Picture quality on the DCS-942L was good for an IP camera. I took several comparison pictures with it, a Nikon D5000 DSLR, and an $84 Foscam FI8918W IP camera in full room light in our downstairs junk room. I placed a vaccum at 15 feet from the camera with a sign on it that simply read, "15 feet". This was meant to show camera clarity at 15 feet, as well as to test D-Link's 5 meter claim for night illumination.
Figure 11 is from the Nikon D5000 DSLR, which will be our control.
Figure 11: Control image taken with Nikon D5000 DSLR
Figure 12 is the D-Link DCS-942L. You'll definitely note the picture isn't as sharp as the DSLR, but you wouldn't expect it to be.
Figure 12: D-Link DCS-942L day mode
The last picture, Figure 13, is the Foscam FI8918W, with the vacuum replaced by a Linksys WRT54G router.
Figure 13: Foscam FI8918W day mode
A couple things to point out are the DCS-942L's colors, which look pretty good for an IP camera, and the writing on the "15 feet" sign, which is washed out. Overall, though, there is enough detail for security duty if careful attention were paid to its field of view. The colors look much more washed out on the Foscam ,as you would expect for a cheaper camera. However, some edges appear sharper than the DCS-942L, such as the edges of the ironing board and the mirror beyond 15 feet.
One thing to compare in all three photos is the clarity beyond 15 feet. On the Nikon control picture, the furnace ducting is clearly visible through the doorway, as are some plastic storage containers. Those same items can be identified in the Foscam picture as well, although not nearly as clearly. With the DCS-942L, however, I cannot see them. So careful placement and consideration should be used when placing the DCS-942L for optimal security coverage.
Before going into how well the DCS-942L camera does in night vision, I should point out something I noticed. The light level in the three images above looks like a very lighted room, however the DCS- 942L wanted to be in night vision mode. To get the day image in Figure 12, I had to manually set the camera to Day Mode. I also found this to be a common complaint in the D-Link forum.
Figure 14 below shows the image the D-Link presented with the room light on. Notice how it's still in night mode, but you can clearly see the lights on in the mirror on the top right.. As a security camera, I wouldn't label this a deal breaker; such clarity in night mode during the day is still very good. But the camera seemed to transition between day and night mode much easier in response to natural light than it did to room lighting. It's easy to tell when this is happening, due to the loud click sound it makes. If you want to stop the clicking, you'll need to switch the camera to Manual day/night mode.
Figure 14: D-Link DCS-942L still in night node while set to "Auto" with the lights fully on
Figure 15 shows the true night vision mode of the DCS-942L. With the vacuum at 15 feet, you can see that everything around it can be identified, although the sharpness has definitely declined. The door frame five feet behind the vacuum can still be identified, however it is hazy around it.
In the 15 foot range that the specs of the camera indicate, it works moderately well. Jump back and forth between Figure 14 and 15, pick out an item in Figure 14 and look for it in Figure 15.
Figure 15: D-Link DCS-942L night mode
Figure 16 is the Foscam FI8918W. The Foscam has eleven IR LEDs to the DCS-942L's four, plus a wider view angle. So it's not surprising more items are visible, even back into the furnace room. I do not like the LED washout of the Foscam, however, which you notice on the carpet directly in front of it. However, it does illuinate the room better.
It should be noted that the Foscam only supports 15 fps at 640x480 and I've realistically seen only about 7-10 fps in Blue Iris. The consistent 30 fps at 640x480 with the D-Link would provide much clearer video and stills for fast-moving intruders vs. the Foscam.
Figure 16: Foscam FI8918W night mode
I did have a fair bit of trouble with quirkiness with the camera's admin interface, such as motion detection, frequent transition between night and day mode and SMTP email settings that didn't work for me. The camera's soft plastic ball and socket feel cheap and may prove to be problematic over time if careful attention isn't paid to controlling tension on power and ethernet cables.
On the plus side, the DCS-942L showed consistent 30 fps framerates and daylight picture and video quality were good for a relatively inexpensive IP camera. Night vision capabilities were also good for the five meter range that the specs indicate. Wireless range on the camera seemed good, too making it through a brick wall back to my main router three rooms away.
As a static security camera, monitored by something like Blue Iris or Surveillance Station on a NAS to get around some of the admin interface shortcomings, I do believe the DCS-942L has value to justify its higher price over the DCS-932L. Just be sure to shop around. With Pricegrabber showing prices from $126 to $184 as I write this, you definitely can overpay if you don't do your homework.