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Part 2 - The Acid Test (or can I make a really sharp A3+ print from 6x7?)

I picked this shot, which is from my first outing with my new Mamiya 7II, not for its artistic merit but simply because it had plenty of detail in it and it looked very sharp under the loupe. Just out of interest, notice the purple colour of the clouds and the river - this seems to be typical of Provia 100F and I intend to stop using it in future! The results from the Astia I shot on the same day are much better for colour.

Anyway, I scanned the slide in the slide holder, and was somewhat unimpressed with the sharpness. It looked fine at 10x8 inches but was starting to look less than eye-popping at 16x12. But following the improvement I'd achieved by scanning negatives directly on the glass of the scanner rather than in the holder, I tried the same with the slide. The holder makes a useful mask which can sit on top of the film, pressing it down onto the glass at the edges and holding it flat. I put the slide emulsion side down to avoid Newton's rings.

The result is a very sharp 16x12 inch print. Even if you get much closer than normal viewing distance, it looks bitingly sharp.

I can't really show you this on the web, but what I can do is show a couple of extracts at "actual pixels" size:

The group of people in the extract below are in the bottom left hand corner of the picture, you can probably just about make them out in the shot above!

If the full image was printed at the size these portions appear on the screen, it would be over 3 metres wide, so by the time you stood back far enough to see the whole thing it would probably still look sharp. Suffice to say, it looks very sharp at the maximum size my Epson 1270 printer is capable of printing it, and I'm very pleased. If I need bigger prints than A3+, I would have to get someone else to do them anyway, so the 2450 is perfectly suited to the purpose I originally bought it for - printing my own Medium Format slides.

Shadow detail and noise

We've already seen that the Epson can scan a dark slide of the Hong Kong skyline at night without the deep shades of grey coming out green and speckly, but I've had requests for some REALLY difficult tests of dynamic range. Fortunately I have a couple of slides in my collection which would cause scanner engineers actual physical pain were they to hold them up to the light! Below is a comparison of how the Epson managed, with the Acer as a frame of reference. Not fair? Not at all - I'm only comparing a £270 flatbed scanner which does a nifty sideline in scanning slides with a £270 dedicated slide scanner... The example below is a 35mm mounted Sensia 100 slide (I didn't remove it from the mount for the Epson scan - as seen earlier, doing so may have resulted in slightly better sharpness but this isn't what I'm testing here).

Notice again how the sharper Acer picks out all the dust - it seems particularly good at that, perhaps that's why the latest model (2740S) has dust removal hardware built in!

Noise

A slight advantage for the Acer I think. The darkest black has gone slighlty green but there's very little noise there. The Epson has some decidedly speckly green bits, but not a bad performance by any means.

Shadow detail

Looking at this slide on the lightbox, it looks slightly underexposed. There is clearly detail in the folds in the cover at the front of the boat, but the inside of the boat is pretty much black. There isn't really any detail visible on the lightbox which the scanners have failed to extract. Epson claims a Dmax of 3.3D for the 2450, whilst Acer claims 3.2D. I would say both manufacturers are being cautious with these claims. Better dynamic range would not be on my wish-list for either scanner, as I don't believe there's much more there to extract.

Time to get really nasty

The slightly underexposed Sensia test may have been a little unfair on the Epson, being primarily a print scanner, but it came out smelling of roses. So now it's time for something completely unfair - UNDEREXPOSED KODACHROME!

My conclusion is that both scanners have done surprisingly well with this hideous slide. I would be very interested to see how the new Nikon and Minolta scanners which claim a much higher Dmax than either of these scanners would cope with it. On the lightbox, it doesn't look as if there is any detail in the dark clouds or the foliage. Both scanners have picked out detail in the clouds, and the Acer has certainly resolved some colour detail in the palm trees. From this test it would seem the Acer has the higher dynamic range of the two, despite Epson's claims, but both are surprisingly good. Colour rendition and sharpness are better on the Acer, as before.

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