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29 July 2010

Setting the Focus Distance on the Epson V700 Scanner

... and see what you're doing
Sunset next to the Belltower of St.Georges on Lycabettus

The biggest problem with the otherwise quite splendid scanner Epson "Perfection" V700 (pretentious little product name there) is hitting the right focus distance... and keeping the film flat. Here are some little hints to solve part 1 of that riddle, to find the right focus distance.

The usual procedure is to make a series of test scans, setting your film carrier to each of its three possible heights (or, if you bought the Betterscanning holder, an binary search through a lot of different heights).

The problem with that is, assuming you're using large format (or even "baby large format" 6x9cm, like me), that you won't really be able to see any grain to focus on. So you'd have to rely on having a sharp negative. But how sharp is sharp? When I tried it at first, I didn't know if I'd hit the edge of what's possible with the scanner or if my negative was really not that 100% sharp. So here is what I've learned.

First, switch off any ICE (or in VueScan "infrared") dust removal. It will give you a slightly reduced sharpness, which makes your job to find the right focus hard. It will also speed your tests up a bit, since the scan head doesn't have to make two passes.

Second, use a large resolution, even if it's more than you usually would need. 3200 spi (samples per inch, also called "pixel per inch" sometimes) is probably safe. To save some time, I set the output format to JPEG and only 24bit RGB. I learned to resist the temptation to try to do something that you can later use at the same time.

Detail in the dark parts of that image

Third, the real secret: Use a color negative with some parts that are underexposed (e.g. stuff that is in the shadows). You will get big, fat grain in those parts. See how the grain looks in the "ghosts" of these people there? You can see that you have the right focus distance, even though that part of the image is not technically "sharp".

This is a small piece of that big picture, some people looking at the sunset. The scan is done at 1600 spi, you'd see it even a bit better at 3200 spi. (The small sample pictures are at 100% of the 1600spi scan resolution and not sharpened.)

Detail in the dark parts of that image, corrected

Here is the same piece of the image, with proper color correction and "curves" adjustment layer applied. The grain has disappeared, because well, it's in the shadows anyway.

Fourth, for once, dust is your friend. As much as we hate dust on our scans usually, here it helped me quite a bit. Because dust has 100% sharp outlines most all the time. So when you see a little spec of dust that is sharp... well, you're quite close to the optimal film focus height. The difference of the height of the dust spec probably won't matter much.

As for the 2nd part, getting the negative flat, I can't be of much help there yet, still fighting with that!


Posted by betabug at 16:01 | Comments (2) | Trackbacks (0)
ch athens
Life in Athens (Greece) for a foreigner from the other side of the mountains. And with an interest in digital life and the feeling of change in a big city. Multilingual English - German - Greek.
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Comments
Re: Setting the Focus Distance on the Epson V700 Scanner

I have a V600 and not noticed (yet) the lack of sharpness. But I know about the problem and searched for a solution. Maybe this is interesting http://www.betterscanning.com/ It works with a special plate and glass to flatten the negative.

greetings, Ruud

Posted by: Ruud at September 23,2010 10:14
Re: Setting the Focus Distance on the Epson V700 Scanner

Hey Ruud,

yeah, I've heard about the betterscanning holders. There are a lot of people who swear by them, while a few others seem to think they are not that much better. Personally I'm not going to spend much money on them just now. For flattening negatives, what works best for me right now is a couple of heavy books to place the negs in between overnight.

But even with a betterscanning holder, the need to determine the proper level of focus is still there, so the tips in this post still apply. Even more so, since with the betterscanning holder you'd need to make even more tests to determine the level of focus on a very exact level.

Posted by: betabug at September 23,2010 10:32
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