Cheers Clarky - I'll mention you in my sleeve notes...

Leica make a 50mm/f1 called the Noctilux which is available to special order and costs about £10k. Canon briefly made one in the 1960's (also 50mm) which is rare as hens' teeth and would probably set you back the same as a nice house if you could find it. The only other ones I know of were made by Zeiss specially for NASA to use on the moon landing - I think there were 6 of them and they were sold on to Stanley Kubrick who converted them to cine lenses.

As far as I know, nobody has ever attempted a 300/f1 - now that would be an absolute monster!!

Hi Jeff, if nobody asked questions then forums like this would wither and die so keep it up

I don't have a particular recommendation book-wise but if you pop to your local library and get a book on general photography technique that should do the trick. The basics haven't changed in over 100 years so don't worry if it's not a particularly recent book (fat chance of that in most libraries anyway) so have a browse and get one you feel comfortable with.

George's info above is spot on regarding speed; I'd love a 300mm lens that opens up to f2.8 but they cost an arm and a leg - that's why I have the Tamron. At 300mm it's "only" f5.6 maximum but as long as the conditions are bright that's plenty enough to capture fast-moving bikes - just don't expect results in dimmer conditions to be as easily obtainable.

Just for reference, the apertures for a lens (widest/fastest first) are:

f1 - f1.4 - f2 - f2.8 - f4 - f5.6 - f8 - f11 - f16 - f22 - f32

You can't buy an f1 lens in Pentax mount (and mortals like us wouldn't be able to afford it if they made one) and anything 300mm long with an aperture of f1.4 or f2 would weigh a ton. A f2.8 would be very expensive and quite heavy at 300mm (but good if you could find one), a f4 slightly cheaper and lighter and then we have the f5.6 which is a good compromise being cheap, light and - as I said before - medium paced.

Good luck anyway!

I also shoot a lot of motorsport and you'll probably find that the lens coming with your new camera will be a little short for capturing all the action. In an ideal world you'd want something long (200mm+) and fast, but these sorts of lenses are expensive to say the least!

As a compromise I'd recommend a Tamron 70-300 like the one I use. It's a long telephoto zoom lens (with a built-in macro function that can be good fun!) that's medium paced (f4-f5.6) and will work on film and digital cameras. It auto focusses quite swiftly and - best of all - it's cheap! Most places will sell you one new for £100-120 but used ones come up on eBay from time-to-time for less money.

It'll make an excellent companion to your 28-70 and if you stand on the banking just after the hairpin and before the start/finish straight at Mallory Park you'll find you can track a car/bike around virtually the whole circuit - happy days!


PS. Warehouse Express have one in their January sale for £69.99: http://www.warehouseexpress.com/?/specials/Jansale.html#Digital%20:%20Lenses (Tamron AF 70-300mm f4-5.6 Di LD Macro 1:2 - Pentax).

The following is a rough guide (I've over-simplified a bit) as there are exceptions to every rule, but this should get you started (all based on your new film camera):

A lens with a focal length of 50mm (or thereabouts) is considered "normal"

A lens with a focal length less than 50mm is considered "wide"

A lens with a focal length more than 50mm is considered "telephoto"

A lens that can change its focal length is called a "zoom"

A lens with a fixed focal length is called a "prime"

A lens that can focus very close to the subject is called a "macro"

So you see, you could have a lens that is a telephoto, a zoom and a macro all in one. You could have a lens that is both wide and telephoto all in one (as long as it's a zoom). You can't have a lens that is both a zoom and a prime all in one as they are completely different.

I use a DA12-24 which is "wide" and a "zoom".

I use an FA43 which is "normal"(-ish) and a "prime".

I use a D-FA100 which is a "telephoto", a "prime" and a "macro".

Finally I use a Tamron 70-300 which is a "telephoto", a "zoom" and also has a "macro" facility.

Does that make things a little clearer?

Excellent photo! What liquid are you using to get the colours seperated like that (or was the colouring done in PP)?

