Canon CanoScan 8400F Flatbed Scanner: One Level Up

Are you looking for an inexpensive but efficient solution to scan your pictures and slides? Then our review might be of great interest to you. We are going to discuss another offering from Canon that supports FARE Level 3 hardware dust and scratches removal technology.

by Sergey Samarin
06/04/2006 | 08:39 PM

Some time ago we tested a Canon CanoScan 5200F scanner on our site which featured the hardware dust & scratches removal technology called FARE Level 2 (for details see our review called Canon CanoScan 5200F: Inexpensive Scanner with Hardware Dust and Scratches Reduction).


Today I am going to take a look at the next model in the series, CanoScan 8400F, which offers the next level of the same technology, FARE Level 3. Besides that, the senior CanoScan offers a number of additional advantages I am going to cover in this review, too.

As usual, let’s first check the scanner’s specification.


Let's take a closer look at the claimed official specs:

So, the CanoScan 8400F can digitize at an optical resolution of 3200dpi and a color depth of 48 bits. Its maximum optical density is a good 3.3Dmax which helps get high-quality scans of negative films. An infrared LED is used when you enable FARE technology in the driver and helps identify dust and scratches in the original for further removal. Three holders for transparent originals of all the standard formats, including a holder for medium-format film rolls, are enclosed with the scanner.

Package and Accessories

The CanoScan 8400F scanner comes in this cute-looking box painted Canon’s corporate colors:

The package contains:

The 8400F is compatible with all versions of Windows from Windows 98 and with Mac OS X version 10.1.3 and higher. You get a 5-CD pack of software to use under these OSes:

The remaining two CDs are copies of the first two, but with localized versions of the software.

This is what you are going to find on the Installation CD:

I won’t describe the software in detail just because it doesn’t differ much from the software included with the Canon CanoScan 5200F we tested earlier on our site. I am only going to talk about the special traits of the 8400F if there are any.


The 8400F has a cute case made of stiff plastic that resembles the 5200F model in design. A holographic model logo and a FARE Level 3 symbol can be seen on the scanner’s lid.

So, FARE Level 3 is the next level of technology for automatic retouching and enhancement of film scans (there is an analogous technology for photographs called QARE). When this technology is enabled, scanning is done in two passes, one in infrared light. Identified defects like dust or scratches are removed in the final image by the driver, but the intelligent retouching doesn’t end here. For example, the Color Reconstruction option helps make the colors of an old photograph rich and vibrant once again. The Grain Equalization and Management feature reduces the graininess which often occurs on highly sensitive film. FARE Level 3 also corrects the back lighting by intelligently identifying the areas of image that need such correction.

Canon’s CanoScan 8400F has come to replace the 8000F model and brings about such improvements as a new scanning block featuring high digitization speed and performance. The mercury-based fluorescent lamp takes only about 20 seconds to warm up after you’ve turned it on. The warm-up time before pre-scanning is a mere 2 seconds. All this means that scanning is done much faster than before. By the way, there’s a dual fluorescent lamp in the scanner’s carriage.

Like the previous model, this scanner is equipped with four quick scan buttons (Copy, Scan, PDF and E-mail) that are located on its face panel.

The buttons are linked to the scanner’s preinstalled applications and their purpose is clear thanks to the pictures and labels. Each button can be programmed to perform a certain task using the scanner’s software, for example to send the scan right to the printer (to simulate a copier).

The CanoScan 8400F is equipped with USB 2.0 interface which, combined with other technologies, ensures its rather high scanning speed.

Before connecting the scanner to your computer, you must first open the transportation lock at the bottom of the device. There are stickers on the scanner’s case that remind you of doing that and pointing to the position of the lock.

As I said above, the Canon CanoScan 8400F allows digitizing 35mm film (in strips or in slides) and medium-format 120 film rolls. There are special holders included for all the film materials supported. The holders are handy even for very tight-rolled film.

The slide-adapter’s carriage and lamp is in the scanner’s lid. You can access it by removing the screen:

The adapter’s cable is to be attached to the appropriate connector at the scanner’s back. Once the screen is removed, you should use a holder and specify your settings in the scan program.

The intuitive driver interface is friendly to power and novice users alike, offering Advanced Mode for the former and Simple Mode for the latter. I don’t think you’ll have any difficulty mastering this software.

