I know some of the recent Nikon and Canon models have that facility. I do not want to go into a lot of specialized lens, maybe I can start off with stock lens if I am purchasing a combo and then go for another lens once I am comfortable with handling the camera. I do not wish to buy a DSLR just for the heck of it because everyone and their neighbor these days has one, I am actually interested in improving my photography skills.
First of all, don't pay any attention when people say "you can't go wrong with brand X" or the like. Every camera maker out there has at least a few lousy cameras in the lineup. Trust me, I've found them. Sometimes it's the quality, sometimes it's the price, sometimes it's the flexibility, and sometimes all three. No company has a perfect lineup and you can absolutely go wrong with a Canon or Nikon if you don't do your homework first.
One thing that would make it a little easier to give useful suggestions is if you could tell us what your primary goal is. Photos? Movies? Flexibility? If you're mainly looking for overall flexibility I'd probably go with a Canon. I honestly think they have some of the best glass out there and the market for used Canon lenses is huge, although they're still expensive if you're starting from scratch. You can easily spend double or triple the cost of an entry-level DSLR on a single quality used lens. With Canon you can attach a large number of lenses to a huge number of camera bodies, which is part of the reason the market is so large.
If you want the best sensor that requires the least amount of post processing to look good I would probably go with Nikon as I feel their glass is still very good and they have generally had the best sensors for still images. However, this point depends entirely on actually having a Nikon sensor in your Nikon branded camera. I have been rather disappointed with Nikon's point-and-shoot cameras of late. Sloppy controls, third party sensors, and questionable lens quality just did not add up for me at all.
If you want a general purpose camera that puts as much focus on movie making as still images with more 'bang for the buck' you might want to look at something like an MFT DSLM...
I would like a DSLR that can also take HD video.
This brings us to an interesting conundrum. If the mirror has to be out of the way while the video is being shot, then why do we still need a mirror at all? The reason we use DSLR's for video is obvious. The sensors are already exceptional, the glass is among the best, and it's great to have everything you need in a single package. However, one of the more interesting developments over the past few years has been the growth of the Micro Four Thirds lens system and the Digital Single Lens Mirrorless camera body.
In theory, what you save in size and cost by removing the mirrors and prisms and reducing the lens size can be used for more lenses and/or better electronics in a smaller size that weighs less. There are already several good lenses for MFT, but if you want something that is not yet available or is unlikely to be made again you can attach an adapter for using more conventional lenses as well, with the usual caveats for adapter use.
If you have the money, by all means go the full DSLR route, but be prepared to hand over several thousand dollars over the next few years for a nice range of quality lenses and all the other wonderful things that DSLR's allow but don't include with your initial purchase. After which your electronics will be outdated. Followed by a new camera body that exposes the flaws in your lenses. At which point you can start the upgrade process all over again.
On the other hand, if purity of the glass and sensitivity of the sensor aren't at the top of your priority list then you might want to consider a less expensive and more balanced approach. A MFT DSLM like the Panasonic GH2 can still compete favorably with mid-range Nikons and Canons for video quality and lens flexibility at a lower price and smaller size. This is especially true if you're willing to side-patch the firmware to allow for higher data throughput.
I am currently using a Canon SX20 point and shoot which can be called an intermediate between pocket sized camera and DSLR. One thing I HATE about that camera is that Canon has no option to show how much battery life is left and on more than one occasion the camera has given up on me exactly when I wanted to shoot something very interesting. Do Canon DSLRs also have the same deficiency?
Even my ancient Canon 350D keeps me informed of my battery life and does what it can to avoid wasting energy. However, in my experience you really need to have more than one battery to avoid this sort of thing. Simply knowing that the battery is dying won't give you the extra juice you need to get the shot you want when it actually happens. I've used non-Canon batteries in the past, but they don't last as long as the real thing and you probably wouldn't want to leave them in your camera for any extended amount of downtime.
If you move up to a full DSLR it will be able to give you information on battery life, but even more important than the information is the ability to attach a dual battery pack to avoid running out of juice in the first place. Of course, this is just one of many ways that an entry level DSLR can end up costing a lot of money by the time you've given it all of the advantages that DSLR systems are known for. Top of the line DSLR's already come with this sort of thing built-in, which is part of the reason they can cost as much as a car or truck.
Does anyone have personal experience on using Nikon D3100 and D5100? What is it about D5100 that makes it worth, or not worth, spending additional $150 over D3100? I see Amazon has
D3100 for $499 and
D5100 for $649.
In general with the D5100 you're getting better overall image quality thanks to a higher source resolution, lower noise, more dynamic range, a much higher resolution flippable screen, an external mic jack, in-camera HDR, better light sensitivity, longer battery life, and faster shooting speed. I'd probably spend the extra $150 if it were me, assuming it didn't prevent me from buying a decent lens to pair with it.
