Not all megapixels are equal

I suppose it was enevitable but photographic film products are slowly slipping away. I’d still like a Hasselblad Xpan II, but they are rare (and expensive) – and even if I did get one, I’m not sure that I’d use it (when I bought a DSLR, I kept my film body but it’s been sitting in the kit bag ever since). Over the last few years, we’ve seen film companies struggle, whilst the likes of Nikon and Canon announce record profits. I hope that film doesn’t die completely (there is something magical about developing photographic film with chemicals and producing prints) but film products will inevitably become expensive and niche.

Digital photography has many advantages but one of my main frustrations has been the lack of dynamic range that the current crop of cameras can capture. Whilst negative film has around 12 stops of latitude, and slide film has around 4.5 stops, digital cameras can be even more restrictive at times and, in order to capture shadow detail, burnt out highlights become apparant although, just as when shooting slides, using neutral density filters can help (a lot).

Then there is the issue of noise. With film we could push film a couple of stops beyond it’s intended levels and correct it at the processing stage – there was a corresponding increase in grain and some colour shift too but it helped to grab images in low-light situations or when there was fast-moving action. Try that on most digital cameras and you’ll see a lot of noise (the digital equivalent of grain but far less attractive) although this is starting to change and the latest digital cameras are reaching new levels with perfectly usable photos at high ISO levels and some reports of being able to shoot handheld at twilight and still capture a good image.

Meanwhile, the digital camera manufacturers have induced a state of megapixel madness. Consumers now know to look at the number of megapixels that a camera has but it seems that not all megapixels are equal – the images on my 7Mpel compact camera are fine for snapshots, but no-where near as good as the ones that my 6Mpel DSLR produces. It’s all down to the technology in use like the type of sensor (CCD or CMOS), the technical differences between picture elements (pixels) and photosites, the firmware and software supporting the imaging chip and even the size of the pixels. Even after all of this, the quality of the lens through which the light must travel to reach the sensor is still a major factor (ditto for filters).

A new DSLR is not an option for me (I have a 4-year old Nikon D70 that will last me for a while longer – at least until Nikon release an FX-format prosumer SLR) so, for the time being at least, I’ll be continuing to use a tripod and long exposures in low light and hopefully this summer I’ll have a go at creating high dynamic range (HDR) images (one image from multiple exposures) to increase the dynamic range.

One thought on “Not all megapixels are equal


  1. After spending most of the last fortnight trying to pull together the various threads that make this post, I was interested to learn that Lifehacker (a site I highly recommend but which produces far more output than I can keep up with) published a post last week about the hype surrounding megapixel counts. I didn’t read that before writing this though!

    One point that’s worth noting – high megapixel counts can help when digital zoom will be used (significant cropping of the image); however that’s still going to be affected by the various technical features around the camera’s sensor – and the quality of the glass in front.

Leave a Reply