UV/IR woes...

[jaapv]

Why not place an AR-coated UV/IR filter over the actual sensor? Is there space to do that?

There are UV/IR conversions done by companies like maxmax for digital UV/IR shooting that remove the need to put a vis-blocking filter on your lens... this is of course done on dSLRs so that you can compose TTL and AF normally. All they do is take out the normal hot mirror or sensor cover and replace it with whatever you want. So you can do Uv, IR, UV+vis, IR+vis, UV+IR only, etc. It seems to me that one could just as easily put any desired hot/cold mirror over the M8 sensor itself, as long as there is ~1mm of space in front of the sensor to do this. I use thin filters for microscopy in my lab all the time. No big deal.

In fact, I'd be totally shocked if somebody isn't doing this and selling the service- it would be a ten minute operation, and the glass plates that would be installed can be mass produced for maybe a hundred bucks apiece, including AR coating for the visible.

(N.b. I will not speculate on what Leica will charge you for what I am describing)

With all due respect to some of the posts above... habitually using a physical or software filter because of unwanted UV / IR sensitivity of your sensor... well I'm not going to say it. You just have to be kidding.

Apologies to offended readers if I am overlooking something obvious about your particular sensors, which I have not yet seen, but I have been following this M8 issue from a distance. There is an M8 in a local store and I could stop by and look and see if it is possible to do what I am saying.

Yes- there is something obvious, you probably were not around here when it was discussed extensively. On an RF the distance between lens and sensor is about half of a SLR and many lenses stick into the body to get even closer. That means the angle of incidence of the light on the edges of the sensor varies wildly. As IR filters are sensible to this angle the images would have deteriorated unacceptably, uncorrectable in software as well. This makes an IR filter in that spot impossible at the present stage of technology, a larger sensor impossible and the current camera a miracle.

 

[keithwms]

Yes- there is someting obvious, you probably were not around here when it was discussed extensively. On an RF the distance between lens and sensor is about half of a SLR and many lenses stick into the body to get even closer. That means the angle of incidence of the light on the edges of the sensor varies wildly. As IR filters are sensible to this angle the images would have deteriorated unacceptably, uncorrectable in software as well. This makes an IR filter in that spot impossible at the present stage of technology, a larger sensor impossible and the current camera a miracle.

Jaap, actually, I did know that, but I thought about it but didn't think it would be a killer, but yeah, now I see I'm wrong. Now I see that this issue you describe is a sensitive function of coverage / focal length of the lens, so an ordinary hot mirror won't cut it, it'd have to be a lensing hot mirror, yikes! 🙄 Thanks for bringing me up to speed.

So...another solution! How about coating the back elements of the lenses. You could coat the fronts but probably you don't want to screw with the multicoating there. Anyway lens coatings are not outrageously expensive... not nearly as expensive as certain camera companies would like us to believe 😉

If anybody has a not-too-dear M lens they want to try, I can dig up some names of companies that do an IR blocking front or back coating. This would get around the problem Jaap describes.

 

[jaapv]

Actually the best thing to have is a filter next to the aperture blades, where the light is more or less parallel. I have one lens with this feature, a 9.8 mm (!) wideangle, and it has no cyan problems at all, obviously without coding.
I'm not sure a coated lens would be suitable for film use.

 

[bluepenguin]

I know what happed to my picture and how the UV/IR affects under certain light point.

Why don't you try it yourself then we can talk more.

Try to take a picture of the object and make 70~90 degreen angle with your filter and strong light source.

You will see the uneven spreading ghost/flare on your picture.

 

[Richard Marks]

I know what happed to my picture and how the UV/IR affects under certain light point.

Why don't you try it yourself then we can talk more.

Try to take a picture of the object and make 70~90 degreen angle with your filter and strong light source.

You will see the uneven spreading ghost/flare on your picture.

I am sure that one can create conditions that produce flare, but this is not necesarilly the fault of the filter. The skill is to re compose so avoiding the problem. It is usually possible. Incidentally one of your earlier posts makes reference to Zeiss glass. There are now plenty of m mount Zeiss lenses. Why did you not try one of these?

