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Re: [APML] 2 new images
I have seen the Konica stuff at one of my local camera stores in the past.
The data sheet can be found here...
http://konicaminolta.com/products/consumer/photo/pdfe/pdf/csuper400.pdf
The curves don't look too bad, with only a slight drop-off at the 654nm
line...
Frank
----- Original Message -----
From: "Bobby Middleton" <bobm@koyote.com>
To: "Steve Lindsey" <stevelindsey@earthlink.net>; "Discussion of Film
Astrophotography" <astro-photo@seds.org>
Sent: Friday, February 27, 2004 4:12 PM
Subject: Re: [APML] 2 new images
> Here's one link for the stuff:
> http://www.dealtime.com/xPO-Konica_ISO_400_35mm_Film_2_Pack
> Bobby Middleton
>
> ----- Original Message -----
> From: "Steve Lindsey" <stevelindsey@earthlink.net>
> To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> Sent: Friday, February 27, 2004 2:44 PM
> Subject: Re: [APML] 2 new images
>
>
> > Incredible work Wei-Hao. Both are just stunning. Please pass on info
as
> to the availability of this film in the US. Your work breathes new hope
> into the survival of high-end film-based astro work for a while!
> >
> > Steve
> >
> > -----Original Message-----
> >
> > ALOHA,
> >
> > I processed two of my new images taken this month. (Others will take
> > long long time to process.)
> >
> > The first one is Subaru Deep Field:
> > http://www.ifa.hawaii.edu/~wang/gallery/picutres/subaru_deep_field.htm
> >
> > This one made use of my new flat field technique. Despite the new
> > technique, there is still difficulty in the image processing. The
> > main problem is sky gradient. In the unprocessed image, the sky
> > gradient and the vignetting pattern are mixed. I cannot find a
> > unique solution to decouple these two (perhaps I didn't try hard
> > enough). Therefore, both flat fielding and gradient removal are not
> > perfect. I did a lot "twist" in PhotoShop to correct these effects.
> >
> > For this reason, I don't trust any brightness change in this image
> > that is larger than ~30% of the image size (i.e., large nebulas).
> > They may be just remnant of the imperfect sky gradient and vignetting
> > removal. For small-scale brightness changes smaller than ~25% of the
> > image size (small nebulas), I'm pretty sure they are real and are not
> > artifacts.
> >
> >
> > IC2177:
> > http://www.ifa.hawaii.edu/~wang/gallery/picutres/I2177-2004.htm
> >
> > The new flat field technique failed on this one. The vignetting
> > is corrected using my old method that assumes axisymmetry for the
> > vignetting pattern. The reason why flat fielding failed is unclear.
> > There seems to be some strange scattered light in all the 3 stacked
> > images, which doesn't appear in the flat field shots. Perhaps
> > such scattered light is caused by the 1.4x rear converter. This
> > rear converter is designed for Pentax 67 lenses but not for the
> > telescoep. (The one for my telescope is discontinued.) And because
> > of this scattered light, my old method doesn't work well, either.
> > Again, I did lot of manual twist in PhotoShop to remove the leftover.
> >
> > Centuria 800 is quite grainy, comparing to Centuria 400. Of course,
> > one hour at F9.4 is too under exposed. This is part of the reason why
> > it's grainy. Although I stacked three images, the stacked image still
> > looks grainy, and noisy. Surprisingly, stars are extremely sharp and
> > have well-defined shape. (Centuria 400 also produces very sharp stars.)
> > The finest stars on the film have diameters about 40 micron, as small
> > as I measured on E100S. Unfortunately, I have to do some smoothing in
> > PhotoShop to remove the grains. This slightly demaged the resolution
> > of the image. I may take 3 or 4 more 1-hr exposures next year to
> > improve the S/N so I don't need to smooth the grains and can keep the
> > very sharp stars.
> >
> > Any comments are welcome.
> >
> > Wei-Hao
> >
> > ______________________________________________________________________
> > Wei-Hao Wang :)
> >
> > Institute for Astronomy at University of Hawaii
> >
> > Address: Phone: 808-956-9867
> > 2680 Woodlawn Drive Personal Website:
> > Honolulu, HI 96822 http://www.ifa.hawaii.edu/~wang
> > ______________________________________________________________________
> >
> >
> >
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>
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