Tech Tips
July 2009

by Chuck Westfall

Q:I'm wondering what the attitude at Canon is regarding the so-called megapixel race. It seems many digital camera makers, Canon included, keep packing pixels into their cameras in an ever-escalating race to have the most. However, if you asked the average amateur photographer if they feel they need more pixels they would most likely tell you no. And what's funny is nobody really disputes the fact that sensors are reaching and sometimes exceeding the ability of lenses to provide detail and the fact that increasing pixel density, all else being equal, reduces the signal to noise ratio and increases noise in the images. Despite the fact that these things are known and not disputed, why are camera companies continuing to increase pixels with every new iteration?

I own a 20D, 40D and 5D Mark II and love them and their abilities but don't always have them with me. I would like to get a small point-and-shoot camera for convenience and have looked at them for years. I have not gotten one yet, and would prefer a Canon version but have not because with very little exception they all have very bad image quality at ISO 400 with noise that essentially ruins the pictures. I can't understand why companies make these small sensor cameras and put 12 and 15 megapixels in them. I don't want or need that many pixels in a point-and-shoot camera. And I bet if the public were educated about this and realized how they actually use them they would be quite happy with 6-8 megapixel images. I would be very pleased with manageable noise in a 6-8 megapixel point and shoot at ISO 1600. I'm not sure any company is close to achieving this yet; instead they start with unusable ISO beyond 400 and increase pixels and maintain the bad high-ISO performance. It makes no sense to me.

And Canon seems to do this to a lesser extent with the EOS line. Instead of modest one-stop noise improvements from one generation to the next with large jumps in pixels, why not maintain the amount of pixels and give 2-3 stop noise improvements? I think photographers would be ecstatic over this. What could an improved 5D's 12-megapixel sensor look like with the latest sensor technology? Is it unreasonable to think it could be 2-3 times better at managing noise? And let's be honest, how many people will ever in their lifetime make prints that need more than 12 megapixels? Don't get me wrong, I love the 21 megapixels of the 5D Mark II but I'd gladly settle for 16-18 megapixels to get an improvement in noise.

A: First of all, thanks very much for sharing your thoughts with me. I'll be happy to pass along your requests to Canon's R&D group for consideration towards future products. In answer to your main question, I would say that Canon's primary concern in terms of new product development for digital cameras is the ongoing improvement of overall image quality. Image quality is judged not only by what can be seen on a computer monitor, but more importantly what can be seen on a high-quality print. That is one of the main reasons why Canon is so heavily invested in color printing technology, as seen with the imagePROGRAF line of large-format photo printers, as well as EF lenses, CMOS image sensors and DIGIC image processors for EOS cameras.

If the quality of the printed image is kept in mind, experience shows that an increase in sensor resolution can and often does result in an improvement in image quality at any given enlargement ratio, assuming that all other factors are equal. As a case in point, consider the 5D Mark II vs. the original 5D. In this case, most photographers who've used both cameras will agree that although the image quality of the original 5D is outstanding throughout most of its ISO range, the 5D Mark II is capable of producing prints with superior levels of detail and less noise, especially at high ISO speeds. It's understandable that some photographers would be willing to sacrifice increased resolution for reduced noise levels, but at some point the law of diminishing returns starts to kick in. The larger the print size, the sooner this point is reached.

In the realm of compact digital cameras, there is no question that the high end of the market is looking for better image quality than current cameras provide, especially at high ISOs. But I'll bet that the eventual solution to that request is going to be larger image sensors with high resolution rather than small sensors with reduced resolution. Time will tell!

I am concerned about the potentially detrimental effects Movie Mode may have on my gear, specifically Lens IS and CF Cards. If Lens IS is running continuously for the duration of a movie, is that an issue for the lifespan of the IS unit? Do you recommend that IS should be turned off during Movie Mode to conserve its life? Also, my 5D Mark II makes CF Cards very hot, especially when using Movie mode. Is this likely to cut down the lifespan of the CF Cards?

According to Canon Inc., it's not a problem to run the Image Stabilizer function of an IS lens during movie recording. In fact, they encourage the use of IS for handheld shooting of movies and stills. And use of IS for movie recording has no significant effect on the lifespan of the IS mechanism. However, if you use a tripod while recording movie clips, in most cases you'll lose the benefits of image stabilization. Under those conditions, it's best to shut off the IS during tripod use. This will also reduce power consumption, thus extending battery life. Canon recommends that microdrives should not be used for movie recording because of heat buildup issues, but there are no recommendations against the use of chip-based CF cards, except the need to use a card that can write data at a rate of at least 8 MB per second. Canon does not manufacture its own CF cards, so you should consult your CF card manufacturer for official recommendations about their products.

