flamed apodization filter

IB123 · Joined: 30 Dec 2013 Posts: 9 Location: VA

I tried the candleflame apodization filter creating a layer of soot on my helios 44-2 rear element, front face of the glass. The holder is a whisk from Walmart, cut the wires and remove 1/2 of them leaving 5, it could hold the glass with just 4 or probably 3. Keep that spreader plate and use it to open the wires when loading/removing the lens. I made 3 test variations, each of which took several attempts to get a keeper. I found it best to lower the glass to just over the midway position in the flame's height, set the edge of the glass in the middle of the flame's width (over the wick), hold the glass tilted at a slight angle so the displaced flame is kicked to the edge of the lens, go round the circumference 2-3 times and let it build up. Soot seems to builds up faster on an already hot glass.

First photo is straight out of camera wide open aperture, look at the glass cleaner bottle behind the towel in each photo for comparison.

this is the soot ring with the widest aperture, I believe its the best.

This one has a narrower aperture, it actually does less blurring than with no apodization because it has the effect of increasing depth of focus.

This was an attempt at a faint apodization, I didn't let it go black on the edge. It is too tight and increases depth of focus too much like the former pic. Take-away is that it doesn't seem to take much darkening to cause the effect.

My next attempt is to redo the first one, a wide aperture but go faint. It is easy to go faint if you hold the glass level instead of tilted and dip the glass into the flame, withdrawing it immediately. The problem with this is is hard to control where the soot goes - at least when tilted you know the soot will go from low point to high point. Anyway I didn't find much on the net for this method other than Markus Keinath's excellent post which was my inspiration.

mo · Expire: 2016-07-30

Never heard of this,does it harm the glass at all? The results are certainly interesting but not sure if I would risk my lenses Smile

ZoneV · Expire: 2011-12-02

Thank you for your post Ian!
I thought about soot too, but it was a bit too delicate to handel the lens afterwards in my opinon.
But the soot is really a neutral black and very fine, which is very good. So probably I will come back to this way too.

I try to get very dark borders, to avoid the hard bokeh in very over exposed blurred parts like sun on water.
With the different options with very dark borders, but less transmission and larger DOF, or smaller DOF and less apodization effect it is hard to decide.

My next step is likely to take one of my tinkered very fast lenses and use there apodiszation. So I get a smooth bokeh + more sharpness as well.

CuriousOne · Joined: 31 Dec 2013 Posts: 669 Location: Home

There are spray paints for gun shooting sights, they provide way better characteristics than candle flame.

dan_ · Expire: 2016-12-19

I've tried to use a spray paint for making an apodization filter.
I had 3 problems with it:
1- the paint drops were not the same size;
2- the paint was not perfectly neutral black;
3- it's hard to control the gradient.

An airbrush with masks would probably help if a neutral black paint could be found, but I don't have one anymore.

After that I've tried to transfer the gradient from a laser printed paper to a glass UV filter using heat. It only worked partially, when the glass didn't broke. Embarassed

I'm still to try the laser-print-transfer method with special transfer papers, like the ones used for drawing the electronic circuits, when I'll manage to find some. If it works the transfer could be done directly on an inner lens, not on an UV filter placed in front of the lens.

I've never tried the slide-film-method presented on Markus site(http://www.4photos.de/camera-diy/Apodization-Filter.html) because of the shortcomings he mentioned in his topic there. Probably using a thin B&W copy film to make the filter could be the best, non-aggressive, method to make a lens benefit from apodization. But optically, IMO, to paint the filter directly on an inner lens could be the best approach.

CuriousOne · Joined: 31 Dec 2013 Posts: 669 Location: Home

Everything will be looking way better, if glass will be rotating around it's axis quite fast, when coating applied.

ZoneV · Expire: 2011-12-02