Getting a solid focus on grain with DSLR scanning?

loccdor said:

Cheap flatbed scanners can pull plenty of resolution out of a 4x5. And it's a lot easier and less finicky. I'd use DSLR scanning only for 35mm and (maybe) medium format. Unless you want to make ultra large stitched images from lots of offset exposures, which is something best done on a one-off basis as it takes too much time to do for large groups of pictures.

As others said, I would recommended a dedicated prime macro lens, that has very positive test results.

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Exactly. With large format, even the cheapest scanner available that can scan 4x5 can easily make positively huge scans at 1000+ dpi.

Adrian Bacon said:

Exactly. With large format, even the cheapest scanner available that can scan 4x5 can easily make positively huge scans at 1000+ dpi.

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But HUGE scans don't give better results. As an example the Epson V850 craps out after 2400ppi for medium/large format and any increased scanned resolution is simply making the file bigger and not better. Clearly the increase in input size (neg area) is an advantage, which answers why 35mm scans from the same scanner fail miserably because of the small input size (scanning at the genuine max 4800ppi results in the equivalent of an 8mp camera 'scan', which is pathetic). But the V850 can do good medium and large format scans. But thinking HUGE equates to quality isn't understanding the bollocks scanner manufacturers feed you with the published headline figures.

250swb said:

But HUGE scans don't give better results. As an example the Epson V850 craps out after 2400ppi for medium/large format and any increased scanned resolution is simply making the file bigger and not better. Clearly the increase in input size (neg area) is an advantage, which answers why 35mm scans from the same scanner fail miserably because of the small input size (scanning at the genuine max 4800ppi results in the equivalent of an 8mp camera 'scan', which is pathetic). But the V850 can do good medium and large format scans. But thinking HUGE equates to quality isn't understanding the bollocks scanner manufacturers feed you with the published headline figures.

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I have a v850 Pro. Yes, it tops out at ~2400dpi, which for a 4x5 negative is more than good enough for a 40x50 inch (!!!) print at 240 pixels per inch. If that's not a huge scan for you, then you operate way outside of what mere mortals need.

2400 dpi on the 120x97mm area of a 4x5 negative is 104 megapixels which is enough to produce prints of whatever size you want when they are viewed from an appropriate viewing distance.

Of course there’s something like 2-3 times that much information in the film depending on the emulsion but there’s not a lot of use for all of that except if you really like to pixel peep.

_T_ said:

2400 dpi on the 120x97mm area of a 4x5 negative is 104 megapixels which is enough to produce prints of whatever size you want when they are viewed from an appropriate viewing distance.

Of course there’s something like 2-3 times that much information in the film depending on the emulsion but there’s not a lot of use for all of that except if you really like to pixel peep.

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That was also my point. If ~100MP isn't a huge scan, then I don't know what is. That's enough resolution to crush a lot of computers just trying to handle the file and do basic manipulations on it.

Adrian Bacon said:

I have a v850 Pro. Yes, it tops out at ~2400dpi, which for a 4x5 negative is more than good enough for a 40x50 inch (!!!) print at 240 pixels per inch. If that's not a huge scan for you, then you operate way outside of what mere mortals need.

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Did you miss me saying "the V850 can do good medium and large format scans"? I'm confused, you are using dpi and ppi interchangeably but they aren't the same thing. '1000+ dpi' is far more than a common inkjet printer can manage which is why I was referring to an artificially bloated file size in case you thought that is what you could print at. But so far you've used 1000+ dpi, 100mp, 2400 dpi, 240 ppi all seemingly to mean the same thing and to be honest it's too confusing so I'll leave it with you and say goodbye.

250swb said:

Did you miss me saying "the V850 can do good medium and large format scans"? I'm confused, you are using dpi and ppi interchangeably but they aren't the same thing. '1000+ dpi' is far more than a common inkjet printer can manage which is why I was referring to an artificially bloated file size in case you thought that is what you could print at. But so far you've used 1000+ dpi, 100mp, 2400 dpi, 240 ppi all seemingly to mean the same thing and to be honest it's too confusing so I'll leave it with you and say goodbye.

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No, I saw that. I just happened to take exception to you effectively calling me stupid. If that’s not what you meant to convey, then my apologies. You seem to be terribly bent out of shape about something, and I doubt it has anything to do with me, so I’ll leave it at that.

dpi is what you scan at, ppi is what you print at. I do believe I used dpi when referring to scans and scanners, and ppi when referring to prints and printers.

