Tuesday, April 07, 2009

Digital Camera Guide Part 2

Okay so I've dealt with the myth of the Megapixel, perhaps in too much detail, and I've dealt with lens size. So what's next?


This is a straightforward choice - bog-standard over-the-counter batteries or proprietary manufacturer's own; okay the third option is mains powered which is great if you're running a studio, but I'll assume you're not.

Which of the two is better? The answer as always is - it depends. If you go for the normal batteries you can pretty much buy them anywhere, if they run out you don't have to worry about having the special recharger with you or if you've bought one of the, normally, hideously expensive spares that you've had to remember to keep charged.

However normal batteries are heavy compared to the proprietary ones, don't normally last as long, and with the rechargeables die quickly rather than fade out. So swings and roundabouts.

With some DSLRs you can have the option of a proprietary battery and an optional battery pack which takes over-the-counters; best of both worlds.

However it doesn't matter which type of power source you use if the camera is a power glutton.

Viewfinder vs Screen

The viewfinder has been almost completely removed from every ultra-compact and seems to be in the process of being phased out on the compacts too; in a way it makes sense. If the viewfinder isn't tied to the lens what you see through it isn't the shot you'll take, if it does then you're simply duplicating the screen and having to use more space and throw in more electronics to make it work.

Except the DSLRs still keep the viewfinder, is this just a static tradition appeasing the old-fogey photographers? Nope, the viewfinder is still of importance in a variety of ways.

First off is viewing the screen itself. The marketting bods still love to slap reflective layers onto screens to make them look shiny and appealing; looks great when off, but means you can't see anything when you're composing a shot under any form of bright light.

Next is focussing, difficult on the lower resolution screens especially as you may have to adjust the distance between the camera and your eye to be even able to see what you're taking.

In conjunction holding the camera out at arms length or anything between is less stable than next to your face and can introduce camera shake.

And finally using the screen burns power something the lens may not do or only do minimally.

So viewfinders rule, but some are better than others. Firstly in compact cameras the scene through the viewfinder is not necessarily the photo you'll be taking. If the viewfinder isn't tied to the lens you are really 'looking over the shoulder' of the lens resulting in a slightly different view.

The second problem is that what you're seeing through the viewfinder isn't necessarily the full picture you'll be taking. Viewfinders can show anywhere from 80% of the scene upwards. That means you might think you have a perfectly framed shot take it then find something extraneous on the very edge of the frame you couldn't see.

Obviously the higher the percentage the less is hidden. Even DSLRs can suffer from this though their percentages are normally in the high 90s. However DSLRs don't suffer from the 'over the shoulder' as they're tied to the lens, the view through the lens is directed to the viewfinder - what you see is what you'll get.


This is a big problem as Dan stated and can be the biggest cause of frustration for photo takers. There are four forms of lag (or slowness) inherent in digital cameras.

1. Shutter Lag. You press the shutter and think you've got the photo you want, but it seems you haven't.

2. Focus Lag. If you're using the auto-focus how long until it works out what you want to take a picture of?

3. Write Lag. You've taken one picture and want to take another, but you have to wait for the camera to be ready again.

4. Start-up Lag. Hah that was so funny if only you'd managed to take a photo, but you were waiting for your camera to switch on.

Decent reviews will produce figures for all these points. Don't be fooled by the apparently low figures; a shutter lag of 1 second may sound tiny, but imagine taking a photo of Formula 1 racecars - you frame the shot, press the shutter and... get a photo of the rear of the car.

Focus lags are normally minimal. Some cameras will try to continuously attempt to find a focus lock while switched on others only after you've pressed the shutter button introducing more shutter lag. The former is fine but can eat power, the latter you obviously want to avoid, the third option for the majority of cameras is half-pressing the shutter button and forcing the camera to focus before you fully depress the button. The length of time that takes is dependant on the electronics and software for each camera.

Write lags can be minimised if the camera has it's own internal memory buffer, it simply writes directly to that then moves it to the external card in its own time.

Start-up lag is normally dependant on whether you can use a viewfinder or have to use a screen. Even DSLRs can have a start-up lag comparable to a compact if you need to see the screen to change settings, but if you're happy with the settings you can normally just raise and click.

With all of these timings DSLRs win hands-down with almost immeasurable shutter and start-up lag, and often with an internal buffer so minimal write lag.

Camera Shake

The majority of cameras now feature a little icon that kicks in when it thinks you might end up with a blurry picture due to camera shake. The reason for this is normally that the camera is using a low shutter speed and will pick up even the tiniest of movements during the exposure. The obvious solution is to use a tripod, but that means carrying it around with you. The new solution is Image Stabilisation, or Vibration Reduction, or whatever trademarked phrase a manufacturer wants to use. Their function is, well what it says on the tin, compensation for any movement that occurs during the exposure. There are two ways of doing this:

1. Physical
2. Software

The physical option means moving either the sensor or the lens in the direction opposite to the movement. The software option means the camera looking at the picture you're about to take and essentially guessing what things would look like if they or you weren't moving.

Like everything to do with software doing it this way can introduce yet more lag at some point. The physical option is normally the best because it's adjusting to the movements of the camera/lens and not the subject and has zero lag.

Image stabilisation has advanced greatly in only a short amount of time and can sport a number of extra features, one that may be of particular interest is vertical only stabilisation. This means if you're shooting a video and panning around it'll only try to stabilise any up or down movement and thus keep your video level.


