versus interference, etc. Does this mean all that cash I spent on B+W filters was a waste of money? I know need rush out and get the far more expensive Leica (interference) filters. My head hurts. Where are we at here with filters, sorry Guy but I am tempted at this point to take them all off and not worry about it Has anybody done a definitive test that clearly demonstrates the superiority of over the other. Sigh...so much fun, I can't stand it!  Terry.  Cmon, this is not rocket science, this is high school physics -- it's within the reach of, say, 75% of us.... Here's what we want to know -- how different are the color shifts and vignetting effects of each of the three (four?) groups of filters? So put each filter on the widest angle lens you have, turn lens detection OFF so there is no chance of firmware correcting anything, put an Expodisk or even better, just a sheet of frosted glass or plastic over the lens, set focus distance to infinity (lens as close to the imager as possible) and shoot a cloudy sky using aperture priority at each aperture from wide open to f/8. For each filter. Keep careful notes and label the shots. Turn the resulting images into 900x600 jpgs, keeping them labelled and using the same development defaults. Poke at them in Photoshop, IrfanView, or any tool that lets you plot the RGB values. See if you can tell apart the various filters at a given aperture. Or send them to me and I'll plot them up. If all these filters give the same result to within a few percent, then what works for Leica will work for the others.  Nothing that I said above requires waiting for 1.10, since the real question is whether the filters give different effects, and we can see this before asking how well the corrections in 1.10 work.  scott Link to post Share on other sites More sharing options...
terrycioni Posted April 5, 2007 Author Share #6  Posted April 5, 2007 Oh no... I must have been away for that particular high school physics lesson. I am relieved to hear it is not rocket science - whewww.  I must have missed the UV/IR filter lesson in photo class too!  Scott: I do have a 67mm Rodenstock UV/IR filter but no Heliopan  Oh well Link to post Share on other sites More sharing options...
eronald Posted April 5, 2007 Share #7  Posted April 5, 2007 Advertisement (gone after registration) Actually, I am not sure it's not rocket science - I had never heard of interference-based filters with such a large pass-band before this. Amazing teh things that can be done with "simple" physics. However I would expect the transmission factor at a given light frequency to be also influenced by the angle of incidence of the light, yielding some very strange frequency-dependent vignetting effects, which will of course be compounded by the sensor.  Edmund  Oh no... I must have been away for that particular high school physics lesson. I am relieved to hear it is not rocket science - whewww.  I must have the UV/IR filter lesson in photo class too!  Oh well Link to post Share on other sites More sharing options...
scott kirkpatrick Posted April 5, 2007 Share #8 Â Posted April 5, 2007 Actually, I am not sure it's not rocket science - I had never heard of interference-based filters with such a large pass-band before this. Amazing teh things that can be done with "simple" physics. Â The filters themselves are really cool, and it takes a lot more than high school physics to see how they work. I went through half a dozen textbooks in our engineering library without finding a good worked out example. Optics is not a very active field in engineering education, I guess, except for high speed optical communication and switching, which does use this kind of trickery. Â But comparing two filters to see if they do different things is well within the range of a high school science project. Figure out how to make a nearly uniform white or grey image, and see how the filter changes it. Then compare the changes resulting from each filter... Â regards, Â scott Link to post Share on other sites More sharing options...
wparsonsgisnet Posted April 5, 2007 Share #9 Â Posted April 5, 2007 Clearly the *use* of the filters is not rocket science, because I got it. The whole idea of multiple depositions of microscopic layers, all exactly the same thickness, does blow my mind. Â Much more demanding than the smoke chamber for tagging fingerprints on CSI. I have noticed that the actors in those shows do not look like they have PhD's in physics. Link to post Share on other sites More sharing options...
scott kirkpatrick Posted April 5, 2007 Share #10 Â Posted April 5, 2007 The whole idea of multiple depositions of microscopic layers, all exactly the same thickness, does blow my mind. Â Who said they are all the same thickness? There could be a carefully designed sequence of thicknesses, each canceling a different band of wavelengths... I haven't seen a description of exactly how it is done, but there is probably a literature in optics journals about it. Â scott Link to post Share on other sites More sharing options...
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