Why P&S's should do some reading before taking the plunge with realcameras

Perfect example. Guy shoots a Panasonic GH1 hand-held at 1/3 sec and
f16 and wonders why his shots aren't sharp. P&S's are weaned on
cameras that have infinite DOF and limited apertures (often don't
close down to lower than f6.3) so to them, the discipline needed to
shoot a DSLR or EVIL camera is alien.

http://forums.dpreview.com/forums/read.asp?forum=1041&message=35451698

 

Is that at maximum zoom?

DanP

 

Here's one with the camera (well, the G1, GH1 with lesser sensor) he
couldn't get a sharp shot with and a long lens.

http://www.pbase.com/andersonrm/image/116038333/original

 

It looks like it was shot through a telescope.
Awesome.


DanP

 

In 35mm terms that is 840mm.
I have taken this http://www.flickr.com/photos/danpetre/4629841983/ at
250mm, it has been cropped to 390 pixels square.
Yours is cropped to 1024 x 816.

Your day shot looks better than mine but your next does not.
To be fair it could have been better, the settings used (ISO 1600,
1/1250 s and f/8) were not the best choice.
Try ISO 100, 1/250 s and f/5.6 for a night shot of the moon.

The EF-S 55-250mm f/4-5.6 IS has cost me £140, no warranty. I could
have got it for £180 with warranty.


DanP

 

I have been posting exactly this view - that P&S users will encounter
focusing problems with Micro Four Thirds and larger sensors - for some
weeks now.

They do say that imitation is the sincerest form of flattery, so I
thank you for your sincere flattery. ;-)

 

$300.00 I built it myself. All it is is a 120mm wide, f8 1000mm
achromat.

 

Good thing though, the EVIL cameras have much less shutter slap and
are able to produce sharper images with extremely long lenses.

 

The only camera I owned that had a problem with shutter slap was a
Zenit B 35mm SLR, and that was back in 1973.

I must give shutter slap some credit, though. It is a red herring
that has been around for a great many years, but still appears fresh
to some people. ;-)

 

Just because you've never measured the image degradation it causes in your
own cameras bought today doesn't mean it doesn't exist. Others have
measured it. It still exists, at all shutter speeds.

 

Find a better shot of the moon taken with a P&S.


DanP

 

You want me to trust you? A bit of a stretch, I think ..

Seriously, though, I accept that there might be a problem at longer
focal lengths than I normally use. I rarely go beyond 300mm but I
have just bought a 400mm lens so I will carefully monitor the results
for shutter slap. Perhaps I will need a heavier tripod. ;-)

 

You'd think the heavier lens would help, but maybe the greater moment
arm counters that. Depends on the lens, I guess.

 

Perhaps some sort of counterweights in the camera, moving opposite the
mirror & shutter, would help. Are there higher-end cameras with such
features?

Making the moving parts of the mechanism more lightweight would help
too.

 

So explain me why my shot of the moon taken with a Canon SX100 at
360mm equiv is worse than the one taken with the Canon 500D at 250mm?


DanP

 

This is true, but for the pixel-peeper, the above is valid information. You
will not get pixel-level resolution on any DSLR unless you lock up the
mirror and allow vibrations to damp-down before the exposure is made.

 

Yes, it is a telescope. Basic refractor telescopes are uncompressed
optics (for the most part), no heavy negative elements to make them
small. The lens and cell came from Sky Instruments, about $220 it and
the focuser. The tube was surplus aluminum tube. The rest I did
myself.

http://www.pbase.com/andersonrm/image/125151707

 

So, for the moon shot, what was the focal lengths for the eyepiece and
camera?
Magnification is huge.

DanP

 

Unless the shutter speed is fast enough.