[Leica] Some M8 Images

[henningw at archiphoto.com (Henning Wulff)]

Hi Geoff,

Sorry; my comment was rather abrupt and gruff. I sent it too quickly. :-)

With the IR thing I just meant that window glass isn't that useful in 
attenuating IR to any degree; it's better at blocking UV, especially 
if it's glass that's been installed in the last 10 years. Most glass 
now has some degree of UV protection.

On a summer's day you'll see all kinds of IR induced changes to an 
image; in the winter it's a lot less.

Regarding reflections; note that in your shot of the moon the 
spurious image is located symmetrically; ie, the image is on the 
opposite side and the same distance from the centre. That's the usual 
location when the reflection occurs off flat surfaces like a filter. 
It's not always the case, as there are possibilities for other 
reflections, but they are usually of a lower order.

If you see multiple images close to each other when shooting through 
glass it's usually due to reflections off multiple layers of window 
glass; ie, double glazing. The two layers of glass deform 
differentially as the temperature changes; then the two layers aren't 
parallel anymore and will show reflections just a little apart. If 
two spots are fairly close together and not hugely different in 
intensity, this is the usual cause.



At 7:52 PM +1000 2/13/09, Geoff Hopkinson wrote:
>Henning I meant that I wouldn't expect significant IR from those subjects
>behind glass. I agree those subjects would not be big IR candidates anyway.
>I assumed that the window glass would attenuate IR as well. Sounds like I
>should not have linked the two ideas. I'm no scientist there certainly. For
>fun I must have a play and educate myself on that now.
>
>Regarding the small blue highlights, I have seen secondary mirror images of
>point light sources in some of my shots. For example this shot with the 75
>Summicron and UV/IR. (4 second exposure). You should be able to make out a
>ghost image of the moon crescent as well as some stars repeated as blue
>dots. I assumed this was due to reflections back into the camera from the
>filter. I based that on an article in the Feb 2007 LFI demonstrating this
>with a night street shot of street lights and headlights. The article states
>that the ghost images are caused by the presence of the filter.
>http://gallery.leica-users.org/v/gh/a/ns/Sky.jpg.html
>
>In Chris's shot you can certainly see a set of reflections on the window
>glass. I love to play with reflection shots like this myself which is partly
>why I was staring into this enjoyable one by Chris. I believe that the two
>blue spots above the girl to the left, are a ghost of another set of
>reflections on the window glass! The blue colour is a clue to me. Note the
>yellow original sets above and to the left that are on the window glass I
>think. Never mind just some technical opinion from me that I thought might
>be of interest. As a practical matter those spots are easy to retouch of
>course.
>I put another up for discussion on this subect
>http://gallery.leica-users.org/v/gh/a/usa/f/Cantina.jpg.html
>This is a 28 uncropped, through a window at close range. Of interest maybe
>is you can see my left arm and watch over the back of the guy to the left
>and I think our table edge on the lady's back to the right. Look at the hat
>of the background guy to the right and the blonde hair of the lady just
>below her left ear position. You probably need to look at the larger version
>to see more clearly. Anyway I find these details fascinating to learn about.
>I'd value any comment from you, or others.
>Cheers
>Geoff
>'Licence to Chill'
>
>
>
>2009/2/13 Henning Wulff <henningw@archiphoto.com>
>
>>  A nice set, Chris but to clarify what Geoff has written:
>>
>>  The window glass won't do anything for/against the IR. Your available 
>> light
>>  just happens to be low IR content, which is usual in winter.
>>
>>  The reflection may or may not be due to the UV filter. It looks like the
>>  picture is shot through glass, the most likely cause is the window glass 
>> as
>>  that causes way more reflections than filters, an of a somewhat different
>>  type.
>>
>>
>>
>>
>>  Chris that is a thoughtful and well constructed group. The second ice 
>> shot
>>>  is especially appealing.
>>>  There's nothing in any of the content that might provide a reason for 
>>> the
>>>  UV/IR .
>>>  If you'd like a technical comment on that aspect,look at the
>>>  Selfridges shots. I suspect that the window glass has prevented any
>>>  possible
>>>  mis-rendering of the dark fabrics anyway. But your UV has given you the
>>>  same
>>>  minor artefacts that a UV/IR (or any filter) would have. See the small
>>>  blue
>>>  internal reflections (second shot) of the point light sources?
>>>
>>>  2009/2/13 Christopher Birchenhall <crbirchenhall@googlemail.com>
>>>
>>>   LUGers
>>>>
>>>>   I took my recently acquired M8 out with a LTM 50mm Summicron f2
>>>>   collapsible on two occasions. This lens came as part of a very
>>>>   collectible IIIf R/D kit. I am not a collector so I decided to cash in
>>>>   the body and case (sigh). But the lens is for me one of my best. We
>>>>   get on very well.  We "clicked" :-) One or two of these pics may
>>>>   appeal but I can't but offer to share my delight at using the new
>>>>   electronic camera with a "peach" of a classic lens (with a standard UV
>>>>   filter and no 6-bit coding).
>>>>
>>>>   I managed to get into the centre of Manchester (UK) with some good
>>>>   winter sunlight. Some of the subject matter (graffiti/street art?) may
>>>>   not appeal to all but I am ok with this stuff - a couple do involve
>>>>   the "fair" sex?
>>>>
>>>>   http://gallery.leica-users.org/v/crb/M8/Manchester/
>>>>
>>>>   We had a quick walk along my staple venue (Macclesfield Canal) when it
>>>>   was cold and the canal was partly frozen - a barge had clearly passed
>>>>   through and broken up the ice - we had a fine half pint of a winter
>>>>   warmer ale half way through!
>>>>
>>>>   http://gallery.leica-users.org/v/crb/M8/canal/
>>>>
>>>>   Needless to say C&C are welcome.
>>>>
>>>>   Chris B


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