Testbed and Methods

The configuration of our testbed remains the same, so you can compare the results with those we got in our earlier reviews:

Scanning Speed

It’s not a big problem to measure a scanner’s speed, the only disadvantage for the hardware reviewer is that sometimes you have to wait long for the results. I measured the speed of the CanoScan 8400F by digitizing two originals of standard form-factors (a 10x15cm photograph and a 35mm slide) at four resolutions (300, 600, 1200 and 3200dpi). At first I scanned them choosing the Recommended settings in the driver and then with enabled FARE technology.

So, I start my stopwatch the moment I click on the Scan button and stop it the moment the scanned image is fully transferred into the control program (Photoshop). Here are the results:

*- the second value indicates the time it takes to complete the task with enabled FARE

Why it takes so much more time to make a scan with FARE? Because the scanning is performed in two passes. During the first pass the original is lit by an infrared light source that reveals surface defects; the second pass is a standard digitization operation. At high resolutions quite a lot of time is also spent for software post-processing of the scan by the driver before it is exported into a file or application.

It should be understood that the speed characteristics of any scanner depend not only on the scanner itself, but also on the configuration of the computer. If you want to have some comfort while scanning at high resolutions (when the image file may be over 100MB large), make sure you have enough system RAM to do all the operations without accessing the hard drive. If you use Photoshop, try setting the Memory Usage option at 100%.


Resolution is usually listed by the manufacturer in a scanner specification, but the real optical resolution depends not only on the number of elements in the light-sensitive device but on the optical system, too. Good resolution means the scanner’s ability to reproduce all the minutest details of the original and sometimes a scanner with a high optical resolution may produce a worse-quality scan than a model with a lower optical resolution.

This can be tested in practice by means of special patterns with alternating black and white lines. The spatial frequency parameter of a pattern is expressed in the number of line pairs per inch (lppi). A pattern looks like that:

Applied Image QA-69-P-RM test target

There are five patterns here with a different spatial frequency (30, 70, 95, 140 and 180lppi) and I will scan them at the maximum optical resolution of the 8400F scanner.

The image contrast tends to degenerate at higher spatial frequencies – this tendency is characterized with modulation. By measuring the modulation for the five patterns of the target it is possible to see the dependence between the image contrast and the spatial frequency. I publish the results of two other scanners for the sake of comparison.

Next, I will calculate the modulation transfer function (MTF), which is the frequency characteristic of the scanner’s optical system.

The graph above shows you the MTF for the test patterns and corresponding histograms. I took the leftmost, 30lppi pattern of an Applied Image QA-69-P-RM target as the reference area. The MTFs are calculated for the green channel of the target image. The following MTF diagram is based on the obtained data:

Image Noises

Virtually every digital image produced by digital cameras or scanners has noise constituents due to interference in the useful analog signal of the light-sensitive device before it reaches the analog-to-digital converter. Noise can be either random or correlated, so we have two test steps in this section.

Random Noise

The diagram below shows the dependence of the amount of random noise on the reflection power of the grayscale sectors of the KODAK IT8.7/2 Q-60R2 target.

The delta SNR parameter is the total of the measurements.

As you see, the electronics of the CanoScan 8400F is superbly protected against interference.

Correlated Noise

Unlike random noise which shows up as the “snow”, correlated forms of noise show themselves in the scanned image as regular patterns, stripes, and diagonal, horizontal and vertical lines (relative to the raster lines). Each form of correlated noise can be identified visually.

The vertical form of correlated noise – streak noise – is an inherent defect of the CCD technology. Raster-correlated noise can appear due to uneven light intensity of the scanner’s lamp as well as due to electrical interference of the light-sensitive array. The diagonal form of noise may appear as a result of interference in the useful signal that is transferred from a digital to an analog device (for example, as a result of a failure in the coordination of the digital timer and the carriage movement mechanism).

So, there can be various forms of correlated noise, and we can measure its amount in numbers. The amount of correlated noise produced by the CanoScan 8400F is compared with the results of some earlier tested models.


The profiling procedure helps to determine the gamut range of the scanner. This qualitative parameter reflects the deviation of the colors from the required values. As a result of this procedure you get a profile for the scanner that can be used later with any scanned image. Besides the profile proper, you also get numeric values for all the colors of the test target. The following gamut range diagram is based on them:

The gamut range of the scanner in the visible spectrum is identified with a triangle in the diagram.