Adrian Bacon said:

I just happened to take exception to you effectively calling me stupid.

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Gentlemen, please. No name-calling, insults etc. This applies to everyone, equally.

250swb said:

'1000+ dpi' is far more than a common inkjet printer can manage

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@Adrian Bacon was referring to 1000+dpi scans from 4x5" negatives. Whether the files generated are 'huge' is a subjective issue; some would call 20Mpix + 'huge', others may reserve the term for yet bigger files.
How this relate to print dpi of course depends on how big the image will be printed.

250swb said:

1000+ dpi, 100mp, 2400 dpi, 240 ppi all seemingly to mean the same thing

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I think you need to read more carefully; I don't see any overt misuse of the terminology.

250swb said:

scanning at the genuine max 4800ppi results in the equivalent of an 8mp camera 'scan', which is pathetic

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It's not entirely clear what you mean by this. A true 4800dpi scan would be a 32Mpix file from a 35mm negative. However, no flatbed scanner actually achieves an effective 4800dpi resolution as you also pointed out; I agree with you that they mostly top out at 2400dpi if you're generous. For a 24x36mm negative, this yields a little over 8Mpix, which in practice allows for reasonably large prints to be made with good resolution (11x14" print size still being acceptable for most purposes).

koraks said:

It's not entirely clear what you mean by this. A true 4800dpi scan would be a 32Mpix file from a 35mm negative. However, no flatbed scanner actually achieves an effective 4800dpi resolution as you also pointed out; I agree with you that they mostly top out at 2400dpi if you're generous. For a 24x36mm negative, this yields a little over 8Mpix, which in practice allows for reasonably large prints to be made with good resolution (11x14" print size still being acceptable for most purposes).

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I said ppi not dpi. Dots per inch are for printing, you don't have 'dots' in digital files you have pixels, hence a 1000dpi print being unimaginable with an inkjet printer in todays technology.

But if you are really interested in the resolution of the Epson V850 for 35mm scans please read down near the bottom of this review which makes the point.

https://www.filmscanner.info/en/EpsonPerfectionV850Pro.html

Adrian Bacon said:

No, I saw that. I just happened to take exception to you effectively calling me stupid. If that’s not what you meant to convey, then my apologies. You seem to be terribly bent out of shape about something, and I doubt it has anything to do with me, so I’ll leave it at that.

dpi is what you scan at, ppi is what you print at. I do believe I used dpi when referring to scans and scanners, and ppi when referring to prints and printers.

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Again, you print with DOTS you have digital files with PIXELS, not the other way around. Admittedly we all get confused and many people interchange the terms so I'm not calling you an idiot, but in reality no inkjet printer can achieve 1000+dpi but your scan may indeed exceed 1000+ppi, the only thing I questioned was did you know the difference given some people may indeed think on reading it that they'd get a 1000+dpi print out of it.

250swb said:

Admittedly we are get confused

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I don't think anyone is very confused about this. Sloppy, perhaps. But confused, no.

All of the things you said weren't really being argued against or put up for discussion. You're welcome to state them, of course.

koraks said:

I don't think anyone is very confused about this. Sloppy, perhaps. But confused, no.

All of the things you said weren't really being argued against or put up for discussion. You're welcome to state them, of course.

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Confused is a term you've introduced, but given you've argued and doubled down on it by stating there is no difference between dpi and ppi I think perhaps confusion is the wrong word. Perhaps threads should be moderated at the very beginning if things aren't open for discussion?

250swb said:

Confused is a term you've introduced

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Eh? First used here:

250swb said:

we all get confused

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250swb said:

by stating there is no difference between dpi and ppi

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Eh?? Never said anything like that.

koraks?
Are you becoming Canadian?
Eh.

A few additional considerations:

There are well established methods for close up photography that don’t use a dedicated macro lens. Many are very cheap solutions:

1. Extension rings - probably the most practical if you know your best lens and you can source them cheap from China etc.

2. Reverse mount one of your primes directly to your camera body using a cheap but specific ring made for the purpose. Many lenses can work well for close up work if they can be reversed.

3. Reverse mount a short prime directly onto the front filter thread of a longer prime using a lens coupler & any necessary step down rings.