Richard

 

[bluepenguin]

Richard,

The problem is due to using an UV/IR filter.
The leica put the temporary solution on their problematic CCD.
Using an UV/IR filter solution was a fault from the beginning.

It is a skill to make a good results. (Yes)
It is a good digital camera that has an antialiasing filter with CCD. (Yes)
It is not a good solution to use UV/IR filter on lens that may cause problem.

 

[jaapv]

I know what happed to my picture and how the UV/IR affects under certain light point.

Why don't you try it yourself then we can talk more.

Try to take a picture of the object and make 70~90 degreen angle with your filter and strong light source.

You will see the uneven spreading ghost/flare on your picture.

I is very hard talking about this if you do no show your examples. The number of times I did have flare because of an IR filter is very limited and veiling flare even more rare.

 

[Paul Kay]

The M8 and UV/IR filters are hardly unique in being able to produce flare under certain conditions! I can 'force' flare with pretty much all cameras/lenses which I do (or have) owned! Actually I sometimes do this because I want to create a particular effect (and quite like the results). You can even add flare in Photoshop. Where now?

 

[TJV]

From what I understand it is impossible to put an anti-reflectice coating on top of, that is to say on the same side of the filter as the IR filtering coating. Leica have stated this (or was it Schneider?) As someone else said, the IR coating is easily scratched so the anti-reflective coating is facing outwards because it's harder wearing. I ALWAYS use UV filters so I'm not against using filters but I'm guessing using a UV/IR is more prone to causeing INTERNAL REFLECTIONS, not flare as such, than good quality multi-coated UV filters because the anti-reflective layer isn't where it counts for digital - sensor side to stop light bouncing of the mirrored surface of the sensor and back off the filter etc.
I think it's pretty bad if one needs to constantly re-check ones self in situations that may cause ghosting artifacts. It doesn't exactly inspire a feeing of creative freedom that I expect (wrongly or rightly!) with my film M's. I was never able to shoot my M8's with UV/IR filters so I can't claim to know the real world practical issues of using the M8 with them. I only know what I've read and my experiences without them.

Thoughts?

I'm seriously thinking of getting another M8 now the initial dust has settled. It's a great camera and the only digi I'd consider buying at this point in time. I would never have gotten a refund on my M8 (which I used for three or four months) if I didn't have important work to do at that time.

 

[Paul Kay]

I shoot both film and digi Ms - sometimes I shoot using inappropriate filtration (UV/IR on film or UV on digi) due to inability to remember to change them. Problem is that I am mostly hard pressed to tell and certainly have seen no evidence of an increased flare tendency with UV/IR. I've had lenses in the past that produced awful flare (the standard Zeiss zoom on the Contax N1 suffered from a very hard, white flare spot at times which I found pretty objectionable as an example - and zoom creep if pointed downwards at all), and I always use lens hoods on the fast Canon L primes that I use extensively as these too suffer from flare at times (hardly a surprise). But my M8 and lenses and UV/IR filters certainly doesn't show flare anywhere near enough for it to be a real problem for me and I doubt that I'm unique. I'm not defending the M8 here but I'm still unsure of the original poster's intent!

 

[jaapv]

From what I understand it is impossible to put an anti-reflectice coating on top of, that is to say on the same side of the filter as the IR filtering coating. Leica have stated this (or was it Schneider?) As someone else said, the IR coating is easily scratched so the anti-reflective coating is facing outwards because it's harder wearing. I ALWAYS use UV filters so I'm not against using filters but I'm guessing using a UV/IR is more prone to causeing INTERNAL REFLECTIONS, not flare as such, than good quality multi-coated UV filters because the anti-reflective layer isn't where it counts for digital - sensor side to stop light bouncing of the mirrored surface of the sensor and back off the filter etc.
I think it's pretty bad if one needs to constantly re-check ones self in situations that may cause ghosting artifacts. It doesn't exactly inspire a feeing of creative freedom that I expect (wrongly or rightly!) with my film M's. I was never able to shoot my M8's with UV/IR filters so I can't claim to know the real world practical issues of using the M8 with them. I only know what I've read and my experiences without them.

Thoughts?

