Digital Camera advice: which specs are important?

February 16, 2009 12:45 AM

What factors should I be looking at when considering the purchase of a new digital camera. I know that a lot of people think more megapixels = better quality. But I have a 4 megapixel SLR that takes *infinitely* better pictures than a friend's 10 megapixel camera. Looking at the cameras, it is obvious: my SLR has huge lenses that are expensive, his has a tiny hole in the front. But I have no objective idea what makes the difference. Some cameras have "big lenses" that seem to be mostly for show. So I am trying to figure out what really goes into making a good picture, and how to calculate it. What specs should I look at and how should I look at them?

By the way, there are a few things I know coming into this. I am not looking for another bulky SLR, but a small one that could fit in a back pocket with some wrangling or fit into a cargo pocket on cargo pants. The photos won't be going into museums, in fact, they'll mostly be going to facebook. However, I do notice when photos look bad, though I can't always put my finger on what exactly is wrong. I do want to be able to print these out at a photo print station at my supermarket and have them look good.

I am looking for something really cheap, and I think that if I really knew what to look for, that I would be able to know when I find a cheap camera if it's just "cheap" or if it's actually a good deal for a good camera.

posted by brenton to technology (24 comments total)

Wikipedia points out that "Compact digital cameras and Digicams typically have much smaller sensors than a Digital SLR and are thus less sensitive to light and inherently more prone to noise."

So maybe I want to find a camera with the biggest sensor? Will that even be listed when I'm shopping?
posted by brenton at 12:51 AM on February 16

One of the main differences between DSLRs and digital point and shoot camera is the sensor size.
posted by afu at 12:55 AM on February 16

I was two paragraphs into tying a response when I noticed that it's not clear from your post whether or not you want a DSLR or just a compact digital camera. Can you clarify?
posted by imjustsaying at 1:13 AM on February 16

Above, should be "typing" and not "tying". Sorry!
posted by imjustsaying at 1:14 AM on February 16

It's all about the sensor. You may be interested in this new FujiFilm that supposedly has a really nice sensor.

Also interesting is that it has a special low-noise mode where the CCD basically doubles the pixel size and halves the pixel count by doing something sneaky, explained here.
posted by floam at 1:21 AM on February 16

Also cool: wide-angle lens.
posted by floam at 1:22 AM on February 16

@imjustsaying: I am definitely lookinf for a compact digital camera, not a DSLR. I need something that is easier to carry on hiking and backpacking trips. :)
posted by brenton at 1:24 AM on February 16

Besides more durable moving parts (shutter), sensor size and quality, and physical characteristics of the lens, you're paying for the software technology with a DSLR (which in turn requires more processing power, which means more expensive computing hardware on the camera). People often grossly underestimate just how much it costs to develop software (e.g. they say 30% of any new car's cost is the software -- it's almost certainly way higher for DSLRs). So I disagree with the posters above -- it's much more than just the sensor.

These are things to consider when getting a non SLR point-and-shoot -- what's the build quality? what're the zoom capabilities of the lens? how well does the software work (i.e. is it really slow and take forever to "process" once you've snapped the shutter)? etc.

The answers vary, and your eventual choice depends on your exact definition of cheap.

Nikon and Canon point-and-shoots tend to be pretty high quality because they inherit some of the older technology from their older siblings. You can pick up a basic Nikon Coolpix for like $100-$120 these days from a big box store. Before you do that, though, I'd do two things once you've narrowed down your choices:
1. Read the reviews on dpreview.com -- they're pretty reliable, thorough, and folks generally trust 'em.
2. Search flickr for pictures taken by that particular camera (you can search by camera here) to see real-world examples.

Other than that, your intuition that megapixels are the only metric for your decision is correct. Look at the camera as a whole, and don't forget the little details such as whether or not the camera accepts & includes rechargeable batteries, battery life on a single charge, flash, memory, and so on.
posted by spiderskull at 1:32 AM on February 16 [1 favorite has favorites]

I'm a fan of dpreview.com as well and all of my cameras have been "Highly Recommended" by dpreview.

If you want a great camera that's pocket-able, please take a good look at the Panasonic Lumix DMC-LX3. The LX3 is another camera where Panasonic did not jam in more megapixes, but made do with less and got a better quality image.
posted by gen at 1:38 AM on February 16

As mentioned above, it's all about the sensor. There's a practical limit to the number of high-quality pixels a tiny sensor will hold. The marketing people at the camera companies keep pushing for more megapixels because they know they can sell more cameras. The result is that photos taken with some newer small cameras are getting worse, not better. The megapixel technology threshold is being exceeded... due to marketing demands. I believe the reasonable limit for a small image sensor is about six megapixels. Beyond that, your images suffer from lack of detail, noise, and artifacts produced when sharpening and noise reduction techniques are employed to attempt a fix.

