What devices support reading scanned PDF documents well?

Question

To focus, please assume I care only about one thing: The experience of reading "side loaded," scanned PDF files of books downloaded off the Internet on a portable device. There is an upper bound of around 200MB for a single file.

I am not interested in "native" PDF files (re-flowable), EPUB, or any other e-book format. I am not interested in reformatting the PDF files, optimizing, ORC-ing, etc. Not interested in e-book marketplaces or dictionaries or apps or note-taking or games or other bells and whistles. Here's the workflow: I search Google for an old book, find it on archive.org, download it, copy/sync it to the device, read, rinse, repeat.

There are plenty of reviews of devices that cover reading different e-book formats, but rarely do they cover reading scanned PDF books. If mentioned in a review, the topic usually gets a sentence or two, and that's it. Or it only talks about "native" PDF support. Or the review is from 2011 and out-dated.

I have for months been trying to get an answer to this, and this is what I've found so far as my options:

• An e-reader with e-ink
• An Android tablet (or other vendor) with a decent display
• An e-ink Android tablet
• Sony Digital Paper
• Laptop computer (I already have one, I'm looking for a better experience)

E-ink would be best, because these books are all scanned black-and-white. I work all day on the computer, the last thing my eye balls need is for me to stare at another lit screen into the wee hours of the night. But most e-reader reviews that I've read said they just don't handle navigating scanned PDF files well (if they can even open them). Is that still true? Besides software support and ease of use (which is probably the biggest issue), the amount of RAM and processor power is likely a concern, too.

A tablet would work if it had a good, crisp display. But the big concern here is eye strain. At least a decent tablet will have enough RAM and processor power to handle a large PDF and allow me to navigate it. So this is a workable option. I have actually read a large scanned PDF book on a first generation iPad -- the PDF app kept crashing and the display was poor and pixel-y, but I persevered. Still, my eyes hated me.

A hybrid would be the Onyx Boox which appears to be an Android tablet that uses an e-ink display. This might work. Reviews suggest it isn't a perfect device but still works well for PDF files. But I can't tell if the reviewers are talking about scanned PDF files or "native" again. Anyone have experience with this one?

Sony Digital Paper. I was going to say that cost doesn't matter, but at $1000 I have to set a limit and this is just too much. This thing apparently will have no problem loading and displaying and navigating any PDF, so this would definitely be an option, except for the prohibitive price. Has anyone used one of these? Is this a good device if one intends to use it to read exclusively and not do any note-taking? Hmm, my wife would kill me.

Getting PDFs on it matters: USB or syncing would be best. I use Linux exclusively and don't have access to Windows or Mac OS X, so this has to be possible via Linux (e.g., Dropbox support is good on Linux). But I'm still more concerned with how well the thing supports actually opening and navigating the scanned books.

Back to the question: What devices support reading scanned PDF documents well? I want to be able to turn the page without waiting 30 seconds. I want to view a page and scroll around (if need be) without fiddling too much with zooming and waiting too long for rendering. And likely there are important factors I'm not considering. Please give me the lowdown. If the market still isn't prepared to support this use case, that's fine, too, I suppose. Thanks for your help.

Answer 1

I read scanned PDFs on my Android tablet pretty regularly and without problems.

I presently use a Lenvo Yoga 10 HD+ (previously I had an Acer Iconia A200), but any reasonable spec tablet should do you. I usually use ezPDF reader, but there's a lot of PDF readers out there that work fine (ezPDF was the first that I found that performed well for most things I look at).

If you're trying to quick-flip pages one after the other, it'll take a second or three to go to the next one. If you actually read each page, though, you won't see that, because it renders the next page in the background.

Things to look for:

• Quick page flip (or at least page flip you won't notice)
• Controls that make sense to you
• Pan and Zoom controls appropriate to the platform
• If you close the PDF and re-open it later, does it come back to the same place? I know a couple of readers I tried DIDN'T do that.
• Reasonable screen size - the 10" display on my tablet is fine for 8 1/2x11 pages, as long as the type isn't minuscule.
• Make sure the device takes an SD card - you'll want lots of space to store PDFs.

I find it's nice to side-load stuff to the SD card, and read from there.

Answer 2

I currently use 9.7" Onyx Boox M96, a device from 2014, and find it adequate for the job. To answer your questions:

• the largest PDF file I have is a 330MB scan of a book at 300dpi
• no problem with opening such files, browsing, scribbling on, zooming, (auto)cropping, bookmarking - you can do that all
• this depends on the size of the book of course, but I generally do not have the need for scrolling/panning, I find the 9.7" size screen sufficient but there is a 13.3" model too if that's not enough for you
• depending on the size/resolution/complexity turning a page of a scanned PDF file can be up to 3 seconds (e.g. my 300/600 dpi scans can take this long); if you want to skim through scanned books that's a no go, but if you read cover to cover it doesn't matter much
• no eye strain and possible to read on a sunny day in your garden or by the window (no glare)
• connectivity: USB, microSD, wifi, bluetooth

You may also want to have a look at my answer to this question where I talk about my general reading experience with this reader.

Answer 3

I've used multiple devices to read scanned PDFs, including iPad, Android phone, and Sony e-ink reader. The biggest problem is that the font in scanned PDFs can't be resized, and the text doesn't reflow. On a small device, such as a phone or pocket e-reader, you need to zoom in and then pan across the page. Reading is difficult in this situation, and can be exacerbated when the scanned document consists of two sequential pages.

The e-ink reader was terrible and I stopped using it for this type of document, despite being my reader of choice at the time. The phone was marginally better, as moving the page around was faster and easier. The iPad worked well.

Ideally, I would aim for a device that can hold at least the full width of the page on one screen and still be comfortable to read without further zooming.