Just to prove that you can't please all of the people all of the time, I rather like the jaunty angle of number 2 - looks like the sort of view you'd get when you wake up on the pavement after a really heavy night!

Congratulations Gwyn and well done Dirk - that was a tricky one to judge!

K10D / DFA100 / f4.5 / 1-250sec / ISO100

30 August 2007

When I was a little kid and my Dad was teaching me photography he gave me a good analogy which I'll pass on to you now;

In order to create a photograph you need to take your film (sensor in these digital days) and coat it with light (the word photograph literally means "light painting". First you need to know how much light you actually need - back in the day photographers could judge a scene by eye, these days we've become reliant upon our cameras to measure the amount of light they see and work out how much is needed for an "exposure" - that's because cameras are usually more reliable and better able to adjust to prevailing conditions than we are.

Now, let's substitute "light" for "water" and assume the camera tells us that a pint is required to satisfy its needs. If you take your pint glass to a tap then there are many ways you can fill it - at one extreme you can turn the tap a tiny amount and let the water drip into the glass until it's full; at the other extreme you can turn the tap on full and let the water gush in. Of course there are countless variations in-between.

The aperture of the lens is the tap in this analogy - the wider it is turned the faster the light pours onto the sensor so the less time it needs to be open for (the shutter speed is represented by the length of time you leave the tap on for). Be aware though that having a tap on full will result in the glass being filled in a messy fashion with lots of splashback, similarly a wide open aperture will result in a very narrow depth of field (amount of the scene in focus) and in most cases a rather "soft" picture.

Finding the right balance is what it's all about. Sometimes you will want a really fast shutter speed in order to freeze action or to prevent camera shake, sometimes you may want a very narrow depth of field for artistic purposes (like you aimed for in your MG picture). These require BIG apertures (lower f. numbers)

Conversely, there may be times when you want everything from very nearby to the far distance to all be in focus (warning: this means a slow shutter so use a tripod) or a slow shutter for artistic effect (think of those night pictures with the light trails of the traffic or those pictures of waterfalls where the water is blurred to look like a sheet of silk). These require SMALL apertures (higher f. numbers).

Usually though you'll want something in the middle but it'll vary from picture to picture and that's where your artistic interpretation and eye for a picture can never be second-guessed by your camera no matter how smart the maker claims it to be!

On the top dial of your camera you'll find your mode dial. I'd suggest setting it to "Av" where you set the aperture and the camera will set a shutter speed to match it and give you that "full pint of water". Take lots of pictures of the same scene at different apertures and compare them to see the difference it makes. Once you've got the hang of that then you'll find yourself naturally moving into other modes and experimenting with them to see what they do. You'll pick it up sooner than you think.

For a first effort I think they're excellent!

As for what settings, etc to use I'd recommend a trip to your local library to find a book on photography basics (don't worry about it being specific to any camera or even digital cameras - the basics haven't really changed that much in over 100 years). Learn how to use shutter speed and aperture and how they relate to one another and you'll be 90% there - the most important aspect of photography (IMO) is having an eye for a picture and that tends to be something you either have or you don't, I don't think it can be taught.

If I take one of your shots as an example (the silver SEAT), you've got the front of the car in focus but the girls' faces are out of focus (maybe that was deliberate but I doubt it was). If you'd used a smaller aperture (larger f. number) with a slower shutter speed you would have increased the depth of field (the amount of the picture that appears in focus). The downside is that the slower shutter speed would have meant a greater chance of "camera shake" (blurry picture) but this is one of many compromises that photographers have to consider with each photo. A way to mitigate it would be to increase the camera's ISO speed (the sensitivity of the sensor to light) although again there's no gain without pain as this would also increase the amount of noise in the picture.

If you can follow the above paragraph then that will tell you most of what you need to know to take photos. The camera will help you out in a lot of situations but there's no substitute for having a basic understanding of what the camera's doing and why it's doing it.