At the very least, consider the sensor size in the cameras you look at. Don't choose one based simply on its pixel count. I've gotten much better photos with a 5-megapixel 38mm image sensor than with an 8-megapixel 25mm image sensor.
posted by netbros at 1:39 AM on February 16

Ah, I just saw the part about "really cheap". A new camera won't be really cheap but if you look for an older camera that did really well, like the Fujifilm F31fd you might find one used or new for cheap somewhere.
posted by gen at 1:48 AM on February 16

Sensor size is important of course, as mentioned. And too many megapixels on a small sensor can indeed produce worse pictures than less megapixels. But there's also a lot of technology that may not be so easy to measure that affects image quality.

Cutting to the chase: in my opinion, the best bang for the buck in a compact camera is the Sony Cybershot DSC-W120. It's a 7.2 megapixel camera, which is plenty without being too much, and you can find it for around $110 to $130. You'll have to buy a memory stick if you don't already have one, so add another $20 to $30 for that.

I bought one of these for my daughter and I'm going to get one for myself soon. I usually shoot with a Nikon DSLR, but I'd like a compact camera as well. I shot dozens of photos with the Cybershot and was very impressed with the quality of the photos, the ease of use, the simplicity of choosing different modes and the low light performance. Plus it is tiny and sleek.
posted by Fuzzy Skinner at 2:43 AM on February 16 [1 favorite has favorites]

to put it in context, the FujiFilm f31d mentioned above is the gold standard in compact digital camera quality. the noise (or lack of noise) quality rivaled cheap dSLRs. Then Fuji went the whole 'more megapixels more better' route and replaced it with the f50 which had a higher density sensor but noisier quality. fuji says the new f200 will make up for the f31 but i guess we'll see..

sigma makes a compact camera with a dslr sized sensor but at $600 it's more than some dSLRs.
posted by sammich at 2:49 AM on February 16

Sensor size in cheap compact cameras is pretty much the same across the board (with the exception of the Fuji cameras with the "super-CCD" sensor). Canon, Panasonic and Nikon make cameras with slightly larger sensors like the G10, LX3 and P6000 but these are not cheap cameras.

Spiderskull is right about the software of the camera being an important aspect. Nikon cameras have Sony sensors but compare the two brands have different imaging characteristics. I generally find Canon, Panasonic and Fuji to have good processors in their compact cameras.

Of course, you should also make sure the camera is easy to use. I find Canon and Panasonic cameras the easiest to use. However, I should add that I work at a camera store part time. Usability for me means lots of options easily accessible. For some people this actually translates to lots of small writing/pictures -> confusion

I'm getting lazy so this will degenerate into a list of things to keep in mind
- digital cameras become obsolete really quickly
- check the memory card format
- test focusing speed
- poor light, harsh contrasty light, sun flare, bad composition will make most cameras look bad.

1. Get a budget
2. Internet research narrows options down to 2 or 3 cameras
3. Visit a store. Handle the cameras.
4. ?????
5. Buy from B&H Video or Adorama

Some Fuji cameras are pretty good.
posted by quosimosaur at 2:51 AM on February 16 [1 favorite has favorites]

I should add that I live in Sydney and I'm not affiliated with B&H or Adorama. On second thoughts you should probably check around for pricing instead of just ordering from B&H. But I have heard in forums of their competitive pricing.
posted by quosimosaur at 2:58 AM on February 16

At this point in the technology it is mainly the sensor that makes the difference. It is the weak link. Even the very best sensors are only now approaching what film has provided for decades. At some point all cameras will have great sensors and the most important factor will again be the lens. The lens remains hugely important though, even with good but not the best sensors, such as on an entry level DSLR. Most of those will come with essentially a throw away lens. Read up on lens tests from back issues of photo magazines or now the many web sites and find some better replacement lenses. You probably also want to like into prime lenses (non-zoom) if you desire to take pictures at wide apertures or long focal lengths, and to some extent also at very short focal lengths. In short, get the best sensor you can afford, and get a great lens to go with it. That probably means buying a body only and a separate lens unless you are near the upper end of the range where they start to come with quality lenses. Also, you are choosing an entire system, not just a single camera when you go with an slr. Given the utter turmoil in the industry I would not choose anything other than Nikon or Canon. The others just might not be there in a few years.
posted by caddis at 5:10 AM on February 16

I looked at the sensor links and found them either very dense in information or not enough of the info I need. I'd like to be able to compare sensors between cameras. So, what does the nomenclature actually mean and, looking at the specs, how I can I read the sensor specification and compare that to another camera.

For example: my present Panasonic TZ3 has a 1/2.35 " Type CCD sensor. What does this mean and what would be a better sensor? The specs on the upcoming Panasonic TZ7 says "The TZ7 has a 12-megapixel CCD and shoots with up to 10-megapixel resolution [because it allows you to take photos in three aspect ratios (not just cropping to those ratios)].
posted by Taken Outtacontext at 6:21 AM on February 16 [1 favorite has favorites]

Other things being equal (and they usually aren't), the size of the sensor matters. More to the point, pixel size matters. Smaller pixels capture fewer photons and perform less well in low light, which means higher noise.

