Magenta Problem

[hugo_ghiara]

Did leica solved the magenta problem , and if so starting in which particular

serial number?

Thanks

[umut_arslan]

No, it will be solved when m9 comes out

[stuart_richardson]

The solution is to use IR blocking filters...combined with coded lenses for focal lengths

35mm and wider. The IR filters eliminate the problem but are expensive (though two come

free with the camera...eventually) and can cause additional flare and reflections compared to

use without a filter. It is pretty much necessary to use a coded lens (by Leica or self-coded)

with wide angles, because the IR filters cause cyan vignetting with lenses 35mm and

wider...the wider the lens, the more apparent the vignetting. The coding eliminates this

vignetting.

[fred_c1]

All you need to know: http://leica.nemeng.com/004f.shtml

[dan flanders]

I am familiar enough with the principles of optics to know about the issue of filters possibly introducing flare, but have never seen any hard data about quantifying it. Nor have I ever been able to introduce and repeat it under controlled conditions. Yet, just in case, I remove my protective UV filters in situations where flare might be a factor though it is doubtful that it makes any difference that can be detected by normal observation. Ergo, in my most arrogant opinion it is nothing more than another bogey-man to be paranoid about!

[christoph_hammann]

It's not a bug, it's a feature ;-)<br>

The IR sensitivity is said to give differentiation in the shadow areas in B&W photography

under some lighting conditions.

[stuart_richardson]

Dan -- it is real and it is annoying. The issue is that the IR filters cannot evidently be

multicoated on both sides. Only one side is coated so it leads to reflections. Shooting into

the sun, I have had problems a few times. I have had some severe flare and I have had

reflected images (where a bright source of light is reflected back onto the sensor...so a

bright blown out window reappears again as a ghostly reflection at the bottom of the

image). Here is an example: <P><img src="http://www.stuartrichardson.com/75-IR-

flare.jpg"><P><img src="http://www.stuartrichardson.com/28-IR-flare.jpg"> <P>Both

of those shots are from the M8 with the 486 B+W IR filter. The first is the 75mm

Summicron, and the second is the 28mm 1.9 Ultron. Neither are very flare prone lenses,

both were used with a hood. The IR filter is the culprit here...

[fred_c1]

Hood/filter or not, a stong light source shining directly on the front element (even from outside the frame) will cause flare/ghosting most of the time.

 

Another often-overlooked shortcoming of an RF camera is that you often can't tell when the lens is not sufficiently shielded.

[ronald_moravec1]

I see no reason to leave the ir filter in place all the time. The magenta problem only occures when certain fabrics etc are present. The few times it shows up, just fix in PS as it is a quick fix. For the examples shown, the pic would have been better off without the filter.

 

If you are doing a wedding and don`t want to fix every pic, leave it on the lens all the time. But for street shooting, nature, landscape, and archicture, do you really need it?

 

Now the question is, if you leave it off and shoot with coded wides, does the camera try to correct cyan fringing that is not there? Maybe the coding could be undone with black tape over the camera receptor.

 

Just some thoughts as I do not have an M8.

[stuart_richardson]

Ronald -- I think if you had an M8, you would see that the problem is always there. Colors

aren't "right" without the IR filters. With the filters they are spot on. As I am sure you know,

infrared light is with us everywhere, and with a sensor that is susceptible to it, it influences

all the colors. Certain things are more influenced than others, but it is more than just "certain

fabrics". Even the fabrics are really common. Try it if you get an M8...most clothes these days

are no longer pure cotton or wool...almost everything is blended with synthetics...this is not

to mention thing like winter jackets, backpacks, bags, hats, gloves and so on. <P>As for the

wide angles, you have three options in the menu for coded lenses -- off, on, and on with UV/

IR filter. Only the last one will perform the cyan vignetting correction.

[Brad_]

>>> The few times it shows up, just fix in PS as it is a quick fix.

 

Not true.

 

Other colors will be modified in the correction process. I suppose it might be OK if you're

not fussy...

[bobtodrick]

Just a thought (a sarcastic one, though-be-it). So leaving the IR filters affects all colors somewhat. I remember when Velvia was first introduced...AND PRAISED to high heaven...because of it's pumped up, artifical blues and reds. It really is true...ya just can't keep a Leica owner happy ;-(

[bobtodrick]

Sorry, just had to add a serious component to the above post.

 

At all time in photography we've dealt with color issues. Kodachrome gave such natural skin tones...Ektachrome was too blue...3M, well hell, no one could figure out the color on that stuff. Even today...EPP, EPN, VS, G, GW...and this is the Kodak line only. All with different contrasts and variations in color. At no time did we ever really expect a film to be dead accurate.

 

With digital Nikon color is a little different than Canon, which is different than Leica, which is different than...

 

My point is that Leica did make a decision (granted, it might have been wrong, though sold out M8 kind of show they didn't) to leave off the IR filter to give the absolute best, sharpest B&W file. Bus as I said above...we Leica owners will always find something to complain about. (really no different than anyone else...check out The Nikonians sometimes...those boys get testy!!)

[dan flanders]

Please re-read my post and note that I said that I had never seen any hard data regarding flare caused by filters! I have studied and experimented extensively with filters and hoods in 'contre-jour' situations and though I have been able to control the flare that certain lenses are prone to (particularly collapsible Summicrons), I have not been able to repeat the results on a reliable basis. Even using a deep rectangular shade constructed according to the shape of the rectangle enclosed within the cone of acceptance of the lens, to completely eliminate the flare would require a hood several feet deep that would completely obscure the scene through the VF. Such a hood can significantly reduce flare without inducing corner fall-off but some peripheral light will reach the lens anyhow. As I also stated, I accept the notion that filters theoretically will induce internal reflections that will cause flare and sometimes ghost images, I have been unable to detect any significant reduction in image quality that can be repeated in experiment. Accepting the notion, and complying with indicated corrections does not mean that I don't 'have me doubts!' I don't have an M8 and it is unlikely that I will acquire one in the near future -- my comments were related strictly to experience with film cameas!

[stuart_richardson]

Dan -- I read your post; I just disagree with it. If you do so much as pick up an IR filter you

will see how the potential for flare exists with them. Straight on they are clear, but even at a

slight angle they are completely red or green depending on the angle. They are like mirrors if

you look into them. The examples of flare that I posted above perfectly match the color of

the IR filters. I have shot with both the 75mm summicron and 28mm ultron in very similar

lighting situations without the filter and have not had any flare like that. I would agree that

something like a B+W MRC UV filter would not contribute significantly to flare, but these IR

filters are very different beasts. I truly wish I didn't have to use them, but they are necessary.

It is a testament to the M8 that I am willing to put up with them.

[ronald_moravec1]

The easy fix I have tried with posed images is color selection tool in CS 2. Point to the magenta and adjust fuzzyness. Then desaturate.

 

If you have real magenta in the selection, use the laso to deselect that area.

 

Not bad for one pic I know, but a royal pain for a wedding

 

I know I can`t compete with M 8 owners in knowledge on this, but maybe I will get one. Better yet, I will wait for a Digi R. In the meantime I`ll use my Nikon D200 18/70 and Viso lenses with CameraQuest adapter.