So they're not the cheapest thing sin the world, but SanDisk have just announced their latest CF cards - and they are the UDMA Mode 6 cards we've been hearing referenced in the EOS 5D Mark II, EOS 50D and EOS 7D product specs.

With sizes from 16GB to 64GB and a write speed of up to 90MB/sec (double the current fastest cards, the Extreme IV), the SanDisk Extreme Pro cards will be the ones to be using if you want to make the most of your camera's burst shooting functions. 

The EOS 5D Mark II, EOS 50D and EOS 7D can all make use of these UDMA Mode 6 cards, so expect to see increased buffer performance as the camera writes data from the buffer to the memory card quicker, thereby freeing up the buffer for more images. 

For more information, get over to the SanDisk website.

To achieve such high speeds, they're using a dual core processor to handle the data. Prices from £197 to £657 depending on capacity. (16GB, 32GB, 64GB)

Did you know that Canon and SanDisk were two of the original partners in the CompactFlash card alliance? Because they both subscribe to the specifications of the group, SanDisk memory cards and Can cameras always work well together. In fact, I don't think I've ever heard of an issue with a SanDisk card and EOS camera. 

Right then, well it seems you mostly did pretty well in the quiz from last week. The question was “What is the maximum sync speed of the EOS 50D?” The answer, as 73% of you got right, is 1/250sec.

So what is the maximum sync speed and why is it useful to know? There are two main reasons for using High Speed Sync – the first one being to make the background darker – in other words to achieve a shutter speed fast enough that the background (ambient) light forms less of the exposure, with the flash lighting the subject. We’ll deal with this more in a future post, as today we’re going to look at the second reason – the use of flash with fast lenses. The following two images were taken a couple of seconds apart. The lighting is exactly the same in both of them – a flash off camera to the left of the subject. They were taken on an EOS 5D Mark II with an EF 50mm f/1.2L USM lens. If you don’t use high speed sync flash, you end up with a situation where your shutter speed is locked at the maximum sync speed. This varies by camera, so here’s a quick list for the current models:
EOS 500D – 1/200sec
EOS 40D/50D – 1/250sec
EOS 5D/5D Mark II – 1/200sec
EOS 1Ds Mark III – 1/250sec
EOS 1D Mark III – 1/300sec

The problem with not going higher than the sync speed is that to get the right amount of light from the ambient light sources (ie to avoid overexposing the image) you need to stop down the aperture. This leads to image number 1 – not a bad shot, but too much of a distracting background.

1/200sec, f/11

If you enable high speed sync flash, then you can turn the shutter speed up – all the way to the maximum shutter speed  (up to 1/8000sec on most EOS models). That gives you picture 2: - a better image due to a less distracting background. Notice how the exposure and lighting are the same in both.

1/6400sec, f/2

The idea of high speed sync is that the flash fires several times rather than just at the start or end of the exposure. It needs to do this as the shutter only uncovers part of the sensor at a time during the faster than sync speed shutter speeds. Think of it as a moving slit passing over the image, since that is actually what's happening.

It’s not free though – you’ll lose some flash power as the flash has to work harder over a longer duration, so you may need to move your lights around to get them closer to the subject, or use more than one Speedlite to increase the amount of light available to you.

High speed sync is available on the Speedlite 550EX, 580EX, 580EX II, 420Ex, 430EX, 430EX II, Macro Ringlite MR-14EX and Macro Twinlite MT-24-EX.

I was chatting to someone the other day and they told me that their EOS 50D was too loud for some of the work they do, that being weddings and theatre work. Fortunately, there is a way around it (isn't there always?!) and it's called Live View. 

Most of the noise when taking a picture comes from the mirror moving. With Live View,  the mirror can be taken out of the equation. If you go into the menu and set the camera to Silent Shooting Mode 2, you will make the camera as quiet as it can be (this is the same if you use an EOS 5D Mark II as well). Essentially on activating Live View, the mirror raises and then when you come to take a picture, it doesn't have to move. The sound you hear (which is a very quiet click) is the second shutter blade moving at the end of the exposure. Notice there's no noise from the first shutter blade either-in this Live ViewSilent mode, the first shutter blade is done electronically - ie no mechanical moving parts.

In this mode, you can't take a sequence of images without releasing the shutter button and pressing again, as the shutter blade will not reset until after the shutter button is released.

It may not work for every situation, but it's nice to know it's there if you need to take a shot discretely without creating a lot of noise.