Something now considered a standard feature is the ability to shoot video with your still-image camera. The first thing to point out is that if you want to take lots of videos you're still going to be better off with a dedicated video camera, if you just want to take the odd pratfall etc. then a still camera is likely to be fine with the following warnings.

Despite having the megapixels a lot of cameras are still stuck to taking movies at a resolution of 640x480 at 30 frames per second. If you just want to show off these videos on a standard definition television that's fine, oh wait no it's not as in the UK television is set to 25fps not 30. Some cameras allow a faster fps but at a cost of reducing the size down to 320x240. These for the most part aren't that good. Here's an example of a 640x480 video; viewable, but not pretty.

However some cameras now allow HD video, by which they normally mean 1280x720, much better.

The second warning is about what functionality you retain while shooting a video. To give an example with my Canon A620 if I zoom into a scene then start shooting I can no longer zoom out. That level of zoom has been set as the base so if I know I'm going to be zooming in and out I have to start shooting with no zoom then zoom in straight away.

The third and final warning is about how the video is shot. Again with the A620 I can start shooting, but when I stop only then does it seem to write to the card. If the power cuts out or the card becomes full I lose either the whole video or the end of it.

Ease of use

In the next part I'll be dealing with shutter speeds, aperture settings, ISO, focus, zoom and all the things that might mean taking the shots that you really want to see. However no-one is going to alter any of these settings if it means fiddling around for ages with the camera's menu system.

So two things to try before you buy - does the camera feature the settings you're going to change in an easy to use way, and secondly when you hold the camera in the manner most comfortable to you can you reach said features?

Again with my A620 it's a bit of a mix. The zoom surrounds the shutter so it's easy to use, and the dial with various modes on sits naturally under your right thumb to switch around. However unless you know that the mode you've chosen is set the way you want you have to step back and use the screen. For some modes this is quite quick, both aperture and shutter priority means pressing left and right to set; flash modes can be toggled with up and macro and manual focus with down. ISO settings you need to head into the menu for, the same goes for white balance, and drive motor settings.

It boils down to what settings are you going to alter the most and how easily can you get to them.


I can't believe I missed out Zoom


Zoom can be broken down into two types optical and digital. Optical zoom is magnification achieved by physically moving the lens; digital zoom by the camera guessing what pixels might appear between ones it has captured via optical zoom and inserting them into your photo. If you have an optical zoom of 4x and a digital zoom of 4x then in theory you have a combined zoom of 16x. While digital zooms may allow you to take a full size shot of a far away object, the actual image may not be what is really present. Simply put choose optical over digital.

Okay here ends part two. next part here


Orphi said...

As I wrote on my own blog, one of the big problems with my current camera is power usage. It eats batteries within hours. You don't even need to turn it on. Just putting batteries into it is enough to drain them within an hour or two. Personally, I find it hard to believe that this isn't a malfunction of some kind.

Another problem, as you mentioned, is that with the onboard LCD, you really can't tell what the hell you've shot. It's useful for determining how black the picture is going to be, and which objects are in shot, but not much else. (My camera has an LCD on the back, and also a “viewfinder” which is also LCD.)

I am slightly worried that it might not be so easy to look through an eyepiece while wearing glasses, but hey. At least you'll be able to see what you're shooting in glorious hyper-definition.

My current camera lags, but not all that badly. Gotta wait a tad longer before you can take the next shot. Again, not all that long.

Start-up lag is about one second. The real problem is that, due to power issues, you must physically remove the batteries at all times except when shooting. So each time you want to use it, insert the batteries and spend a few minutes putting all the settings back to how they should be.

Focus lag is more or less non-existent. Also, you can point it, focus it, repoint it and then shoot. (Presumably most decent cameras can do this?)

I think the big one has to be easy of use. I wonder if any camera shops will let me actually touch a camera I haven't paid money for yet? I rather doubt any will let me take one for a walk through Salcey Forest while I try it out! :-P

Dan H said...

Yes, any decent camera shop will give you the camera to try taking a photo or two with in the shop without being asked.

As for the batteries, yes, it does sound like a malfunction. Are these standard alkaline cells or proprietary ones? If the latter, or if you're using rechargeables, I'd say it is probably the batteries at fault. As for losing the settings when you change the batteries, better cameras don't do that.

You are worried about using a viewfinder with glasses, but again, decent cameras are designed with this in mind. SLRs tend to have a removable eyepieces over the viewfinder, which can be replaced with a longer one or one with a 90° kink (and a mirror) so you can look into it from above.

FlipC said...

As Dan says, also check my comment about me looking over the D60 in Jessops.

Battery-wise again I agree sounds like the battery, unless it's a short circuit in the camera itself. Losing the settings on battery removal is nuts.

As for the viewfinder, to add to Dan's comment about eyepieces, some DSLRs also have a diopter adjustment which means you can match the viewfinder to your own prescription, so you can take your glasses off; buggers it up for anyone else who wants to use the camera though :-)

Orphi said...

The batteries are just normal AA ones. It takes 4 of them. And it sucks them dry with absurd speed.

I think I might pay Jessops a visit, just to see the crestfallen look on their faces after I spend an hour poking and prodding the camera and then don't buy it. ;-)

FlipC said...

Sounds like the camera then, I'm getting around 400 plus shots out of four AA's dependant on type and settings. I'm also guessing that it's out of warranty :-)

If not Jessops somewhere like Currys.digital or one of those types; just for the fun of probably knowing more about the cameras than the person trying to sell it to you.