Urgh. Flare. Sometimes it's great, but most of the time you just don't want it. I've waxed lyrical many times before on the benefits of lens hoods for protecting the front of the lens, but there are times when you can't fit a lens hood - like when you're using a Lee, Cokin or HiTech filter for example. A lens hood just won't fit. But that's no excuse, and the two images coming up with show why lens hoods or shading the lens is crucially important if you want to get the best image quality from your camera and lens combination.

First up, what is flare? Well, I can tell you it's not dodgy trousers appearing in your images. But there are several types of flare you may see - there's the flare caused by the sun shining directly into the lens, causing circular patterns to appear across the image. This is essentially reflection of each of the lens elements on the image sensor and it can be turned into a feature of the image - just don't go doing it on every image! 

So this type of flare, while annoying when you don't want it, is at least creatively useful on occasion. The other type of flare, caused not by the sun shining directly into the lens, but raking across the front element is much more irritating, because it can turn a good image into one that looks horrible and washed out. 

As light cuts across the front lens element, some spills into the lens. While it doesn't funnel down into the lens and through to the sensor, it bounces around inside the lens dramatically reducing contrast and image sharpness. 

Take the two following images as examples:

The image on the left has no lens hood or lens shading, while the one on the right has a lens shade used to cut any external light away from raking across the front lens element. The colours are more vibrant, the contrast is greater and the image looks better. Now, before anyone says it's just photoshop or RAW processing, these two files had EXACTLY the same done to the in RAW and photoshop. Namely I changed the Picture Style to Landscape and then in Photoshop I sharpened both the same, resized them, sharpened again and then converted to sRGB. There's nothing else. The difference you're seeing is solely down to the use of a lens shade. 

You may noticed I keep saying 'lens shade' rather than lens hood. It's because for these two images, I was using a polariser and ND grad filter so my lens hood wouldn't fit. Instead I used a rectangle of black card I keep in the bag for just this use. I simply held the card to the side of the lens and moved it around until a shadow fell over the front of the lens - as long as the card is not in shot, you're good to go. 

So, if you don't have a lens hood for each lens, get one. If you don't want to go to the expense of buying lens hoods, then as long as you're using the camera on a tripod, you can used a piece of black card or plastic, or even your hand. Anything that will shade the front lens element to stop the internal reflections from ruining your pictures. 

For those of you who don't subscribe to the newsletter, or those that don't read all my my long missives, here's some info as a follow up to a post I made about Energizer Lithium batteries a couple of months ago. The original post: AA Batteries - which ones? explained why I have switched over to Energizer Lithium batteries most of the time. However, one regular blog reader had a go with them and discovered that they get rather hot in use in a flashgun, especially when shooting lots of images in a short time period. Becasue of this he was worried about over-heating.

Well, I went away and did some research on the matter and found out that there is no need to be worried. As it turns out, the Energizer batteries will become hot in use, that's just their nature, but because of this they do have a thermo cutout system for when they get too hot. Failing this, the Canon Speedlite 580EX II also has a thermo cutout switch which will power down the flash if it gets too hot. So, you can use the Energizer Lithiums without worrying about killing the flash - just be aware of them getting hot and if you're still not sure in use, take them out and give them a rest to cool off again.

Before the site downtime, I'd set a weekly quiz question about Image Stabiliser modes. The question was: "Which IS mode would you use when panning with a moving subject?"

The Options were Off, Mode 1 or Mode 2. 

The answer is Mode 2 and 65% of you got it right. 

Now, not all IS lenses have the two modes, but for those that do, this is how they work:

Mode 1 - the lens will stabilise camera shake in both an up and down and side to side orientation. So any camera shake will be corrected for. 

Mode 2 - the lens detects the direction of panning and then instead of trying to compensate for that horizontal motion, it ignores it and concentrates on the motion at 90degrees to it. This way you can get smooth pans without fighting the IS mechanism. 

Clearly if you don't have a Mode 2 on your lens, you're left with Off and On. Our recommendation is to turn it off. You'll need to be smoother with your panning and having a tripod or gimbal style head will help, but as long as you move through a nice smooth arc, you can still get good results. 

Well done to those that got it right. This week's weekly quiz question is along the IS lines as well. Go give it a go. And if you don't know, guess! Your entry is anonymous so there's nothing to be worried about if you get it wrong!