Purple fringe problems on Leica M9

[moberg]

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Here is a Kodak video which around the 10 minute mark talks about this fringe and why it happens on digital cameras.

 

If you have time you should watch the whole video. Quite interesting.

[jaapv]

Thank you for that video. It eliminates the need for fights on this forum on about 90% of technical sensor matters including hot pixels and red lines.

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[roydonian]

It was interesting, but I can't envisage telling my clients that I can't fly to assignments because high-altitude radiation will degrade my camera's sensor.

 

Best regards,

 

Doug

[kokoshawnuff]

Very interesting video, I have yet to see a degraded sensor that is the result of flying too often, but it sounds plausible.

 

Also what can be picked up from the videos is that, until the actual design of sensors are changed, every digital camera from the canon/nikon to leica to hasselblad will be susceptible to CA at varying degrees. But that's what post-processing is for.

[Washington]

Gregory,

With all due respect: you are just wrong.

[Lindolfi]

Here is a Kodak video which around the 10 minute mark talks about this fringe and why it happens on digital cameras.

 

If you have time you should watch the whole video. Quite interesting.

 

The ray tracings in this video are completely incorrect. A ray that comes in at an angle to the film plane does not bend to an angle at 90 degrees to the film plane in reality. Impossible with optical laws. The rays drawn in the presentation coming into the micro lenses and refracted by them as well as reflected by them do not obey the two laws of optics of refraction and reflection.

Edited August 14, 2011 by Lindolfi

[mjh]

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The ray tracings in this video are completely incorrect. A ray that comes in at an angle to the film plane does not bend to an angle at 90 degrees to the film plane in reality. Impossible with optical laws.

Well, if you could manage to believe light rays can be bent that way, maybe you were also prepared to believe that taking your digital camera on a plane flight will ruin the sensor, another claim made by Rob Hummel.

[ddp]

Hand ground?? That was the first version of the Noctilux - a collectors item. All asphericals at Leica are blank pressed and GNC ground.

 

I believe he was referring to the original 35/1.4 Summilux aspherical for the Leica glass and the Nikkors as far as hand ground goes.

Edited August 14, 2011 by ddp

[jaapv]

Well, if you could manage to believe light rays can be bent that way, maybe you were also prepared to believe that taking your digital camera on a plane flight will ruin the sensor, another claim made by Rob Hummel.

 

Well, in the M8 and M9 manual Leica does warn for negative effects of air travel. Having said that, a few Kms of atmosphere don't do too much to reduce the high-energy cosmic rays that do the damage to sensors either. Some can even be detected in the deepest mine shafts.

[Washington]

I wonder: do some people buy a Leica just to have something to worry about?

[mjh]

Well, in the M8 and M9 manual Leica does warn for negative effects of air travel.

It’s also bad for our health (contrary to Rob Hummel’s claim that gamma rays won’t hurt us). The effect of cosmic rays on the circuits of flight control systems would be a more pressing concern than its effect on our photographic gear. Yes, cosmic rays can and do occasionally cause malfunctions in electronics, but these are mostly of the transient kind – there may be pixel errors in images taken during the flight but that doesn’t mean the sensor is permanently damaged. Lots of digital cameras of various brands (Nikon, Olympus, Samsung etc.) have been used for extended periods on board the ISS where cosmic radiation is even stronger than on a plane.

[menos I M6]

A "pixel error" is in fact a permanent damage to the sensor.

As long, as these damages are restricted, they can be mapped out by software.

 

I read an interesting short article recently about the NASA having actually standard procedures towards the then used Nikon digital cameras regarding checking for sensor issues and marking for reflight or scrap after periods in space due to gamma ray damage to the sensor.

 

The problem is real, although generally not a widespread issue, as of rather short periods of low exposure during flights.

[SJP]

It’s also bad for our health (contrary to Rob Hummel’s claim that gamma rays won’t hurt us). The effect of cosmic rays on the circuits of flight control systems would be a more pressing concern than its effect on our photographic gear. Yes, cosmic rays can and do occasionally cause malfunctions in electronics, but these are mostly of the transient kind – there may be pixel errors in images taken during the flight but that doesn’t mean the sensor is permanently damaged. Lots of digital cameras of various brands (Nikon, Olympus, Samsung etc.) have been used for extended periods on board the ISS where cosmic radiation is even stronger than on a plane.

Numbers, numbers

 

See here

 

Just to add some numbers a transcontinental flight will give an additional radiation exposure of about 70 microSievert (Paris to SF, London-Tokyo), annual natural radiation exposure is typically about 2.8 milliSievert, so about 40x more. Bury your camera in lead and concrete when not in use.

 

Adding 2.5% of extra radiation to natural levels is hardly "bad for your health", sitting at the airport waiting for the darn plane to arrive is of course.

Edited August 15, 2011 by SJP

[Washington]

Oh Lord Help Me!

Now it’s gamma rays. Would lead camera cases help?

I really think radon creeping in from your basement is a MUCH bigger worry.

Personally, I’m more worried about getting run over by a trolley-car while crossing

the street with my equipment.

[jaapv]

Numbers, numbers

 

See here

 

 

 

Adding 2.5% of extra radiation to natural levels is hardly "bad for your health", sitting at the airport waiting for the darn plane to arrive is of course.

 

There are reliable studies showing significantly higher levels of Glioma (brain cancer) in aircraft crew on transpolar flights.

 

 

Of course a transpolar flight and multiple exposures is a worse case scenario.

 

 

Eating aircraft food poses a far larger health risk.

Edited August 15, 2011 by jaapv

[SJP]

and withdrawn: Brain cancer, flying, and socioeconomic status: a ... [Aviat Space Environ Med. 1996] - PubMed result

 

I agree about the aircraft "food" especially KLM food is abysmal nowadays. BA, Emirates are considerably better, to name a few.

[mjh]

There are reliable studies showing significantly higher levels of Glioma (brain cancer) in aircraft crew on transpolar flights.

 

 

Of course a transpolar flight and multiple exposures is a worse case scenario.

Well, that’s the point, isn’t it? While there is a real, statistically measurable risk that a sensor pixel of your camera might sustain permanent damage or you get cancer, you generally don’t have to worry even if you are a frequent plane traveller (being a member of the crew would be a different matter; for good reasons radiation exposure is monitored for flight personnel). As a rule, your camera won’t fail when you take it with you on a plane, and you won’t get brain cancer either.

 

Anyway, this Rob Hummel guy strikes me as somebody who wouldn’t get facts in the way of a good story, i.e. not a good reference when it comes to sensor facts. (If his supposed explanation of purple fringing was correct you would expect purple fringing to occur only with wide angle lenses and mostly near the edges of the image.)

Edited August 15, 2011 by mjh

[jaapv]

and withdrawn: Brain cancer, flying, and socioeconomic status: a ... [Aviat Space Environ Med. 1996] - PubMed result

 

I agree about the aircraft "food" especially KLM food is abysmal nowadays. BA, Emirates are considerably better, to name a few.

 

Yes - and the study by Blettner, Grosche and Zeeb of 1998 reinstated the risks - it is science, so the ping-pong match continues;)

[Washington]

I remember when while flying you were treated to a luxury experience .

Now, you are less than cattle. More’s the pity.

I miss the LZ-129….. Hindenburg.

What does ‘’purple fringe’’ have to do with this anyway?

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Hallo,

Look here: Leica M

[jaapv]

Nothing - you are perfectly right, it is going of at a tangent