Rules is rules and I agree, health & safety doesn't feature much in spanish working life, but it does on the race track (well, mostly).

I'm not sure Mike. I didn't have it with me at the last race meeting but I'll take it to the next one on Sunday and give it a try out.

I have used it before when the light was better a month or so ago.

Problem is that racing doesn't start until 7PM (or when the ambulance gets there, elph 'n saphety, init) and this time of year I have about 1 hour of sun, and that's quite low in the sky.

I think most users have found the same Mike, little or no difference. It is nice to have a stable image in the viewfinder though.

Mostly DA* 50-135mm & TAv mode on the K5. I tried both the DA* 300mm and Sigma 150-500mm, both were too long and too slow, or maybe I just need more practice.

I only use the K20D & DA* 16-50mm for close ups of the drivers and cars when I can also use flash (if I can get the darned thing to focus).

Looking at your karting shots with the 150-500mm, they look as if they were taken in good sunlight. I'm faced with a dimly and patchily floodlit track.

My images from the summer, and in sunshine (we do get a lot of it) are fine.

Hi Steve, to illustrate what I'm up against I'm posting all of the images I took at the last meeting, including the rubbish ones here.

They are uploading now so give it 30 minutes or so to see the later ones that I'm having trouble with.

Motor sport photography is always a compromise on shutter speed. Too slow and you get blurring, too fast and everything freezes. I don't always get it right, as you'll see.

I even tried using flash on some of the later ones. Not good results.

Do you use a tripod or monopod to help with camera stability?

My main quandary at the moment is, do I persevere to get better results with what I have, or buy this lens and hope that I'm not going to be disappointed by the IQ wide open.

I'm again considering buying this lens so does anybody have anything new to add?

I'm involved with our local race track, the Velocity Racing Cartagena Oval, where I take photo's of the cars and drivers, both static and racing.

My lens weaponry coped very well during the summer months, but now that the light is gone by around 8PM, they (or me) are struggling.

I mainly use the DA* 50-135mm 1:2.8 for it's wide aperture on the K-5 for racing pics, and the DA* 16-50mm on the K20D for driver closeups, but the 50-135mm sometimes is not long enough. I tried the DA* 300mm 1:4 last week and it really wasn't happy working in the relatively dark floodlit track, I also found that it was a bit too long.

So I'm thinking that the Sigma 70-200mm 1:2.8 OS lens might fit the bill. I've read most of the reviews that say it's soft wide open (which is how I'll probably be using it), but I'd rather like the views of actual users, especially those that might use this lens for motorsport work.

I appreciate that some users have the older non-OS versions, but I'm not interested in information about those as the OS version is an entirely new design and therefore can't really be compared with older versions.

Just to add to JR's post, sometimes the SMC is written in lower case (smc). Neither one is inferior to the other by design, it just seems that somebody at Pentax decided to change it.

A 28mm/1:2.8
M 50mm/1:1.7
FA 50mm 1:2.8 Macro
FA 100mm/1:2.8 Macro
Sigma 180mm 1:3.5 Macro
Sigma 150-500mm

If Pentax have any sense they will automatically crop/expand the saved image when non-FF compatible lenses are fitted to their FF body. In which case, they'll all be fine.

Did they repair it FOC?