Very interesting test results. When I looked at AG's website he said
this about the sensor he was testing:
"I have also found that when the sensor is noisy due to warmness (hot
summer day or extended operation) or higher ISO setting are used..."
That got me thinking as to why digital cameras and their sensor chips
aren't themoelectrically cooled. Surely this would reduce the noise seen
in many digital images, it does on astronomical CCDs. OK they are quite
cool and sometimes quite large but surely it is possible to cool a
digital camera sensor in a similar way? Are there any digital cameras
which do this?
As an aside in the ever exapnding film vs. digital debate I passed by a
music shop today and emblazened on a poster in the window was an advert
for a band which was releasing its new album on vinyl! Hopefully film
will stick around like vinyl for the purists in the coming years.
All the best,
Gareth.
AG Schnozz wrote:
> I'm doing some additional resolution testing lately.
> Interesting results. The more I try, the harder it is to beat
> the old glass. However, I am highly pleased at how well the
> digicam holds up.
>
> Using an old fashioned line-pair resolution chart (you know, the
> ones with three vertical and three horizontal bars arranged in
> an ever decreasing size and circling in on itself), I've found
> that when comparing same-size images, the Zuikos outperform the
> digicam by over eight steps.
>
> Ok, sure, I'm comparing to a 5MP Minolta A1, which isn't known
> for having a perfectly sharp lens. However, when drilling down
> to pixel level, five of those steps are beyond the resolving
> capability of the sensor! I ran out of pixels.
>
> So, what does this mean? A 5mp sensor is beat by film by a fair
> margin. It also means that several of my ancient Zuikos should
> be sharp enough for mating to a digital body. I'm sure there is
> a point where they'll puke out, but overall, they do quite well.
>
> Ok, for the sake of full-disclosure, the Zuiko lens tests were
> performed using Delta 100 B&W film, processed DD-X (which is a
> slightly soft developer) with the test prints blown up to the
> equivelent of 24x36". Hopefully, later tonight I'll post some
> of these tests on my website. If not tonight, sometime during
> the week.
>
> www.image66media.com
>
> The biggest suprise was how well the A1 actually did. The trick,
> though, is to shoot RAW. I lost an entire step, and sometimes
> more, when shooting JPEG.
>
> Oh, when scanned, most, if not all, of that resolution gain with
> the film is gone. As long as I stay optical the increased
> resolution is gained. The moment I digitize, the playing field
> is leveled. I wonder what a 5400dpi scanner must be like...
>
> This addresses one of those things that has always caused me to
> scratch my head about resolution differences between film and
> digital. We're almost always comparing digitized to digital. In
> this particular test, I tested full-analog to full digital.
>
> How does this parlay into real-life? I'm getting about a 1/2 mm
> blur in 24x36" B&W enlargements. Imagine what it could be if I
> used an unsharp mask!
>
> Course, that's when you use mirror pre-fire, cable-release, yada
> yada yada.
>
> But, through it all, it also means that a quality 8MP sensor
> will equal the Zuikos maximum resolution. But the film itself
> (Delta 100 or PanF+) is still another order of magnitude beyond
> anything the lens is capable of doing. I've maximized ISO 400
> films and even ISO 100 slides films, but I've never outdone
> Delta 100, PanF+, Kodachrome 25 or Velvia 50.
>
> Ag
> AG
>
>
>
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--
Gareth.J.Martin
Research Postgraduate
School of Geographical Sciences
University of Bristol
University Road
Bristol
BS8 1SS
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