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I've always removed the cards from the cameras and used a high-speed good quality card reader, and find it totally strange to connect the camera via USB instead. A comment elsewhere prompted me to rethink this: I've always done it that way, and years ago the cameras were slow (even pathetically slow, using USB 1.1 speed only!) and connection software was clunky and non-standard.

There are some answers here as recent as 2011 that still bring this up. “a good card reader will be so much faster than the camera you'll never ask this question again” and also this question addressed in 2010.

Now, cameras can use faster memory cards, but I expect card readers are available, along with even faster cards, that are even faster than the camera's USB connection will support. So what's the current situation seen by people who do use the camera connection?

Also, the software connection thing has improved, with a standard USB protocol used in cameras (or are they?) and already known to desktop operating systems.

Before, it was noted that running the camera as a reader would drain its battery. Do they charge the battery now, instead?

So how does the comparison weigh in now? What are the pros and cons of attaching the camera via USB vs. taking the card out and using a dedicated card reader?

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JDługosz
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  • This is a community WIKI. You can edit in specific examples and whatever instead of adding another answer. – JDługosz May 08 '16 at 23:27
  • See meta: How Do I “Refresh” a Question? – mattdm May 09 '16 at 13:47
  • The cited "duplicate" is exactly the question I referenced in this one. The "2 existing answers" makes it sound like the last four paragraphs were ignored. I acknowledged the old questions and explain why I posted a new one. – JDługosz May 13 '16 at 12:43
  • I know. See meta: How Do I “Refresh” a Question. If the previous question is out of date because times have changed, it should be updated. – mattdm May 13 '16 at 13:13
  • Completely change the question except for the title? It relates to his experience and wonders about others, rather than introducing the subject generally. It also already has an accepted answer. The meta post states "your question is a twist on or a followup to the earlier question, ask a new one and link to the old one as part of your question" which is exactly what I did. You make it sound I never read it. – JDługosz May 13 '16 at 15:58

3 Answers3

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Card-Reader Can Still be Faster

A camera might be designed to write 35 megabytes per second to the card and handle the “U1” standard, and reading back out is oddly capped at 20 Mbytes/s due to the USB chip used, which is only USB-2.

You can buy even faster cards, e.g. “U3”, and USB-3–based readers that can let you dump the card at 95 Mbytes/s.

This will probably always be true as the hardware cycles up. You will be able to find even faster cards that are compatible with the camera, and even faster readers to use when dumping them.

Camera's Reader Might be Hard to Beat

The Canon 1D X Mark II has gigabit ethernet for a transfer interface. The camera's CFast card is faster than any USB-3 card reader could produce.

Built-In Bridge is Not Nice

Although the OS has built-in knowledge of a standard file transfer protocol for cameras now, some cameras might not be quite compatible with that and demand their own special drivers and bloatware, even if you then ignore that and use standard file transfer tools.

The camera mounting might not be a full file system that appears for use with all file-based tools, but only works with the operating system GUI shell for dragging files. That makes it difficult to use a script to copy-and-verify, for example.

Camera's Utility Software Can be Good

The EOS utility might in fact be your preferred transfer method.

Bundled brand-specific software might take specific advantage of the camera's direct connection. 3rd party software is likely to use a file system mount as well as photo-transfer protocol, if copying the files is all it's doing.

Power—good

Some cameras might recharge on the USB, so you can charge and transfer at the same time. Or at least transfer and then turn off to charge without moving it. If it takes 2 hours to copy the files off, hopefully it will turn off by itself or switch to charge mode by itself unattended, so that's more of a potential benefit. (Please edit with real examples if you have one and use it that way)

Power-bad

The spent cards and battery get taken out of the camera, with the batteries going to the charger and the cards going to the computer. Leaving a battery in to use the camera as a card reader would be more hassle.

With it taking hours to transfer all the files from a large card, the use of battery power on the part of the "reader" might be a bad idea in general.

