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Akira

Contributor
  • Content Count

    7,682
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  • Days Won

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  • Country

    Japan

Akira last won the day on 27 April

Akira had the most liked content!

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1,189 of my posts have been liked

3 Followers

About Akira

  • Rank
    Homo jezoensis

Profile Information

  • Real Name
    Akira Sakamoto
  • Gender
    Male
  • Location
    Tokyo
  • Photographic Interests
    Music of all sorts, so long as they are worth listening to.
  • Edit my pics?
    Yes
  • Fav. Camera
    Sigma fp
  • Fav. Lens
    Sigma 45mm/f2.8 DN DG, Nikkor-O 55/1.2
  1. Akira

    First flowers

    Nice to seeing your images of the motifs different from your usual citiscapes. Thank you for sharing!
  2. Akira

    Manhattan skyline

    Impressive images. I like the B&W ones more. Somehow, the first image reminds me of the "Starry Night" of the screen saver for the ancient Mac.
  3. Akira

    Sunrise @ 2000mm

    Amazing shot, Aguinaldo! The seagull (?) a nice touch to the image. The framing looks perfect to me.
  4. Glad to know you are all right, Dallas. I'm all right and my job is not really affected by the lockdown or COVID-19, at least currently. However, as with most parts of the norhern hemisphere, the lockdown has been damaging many of the business in Japan. The government seems to be very reluctant to support the affected business and act too slow. I go out to the supermarket to buy food and daily necessaries once or twice a week and haven't used any public transportation service for nearly five weeks. Hope the COVID-19 to disappear as soon as possible...
  5. Akira

    Patience test

    Amazing capture. I also like the backgrounds of #1 and 3.
  6. Akira

    Easter eggs

    Thank you, Dallas. Here are the "objects" under the more normal (LED room light) condition: a boiled egg with its shell removed (fluorescing in lime green), a brown raw egg (in red) and a sheet of kitchen paper with the towel-like texture (in gray-ish blue).
  7. Akira

    Easter eggs

    Shot with the 365nm UV flashlight as the only light source. No color manipulation is involved in the processing. Only the exposure, contrast, shadows and highlights were adjusted to taste.
  8. Sorry for my belated response. Images of such historical monuments never cease to be joy to appreciate. Your 6MP D70s captured the details of the reliefs and the textures of the stone monuments very well. Thank you for sharing, Luc!
  9. Allan, thank you for sharing your solid experiences with IR. I've heard about the sd Quattro with the UV/IR cut filter that can be removed on the user's side. The biggest challenge would be to find adapters for Sigma sd mount. The ones for M42 seems to be readily available, but not for Nikon F. There have been good amount of info on Nikkor lenses that don't show hot spots when used for IR, and I already have two Nikkor lenses that aren't hot-spotters. I have tried to shoot distant scenes to see if IR cut through the atmospheric haze here in Tokyo but haven't succeeded in that yet. By the way, could you handhold the Quattro sd for IR?
  10. It might, but that could be the niche of the niche.
  11. Thank you, Chris, for your comment. So far as I remember, D40 was the last Nikon DSLR that shows reasonably usable IR sensitivity without modification. D2H was more sensitive but instead it suffered from the strong IR contamination in normal use. Interestingly, Sigma fp seems to be more sensitive to IR than at least D40, but doesn't show any hint of IR contamination at all. With R72 filter and set at ISO 3200 and f5.6 or so, you could even handhold the camera on a bright sunny day. Fujifilm digitals have been know for their capability for the astro-photography thanks to their relatively high sensitivity to H-alpha spectrum. But unfortunately, trying to shoot IR didn't come up to my mind while I was shooting with X-E3 or X-T3.
  12. You are welcome! The UV flashlight is actually not for any IR photography. It can be used as the light source either for the reflected UV capture (like the bull's eye pattern of some flowers), for inducing UV fluorescence (like the image #3) or for hardening UV-cure resin.
  13. Thank, Dallas and Aguinaldo, for the comments. The digital sensors are potentially sensitive to the wavelength outside the visible range. But normally the wavelengths outside the visible ranges (both longer and shorter) are blocked by the UV/IR-cut filter placed right in front of the sensor, because they cause haze and color shift which is difficult to correct. The UV/IR-cut filters in earlier digital cameras like Nikon D2H or D40 were not efficient enough to cut these wavelengths, so they suffered from color shift (green textile rendered in brown, for example) and could shoot IR images. On the other hand, the modern digital cameras have much improved UV/IR-cut filters, and you would have to the camera modified to shoot in UV or IR. So, I took it granted that Sigma fp, one of the latest cameras, cannot be used for shooting outside the visible range. I found that Sigma fp showed some usable sensitivity to IR purely by accident when I tried some IR-pass filters on the camera on a whim. The exposure time ranges from 10sec. to 1/8sec. depending on the density of the filters, and thus you always have to use a tripod, but the resulted images are pretty amazing. The first two images were shot with Sigma fp, Nikkor-H 50mm/f2.0@f5.6, and I put a Fuji tri-acetyl-cellulose IR90 filter in front of the lens. The filter is so dense that it looks totally opaque to the naked eyes. On the other hand, the UV flashlight was used to induce fluorescence of the egg shell and the kitchen paper spread under the objects. Under UV light, the egg shell made of calcium fluoresces in reddish orange, and the paper with some fluorescent dye (in order to make it look brilliant white) in blue. The UV flashlight emits faint visible portion of light as well, which cast some shadows on the objects.
  14. In the past few weeks, I was experimenting with invisible ranges of light using Sigma fp. I found that the camera showed usable sensitivity to IR without modification. Also, I realized that the egg (more precisely, the egg shell) fluoresced in passionate red under UV flashlight. These are a few results of the experiments. The 1st and 2nd images were shot with Nikkor-H 50/2.0 with Fuji IR90 filter. The 3rd one was shot in the total darkness with Nikkor-O 55/1.2 a.k.a. CRT Nikkor and a 365nm UV flashlight as the only light source.
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