Q We just upgraded our digital SLR camera to a Canon Digital Rebel T2i. It uses SDHC memory cards with Class 6 being recommended, especially for video use. All we have are Class 4 SDHC cards left over from the previous camera. Is it OK to use them?

A The SDHC Class rating refers to the card's read/write speed. Processing video, especially high-quality video from a large sensor camera such as the Rebel T2i, takes up a lot of memory space and requires a lot of data to be crammed on the card as you record video. That's why the Class 6 cards are recommended. They're significantly faster than the Class 4 cards, which are speedy to begin with.

You can use your Class 4 cards with your camera for still photographs, and they will work just fine. If you plan on doing video, you really should use Class 6 cards or even Class 10 cards.

There are a few Rebel T2i users who reported being able to record video on their Class 4 cards, but there are a lot more who ran into trouble when trying to do so. What's more, certain brands seem to work better than others, with some users reporting problems with Class 6 cards from budget brands. Sandisk was reported to be reliable, and Lexar cards are always a good choice, too.

When you start using your new camera, be sure to format all of your memory cards, new and old. After you insert the card, go into the setup menus and find the format command. Formatting will erase the memory card and set it up for optimum operation for your make and model of camera. Just be careful because formatting erases everything on the card.

Getting HD cable

Q We have two TVs. On one television, we have a Comcast HD converter box. On the other, a Sony KV-20FS120 tube TV, there is no box and thus we don't get the HD channels on that television. Is there a way to get the HD channels on the second TV without having to pay Comcast for a second converter box?

A Your TV doesn't have a digital tuner, so at the least you would need a full-fledged HDTV tuner, not a $60 converter box, and HDTV tuners are getting expensive and hard to find since all TVs have them built-in now.

Even with the tuner, you would only be able to get free local HDTV channels, whether you got them from Comcast's feed or an antenna. Comcast used to broadcast local digital stations for free on the coaxial cable, but I don't know if it still does so. Everyone I know with Comcast got switched to converter boxes (some against their will) and lost their free HDTV as a result.

Get another TV with a built-in tuner, and try it with your cable line. If it doesn't work, get an antenna to receive free local HDTV.

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