I'm seriously thinking of getting another M8 now the initial dust has settled. It's a great camera and the only digi I'd consider buying at this point in time. I would never have gotten a refund on my M8 (which I used for three or four months) if I didn't have important work to do at that time.

I can only confirm the previous post, yes, flare can be induced, mostly in the form of a green spot somewhere, easily cloned or one of those upside-down refelections of a specular highlight, but seldomly and usually easily cloned. Veiling flare is rare. In short, nothing but the daily photographic routine we all know and are used to.

 

[bluepenguin]

Here is the sample picture

Here is the sample picture

Since many of you want sample picture, here it is.

As you can see, I'm taking a picture of the object and the sun is getting on my way and making interesting flare.

Take a picture of graduation ceremony inside a dorm:

You have to use an UV/IR filter due to everybody dressed in black.
But if you use the UV/IR filter you will have a high possibility of having a flare due to dorm's strong lights from above.

 

[jaapv]

Thanks. Yes- veiling flare. Rather nice artistically btw, but that is beside the point. I would have believed you as well if you had told me this is without filter, because a lens-any lens- can produce something like this just as easily in these lighting conditions. But yes, a filter can do this. So maybe it should have been removed here, as there is no IR problem.

 

[rsl]

Since many of you want sample picture, here it is.

Keep it. It's very good surrealism.

 

[keithwms]

From what I understand it is impossible to put an anti-reflectice coating on top of, that is to say on the same side of the filter as the IR filtering coating. Leica have stated this (or was it Schneider?) As someone else said, the IR coating is easily scratched so the anti-reflective coating is facing outwards because it's harder wearing.

....

Thoughts?

I am thinking one could apply IR coating to an interior element. Then, no scratches, and no problem interfering with the normal AR coating.

 

[jaapv]

All glass-air surfaces on Leica lenses are coated, also the interior ones.

 

[Ben Z]

Since many of you want sample picture, here it is.

As you can see, I'm taking a picture of the object and the sun is getting on my way and making interesting flare.

Take a picture of graduation ceremony inside a dorm:

You have to use an UV/IR filter due to everybody dressed in black.
But if you use the UV/IR filter you will have a high possibility of having a flare due to dorm's strong lights from above.

I've had similar results in similar situations to the example photo many times, with many lenses, with no filters at all, on film and digital.

I was also very concerned with the possibility of getting increased flare from overhead spotlights in otherwise dark rooms (jazz clubs, theaters, receptions, etc.). When I first got my M8 I took hundreds of shots in those situations in an attempt to develop a sense for when the IR filter would cause extra flare and therefore would need to be removed. I found no such situations. I did get some flare, yes, but it was the same with and without the IR filter. The only IR filters I have used in such situations are Heliopan (the only non-Heliopan filter I use is a Leica brand on my 15mm and I've never shot that one in a room with overhead spotlights). After reading someone on the net mention about it, I examined my Leica and 486 filters next to Heliopans and I can definitely see much less surface reflections coming off the Heliopans. Whether that translates to more transmission/less contrast loss as it would seem to, intuitively, I can't say for certain because I'm not an expert on optics. But it's the same difference between a regular B+W UV filter and an MRC, and those definitely have better transmission and less reflection.

 

[bluepenguin]

I use my summicron 35mm 1st most of time and without UV/IR fillter it would generate good rendition of the light instead of flare.

M8 is a great camera and I dont' doubt that.

But I wish that Leica would make CCD with right low pass filter so all of us don't have to use UV/IR filter.

 

[jaapv]

I'm sure Leica engineers have wished the same all along 😉

 

[furcafe]

Yes, the flare problems I have encountered have always consisted of the green(ish) reflected spots. Unfortunately, they tend to pop up quite often when shooting in stage & stage-type lighting (away from stages, candles are usually the culprit) where I do the bulk of my digital shooting, & they are not always easily cloned out (e.g., when they cover an entire eye).

I can only confirm the previous post, yes, flare can be induced, mostly in the form of a green spot somewhere, easily cloned or one of those upside-down refelections of a specular highlight, but seldomly and usually easily cloned. Veiling flare is rare. In short, nothing but the daily photographic routine we all know and are used to.