4. Combine an enlarger lens with a helicoid on the camera. Enlarger lenses often outperform macro lens optically for close up work provided you can find a way to mount and focus them. The Naked Photographer channel on YT has an excellent feature comparing that set up to others for dslr scanning.

All cheap options - you need to experiment and research more to get the best results.

Two more ideas:

If there is a way to use off camera flash as a light source- consider that. It’s my preferred way, and has several important advantages.

I use a small piece of mirror which I place on the same surface my film will rest on, under the lens. In live view I can see the camera & lens reflected. It is quite easy to see if the lens front isn’t perfectly round in its reflection, which means the camera is not perfectly perpendicular to the mirror surface. I’ve got bubble levels on everything and they aren’t foolproof, because they are not on the sensor itself. Using this very old school method I can see as the sensor sees, and if the lens ain’t central and perfectly circular when I punch into it in live view, it doesn’t matter what any bubble level says, the sensor and the mirror are not parallel. Need I say, you remove the mirror and replace it with the film to scan!

Good luck with your studies.

250swb said:

Again, you print with DOTS you have digital files with PIXELS, not the other way around. Admittedly we all get confused and many people interchange the terms so I'm not calling you an idiot, but in reality no inkjet printer can achieve 1000+dpi but your scan may indeed exceed 1000+ppi, the only thing I questioned was did you know the difference given some people may indeed think on reading it that they'd get a 1000+dpi print out of it.

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Yes, I am intimately familiar with what the differences are.

Whether you agree with it or not, most if not all scanner manufacturers use the terms 'dpi' or 'dots per inch' when referring to the resolution the scanner can scan at, and that's generally the terminology I use when talking about scanner resolution for no other reason than to at least use the same terms the manufacturer used. Case in point: Epson's product page for the V850 very clearly uses 'dots per inch' and 'dpi' when talking about the resolution of the scanner with nary a 'ppi' or 'pixels per inch' in sight. https://epson.com/For-Work/Scanners...erfection-V850-Pro-Photo-Scanner/p/B11B224201

Regardless of the terminology used to describe scanner resolution, you'll end up with an image that is however many x by y number of full RGB color pixels. You print it by defining how many full color RGB pixels per inch you want to print, and the printer renders those full color pixels using dots of ink at whatever dots per inch it's print head can lay down on the paper.

If you really want to get nit picky about it, if you're using a digital camera to scan film, you're back to dots, or more appropriately, sensels, because each position on the sensor is only going to sense one color from the color filter array that is on top of the sensor and you don't get to actual full RGB pixels until you've taken that raw sensel data and done something with it to get to RGB. If you stop and think about it, technically Epson using dpi terminology isn't wrong either if you view each color on the sensor as a dot, much the same way each dot of ink on the paper is a specific color, and it's the combination of multiple dots of ink that make up a full color that we can see. The same goes for the sensor, it takes multiple dots of different colors to get to a full RGB, so they're kinda not wrong.

But, all that being said, if there's one thing I do agree with you on it's that it's way too easy for people to be confused about what the terms mean.

f/Alex said:

add on: anything I do in color ends up with this sort of rainbowy effect on the edge of things? I've noticed my sensor does seem to have very high amounts of noise, more than other folks have reported with a 5D, maybe it has something wrong with it? or is this the fault of using an oled tablet as a light panel? (I have a diffuser between the film and panel)
View attachment 374966


Even when attempting to focus on the lettering on the edge of the film, I still encounter the same sort of jumbled up mess
View attachment 374967

looking closely, it's almost making me consider the possibility that the camera might be unable to capture at a high enough resolution? If this might be the case, my next move will be attempting to find a nearby library with a half decent flatbed scanner.

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Just offering a thought about the lighting. An OLED, or indeed any three colour luminous display, is only outputting a limited set of red, green and blue frequencies of light,

Natural light and various other types of artificial light have a much wider range of frequencies.

If the RGB frequencies from the tablet doesn't line up with the RGB frequencies of the sensor sites on the camera, then I imagine you could get some odd colour effects.

Prints can have an effect where they look different under natural light, than under limited frequency artificial lights. Called metamerism. Because some of the pigments fall into band gaps not present in the artificial lights. Perhaps there's something similar here?

Of course, I may be entirely wrong.

But I wanted to offer it as a thought.

JokerNZ said:

Of course, I may be entirely wrong.

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No, you're not, and to an extent, this can explain some of the color fringing shown in the first post.