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Ways to avoid white Vignetting?


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Hi, I notice lot of times when I use the Speedboser a 50mm with a Kowa 2X, an anoying white vignetting cover most of the edges of image I guesss because of the sun reflection. I wondered if there is any way to avoid this during the day? When I use the 85mm I didn't notice  that. I wondered if  a Rangefinder or CoreDNA minimize it

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36 minutes ago, andycorleone said:

Hi, I notice lot of times when I use the Speedboser a 50mm with a Kowa 2X, an anoying white vignetting cover most of the edges of image I guesss because of the sun reflection. I wondered if there is any way to avoid this during the day? When I use the 85mm I didn't notice  that. I wondered if  a Rangefinder or CoreDNA minimize it

Watch this. 

:)

 

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Hi, Tito is the man indeed!

Like the OP, I also wonder if the Rectilux (or the Rangefinder) helps reduce veiling glare with anamorphic lenses particularly the Kowas. Does it help? It would be good to know before taking any chance with the edge blackening, which I see as a great but last resort option.

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  • 5 months later...
  • 1 month later...

@jaquet Please don’t try ink or paint on the rear edge of a pre-36...it is not a good idea (even for VD to attempt). These optics are best not to touch if at all possible. An effective way to solve the square rainbow flare by making a custom rubber ring and securing it to the outside edge of the element housing.

As for veiling glare or white vingette on a pre-36? - I’m not sure if that is particularly normal (as it is with Kowa types). @ch_d is your pre-36 displaying any unusual white flare on the edges? Could you post a screen shot of what you mean? (And what taking lenses you notice it with).

Pictured below is a shot of my rubber ring solution to eliminate the square rainbow edge flare that the pre-36 gives with taking lenses other than the factory Isco type that doesn’t have the issue (because that lens has an inbuilt light baffle).

I’ve recently given Tito the details on how to make this ring, so he will probably do a video tutorial on it soon, like he did with the information I sent him about the edge blackening, close focus and sharpness tune up mod for Kowa types.

FC29F5AE-0FFB-4AAB-9970-F7996C697B26.thumb.jpeg.528b0360b162506ef8e7bca7b8679483.jpeg

 

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Thanks Hans! On my Isco 36 SC (not the pre 36) the veiling glare is very prominent. 
So my guess is, that this flare is produced by the edge of the second element.
I think it it worth a try to find the causing element. At an ISCO it it definitely a job for a pro.

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  • 5 months later...
On 5/13/2018 at 4:33 PM, Hans Punk said:

Pictured below is a shot of my rubber ring solution to eliminate the square rainbow edge flare that the pre-36 gives with taking lenses other than the factory

 

Wow, thak you so much gor this information, and provided picture. I will certainly try this out.

I also noticed veiling glare on my pre 36, especially with wide 35mm taking lens used with a speed booster on m43.

The sharpie trick seems nice, but I am affraid of messing around that little beauty.

Is there anything that could be done with the front element of pre 36 that is none destructive yet helps with the veiling glare?

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18 hours ago, mirekti said:

 

Wow, thak you so much gor this information, and provided picture. I will certainly try this out.

I also noticed veiling glare on my pre 36, especially with wide 35mm taking lens used with a speed booster on m43.

The sharpie trick seems nice, but I am affraid of messing around that little beauty.

Is there anything that could be done with the front element of pre 36 that is none destructive yet helps with the veiling glare?

 

The rubber ring trick is very good for eliminating the unique and distracting square rainbow flare on pre-36 models. As for white veiling glare, I’ve personaly never experienced such a thing on my Isco, and I would probably not want to eliminate it if it did. Could you post a picture of the veiling glare you want to eliminate? Sounds like the  speedbooster + 35mm is revealing the light that is catching the edge of the rear optic on the iscorama - when directly exposed to light...I would be curious to see how pronounced it is with your taking lens (what is that lens btw?..have you tried an alternative 35mm taking lens?)

I’d strongly recommend not to go anywhere near an Iscorama optic with a sharpie or anything similar, it won’t reduce the veiling glare (unlike when the technique is applied to Kowa B&H’s exposed front optic edge)...the front optic is not responsible for such a thing on the iscorama. The rear optic of the pre-36 is likely to be the culprit since the edges are exposed and not blackened (unlike regular 36). The rubber ring trick will likely resolve any unwanted veiling glare, or at least minimise it, if you choose to use a slightly larger diameter of ring so as to partially help reduce rear optic edge from receiving direct light.

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1 hour ago, Hans Punk said:

I’d strongly recommend not to go anywhere near an Iscorama optic with a sharpie or anything similar

I totally agree with this.

 

1 hour ago, Hans Punk said:

what is that lens btw?..have you tried an alternative 35mm taking lens?

It is Leica R Elmarit E55. I initially wanted Summicron, but thought Elmarit was a safer choice.
I use two 49mm rings, and 55-49 step down adapter so the rear element of Iscorama is nearly touching the front element of the lens. I have minimal vignetting when focused at 2m, it is almost gone when Iscorama is focused to 3m, and I believe none at 4m.

 

1 hour ago, Hans Punk said:

if you choose to use a slightly larger diameter of ring so as to partially help reduce rear optic edge from receiving direct light.

I am not sure I understand this. What should be the source of the direct light here. I don't think I have any leaks in the rings.

Here is a quick photo I took with my iPhone, it is dark here but I managed to get it when I pointed the lens to TV and overexposed it. Look at the upper left corner.

I will try purchasing different sizes of rubber rings and see which one could fit the rear element. In your solution it seems as if you put the ring on the back of rear element, and then there is another bigger ring which is covering both, the ring and the housing of rear element. Is that correct?

Veil.jpeg

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16 hours ago, Hans Punk said:

Could you post a picture of the veiling glare you want to eliminate?

It's day now so I made a better example. First photo is glare I'd like to remove.
Other photos are to show vignetting. 1st one is focused @2m, 2nd @3m, 3rd @10m on Iscorama so I think this combo is quite usable, but the glare... :)
Taking lens is Elmarit-R 35mm + Kipon 0.7x R2M43 (no electronics) + GH5S in 4k mode.

Thank you.
 

Veil2.jpeg

2m.jpeg

3m.jpeg

10m.jpeg

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@mirekti Thanks for the pictures, that veiling glare is being caused from the rear optic (exposed edges) being hit by light, So the rubber ring trick will eliminate that glare/white vignette. As mentioned before, it will probably be best to experiment with a few sizes of nitrile rings to get the desired effect. The best method I found was to glue two rings together (one with slightly larger outside diameter) this makes it easier to attach to outside lip of the rear element housing, while the smaller diameter sits flush with the rear optic edge..the larger diameter ring can be fixed with very thin strip of double sided tape (1mm wide 3M tape used to fix mobile phone screens with). No adhesive (other than that particular tape) should ever be put near a glass optic, take care whenever placing anything near to the glass.

You will find the perfect fit through experimentation, post your results here if successful :)

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10 minutes ago, Hans Punk said:

So the rubber ring trick will eliminate that glare/white vignette.

Unfortunately it didn't help. I tried with 15/16" inner diameter washer which reduced the rear element's diameter, but I was still able to see the veiling glare.
In the meantime I took it off so picture two actually had electrical tape around it too. Do you think I should try with some other size?
 

wash.jpeg

wash2.jpeg

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