[rollei_list] Re: Article

  • From: Aaron Reece <oboeaaron@xxxxxxx>
  • To: rollei_list@xxxxxxxxxxxxx
  • Date: Thu, 25 May 2006 22:46:11 -0400


On May 25, 2006, at 6:24 PM, Don Williams wrote:

At 02:59 PM 5/25/2006 -0700, you wrote:
Anyone interested in Digital Photography, I was fortunate to have an article published in Ranegfinder.

http://www.rangefindermag.com/magazine/May06/36.tml

Nice survey article. I agree with the notion that some whites and blacks may be out of the range of digital sensors.

I agree with Don. The article was clear and balanced. Well done, Peter.

I got a roll of 120 transparencies back yesterday, and not having a film scanner I put them on my lightbox and photographed them with my little Canon A70 P&S. (This is what I have to do with my B&W negatives as I currently lack a darkroom, but that is another story.) Examining the resulting digital images confirmed that the exposure range of the digital couldn't cope with the range of the transparency film. Shadows and highlight areas that retained good detail in the original image were blown out in the digital image. Please, before you all skewer me, I know this is a ridiculous and meaningless "test" but I have noticed lots of blown highlights in actual digital images, esp. in direct sunlight. The metering seems to have been programmed to compensate for shadows at the expense of the highlights. It's also a three-year-old camera, and technology marches on.


Same size as a cigarette package, although I don't have a package to compare it with.

I believe the current PC simile is "same size as an iPod."

BTW, Peter, I think you may want to revise this passage:

Obviously, the real key to having greater digital resolution is to gain more pixels in the same area with reduced noise (see table 1, page 100). One example is Canon’s EOS 1D Mark II-N, with 8.2 effective megapixels, compared to the original EOS 1D, with 4.2 effective megapixels. Both have a sensor with the same physical measurements of 28.7x19.1mm, but the new Mark II-N has almost twice the number of pixels. For those more familiar with film, this is comparable to using a much finer grain film (the EOS 1D Mark II-N) capable of producing an image that is the equal of the earlier emulsion (the original EOS 1D) at twice the size, say 16x20 versus 8x10.

You've confused linear dimensions with area. A 16x20 requires four times the resolution of an 8x10. Doubling the resolution of an 8x10 image results in something like an 11x14 (area of 80 versus area of 154). This is a minor nitpick but it's the reason I tell friends and relatives to relax, their 5 megapixel camera is just fine, and to instead consider things like focussing and metering accuracy and low noise if they are looking for a new one.


Best regards,
Aaron

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