In this context, the same number of pixels on a larger sensor will be better, as will, paradoxically, fewer pixels on the same size sensor -- other things being equal, which, as I said, they aren't. For example, my 12-megapixel D90 does better in low light than my 6-megapixel D40, even though their sensors are the same size. The technology improved in the interim.

Consider three cameras:

• The Nikon D3's 12.1-megapixel sensor is ~36×24 mm
• The Nikon D90's 12.3-megapixel sensor is ~24×16mm
• The Nikon Coolpix P90's 12.1-megapixel sensor is ~8×6mm

In general, the bigger sensor will be a better performer, so we would expect the D90 to outperform the P90, and the D3 to outperform the D90. Again, other things being equal.

Published compact camera sensor sizes are not as straightforward as digital SLR sensor sizes; Digital Photography Review's page on sensor sizes helped me understand how it works. In general: larger fractions mean larger sensors (1/2" is larger/better than 1/3").
posted by mcwetboy at 6:51 AM on February 16

Panasonic Lumix DMC-LX3

NB: the Panasonic Lumix DMC-LX3 is not a "pocketable" point-and-shoot camera. The lens barrel protrudes. My fiance has a special case with shoulder strap he uses for his. We love the camera, it rivals a low end digital SLR, but it won't fit into your back pocket. It might into a pocket of cargo pants but would be be awkward.
posted by kathryn at 9:03 AM on February 16

I'm trying to compare the Nikon Coolpix P90 with the Panasonic TZ7. Both have the same size sensor: 1/2.33". While the Nikon is a 12 mp, the TZ7 is listed at 12 mp with an effective mp of 10. The P90 has a optical zoom of 24X, the TZ7 is 12X, but the TZ7 is about half the weight.

There are other differences in the camera but I can figure those out. I'd just like to be able to compare these two for picture quality given the above parameters (unless there are other parameters I'm missing).
posted by Taken Outtacontext at 9:11 AM on February 16

It also has to do with the focus angle, plane of focus and depth of field stuff. The closer the aperture is to the sensor, the more "warped" the image becomes on the sensor.

There's also this.

And the ability to save photos in some kind of raw or at least uncompressed format, so that you can make image corrections before any compression is done.

That said, most digital cameras out there today will produce pretty darn good results if you apply some rudimentary photography knowledge to what you are doing. Know what the camera is good at and correct for what it isn't good at. Many point and shoots do a nice job of figuring out how to correct for a backlit situation, but you'll always get better results if you get your subject to be front lit.

And just pick one that looks good to you. When I bought my last camera, I bought a Kodak because in the reviews, all the Kodak models produced images that simply looked better to me.

And, know the role of the camera. If you want a camera to be able to carry it around and take quick snapshots when you are out doing other stuff, a big-ass camera just isn't going to do what you want it to do. Better to get a slightly poorer shot than no shot at all because you didn't feel like lugging a camera bag around.
posted by gjc at 11:21 AM on February 16

Yeah, the main reason I want this is because my DSLR is too big to take hiking. Plus, sometimes I accidentally take RAW pictures with it and it's a real pain to convert them correctly in Linux... the software requires more knowledge than I have.

Has anyone seen that today's woot item is a Pentax Optio E60 10MP Digital Camera?

I am trying to apply the advice given so far, but I'm not quite sure how to evaluate it. The sensor sizes being in fractions is especially confusing to me, I can't tell if 1/2.33" is small or big. Can I divide it and look at the decimal? .429 is a more readable number for me. But I don't have anything to compare it to.
posted by brenton at 3:22 PM on February 16

I think you should start by establishing an estimate of how much you want to spend and then we can make better recommendations. Otherwise you're going to get people throwing out digital cameras all across the price and image quality spectrum.

If you're at the $100 mark, I think you can't do better than the Canon A590IS. While it's a bit bigger than the Optio E60, it has image stabilization (IS) and manual controls which go a long way towards taking better photos.

1. Effective IS is a really key feature because a great sensor doesn't do much good if your photos are blurry from slight hand movements. IS is worth 1-2 f-stops meaning you can take handheld photos in low light that simply wouldn't be possible with the E60 unless you could hold your hand perfectly still.
2. And since you're coming from the SLR world, you probably already know how manual controls (aperture, shutter speed, iso) can improve the output. For $20 more and slightly bigger dimensions than the Optio E60, those two features are well worth it.
3. The A590's 1/2.5" sensor is smaller than the E60's 1/2.33" sensor but only slightly and not significant enough to make a difference (like 8% size difference). That's why you can't use sensor size as a hard and fast rule for "better". It's only relevant when you're discussing a digital compact vs a SLR (400% larger sensor) or vs a high-end compact like the Panasonic LX3 or Canon G10 (50% larger sensor). At a sensor size difference of 1mm, look towards features over raw specs like sensor size.
posted by junesix at 5:55 PM on February 16

@junesix: I do think I'm looking in the $100 or less category. I am a great scavenger though, and I am hoping to find something used online or at a garage sale or something.

I really appreciate the recommendations everyone has been giving. I am having a hard time understanding all of the different factors that I need to consider, so the recommendations are a big help.
posted by brenton at 6:54 PM on February 16