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01-13-2008, 02:20 PM   #76
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QuoteOriginally posted by carpents Quote
So, take a look at this link:
Create Your Own Bokeh (Warning - kitsch link)
That, some messing around "building" a custom cow lens for my Super-Takumar 85/1.9, some time with my own party lights, and fooling around with a new framing action resulted in this:



01-13-2008, 02:23 PM   #77
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QuoteOriginally posted by betsypdx Quote
That, some messing around "building" a custom cow lens for my Super-Takumar 85/1.9, some time with my own party lights, and fooling around with a new framing action resulted in this:
That is absolutely horrible.
01-13-2008, 02:44 PM   #78
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QuoteOriginally posted by carpents Quote
That is absolutely horrible.
It was fun though.
01-13-2008, 02:46 PM   #79
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QuoteOriginally posted by blende8 Quote
I think these filters are already available. Just do a test.
I was able to find 'Center Spot' filters that are grey, but they look like in the following link:
Center Spot Filter @ Camerafilters.com That doesn't look like what I want - it just introduces another hard edge to bend the light.

I was also able to find out that someone made something called the 'Bullseye apodizing neutral density filter' which is exactly what I (re-)invented, but it seems to be marketed towards welders and I haven't seen one for sale. Do you have a link to one for sale?

01-13-2008, 02:49 PM   #80
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QuoteOriginally posted by betsypdx Quote
It was fun though.
There is a reason that many fun things are either bad for you or illegal.
01-13-2008, 02:57 PM   #81
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QuoteOriginally posted by betsypdx Quote
That, some messing around "building" a custom cow lens for my Super-Takumar 85/1.9, some time with my own party lights, and fooling around with a new framing action resulted in this:

LOLOL- thanks for the laugh, that is really funny kind of neat too
01-13-2008, 03:13 PM   #82
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I like that crinkled foil test idea, I did a quick test on one of my pentax lenses with a piece of foil in the back ground- mixed lighting
01-13-2008, 04:30 PM   #83
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QuoteOriginally posted by carpents Quote
I have one more thought on this subject. I came up with an idea using the Minolta 135 STF that we've talked about so much here - we can call it my invention. If you steal my invention and market it, I just ask that you give me a bunch for free in 49mm, 52mm, and 67mm filter threads.

So, take a look at this link:
Create Your Own Bokeh (Warning - kitsch link)

My invention is this: take this idea of putting strangely-shaped cover over the lens and replace it with a graduated neutral density filter. The filter must have the gradations in a concentric circular pattern - darker towards the edges than in the middle. This will result in a softening of those out-of-focus highlights, creating a nice Gaussian blur instead of the typical hard edges. This might also help correct axial chromatic aberrations, which we've established here are pretty common.

What do you think?

Sean,

Your idea does work, I'm currently digging up a thread on dyxum where some users had posted results from such a setup. The good news is that bokeh is largely improved, the bad news is that it someone else got to the idea first. My understanding is that the users created the graduated ND filters by printing on acetate. They also mounted the 'filter' inside the lens (closer to the back element). Something to do with vignetting? When the mods at dyxum find the thread, I'll post it here. It was a post from a year ago, and the search function seems to be crashing at the moment...

D

01-13-2008, 06:54 PM   #84
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BTW, this thread got me testing things out - with the usual disasters (zx10 crashed not one but two rolls of film, never before, and it went through a roll fine afterwards... and that was just one of the things)

What I find is the quality of bokeh depends on many variables - the absolute distance from plane of focus and the relative distance, the amount of light vs the in focus light, and obviously the aperture of the lens. I found I could create really ugly bokeh with any lens, but also minimize it or make it much smoother based on the above variables. It's all a part of learning the craft and the lens.
01-15-2008, 02:10 AM   #85
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QuoteOriginally posted by carpents Quote
Look at that. I love it when I learn something new.
creampuff, d.bradley and carpent;

Here are tow images showing small kitchy lamps once used for a freaked out party. it's the Sigma 30/1.4 and the FA35/2.



and



So, among everything revealed in these pictures it also shows us that aspherical elements are not alone responisble for the concentric circles sometimes seen in OOF bright spots.

