Being an enthusiast photographer for over 35 years that uses Canon gear, my expectations for the RS40 were high. Sadly, I was disappointed in the scans the device produced. I was also confused that most people that had reviewed the RS40 loved it and there were very few people that didn’t.
I was getting lines in my scans. Not from magnified physical lines or other defects in the prints. It’s worse in dark areas but even in mid tones. It varied depending on the lighting in the photo. Colors could also be way off too. Especially when using auto settings. Also blocky sky gradients like in a sunset photo. The best results were when I turned off all auto settings and adjusted the brightness and gamma manually.
I use a Datacolor SpyderX Pro Colorimeter to calibrate my monitor. I compared the scans to an Epson ES-580W I reviewed Jan. 2021, Minolta Scan Dual III slide and negative scanner and to taking a photo of the print with a Canon EOS R and EF 100mm f/2.8L Macro IS USM.
I discovered that the lines were caused by data compression creating patterns with the way a jpg file is created with blocks. Think very highly compressed jpg. When viewed at 300%, you can see the blocks that make the lines at 100% and lower. I got that no matter which file format I used to output a scan. Shadows and blacks could even look like it had a film of haze over it when trying to bring out shadow detail. I didn’t see this as much with preset settings that had higher contrast settings. But why? Firmware? Drivers? Software?
What I couldn’t understand is why the Epson ES-580W Document scanner that’s meant for primarily business use scanning receipts and printed documents, was soundly beating the Canon RS40. The RS40 is designed to primarily scan photos and it should have out performed the Epson. I contacted BB with my concerns and sample scans. They referred me to Canon. I discussed the issues with a Canon engineer and sent them sample scans too. Canon sent me another RS40 to evaluate just to make sure I didn’t have a defective one. I got the same results with a different RS40.
Kinda off the wall, I wondered if it might be related to Windows 11. So I tested the scanner on a computer that is still on Windows 10. Noticeable difference! Different software and driver versions. Lines were only visible if you used extreme settings. Also two different software versions that were both up to date at that time. Now just one version listed for Windows 10 & 11.
I emailed Canon my findings on the replacement scanner and that Windows OS made a noticeable difference. I have read reviews of the scanner on BB and several other places. Looks like I'm the only one to try it on both Windows 10 & 11. I guess everyone that loved it was using Windows 10 or a Mac maybe? Assuming results on a Mac are the same as Windows 10. Yes, the Windows OS is the difference between a 3 star not recommended and a 4 star barely recommended. Lines were still there but much harder to see. Canon said there was only supposed to be one program bundle for the OnTouch software and driver. As of March 23, 2022 there is only one I could find and a newer version than the previous two. It is supposed to be compatible with Windows 10 and 11. After testing it, I still got the lines on Windows 11 and less on Windows 10. The Canon engineer told me he would be sending my findings to the Canon engineers in Japan and they would update the software, drivers (firmware?) if needed. If you own this scanner you might want to keep check on that.
Canon’s packaging is environmentally friendly.
A power supply brick and USB cable are included as is a quick setup guide.
Windows 11 setup went off without a hitch. However, when I went to use the scanner it couldn’t find the twain driver. I had to reload the drivers several times before it would work. If you hit the start button without opening the Capture OnTouch program first it will do it every time and require a reboot to fix the problem. And on 2 occasions it required reloading the driver again. I didn’t have this problem with Windows 10 on a different computer. I also want to note that I have a Canon TR-150 printer installed on both PCs and I had to reinstall the drivers for it on the Windows 11 PC for the printer to work. Both now work fine. Never a problem with the Windows 10 PC.
Comparing it to the Epson ES-580W document scanner. Using its photo presets is about as bad as Canon's, mostly overly contrasty. Like the RS40, I can tweak the settings on the ES-580W to produce excellent photo scans by adjusting brightness, contrast and gamma. Colors are spot on with the Epson too. The ES580W is a 30 bit color scanner and the RS40 is 24 bit. What that means is that you have 8 bits (255 steps) per color channel on the RS40. You have 10 bits (1024 steps) on the ES580W. That’s 4 times the dynamic range. This could also account for the lines and blocks along with digital compression in shadows.
If you’re going to be scanning large photos like 8X10 you probably won’t notice lines. If you’re scanning 6X4 and 3X5 you will in the shadows and even in the mids. If you plan on cropping from a small photo it can be a problem. Then there are the inaccurate colors and high contrasts using presets. See photos.
Both scanners do not produce what they are capable of at default settings. Especially if the photos they are scanning are dark or very contrasty. Same for over exposed photos. Some photos are beyond help with any scanner. You can adjust settings to compensate for those sorts of things, up to a point. However, both scanners should be close and the Canon should beat the Epson since it's primarily a Photo scanner that can do documents and the Epson is the opposite in that manner. And it should be able to do it well at default settings. The Epson beats the Canon and it ought to be the other way around considering their primary uses.
Features and controls are lacking compared to the Epson ES580W too. No WiFi and no color touch screen. No graphic LCD screen at all. Just a green 7 segment display. And costs $80 more. I do want to point out that the Epson - FastFoto FF-680W which is primarily for photos too, costs more, lacks any kind of a display but does have wifi. Has the same hardware specs as ES580W.
Please see photos scanned with the RS40, ES-580W and taken with an EOS R full frame mirrorless camera. After you click to expand the photo, Right click and open in a new tab for full resolution scans. I have description info on the photos themselves.
The RS40 will scan Polaroid and old Kodak ColorBurst instant photos and the ES-580W won’t.
Build quality looks and feels good but the ES580W feels a little better.
I cannot recommend this scanner due to questionable image quality, lack of WiFi, lack of any kind of an info screen and it costs more than one I reviewed a year ago that performs better.
As for my Canon camera bodies and lenses, they are outstanding and I would highly recommend them. But not the RS40.
Here’s a link to the Epson ES-580W I reviewed for those interested.
https://www.bestbuy.com/site/epson-workforce-es-580w-wireless-duplex-touchscreen-desktop-document-scanner/6442937.p?skuId=6442937