Big Camera Test

Discussion in 'Exposure Discussion' started by Aristophanes, Jan 3, 2012.

  1. Aristophanes

    Aristophanes Member

    Mar 4, 2011
  2. Danielle

    Danielle Member

    Jun 19, 2011
    Melbourne, A
    Multi Format
    Moral of that story is that 8x10 sheet film rules? Something a lot of us already knew, pits its so... well... huge! Its not a very real life test though.

    I still think better tests are ones from comparing actual real life prints (eg 16x20/20x24). There's a reason film is still used by us, nice to know there's some data supporting it and not just a 'look' though I guess.
  3. timparkin

    timparkin Member

    Sep 2, 2006

    Quote from the article..

    Printed Results

    The very last task that I undertook was to make prints of all of these images at various sizes from 20?x24? to 64?x80?. Obviously I didn’t print them at full size but I did make 12?x17? crops. The results of these were quite enlightening. At 64?x80?, the 8×10 print was considerably better, it held more detail and the tonality was smooth even though it was slightly grainy. The IQ180 image had that ‘plastic wrap’ look to it that wasn’t particularly pleasing. I did wonder whether adding noise to the IQ180 file would improve that and to a certain extent it did. Although the IQ180 still looked soft in comparison with the 8×10, once noise was added (using Alien Skin’s ‘Exposure’ plugin) the 4×5 and IQ180 prints looked on a par with one another.

    At a more realistic gallery hero image of 30×40? print, the images started to look on a par with each other with the edge given to the 8×10 if you really ‘nosed’ the print (i.e. it has sharp detail in the 20 lines per mm range) and the edge to the IQ180 because of the high acutance at around 5 lines per mm. The 4×5 print holds the same detail as the IQ180 now but looks less sharp because it doesn’t have that high level of acutance. However, there is something aesthetically pleasing about the 4×5 and 8×10 images because they don’t have this acutance – this is a purely subjective thing though

    When you come down to 20×24 prints, the difference between the difference cameras is very difficult to discern a difference between the 4×5, IQ180 and 10×8 images beyond a difference in tonality. The Portra 400 and IQ180 produced very similar images but the Velvia 50 had a definite ability to separate tones, especially in foliage, that both the IQ180 and Portra 400 couldn’t manage. This wasn’t possibly replicated in Photoshop either. Whether you like that difference or not is a subjective decision – personally I like it in some images and not in others. It’s also as impossible to emulate as it is to remove so if you get your Velvia image, you won’t be able to wind it back out again – it isn’t just saturation by a long shot.

    What was a surprise out of all of this was how bad the Phase One P45 managed. The resolution wasn’t a great deal better than the Sony A900 – which was evident when we produced prints of both of them side by side – but the colour was terrible. There was no way to compare the files without making quite dramatic selective colour changes (i.e. removing yellow from the greens and yellow/greens, removing magenta/red from everything and also desaturating the greens). I have an idea that this may be something to do with a clash of the frequency spectrum of the bayer filters/sensor and the spiky frequency spectrum of light reflected from chlorophyll. The reason this may be so is that although plants look green, the actual colour spectrum of chloropyll is a combination of almost an almost ultraviolet purple/blue with an almost infra-red red. Because of metamerism, these two colours get detected in our eye and combine together to give us green. However, digital sensors have all sorts of strange behaviour around the ultra-violet and infra-red ends of the spectrum and any slight imbalance between these two ends will end up with chlorophyll looking a weird colour. However a synthetic green patch that looks identical to our eyes may render perfectly correctly. OK – as a colleague of mine would say “back away from the science Tim”…

    Back to the Sony A900 for a moment. I was incredibly impressed with the output of this camera on the landscape test – the colour rendering was very natural and looked very similar to the IQ180. During this test the results from both this camera and the Nikon D3X have been very impressive and although I’m a bit tested out, I would love to do a comparison of DSLR colour at some point in the future.

    It always pays to read the article before being critical ;-)