I have seen the same thing in pictures taken with the Voigtländer SL 75/2.5.

regards,
01-15-2008, 02:18 AM   #86
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QuoteOriginally posted by mer Quote
hey jonas

interesting post . I am not really sure that bokeh = "quality of the out of focus parts of the picture", as in japanese bokeh , literally means "blur" / "fuzziness" .
... (big chunk of text edited away...
what about the voigtlander 125 apo macro ?

have fun

btw I am quite sure you have read it but for those you haven't this is a nice link for bokeh : bokeh
Hi mer (?),

I'm sorry for the late reply, I haven't checked back here until today.

I tried to describe how the word should be used in my opinion. The examples given works well, don't you think? My first language is Swedish, then I have a couple of third languages, all spoken badly, so I'm not the right person to discuss the these things in depth. If I'm describing the definition I think I'm content with that:

If the definition fits well, and the use of the word in the examples works fine I'm happy with that. I do realize I can't stop people saying things like "There is a lot of bokeh in that picture" but I can try.

If you think I am way off I can reconsider.

I haven't tried the DFA50/2.8 Macro. I like them fast, if possible. The plastic build also scares me. Not to mention the question about money...

The 125mm Voigtländer seems to be a great piece of glass and metal and I have seen many beautiful pictures taken with the lens. I have never tested it. 125mm is a bit long for me and I can't see myself hauling around that thing for occasional use.

kindest,

Last edited by Jonas B; 01-15-2008 at 02:24 AM.
01-15-2008, 02:45 AM   #87
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QuoteOriginally posted by carpents Quote

My invention is this: take this idea of putting strangely-shaped cover over the lens and replace it with a graduated neutral density filter. The filter must have the gradations in a concentric circular pattern - darker towards the edges than in the middle. This will result in a softening of those out-of-focus highlights, creating a nice Gaussian blur instead of the typical hard edges. This might also help correct axial chromatic aberrations, which we've established here are pretty common.

What do you think?
I think you have "invented" the opposite of the filters used for fix vignetting (as with the Hasselblad Pan-X).

I'm not educated, nor an autodidact, when it comes to design anything optical. I'm happy by just using them... But my thoughts are that by placing something gradually in front of the lens it has a gradually visible effect. Think about these grad ND filters for landscape shooters.

I don't fully understand the details about why the Minolta 135mm STF lens works the way it does. I guess it has a lot to do with where the extra aperture is placed. Then again, sometimes one can get surprised so one should never say never... I have seen reports saying that placing a baffle (or an extra aperture opening between the lens and camera) can lessen flare from very fast primes. It sounds strange to me and the reports are a bit contradictory, as so often.

The extra set of aperture blades in the STF lens also closes the lens down, but with another effect than the ordinary aperture blades. The more a closed down, the lesser of bad effects from CA should be visible in the picture as the rays hitting the front element at it's outer areas are stopped. But that is basic, somewhere inside the lens all those rays of light are bent and diverted and I don't know what.

But the DIY stuff is interesting and if something can be done in this area I'm certainly interested.

QuoteOriginally posted by d.bradley Quote
Sean,

Your idea does work, I'm currently digging up a thread on dyxum where some users had posted results from such a setup. The good news is that bokeh is largely improved, the bad news is that it someone else got to the idea first. My understanding is that the users created the graduated ND filters by printing on acetate. They also mounted the 'filter' inside the lens (closer to the back element). Something to do with vignetting? When the mods at dyxum find the thread, I'll post it here.

D
Very interesting. I look forward to learn more about this!

Thank you,
01-15-2008, 02:48 AM   #88
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QuoteOriginally posted by betsypdx Quote
That, some messing around "building" a custom cow lens for my Super-Takumar 85/1.9, some time with my own party lights, and fooling around with a new framing action resulted in this:

"missing image file" I'm highly disappointed!
(And it took 2 weeks, a lot of vitamins and in the end two extra shifts at work to get back to the normal semi normal state of mine. I hope your weekends were a more pleasing experience!)

regards,
01-15-2008, 03:04 AM   #89
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Jonas, thanks for the images. Very informative. Both the Sigma and Pentax have aspherical elements and it does seem that both have concentric circle oof points from you pictures. Obviously the lens construction and aperture blades have a part to play too.
BTW the second image (FA35mm?) is so much nicer
01-15-2008, 03:30 PM   #90
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QuoteOriginally posted by d.bradley Quote
Shot with the Minolta 35/1.4, you can see concentric circular texture in the specular highlights...never figured that one out...
Maybe Newton's rings from cemented or nearly-adjacent lens elements? (You old darkroom gnomes remember Newton's rings, right?)
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