Topic – Medium Format Compared to Canon 5D2

One of my recurring motives is 400 kV power line. True, it is not that a fantastic subject but the size of it is impressive if nothing else. And we often walk by it, so a motive it has become. Recently I took a picture of in good sunlight with Ilford FP4+ at ASA 125. Aperture must have been f/16 or, more likely f/22, and the negative size was 6×7 cm. All in all a good case for studying resolution.

After developing in HC-110 1+63 for 18 minutes and scanning at 4800 dpi on a Canon Canoscan 9000f some small details of the structure could be analyzed. This led me into trying to find what maximum detail could be extracted from the negative.  Here it is in a reasonable sized jpg (5235 x 6584 pixels the scanned original was 10464 x 13168 and about 32 MB):

kilovolt1

 

A detail at the top cross beam just above the centre insulator stack shows some bolts easily:

kilovolt (1)

 

I was sort of impressed that film literally developed in the kitchen sink could produce such fine details. Or is this more a performance issue with the scanner used? What if there is more info in the negative?

Placing the negative in a microscope with a mere 40x enlarging lens shows that there really is more in the negative than the above scan conveys. This is taken with a Canon S95 in raw straight through one of the eye-pieces of the microscope and then inverted in Aperture:

kilovolt (2)

One clearly sees that the bolts have not been resolved any more in this enlargment of the negative. What one can see is that the scanner turned the insulator discs into black blobs while the negative clearly holds more information. A more careful scan would have helped here.

Today I was passing the same power-line with my Canon 5D mark 2 and Ultron 40/2. This photo of it is taken from about the same position:

kv5d2

This detail shows what the 5D2 has in terms of image detail:

Screen Shot 2013-03-23 at 21.04.18

This might well be the most interesting picture in this blog entry! The bolts are clearly there albeit in lower resolution, since the 5D2 sensor simply cannot do better than 5616 x  3744 pixels. It is also clear that the reflexions in the insulators come through here. But look more closely and you will find some artifacts too: the different girders have odd lines and small crosses in them! The insulator discs are not round any longer and have vertical  streaks in them, in fact the leftmost parts seem disintegrated from the insulators themselves!! Very strange. So even if the detail is there it will not appear pleasant when enlarged to maximum… A better scan will make the negative look better until it is exhausted of its details.

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