Pushing the limits of B&W macrophotography

A forum to ask questions, post setups, and generally discuss anything having to do with photomacrography and photomicroscopy.

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Lou Jost
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Post by Lou Jost »

Here's a better one, though not so big, it has a narrow band. I bought it just now instead of the one above.
https://www.ebay.com/itm/263407977643

kds315*
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Post by kds315* »

Lou Jost wrote:That seller has more reasonable prices. I will get this one, which is big and round, though it might not be narrow enough. (The one you indicated is not for sale now.)

https://www.ebay.com/itm/QB29-type-Glas ... SwuhFaGj8m
Yes this 405nm filter is for sale, seller just responded that for $120 he would do a 50mm round one. I had asked him for you.

The filter you bought has a center wavelength of 400nm, which might be a bit critical as your lasers have 405nm center.

Image
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

Pau
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Post by Pau »

Yes, that 400nm passband seems a bit too narrow and will cut at half of light (54% T at 405nm).

Because your source is monochromatic and your application not so critical I think that the Chroma I linked or the Asahi 425 proposed by Klaus could be more convenient.

Because these filters are very reflective it's possible that you could have reflections of the sensor, if so try mounting it with a small angle, although this could alter the spectrum of interference filters some microscope makers do it.

Please keep us informed on how it works, it's a very interesting project
Pau

kds315*
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Post by kds315* »

Pau wrote:Yes, that 400nm passband seems a bit too narrow and will cut at half of light (54% T at 405nm).

Because your source is monochromatic and your application not so critical I think that the Chroma I linked or the Asahi 425 proposed by Klaus could be more convenient.

Because these filters are very reflective it's possible that you could have reflections of the sensor, if so try mounting it with a small angle, although this could alter the spectrum of interference filters some microscope makers do it.

Please keep us informed on how it works, it's a very interesting project
A small angle does not cause that much shift in my experience...

I measured it here with my classic UV Transmitting filter, a highly reflective Baader-U dichroitic filter which I use very often:
http://photographyoftheinvisibleworld.b ... using.html

In an older ZEISS brochure about their metal interference filters, they state that max 10 degrees should be used.
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

Pau
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Post by Pau »

Very interesting, Klaus

I've not done true tests but visually with some fluorescence interference filters for visible light the effect is much more important: at 45º the color can be completely different than the expected at 0º, but about 5º doesn't alter it much
Pau

kds315*
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Post by kds315* »

Pau wrote:Very interesting, Klaus

I've not done true tests but visually with some fluorescence interference filters for visible light the effect is much more important: at 45º the color can be completely different than the expected at 0º, but about 5º doesn't alter it much
In line with my own results Pau and with the Zeiss Statement!

Here the graph from the CZJ document:
Image
(the two lines show the splitting up of the two polarized beams)
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

Lou Jost
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Post by Lou Jost »

Thanks for the interesting advice, and for asking about the 50mm filter. That price is reasonable. But since I already bought the other one, I will see how well it works first. The specs on the filter I bought are that the center of the passed band is 400+/- 5nm; the 5nm figure is the uncertainty in the center of the bandwidth, if I am reading it correctly. The stated half-bandwidth is 20nm. So it should do alright, and if I angle it a bit, I will increase the peak a bit, according to the Zeiss graphs. I have lots of light so some cutoff is fine. I just want to check to make sure fluorescence is not affecting my photos (and I think it isn't, since the photos are very sharp).

kds315*
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Post by kds315* »

Lou Jost wrote:Thanks for the interesting advice, and for asking about the 50mm filter. That price is reasonable. But since I already bought the other one, I will see how well it works first. The specs on the filter I bought are that the center of the passed band is 400+/- 5nm; the 5nm figure is the uncertainty in the center of the bandwidth, if I am reading it correctly. The stated half-bandwidth is 20nm. So it should do alright, and if I angle it a bit, I will increase the peak a bit, according to the Zeiss graphs. I have lots of light so some cutoff is fine. I just want to check to make sure fluorescence is not affecting my photos (and I think it isn't, since the photos are very sharp).
Press thumbs that it'll work out for you Lou. Btw. the peak will be shifted slightly towards shorter wavelengths if tilted, not increased (it actually decreases a little). 20nm HBW should give you enough wiggle room to get enough laser light through.
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

Lou Jost
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Post by Lou Jost »

Thanks, and yes, I wasn't thinking when I saw that graph from Zeiss...I was so accustomed to see the x-axis as wavelength that I did not even notice the axis labels.

Doppler9000
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Re: Pushing the limits of B&W macrophotography

Post by Doppler9000 »

Hello Lou,

I wondered if you had an update, regarding despeckling or any other things of interest.

John

Lou Jost
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Re: Pushing the limits of B&W macrophotography

Post by Lou Jost »

I'm happy with my milk despeckler but I have been meaning to try an arrangement that doesn't diffuse the beam quite so much. Then I could use shorter exposures to reduce the noise, and this might eliminate the need for the cooled-sensor camera.

In other developments, I ended up buying the other Nikon Engineering lens, which turned out to have an even higher NA. The lens I used in the present post is for sale if anyone wants it. I also bought a 405nm 10x 25mm Zeiss photolithography lens which is very compact.

Doppler9000
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Re: Pushing the limits of B&W macrophotography

Post by Doppler9000 »

Thanks, Lou.

What is the image circle on the outgoing Nikon?

Would you still get an astro camera for this project, if you were buying today?

If budget was less of a constraint, would you get an APS-C or full frame camera, or would you stay with the smaller pixels of the Micro 4/3?

Lou Jost
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Re: Pushing the limits of B&W macrophotography

Post by Lou Jost »

"What is the image circle on the outgoing Nikon?"
I can't recall but it was huge. Reversed photolithography lenses usually have image circles that are at least 100mm in diameter.
Would you still get an astro camera for this project, if you were buying today?
They are very inconconvenient since they don't have sd cards or shutter releases. I had to write a robot script to repeatedly click on the controlling program's Test button in synchrony with the stacking device. One nice advance since I wrote this post is that my astrocamera now records tiffs, which fit better into my workflow. I do like having a high-density monochrome sensor.
If budget was less of a constraint, would you get an APS-C or full frame camera, or would you stay with the smaller pixels of the Micro 4/3?
I do have APS and FF cameras, but since these photolighography lenses are all finite lenses, they are designed for a fixed extension, so pixel density is the most important thing for resolving detail on the subject. For that reason MFT still has its uses. Also the cameras are light and small, so it is easier to build a stable sensor-shifting device using them rather than a heavy FF camera.

Doppler9000
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Re: Pushing the limits of B&W macrophotography

Post by Doppler9000 »

Thank you, Lou, this is very helpful.

Doppler9000
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Re: Pushing the limits of B&W macrophotography

Post by Doppler9000 »

PM sent.

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