Re: New Area 51 Photos

Message posted by lone wolf on January 31, 2005 at 20:49:45 PST:

Astia 100F is much lower contrast than Provia 100F. Even when Astia 100F is pushed one stop, it is still lower contrast. However, I don't view the lower contrast as a bad thing. The contrast seems to fit film scanners nicely. Assuming your scanner is at least 12 bits, you can simply run your scanner software in autolevel mode and lower contrast will be compensated.

I can tell you that Astia 100f grain is just barely visible on a 4000 ppi film scanner. I did a scan of a camo dude truck with a 50mm lens and was able to process the image well enough to see items on the dash. This is the same film I used to get photos of a SU-27 coming out of Groom. Not great photos since the plane was 14 miles away and very high, but the film had enough resolution to recover some tiny images, about 100 pixels wide, that were good enough to identify the plane.

Normally film gets grainy as it is pushed, but I haven't seen an increase in grain for one stop on Astia. Provia 100F has substantial grain if pushed one stop. I don't use Provia 100F pushed.

In the Fuji slide film family, Velvia has a magnenta cast, provia has a blue cast, and astia has a slight cyan cast. [You might find different opinions on the net.] Velvia has the most color saturation, while Provia and Astia have less. I believe Astia can resolve 150 lines per mm, but Fuji never says how they get that number. It certainly isn't with a camera lens. I believe autofocus cameras reach about 30 lpmm.

It is only on TIkaboo and TTR long distance photography where you need the contrast. I did a test roll of Astia pushed two stops and the sharpness suffered. [I don't know if the lab screwed up as I only did one roll. You never know.] I'm going to try a test roll at 1.5 stops.

Note that as you increase the contrast of the film by pushing it, you also decrease the grain magnification created by the scannning process. This sounds counterintuitive, but here is why it works that way. The more you need to increase the contrast by moving the low and high limits of the scanner (based on the histogram), the more the grain gets magnified. This is one reason why print film tends to look grainy when scanned since print film gets its contrast magnified greatly to produce a reasonable image. [It is the same reason that print film has a larger latitude than slide film.] If the image on the film has more contrast, then you don't need to move the scan low and high limit inward as much, so you are doing less grain magnification. Obviously, there is some sweet spot.

In Reply to: Re: New Area 51 Photos posted by Trevor on January 31, 2005 at 12:54:48 PST:


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