I have found that while in Live View the 5D Mark II won't fire a strobe that is connected via a sync cable. I've tried all the different Live View settings but nothing seems to work. If I turn off Live View the strobe will fire. A hot shoe-mounted Canon flash also works fine. This is a feature I like to use a lot in the studio with my 1Ds III and sometimes I need to operate two studio sets at the same time so it'd be nice if both cameras worked the same. I posted this question on a photography forum and found other people had experienced the same problem. Am I doing something wrong or has Canon missed something when writing the firmware?

A note at the bottom of page 120 in the English edition of the EOS 5D Mark II Instruction Manual indicates that non-Canon flash units will not fire in Live View mode unless Silent Shooting is set to Disable. Please check your camera to ensure that you've adjusted this setting accordingly.

I received two questions from a chap who bought a Canon 5D Mark II and seems to be in way over his head. I referred him to some Web sites but he's still in the dark. He says:

1. When he transfers images to the DPP program it automatically erases them from his memory cards and he cannot find a setting to prevent this. I find this hard to believe as there must be some way to prevent this -- in fact I would think the default would be NOT to erase images on the cards.

2. Next, he wants to know if there is some way to have the program correct his RAW images for peripheral illumination without forcing a conversion to TIFF. He wants to bring those corrected images into Lightroom without the increased TIFF file size.

My take on this is that it is probably not possible because it would involve altering the RAW image itself, which probably cannot (and should not) be done. I would think since DPP does the correction, (and I'm assuming it cannot be done in Lightroom) then, if he wants that correction, the price he pays is ending up with large TIFF files to import into Lightroom. Anyway, if you would be kind enough to comment on the above, I'd appreciate it.

DPP is one of Canon's image editing software applications, but it does not have a downloading function. Canon provides EOS Utility software for downloading directly from the camera, and Camera Window/Memory Card Utility for downloading through a card reader. EOS Utility does not have an optional Preference for deleting images from the camera's memory card, but Camera Window/Memory Card Utility does. The next time the photographer runs Camera Window/Memory Card Utility, he can use this procedure to reset the Preferences: The ImageBrowser/ZoomBrowser Camera Window opening screen shows up when the memory card is recognized through the card reader. From this screen, select Preferences. This will display the Preferences dialog box. In the Preferences dialog box, look near the bottom for "Other Settings" and uncheck the Preference for "Delete images on memory card after download is complete." Then click OK to register the setting and close the Preferences. Just to reiterate, the "Delete images on memory card after download is complete" setting is not the default when the software is installed, so someone with access to the photographer's computer must have checked it off at some point.

When opening RAW image data, Adobe Lightroom does not recognize various camera settings such as Peripheral Illumination Correction, and it also does not recognize editing instructions from other software programs such as DPP, so essentially the photographer has several choices:

• Shoot in-camera JPEGs with Peripheral Illumination Correction turned on. This will keep the file size down and honor the correction.

• Shoot in RAW mode, and then process the images in DPP to either TIFF or JPEG to get Canon's algorithm for Peripheral Illumination Correction.

• Shoot in RAW mode, and then process the images in Adobe Camera RAW to either TIFF or JPEG to get Adobe's algorithm for Peripheral Illumination Correction. (They offer a slider for Lens Correction Amount in the Vignette menu of the Develop tab.)

I use my EOS 5D Mark II mostly for outdoor portraits. In bright sunlight I have a problem reading the exposure data values below the picture area in the viewfinder. They are just not bright enough. With my former cameras (5, 3, 20D, 40D) I had no problems. From the handbook I know that there is the possibility to dim/brighten the external 3-inch LCD, but it has no effect on the internal LCD display. I have heard from other users in the German forum that they have the same problem. Could this be changed by service or firmware?

The EOS 5D Mark II's current firmware does not allow the service department to make the viewfinder exposure data any brighter than it already is. I'll be happy to forward your request to Canon's R&D Group for their consideration. For now, your best bet is to check the 5D Mark II's top LCD data panel for exposure settings if you find the viewfinder data display too dim to read.

