Would general opinion be that it's worth doing this before it gets stuck, or is it so easy to do, that it would be better to assume that "if it's not bust, don't fix it"?

I have two of them, so twice the chance of one of them suffering in this way!

Keep it for a while. Occasionally put the 28-80 back on it, and be amazed at how wide angle it looks.

Then, admire some of the pictures you've taken with the K20D, and wonder how you ever managed to get such good results on film.

When you feel comfortable with the idea, acknowledge to yourself that there's no going back, sell it on eBay for next to nothing, except for the glow that comes from knowing that it's gone to a good home.

Unless you're like me of course - I'm keeping my ME Super forever. I've had it since 1985; it's gone everywhere with me for, like, ten million years. And I'm keeping it, even though I'll probably never use it again.

It is correct.

The sensor on a digital SLR is smaller than the negative on your 35mm SLR.

So although the lens does exactly the same as it always used to, the sensor crops the central rectangular part out of what you used to get projected onto your 35mm negative.

So when you take a picture with (what you used to think of as) your wide angle (28mm) zoom on your K20D, you don't get as much of the frame as you would have got on film.

Chopping the middle bit out of a negative in this way, and then enlarging what's left up to the same size as before, doesn't change the focal length - but it does change the angle of view.

The best advice seems to be this:

"Forget what X mm used to look like on 35mm, get used to what it looks like on digital."

If you really want to do the math, the rule of thumb is, multiply by 1.5.

So when you stick your 28-80 on the front of your K20D, it will look like 42-120 used to on 35mm.

You really want 18-55 on digital, to get the same range of angle of view as you used to get with 28-80 on 35mm. And that's why the kit lens that you get with a dSLR is usually an 18-55mm!

The K20D is an excellent choice of camera - enjoy it!

With Firefox's Exif viewer add on. Not all people post pics that still have intact information, but many do.

# Camera Make = PENTAX Corporation
# Camera Model = PENTAX K10D
# Picture Orientation = normal (1)
# X-Resolution = 2400000/10000 ===> 240
# Y-Resolution = 2400000/10000 ===> 240
# X/Y-Resolution Unit = inch (2)
# Software / Firmware Version = Adobe Photoshop CS3 Windows
# Last Modified Date/Time = 2009:11:03 17:48:15
# Time Zone Offset = 0,0

# Exposure Time (1 / Shutter Speed) = 1/250 second ===> 0.004 second
# Lens F-Number / F-Stop = 95/10 ===> ƒ/9.5
# Exposure Program = shutter priority (4)
# ISO Speed Ratings = 100
# Exif Version = 0221
# Original Date/Time = 2009:10:31 08:31:11
# Digitization Date/Time = 2009:10:31 08:31:11
# Shutter Speed Value (APEX) = 7965784/1000000
Shutter Speed (Exposure Time) = 1/250 second
# Aperture Value (APEX) = 6495855/1000000
Aperture = ƒ/9.5
# Exposure Bias (EV) = 0/10 ===> 0
# Metering Mode = center weighted average (2)
# Flash = Flash did not fire, compulsory flash mode
# Focal Length = 3500/100 mm ===> 35 mm
# Colour Space = sRGB (1)
# Image Width = 900 pixels
# Image Height = 900 pixels
# Image Sensing Method = one-chip color area sensor (2)
# Custom Rendered = normal process (0)
# Exposure Mode = auto exposure (0)
# White Balance = auto (0)
# Focal Length in 35mm Film = 52
# Scene Capture Type = standard (0)
# Contrast = normal (0)
# Saturation = normal (0)
# Sharpness = normal (0)
# Subject Distance Range = macro (1)

Assuming you haven't done any customisation of the functions of the e-dials, do the following:

Turn the knob on the top left to M (manual) or Tv (Shutter priority).

Half-press the shutter button to engage the metering.

Then turn the front 'e-dial'. This is the knurled knob in front of the on/off switch, that falls naturally to your index finger when holding the camera normally. Turning the e-dial will change the selected shutter speed.

Note that in Tv mode (shutter priority) the aperture will also change, but the camera is changing it in response to your selection of shutter speed.

Agreed. It's not often you get that much cloud as well as that much detail.

Compositionally, I think the moon is a little too central, and perhaps a touch overexposed.

The moon is deceptively tough without a telescope. If you haven't returned shivering into the house with fingers too cold to turn an e-dial, vowing never to bother trying to shoot such a stupid subject again, you probably live in Spain... or Australia.

Thanks, but it's not as good as a couple that others have posted in recent times.

Clarky did very well - much better than mine - with a Bigma and the K10D (I'd like to think it's just the extra 100mm that did it ).

ISTR Mannesty has done some good ones too.

I'd say it is, just about. It's the lower limit for the K10D; I'd guess with good glass it would be a bit better with the extra pixels of the K20D/K7.

Here's one of mine with the K10D and the SMC-A 400mm F5.6:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Misc/IMGP5519-1brsmsh.jpg[/IMG]

At 200mm on a K10D, the angle of view is 6.87 degrees. A one second exposure is therefore 2.4 pixels of movement blur.

If this is really good enough for 'critical work', then presumably 2.4 pixels is not significantly greater than the other factors that lead to loss of sharpness, such as the ones I listed above.

Is this really true?

I recall using exposures of several seconds when attempting to shoot the total lunar eclipse a couple of years back, and sadly, I failed to 'do the math' ahead of time, and the movement blur was well into the range of "totally unacceptable".

This, for instance, had an exposure of 3s, and I'd say it's awful:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Problems/MoonDuringTotality.jpg[/IMG]

So I must confess to being a little sceptical that as long as a second (or half a second at 400mm) would give really good results.

It doesn't have to be this short.

There are 86,400 seconds in a day, during which the Earth rotates 360 degrees.

So the moon moves across the sky at 360/86400 = 0.0042 degrees per second.

Now, the angle of view of a 400mm lens on a K10D is 3.44 degrees, measuring horizontally across the sensor.

So in a second, assuming the camera is set up to have the moon track horizontally across camera's field of view, the moon moves 0.0042 degrees, which corresponds to:

(0.0042/3.44) x 3872 = 4.7 pixels, let's call that 5.

So for movement blur to be less than half a pixel (a tenth of 5), you need an exposure of a tenth of a second or shorter. I usually go no slower than 1/15s to be on the safe side. (I think you'd be hard pushed to distinguish a 1/3 pixel movement blur from other effects in the image, such as lens aberration, imperfect focusing, camera shake, and atmospheric distortion, to name but a few!!)

For shorter focal lengths than 400mm, you can get away with exposures a bit longer than this.

1/125 however, is a lot shorter than you need.