[Leica] Lens reflections from IR cut filter - verified and modified.

[grduprey at mchsi.com (grduprey@mchsi.com)]

I hate to put a damper on all this experimentation and discussion, but if no 
one would have pointed this out I would never have seen this very minor 
reflection imo.  This seems a big deal made over a very minor issue.  I've 
seen far worse in other photos on other sites and most definitely in movies, 
where I think they want it to be there.  Take it for what it is and get out 
there and enjoy making images for all to enjoy.  In all of these and the 
original image, I had to look very hard to see the so called image 
destroying reflections.

Gene

-------------- Original message from Howard Cummer <cummer@netvigator.com>: 
-------------- 


> Hello Luggers, 
> Cementing my reputation as a gear head I have been following Len?s 
> lead and using Howard Ritter?s procedures for checking out 
> reflections possibly caused 
> by IR cut filters. I shot a series of pictures ? placing a flashlight 
> in the upper right 
> corner and looking for reflections in the lower left. I did this with 
> both my 50 Summilux Asph and my 35 Summilux Asph. Findings: with IR 
> filters on at f1.4 
> both lenses exhibited the reflection from the upper right flash light 
> in the lower left of the photo. 
> With filter off there was no reflection with the 50 Lux Asph and a 
> slight ghosting with the 35 Lux Asph ? so at least for the 50mm lens 
> the filter is the sole contributing factor. 
> Here are some snaps at ISO 640, camera tripod mounted, to support my 
> conclusions: 
> 
> 1. The 35 Lux with IR cut filter on at f1.4 showing the ghosting on 
> the books on the lower left shelf. 
> 
> http://gallery.leica-users.org/v/Howard+Cummer/UV+IR+Code+Pix/ 
> Lux35IRonw.jpg.html 
> 
> http://tinyurl.com/3b9vrg 
> 
> 2. The 35 Lux at f1.4 with no filter ? there is a slight blue smudge 
> of ghosting still visible just above the books in the lower left 
> shelf so lens design also contributes to the reflection 
> 
> http://gallery.leica-users.org/v/Howard+Cummer/UV+IR+Code+Pix/ 
> Lux35noIRcutw.jpg.html 
> 
> http://tinyurl.com/2tyl57 
> 
> 3. Here is the 50 Lux Asph at f1.4 with IR cut filter on and 
> the refection is present 
> 
> http://gallery.leica-users.org/v/Howard+Cummer/UV+IR+Code+Pix/ 
> Lux50IRcutfilterw.jpg.html 
> 
> http://tinyurl.com/2tg8ax 
> 
> 4. The 50 lux at f1.4 with no filter and no reflection 
> 
> http://gallery.leica-users.org/v/Howard+Cummer/UV+IR+Code+Pix/ 
> Lux50nofilterw.jpg.html 
> 
> http://tinyurl.com/2jan65 
> 
> I closed down the 50 Lux with the filter on to see when the 
> reflection would disappear. At f4.0 there was still a slight 
> reflection but by f5.6 it was gone. 
> The 35 Lux asph exhibited similar characteristics so I didn?t bother 
> to post thiosde pictures. 
> 
> 
> 5. The 50 lux at f4.0 with filter and a slight reflection 
> 
> http://gallery.leica-users.org/v/Howard+Cummer/UV+IR+Code+Pix/ 
> Lux50withIRatf4_0w.jpg.html 
> 
> http://tinyurl.com/3x88ht 
> 
> 6. The 50 lux at f5.6 with filter and no reflection 
> 
> http://gallery.leica-users.org/v/Howard+Cummer/UV+IR+Code+Pix/ 
> Lux50wIRfilteratf5_6w.jpg.html 
> 
> http://tinyurl.com/37ne4e 
> 
> What does this prove? What we all knew for a long time ? that filters 
> tend to cause unwanted reflections ? and should be avoided for that 
> reason, if possible. 
> But, because of the magenta issue with the M8 that is not possible so 
> we will have to live with it and in 99.9% of my pictures it isn?t an 
> issue. 
> 
> Cheers 
> Howard (in Hot Hong Kong still waiting for his new M8) 
> 
> On 1 Oct 2007, at 3:36 AM, lug-request@leica-users.org wrote: 
> 
> > Message: 1 
> > Date: Sun, 30 Sep 2007 12:28:09 -0400 
> > From: Leonard Taupier 
> > Subject: Re: [Leica] Lens reflections from IR cut filter - Verified 
> > To: Leica Users Group 
> > Message-ID: <18E1602D-E3AD-476A-8940-B6F95C3C84B9@comcast.net> 
> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; 
> format=flowed 
> > 
> > 
> > I was able to duplicate Howard's lens reflection problem using Howard 
> > Ritter's procedure. 
> > 
> > > > Reflection.jpg.html> 
> > 
> > or 
> > 
> > http://tinyurl.com/3blq22 
> > 
> > I was not able to duplicate the problem using a 50mm Summicron with 
> > filter but was able to duplicate it using a Noctilux at f1.0 with a 
> > UV/IR filter. I could not duplicate the problem with the filter 
> > removed. The smaller light is very bright. Also note the coma with 
> > the Noctilux. Unfortunately my Summilux is still with Leica getting 6- 
> > bit coded so I couldn't try it. 
> > 
> > Len 
> 
> 
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