I have an EF 24-70mm lens that started to back focus. Canon suggested that I send the lens in for service. I did that and it is working fine now but this issue got me curious about the Canon focusing system. I use the lens on either a 1Ds or a 5D. When it wasn't working properly the view thru the viewfinder didn't show the back focus problem. It was only when looking at the photos on the computer that the problem was evident. My question is, what does the lens have to do with whether the photo is in focus or not? Shouldn't it work like any control system? The controller, in this case the camera, sends a message to the lens and the lens simply responds until the controller gets what it wants which is a photo in focus. Because the lens caused my focus problem it seems like Canon has some type of feedback loop in the focusing system that can cause out-of-focus system. Why is this? And what advantage does it offer over a simple control system?

I could spend an entire column discussing these issues and it still wouldn't cover the topic completely. One important concept to understand about the EOS autofocus system is that focus confirmation is based on successful completion of the lens drive command. This command originates in the camera body as raw data about the degree of defocus at the focal plane, but it is modified by the CPU of the lens that's mounted to the camera, based on a number of different factors. One consequence of the EOS design is that the resulting image may be out of focus if the lens is not operating completely within its design tolerances.

Recent EOS models including the 1Ds Mark III, 1D Mark III, 5D Mark II and 50D have AF Microadjustment settings that allow users to calibrate their camera according to the lens in use, but there is only one setting per lens. This is sometimes insufficient for zoom lenses since they may require multiple calibrations according to focal length. When that situation occurs, the best remedy is to have the lens calibrated by a Canon Factory Service Center. The fact that Canon's Service Department was able to restore your equipment to proper working order provides solid evidence that the both the camera and the lens are capable of delivering consistently accurate focus when all components are working within their design tolerances.

I just bought the EF16-35mm 2.8L II USM and am confused about protecting the front element with a filter. There is an interesting forum discussion about using UV filters in general at the Arthur Morris site

I believe that you are quoted as saying that you personally do not use protective UV filters unless there is a specific reason, such as with the 16-35mm. So my question is, would you use the UV or is there a different filter you would use instead? I understand that your reply would not be an official Canon position, but I would really appreciate some guidance.

If I knew I was going to be exposing the 16-35mm lens to a hostile environment such as rain, sea spray, car exhaust fumes, etc., I would use a good quality clear or UV filter to protect the front element. I would also consider using a thin-rim circular polarizing filter to cut glare, etc., if the shooting conditions called for it. But in most other cases where the lens is in no imminent danger, I would remove all filters for maximum optical performance, and use the supplied Canon lens hood to reduce flare and help prevent impact damage.

Thanks for reading Tech Tips! That's it for now. See you in August!

You are invited to submit questions about photo equipment, imaging technology, or photo industry trends that may have a bearing on your work or interests. I cannot promise to answer everything, but I pledge to do my best to address the issues that concern you.

P.S.: The purpose of the Comments section is to allow readers to respond to the content of each month's edition of Tech Tips. New topics or questions should be submitted by e-mail (using the link at the end of each column) in order to support the development of future monthly editions. I appreciate your kind support and cooperation. Thanks!

© Chuck Westfall

After earning a degree in Professional Photography from the Rochester Institute of Technology and accumulating some valuable on-the-job experience during a 10-year stint in commercial photography and photo retail, Chuck Westfall began his corporate career with Canon U.S.A. in 1982 as a Technical Representative. He has steadily advanced through the ranks to achieve his present position as Technical Advisor for the company's Consumer Imaging Group, working out of Canon U.S.A.'s headquarters office in Lake Success, NY. Among his many assignments, Chuck Westfall is currently Canon USA’s main media spokesman for new camera products. He also provides a unique insider’s perspective to financial analysts who follow the company’s CIG sales and marketing activities.

Chuck’s involvement with digital cameras began in 1994, when he assisted Canon and Kodak engineers in developing the EOS-DCS series of professional SLRs. Since then, his responsibilities have expanded to include participation in the development and launching of many other Consumer Imaging Group products including Canon's professional and consumer-oriented digital cameras. Most recently, he has been developing content for online and on-site consumer education projects in Canon USA’s Professional Products Marketing Division.

On the personal side, Chuck enjoys sightseeing, photography, reading, music, and family life with his wife Ying and their beautiful daughter Anna.

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