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JDługosz
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  • I've yet to see a card reader faster than a gigabit ethernet connection, which is what the Canon 1D X Mark II has for a transfer interface. The camera has both a CF Card slot and a CFast card slot. The fastest CFast cards have read speeds upwards of 540 MB/sec which is too fast for USB 3 once the USB 3 overhead is subtracted. – Michael C May 09 '16 at 02:12
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    mb/s is "megabits per second". MB/s is megabytes per second. 20 MB/s is the same as 160 mb/s. Also note that UHS-1 refers to the bus speed (104 MB/s) that the card is capable of connecting via. U1 (10MB/s) and U3 (90MB/s) refer to write speeds that a card is capable of writing. – Michael C May 09 '16 at 02:22
  • I spelled out my use of "megabytes per second" the first time and abbreviated subsequently. "Byte" is not a SI unit so there is no official abbreviation; each document must make the usage clear. Normally units have a capital letter for the initial only if named for a person. – JDługosz May 09 '16 at 06:11
  • Use of the lowercase mb for megabits and uppercase MB (or Mb) for megabytes is near universal. https://en.wikipedia.org/wiki/Data_rate_units – Michael C May 09 '16 at 06:15
  • Abbreviations for persons or other proper nouns normally only use an uppercase when referencing a specific person rather than a person in general. Abbreviations for things other than person follow no such rules. – Michael C May 09 '16 at 06:17
  • "Symbols: Unit symbols are written in lower case letters except for liter and those units derived from the name of a person (m for meter, but W for watt, Pa for pascal, etc.)." From http://www.nist.gov/pml/wmd/metric/writing-metric.cfm – JDługosz May 09 '16 at 06:22
  • I'm not sure a shorthand for referring to a number of data bits/bytes are considered units of measurement the way meters, liters, Angstroms, etc. are considered units of measurement. In the case of units of measurement one is describing the dimension, in one way or another of a single entity. With terms such as megabits one is describing how many of something one is referencing. – Michael C May 09 '16 at 06:29
  • We abbreviate hundred as "C" and not "c", thousand as "K" and not "k", million as "M" and not "m" because they are not units of measurement, rather they are shorthand for a specific number of something. – Michael C May 09 '16 at 06:30
  • Prefixes are different from unit symbols. Except for "k", the upsizing prefixes are capital and the downsizing are lower. Yes, "k" (lower) is ISO standard. "M" and "m" are both (different) prefixes. Is "byte" considered a unit? Well, it's no different than "mole" or "coulomb" which are a counted quantity. Furthermore, in information theory bit (1/2 cut of states) and nit (1/e cut of states) are both different units in the sense of scaling factors that you can convert between, and handy to assign a dimension for analysis of units to check work. – JDługosz May 09 '16 at 06:50
  • Either way, bits or bytes are not metric units, which is what the NIST link you shared above addresses. – Michael C May 09 '16 at 06:54
  • Ah, see https://en.wikipedia.org/wiki/Shannon_(unit) . Sh is the IEC standard abbreviation. And nit is standardized as nat 'cause nit was already taken in physics. – JDługosz May 09 '16 at 06:56
  • That short article makes very clear that a Shannon unit when referred to as a bit is still not the same thing as a bit of data... – Michael C May 09 '16 at 06:58
  • Also, you might find the section under "Byte" interesting. https://en.wikipedia.org/wiki/IEEE_1541-2002 "B" *is the universal abbreviation of byte under IEEE 1541-2002. – Michael C May 09 '16 at 07:05
  • It seems that the last standard to rule them all uses B for byte and does not abbreviate bit to prevent ambiguity. ISO/IEC 80000 is "metric", but not SI. BTW, I have a CS degree and have done a bit of Traffic Engineering, a few decades before these standards were worked out. Running on CP/M, if that helps date it. – JDługosz May 09 '16 at 07:11
  • I only transfer a maximum of 20 photos at a time from my compact so I think it's not a huge issue of draining battery. But a semi-pro photographer once told me that he's not sure if it's good for a camera to connect through USB as it begins to charge at all the time when it connects to a computer? And I once thought of using a camera as a card reader... please clarify me those... – user152435 May 09 '16 at 11:28
  • Nothing wrong with charging "all the time" as the bat.man. circuit handles all the details. Li-Ion or LiPo batteries MUST use smart chargers and management. – JDługosz May 09 '16 at 11:35
  • @user152435 I've never seen a DLSR or any other remotely professional camera that can charge the battery via USB. Many compacts once could, but most have a separate DC power jack if the battery can even be charged in the camera at all. – Michael C May 13 '16 at 05:09
  • The Sony Alpha 6000 charges via a micro usb, and does not ship with a separate charger. – JDługosz May 13 '16 at 11:52
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A card reader is still the best way to go. There are numerous advantages but speed is the main one. A few cameras have USB 3.0 connectors and some have Gigabit Ethernet but these are the exception.

