Posts Tagged ‘digital camera’

How many photos will fit on my memory card?

Friday, March 12th, 2010

When taking photos with a digital camera it is useful to know how many photos will fit on your memory card (SD, Memory Stick Duo, USB, etc), and know how large the JPEG images are.

There are a lot of tables out there showing this kind of information. I don’t trust other people’s numbers so I decided to calculate them myself and produce some charts to show how the number of megapixels you use when taking the photo affects how many photos will fit on the card.

MP 0.3 1 2 3 4 5 7 10 12 15
256MB 1896 569 284 190 142 114 81 57 47 38
512MB 3793 1138 569 379 284 228 163 114 95 76
1GB 7585 2276 1138 759 569 455 325 228 190 152
2GB 15170 4551 2276 1517 1138 910 650 455 379 303
4GB 30341 9102 4551 3034 2276 1820 1300 910 759 607
8GB 60681 18204 9102 6068 4551 3641 2601 1820 1517 1214

The table above is what I came up with. I made the assumption that the images are stored as JPEGs and the compression ratio is 15:1. That is a rough average of what my Sony Cyber-shot W80 camera is compressing my photos at.

The compression ratio can have a big effect on the size of your photos. It can for example make the difference between your photo being 2MB in size or being 4MB in size.

This graph shows the JPEG photo size when using low compression (which I’m defining as 10:1) and high compression (which I’m defining as 20:1).

size of jpeg photos vs megapixels

My second graph shows how many photos you can fit on a 4GB card. I chose 4GB as this is quite a typical memory card size for today’s digital cameras. You can see that a small decrease in the megapixel resolution (that you shoot the image at) can allow you to fit a lot more photos on the card.

how many photos will fit on a 4gb memory card

Here’s a table of the average JPEG image sizes for differing megapixel resolutions.

MP 0.3 1 2 3 4 5 7 10 12 15
Size (MB) 0.14 0.45 0.9 1.35 1.8 2.25 3.15 4.5 5.4 6.75

If you take a lot of photos then I’d recommend you try decreasing the number of megapixels in your photos. Most digital cameras will allow you to do this very easily. Today 10MP and 12MP cameras are common, but this level of detail is way more than most people need. Megapixels are a marketing game played by camera manufacturers.

By having the resolution too high you are just decreasing the amount of pictures you can take, increasing the space they use on your computer, and increasing the time it takes to process or upload them.

I have a 7MP camera. I have turned it down to 5MP because I find 5MP to be sufficient. You get great photos at 5MP – they look great on screen and great when they are printed out on 6×4 inch or 7×5 inch photo paper.

Give it a go, and see if you notice any difference.

Sony Cyber-shot W80 digital camera review

Thursday, January 24th, 2008

I’ve been using the Sony Cyber-shot for over two months now, long enough to know what’s good and bad about it.

It is a 7.2 megapixel camera featuring 3 times optical zoom. It has a slightly higher spec than the Sony W55. The extras it has over the W55 are optical stabilisation technology and a microphone. It was about £30 more expensive than the W55 at £140 but I needed a camera with a microphone as I wanted to take some basic videos as well as taking photos.

Sony Cybershot W80 digital camera front

The internal memory is so small that it is not even worth bothering with so you’ll need to budget for a memory stick pro duo card. I got a 4gb card for less that £15 from Amazon’s marketplace.

Before using the camera you’ll need to charge the battery. It charges from an external charger rather than internally which means that if you are travelling you will have to take an extra bit of kit with you. The battery life is very good. I’ve gone out on many a day, taken around 150 photos and some video and the battery still has plenty left in it. Sony say it can take over 300 photos on a single charge.

The quality of the photos are really good for a camera in this price range. You can see reduced sized photos that I’ve taken with this camera at http://www.londonphotoproject.co.uk/blog/. These are all taken with the ‘auto’ setting. There are a variety of different settings for taking photos at night, in snow, at the beach and more. You can also adjust many of the parameters such as ISO, EV and focusing. I haven’t experimented with these as ‘auto’ seems to get the settings right.

The various settings are adjusted with a wheel. I have a slight critisism here, it is very easy for the wheel to get turned without you knowing if you keep the camera in your pocket. It would be good if the wheel could be locked in place.

Sony Cyber-shot W80 digital camera back

It performs well when taking photos at night or in low levels of light, the flash is powerful and adjusts to the light level correctly.

It is not just the quality of photos that matters, the speed at which the camera becomes ready to take photos after being switched on and after taking a photo has been taken is important. This camera is fast at turning on and the turnaround time between taking each photo (shutter lag) is very good too.

I mentioned that one of the reasons for me buying this camera was its video features. If you set the video to ‘fine’ then it will record video at 30fps. The microphone makes a difference as videos with sound are much more engaging than those without sound.

Good points

  1. High quality photos. See some of my day photos and night photos taken with this camera.
  2. Low shutter lag
  3. Video capabilities with microphone

Bad points

  1. External battery charger
  2. Easy to move settings wheel without meaning to when camera is in your pocket.

Overall rating

This camera isn’t perfect but for its price I’m definitely glad I bought it. You can buy it from Amazon here. I’d give it 9/10.

Update January 2011: I wrote this review nearly three years ago, but the Sony W80 is still the camera I use every day. All the photos up to this date on reviewmylife were taken with the W80. I am thinking of getting a better camera at some point in the next year. I’ll again get a compact camera, but perhaps with higher end features. i.e. better zoom, better night photo support, better optical stabilisation. I’ll probably get a Sony again, and if/when I do I’ll review it here.