15mm?


Mmmmm sounds ace!

I'd expect it to have no problems on any of the bodies - I use a 50mm SMC-A f1.7 with no trouble

sorry Liam - should have scrolled up to check the name - was just reading the posts not the authors...

I understand that in principle a prime lens should produce better images than a zoom.

However I think that is a broad generalisation as well as an over-simplification....

A zoom lens allows you to fill the frame far more selectively - if a prime is too short for the shot then i've wasted 3/4 of my pixels if it's only half filling the frame. not much use when you then need to digitally crop to get a proper image.

Conversely if the lens is too long for a shot then you are going to be missing half the subject.

So the right length prime *should* be better than a zoom set at the same focal length - but without any flexibility.

Now i'm happy to agree that a prime lens should be much better in terms of image quality - but that's not to say that it will be - technology does move on, with things like coatings on the element facing the sensor to reduce reflection - APO objective lenses and the like. I'd fancy that the Canon 70-200 f4L is considerably better than many primes.

I think it is easy to forget that there are many other factors that make a lens "good" than the absolute image quality from lab tests.


(just to show i'm not a complete heathen - I do have and love a Pentax SMC-A 50mm f1.7)

Liam - that's what i thought you meant....


But the Pentax lens we're discussing is an f5.6 - while the Sigma is F2.8.

So with the two stops of light lost through the tc the Sigma becomes an f5.6....


I can't understand how that could make the viewfinder darker of focussing harder than on the Pentax lens which is F5.6 to start with.


But as well as being able to zoom out from 400 (back to 140) with the Sigma you'd also be able to still take the TC off, so you'd be covering the whole range from 70-400 with just one lens and TC, at worst the Sigma would be as slow as the pentax, but at shorter lengths it would be two stops faster.

I'd genuinely like to see some comparable images to show just how much better the image quality of the Pentax would be - I think it would have to be quite markedly better for the difference to be worth the massive decrease in convenience compared to a zoom and tc (not to mention how many other lenses you'd need to buy to cover the same range, and how big a bag you'd need to carry them...)

I'd be interested to see comparison between the Sigma and the Pentax in terms of image quality - as I've been very impressed with what comes out of the D with the Sigma on.


As for the TC and focussing issue... Now that one you'll need to explain to me

Just a thought...

While I understand that a 400mm prime lens will generally have advantages over a zoom - how much better would this lens be than, say, a Sigma 70-200 f2.8 EX DG with a 2x tc?

Pricewise I'd expect them to work out similar based on that price for a mint 400mm - obviously the Sigma has some big pros in terms of flexibility (with being a 70-200 f2.8 as well as a 140-400 f5.6 - and a 105-300 f4 with a 1.5x tc) but just how much better would the pentax lens be in terms of image quality?

the main reason I ask is that I was looking at something in the 135-400 range for my IST D to replace my fairly cheap Sigma 80-300 f4.5-6.3 zoom. After looking around at prices of long zooms I decided to go for the 70-200 + tc setup. I'd tried out a mate's canon 70-200 f4L with a cheap TC and was very impressed with how much pic quality was kept even using a 2x tc. Even printed at a decent size it was very hard to tell the difference in images. With mine now I can see the reduction in light through the viewfinder with and without TC, although I think the D viewfinder is pretty damn good regardless.

I shoot mainly motorsport and having seen some of the "pros" spend a fortune on big long fast primes and then struggle when the action happens too close to shoot I was pleased to have gone for a more flexible setup than a big prime. Am I missing out greatly? Or is it only in the really marginal situations that the benefit would show up?

Bit of a funny tangent - why is it that in general the Pentax lenses seem to be fairly slow, particularly the zooms? Or is it just that for the equivalent fast pentax lens I should be looking at more serious prices?

I bought a grip from Mannesty a month or so back (when he was a bit more local!) and it's transformed my view of the camera.

when i had the sigma 28-80 and 80-300 twin lens kit the compact size of the D was a real boon - i could fit all my kit in a very small bag. Now i've moved onto a 24-70 f2.8 and a 70-200 f2.8 i was finding that small body size became a hindrance - especially with handling the 70-200 for long periods.

The grip has transformed it. It seems to add absolutely no weight at all (i still only use one set of batteries) but now I find the camera and lens combination so much more manageable.

If I get a K10D (which i'm sure I will) it will be for my motorsport photography. I'll be keeping the D for my portrait/modelling work (where the extra MP and frame rate are irrelevant as I can always fill the frame) as the wireless flash using the onboard controller is a real boon. I almost never use the 360 on the camera for portrait - I have a brolly set up and use it that way.

The K10D will however need a grip to give me the handling with my long lens that i love on the D. If the camera can only take special to type batteries then i'll have to buy at least a second one (depending on tested battery life) as I can't afford to run out of power trackside.

The K10D's spec is enough to convince me to stay pentax though - I've thought about changing to C/N but I never get bored of getting the camera eyed trackside by "pros" who can't work out where it fits in the pecking order

Well i don't know about the rest of you but i'm truly stunned by that


Obviously we have to wait until the body is actually in our hands for that price to be sure - but at under £600 for the body that's seriously undercutting the competition (especially with SR built in and all the other great features!)


i'm both and

Do you think customs would notice if we clubbed together and someone flew to america to buy a dozen K10D bodies?

i *want* to believe that even 30% of it happens.

But since the D was released i've seen nothing to justify that belief

7 day shop sell a really neat charger (V800 or something) comes complete with mains adaptor with several different plugs, also a car adaptor, it charges 4 x AA or AAA all individually and for a really cheap price. The next best option to that seemed to be to spend a small fortune. Cycling my batteries through this charger a few times seems to have pretty much doubled their life. Mind you - i still carry a couple of sets of normal CRV3s as spares...