Even if your camera supports a maximum write speed, you can use a faster card and a compatible reader can take advantage of that. So even if your camera does not support UHS-II Class 3, you can still put such a card and use a reader to take advantage of that. Some of my cards have a read-speed of 300 MB/s, although I doubt any of my cameras can sustain such speed while transferring via USB.

Additionally, when the card is in the camera, you are using its battery to power the connection, draining the charge means having to recharge it later and that contributes to use up the life of battery. The are a few cameras that charge internally, mostly smaller fixed lenses ones, though.

Itai
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  • Many cameras have AC couplers available to run the camera off mains power, both when shooting or transferring images. – Michael C May 09 '16 at 02:24
  • There's no such thing (yet) as UHS-3. There are Class 3 UHS-I and Class 3 UHS-II cards, but there are no UHS-III or UHS-3 cards. UHS-I or UHS-II refer to the bus clock speed. Class 1 or Class 3 refer to read/write speeds. https://www.sdcard.org/developers/overview/speed_class/ – Michael C May 09 '16 at 06:21
  • The cards say "UHS-1 U3" and have a small roman numeral I above a "u" containing a "3" in the bowl. – JDługosz May 09 '16 at 06:28
  • Yep, that is a UHS-I (bus clock speed at the interface between the card and that to which it is connected) Class 3 (read/write speed of the memory on the chip). https://www.sdcard.org/developers/overview/speed_class/ – Michael C May 09 '16 at 06:33
  • By the way it is NOT UHS-1, it is UHS-I (Roman numeral uppercase "i"). Unfortunately, too many fonts do not make it possible to tell the difference between an uppercase "i", a lowercase "L", and the numeral "1". – Michael C May 09 '16 at 06:40
  • Bus speed https://www.sdcard.org/developers/overview/bus_speed/index.html – Michael C May 09 '16 at 06:40
  • Speed Class https://www.sdcard.org/developers/overview/speed_class/index.html – Michael C May 09 '16 at 06:41
  • Yes, the labeling is confusion but I think people got the point. If you look at the product image, there is an SDXC, a 3, a 10 and a II. shakes head – Itai May 09 '16 at 13:39
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It depends on the camera. My Canon 7D Mark II has a USB 3 connector that is just as fast as most USB 3 card readers. The Canon 1D X Mark II has a gigabit ethernet connector. My Canon 5D Mark III has a USB 2 connection.

I choose to use the camera for different reasons than speed.

Using EOS Utility allows me to group images by date shot, create folders for each date, place the images in the folder for the date they were taken, and automatically rename them choosing from a wide variety of parameters.

It also allows me to see a quick preview of each image during the transfer process. This can give me a good idea where I want to go if I need to turn around a few of the better shots quickly and push them to a waiting party. In that respect the USB 2 connection gives a little more time per frame. The USB 3 connection is sometimes too fast to do a passive quick preview of images. I've never had any trouble using one Canon body to transfer images shot with another Canon EOS body. At times I've even used the same card in two different EOS bodies without issue.

As far as batteries go, the three gripped bodies I use primarily all share the same battery, and I have a total of 12 batteries to rotate between them. I've always got at least a couple of fully charged batteries to put in the body to transfer images while any batteries that need charging are in the chargers.

There are also AC power couplers available for most DSLRs so they can be run off wall power while transferring images.

Michael C
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