To build the next diagram I found the difference between the colors of the original target and the scan. The Color Difference value should not exceed 5.0 or the color discrepancies become apparent for a majority of people.

Scanning Quality

This section will help a potential buyer make his/her own opinion about the scanner basing on the scans it actually made. And first let’s check how good the CanoScan 8400F is at removing dust from photographs. I turned on the Reduce Dust and Scratches option in the scanner driver for that.

I performed a series of tests to see how well the dust removal technology works with reflective originals, i.e. ordinary photographs (as you understand, there’s no sense to remove dust from a scan of a glossy magazine). The originals were scanned at different resolutions and in all the available dust removal modes (Low, Medium, High) and I came to the conclusion that the technology works best at medium resolutions (up to 600dpi) whereas at higher optical resolutions dust is not removed completely. Here are the fragments of scans digitized at 600dpi and scaled up in Photoshop by 300%:

Original photo with the marked image fragment



The different modes help you choose between speed and quality. Of course, High mode brings you the best quality, yet Low mode effectively removes all the small dust specks, too.

It’s somewhat worse with films. FARE technology depends on the type of film, cannot work with negatives (and Digital ICE cannot, either), and often makes small artifacts more conspicuous by mistake. Below you can see a scan made without FARE (left) and a scan with FARE in High mode (right):

A fragment of medium format slide scan (click to enlarge)

On one hand, FARE removed the dust speck (and I should acknowledge that it did a good job of the whole scan, removing quite a lot of such small artifacts), but it also brought about its own artifacts. Well, I think it’s anyway easier to remove manually one artifact than to do the retouching of a whole image. It’s just a matter of what you prefer to do with your own hands.

Medium format film scan with FARE enabled

The following scans help evaluate the digitization quality of transparent and reflective originals (KODAK IT8.7/2 Q-60 R2/E3A color targets). The scanning parameters were selected according to the driver’s three main modes: without color correction (Color Settings: None), with an ICM profile (Color Settings: Canon ColorGear), and with automatic tone correction (Color Settings: Recommended).

35mm slide:

35mm slide scan of KODAK IT8.7/2 Q-60E3A target in Recommended mode

35mm slide scan of KODAK IT8.7/2 Q-60E3A target in Canon ColorGear mode

35mm slide scan of KODAK IT8.7/2 Q-60E3A target in None mode

5x7 photo:

5x7 photo scan of KODAK IT8.7/2 Q-60R2 target in Recommended mode

5x7 photo scan of KODAK IT8.7/2 Q-60R2 target in Canon ColorGear mode

5x7 photo scan of KODAK IT8.7/2 Q-60R2 target in None mode

I want to draw your attention to the fact that you’ll only get good scans if you’ve turned on automatic lamp calibration before each scan operation in the driver’s settings:

This item is off by default and leads to over-bright images after the scanner has worked for some time – the parameters of the mercury lamp change noticeably as it gets warmer.

To end this section of the review I want to show you a scan of volumetric objects – a few soft-tip pens. This scan helps evaluate the scanner’s depth resolution.


So this is the end of today’s tests and it’s time to sum everything up. The Canon CanoScan 8400F has proved to be a really fast scanner with a rather small lamp warm-up time. I want to advise you however not to skip the calibration procedure, which is off by default in the driver, if you wish to have really high-quality scans.

As for FARE technology, it works impeccably with photos. Still I wouldn’t say that FARE Level 3 is much better than Level 2. The back lighting correction, the main feature of FARE Level 3 as opposed to other levels, is performed automatically, but this is only good for those users who cannot or don’t want to process photographs in Photoshop.

The holders for reflective originals handle the film very carefully and are better than holders included with Epson’s Perfection scanners. As I wrote in my earlier reviews, the Epson holder for medium-format film can only take in one frame and a half whereas the holder included with the CanoScan 8400F allows loading as many as three full frames.

Holders for 35mm film are also better in Canon’s version than in Epson’s. I think this is as an important factor for a scanner of this class as high optical resolution or functional software.

The CanoScan 8400F is going to be a good choice for users who need a good and inexpensive machine for scanning photographs and slides. This scanner is surely worthy of the money you’ll spend for it.