bretbysteve wrote:
Hi all,

Not wishing to put a damper on this thread, but I think a word of warning is in order...

Just to say, as good as both MXV and Ffordes have been in the past, I would say to anyone buying items from either of them, to check the items with a very fine tooth comb. I have had to return more than three lenses to both of these dealers within the last few months due to them not properly inspecting them. Some of the lenses had very obvious faults which had been missed. I get the distinct impression that both of these dealers are skimping on checking items properly.

They do give no quibble refunds, but it still takes time and some cost to return items. Ffordes also seem quite prone to often sending incorrect items.

I recently rang MXV about three Minolta MD lenses they had listed...two were marked MINT- and one was marked EXC++. I asked the sales guy to check them closely while I was on the phone....guess what...one had clear coating marks and another had internal haze, so whoever graded them in the first place clearly did not look very closely....so be warned.

Cheers Steve.

George Lazarette wrote:
There comes a point where no AF system can cope. Try shooting TT bikes at close range.

All you can do is pre-focus and hope you press the shutter at the right moment. I eventually found I could do it by ear with a 50/50 chance of success.

G

Dave_Evanson wrote:
I used to think a digital LX would be a good idea after using a *1stD and latter the K10D. But I think the K-7 is getting fairly close to the old LX magic.

I really did miss the excellent interchangeable viewfinder system on my LX while trying to manually focus a long lens in poor light on the K10D, (although I would probably have more trouble with the LX now my eyesight is not what it was) – Since upgrading to the K-7 I miss the LX a little bit less. I don’t know if it’s just the shape of the pentaprism but the K-7 seems to have a bit of an LX feel to it. Using live view has allowed me to start putting the M 400m f5.6 to some use again ...now if only the LCD could be tilted I wouldn’t miss the LX action finder so much

amoringello wrote:
In short it allows you to decrease ambient light using less flash power. It also helps reduce blur seen from ambient light tat might otherwise be frozen by flash.

More explanation...
It helps to understand a bit how the shutter works in these conditions... hopefully I do the expatiation some justice...
Basically the shutter has two "curtains". One opens to allow the sensor to be exposed. A second "curtain" closes to stop exposure. At the maximum sync speed the entire sensor is exposed.
On Pentax this maximum is 1/180 second. Anything faster requires that the second curtain starts closing BEFORE the first curtain is fully opened. This results, at the highest speed, only a small sliver of the sensor being exposed at any given time.

When you use flash, the flash is much faster than most shutter speeds. So Shutter speed will not affect the exposure from the flash. You need to control that with aperture (or with flash power, but lets assume flash power is consistent for now - to make things easier).

If the higest sync speed is 1/180, recall this means the smallest amount of time possible to fully expose the sensor at one time, the flash will therefore affect the entire sensor.

Go any higher than 1/180 on a Pentax and only a small portion of the sensor will see the flash. So you will start getting a dark band on one end of the frame. The fast the shutter speed, the larger the dark band becomes.

This can be used to great effect on other camera brands, but unfortunately Pentax has crippled the camera to not allow normal flash above 1/180 second. ARGH!!!

To work around the issue of getting a dark band, you need to use High Speed flash. This pulses the flash so that the sensor sees some amount of flash throughout the exposure. Of course this means the final flash power is much lower such that multiple flashes can be produced from a single charge.


Higher end cameras will allow the sensor to be exposed down to 1/250 or even lower periods of time.
This is really nice for photographing where you want to bring down the ambient light, for example the sun.
When using flash, ambient light is controlled by the shutter. So you can decrease the sunlight to near darkness and your flash will still properly illuminate the subject .

The difference between 1/180 and 1/250 is pretty minor (1/3 stop??) and I wouldn't worry much about it, but a camera with 1/500 or 1/1000 sync speed can create some interesting images using significantly less flash power.

Even though flash may be as fast as 1/20000, the ambient light may cause the subject to expose enough to leave blur and trails. A faster sync speed helps eliminate some of the blur visible from ambient light.

I just really wish Pentax would allow the hotshoe to fire a flash with higher sync speeds. Sometimes that dark band can be used for creative control and be a desired effect!