jaapv
RFF Sponsoring Member.
Notice the skin colour on the arm is far too hot too without the filter. Synthetic blacks are the least of your worries. Everything containing chlorophyl - that is all foliage!- gets olivegreen or yellow, everything containing haemoglobin - mainly Caucasian skin- gets too red/purplish.Basically all colours shift.
As for sharpness, filters will make the image sharper. IR images are focussed in a different point than visible light images. That means that you will have a (four stop underexposed) unsharp IR image superimposed over your visible light image.
Keith
The best camera is one that still works!
Just saw this post and agree with jaapv totally here ... the black synthetics issue is easy to predict but all the other potential colour shifts aren't and it's not worth the risk of skipping IR filtering IMO.
willie_901
Veteran
I would like to think a lot of things... but physics says whenever IR energy reaches the sensor of a M8, the color parameter estimates from the Bayer interpolation calculations will be in error. The more IR energy there is, the greater the error. The error can be amplified or attenuated by the lens glass elements and coatings and these errors may not be evenly distributed across the image. The parameter estimate errors can not be corrected in post processing because we can't know enough about the distribution and intensity of the IR energy that happened to reach the sensor. And you are right. It's not "too bad" when there is no, or hardly any, IR light is reflected by your subjects. It is even less bad when the IR light intensity is the same everywhere in your subject and your lens elements transmit IR energy equally at all points.
Sean Reid happened to make a mistake in his early analysis of the M8's color fidelity. This doesn't mean the laws of physics no longer apply. It only means even information one has to pay for on the Internet might not be complete. And we all make mistakes... so it goes.
Common sense dictates that IR filters are profoundly important for M8 color photography. Otherwise when people use infrared film all their negatives would be blank. IR film photography is not limited to subjects that that contain certain types of synthetic fibers that efficiently reflect IR energy. Just search for IR film photos on Flickr and see for yourself the range of subjects where IR light is present.
Technically the requirement for IR lens filters is caused by the fundamental nature of Bayer sensors. One can never estimate the true, but unknown, visible-light photon counts measured by a given sensor site because the amount of IR photons also counted by that site can not be estimated. This means that any time IR energy is present, the M8 sensor visible light photon counts are in error. They are wrong.
Some lenses have IR hot spots. This means the errors induced by IR photon counts may not be the same everywhere in the image.
Early in the M8 release cycle people thought they could design Photoshop actions to estimate the true, but unknown, visible photon counts in any given M8 image. This approach failed for the reasons I explained above.
Color reproduction in photography is difficult and complicated. I do not see how looking at images without filters is of any use at all because except for the extreme cases, you have no idea what the visible color was in the first place. A subtle error is still an error. Nor do you know where the intended focal plane was.
dotur
od karnevala
Exactly. I have been using M8 with and without UV/IR Leica filters since 2008-11-11.
The concept of "true color" is a fiction, both in digital and in film photography.
M8 is definitely not designed for critical color reproduction - but it is a mighty tool for color and bw interpretation. Mostly I shoot without filters and do my corrections in LR if necessary - less saturation for magenta (-60) and sometimes the same for purple or blue.
Filters do help, but then you need coding for wide lenses, or you have to use CornerFix.
And forget JPG for color work - shoot DNG.
www.ivanlozica.com
When I first took an M8 along on a trip I wasn't yet convinced of the need for the IR filters, so didn't use them. Mostly it seemed ok, but there were a few instances where the lack was evident. Here's one example, where the false magenta fabric coloring is noticeable but maybe believable. In other instances it was not acceptable, in particular at a banquet with incandescent illumination... Color correction was simply impossible.
squirrel$$$bandit
Veteran
Well, I got a little more money selling stuff than I expected, so I bought a couple of UV/IR filters for my two favorite lenses. I'll do some testing when I get the camera and decide if it's worth investing in them for the rest.
> Technically the requirement for IR lens filters is caused by the fundamental nature of
> Bayer sensors.
The Bayer-Pattern Mosaic filter has Red-Green-Blue dyed layers that do not do very well absorbing Infrared. Too bad the absorption curves of the dye used does not extend into the Infrared as well.
The response of Silicon CCD's is well into the Infrared Range, going out to 11,000Angstroms. The silicon CCD's used typically have the equivalent of a hot mirror over them, or IR absorbing glass. Absorbing glass is very thick, judging by the one that I removed from the Coolpix 950. The Hot Mirror filter of the DCS200c and DCS420c was not strong enough to kill all of the Near Infrared and an extra Hot Mirror in front of the lens was required.
I suspect the Hot Mirror used in the Kodak CCD for the M8 is just not strong enough, and the second Hot Mirror is required over the lens.
In my case, the Kodak DCS200ir cost an extra $4,000 to do a custom run of the CCD with the Hot Mirror left off to get full response in the Infrared. I use a Hot Mirror Filter over the lens if I want "just Visible". Same with the Coolpix 950, now.
Too bad that Gallium Arsenide detectors are so expensive. The response does not go into the IR unless you formulate extra materials into it.
> Bayer sensors.
The Bayer-Pattern Mosaic filter has Red-Green-Blue dyed layers that do not do very well absorbing Infrared. Too bad the absorption curves of the dye used does not extend into the Infrared as well.
The response of Silicon CCD's is well into the Infrared Range, going out to 11,000Angstroms. The silicon CCD's used typically have the equivalent of a hot mirror over them, or IR absorbing glass. Absorbing glass is very thick, judging by the one that I removed from the Coolpix 950. The Hot Mirror filter of the DCS200c and DCS420c was not strong enough to kill all of the Near Infrared and an extra Hot Mirror in front of the lens was required.
I suspect the Hot Mirror used in the Kodak CCD for the M8 is just not strong enough, and the second Hot Mirror is required over the lens.
In my case, the Kodak DCS200ir cost an extra $4,000 to do a custom run of the CCD with the Hot Mirror left off to get full response in the Infrared. I use a Hot Mirror Filter over the lens if I want "just Visible". Same with the Coolpix 950, now.
Too bad that Gallium Arsenide detectors are so expensive. The response does not go into the IR unless you formulate extra materials into it.
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When I had my M8 I used the filters but never bothered with coding. The widest lens I used was a 35 and it wasn't necessary.
That's great news! I still think Leica should upgrade the firmware to allow for the manual selection of lenses like on the M9.
But I'll be shooting 50's anyway.
But I'll be shooting 50's anyway.
scatteredpixelphoto
Newbie
Odd, I just got a VM 50mm 1.5 and I've shot a bunch of pix of different types of black fabrics and no magenta showed up. Is there a special element in that lens that I am not aware of which acts as an equivalent to an IR cut filter?
willie_901
Veteran
It is possible the fabrics were not illuminated by light with a significant IR component.
Another possibility is the black fabrics you photographed does not contain polymer fibers that are strong emitters of IR light.
Another possibility is the black fabrics you photographed does not contain polymer fibers that are strong emitters of IR light.
raid
Dad Photographer
I notice less magenta when using the CV 50mm/1.5 without an IR cut filter on the M8.