Digital Camera Resolutions

Just got a Canon Ixus 430 and the 40m rated waterproof housing to go with
it. I'm planning on taking a load of underwater pictures in the Maldives
next week but I have a question about resolution. The camera is 4Mp and will
go upto 2272 x 1704, but at this resolution the picture quality appears to
drop off - it seems much better at 1600 x 1200. Is that an acceptable
resolution to get decent results if I want to get any of the pictures
printed as "proper" photos (i.e. by Boots) when I get back?

Any advice gratefully received.

--
kAnO
"A fella, a quick fella, might have a weapon under there. I'd have to pin
his head to the panel..."

kAnO wrote:

> Just got a Canon Ixus 430 and the 40m rated waterproof housing to go with
> it. I'm planning on taking a load of underwater pictures in the Maldives
> next week but I have a question about resolution. The camera is 4Mp and will
> go upto 2272 x 1704, but at this resolution the picture quality appears to
> drop off - it seems much better at 1600 x 1200. Is that an acceptable
> resolution to get decent results if I want to get any of the pictures
> printed as "proper" photos (i.e. by Boots) when I get back?
>
> Any advice gratefully received.
>

http://www.photobox.co.uk/quality.html suggests yes, by a long way, and
you'll probably be fine up to A4

"Peter R Cook" <PCook@wisty.demon.co.uk> wrote in message
news:dR8NGTFx$lqAFwZE@wisty.tiscali.co.uk...
> In message <c8dk2u$hq7$1@pegasus.csx.cam.ac.uk>, Stuart Moore
> <stjm2@cam.ac.uk.remove> writes
> >kAnO wrote:
> >
> >> Just got a Canon Ixus 430 and the 40m rated waterproof housing to go
with
> >> it. I'm planning on taking a load of underwater pictures in the
Maldives
> >> next week but I have a question about resolution. The camera is 4Mp and
will
> >> go upto 2272 x 1704, but at this resolution the picture quality appears
to
> >> drop off - it seems much better at 1600 x 1200. Is that an acceptable
> >> resolution to get decent results if I want to get any of the pictures
> >> printed as "proper" photos (i.e. by Boots) when I get back?
> >> Any advice gratefully received.
> >>
> >
> >http://www.photobox.co.uk/quality.html suggests yes, by a long way, and
> >you'll probably be fine up to A4
>
> How do you judge "..appears to drop off.."

The picture is somewhat grainy.

> If its on a monitor, you are looking at about 96 Pixels per inch, so a
> full screen display will only show a small part of the picture - or the
> viewer is down sampling the image. It could be that the fall off in
> quality you see is an artefact of the down sampling.

No, it's at full resolution, so I have to scroll around to see it. My
monitor resolution is 1280 x 960.

> I would expect to use a minimum of 200+ pixels/inch in a reasonable
> print. So 2275X1704 should give 10X8 prints FROM THE WHOLE FRAME.
> 1600X1200 should give reasonable 8x6 prints.
>
> Unless you are "sure" that the print quality is better at 1600x1200 I
> would keep all the detail you can. Best bet is to take a few shots of
> the same subject at each resolution - get them "processed" and then
> choose.

Might be the only way to tell for sure I guess.

Thanks.

--
kAnO
"A fella, a quick fella, might have a weapon under there. I'd have to pin
his head to the panel..."

In message <c8do9b$7d5$1@news8.svr.pol.co.uk>, kAnO <notlikely@nope.com>
writes
>"Peter R Cook" <PCook@wisty.demon.co.uk> wrote in message
>news:dR8NGTFx$lqAFwZE@wisty.tiscali.co.uk...
>> In message <c8dk2u$hq7$1@pegasus.csx.cam.ac.uk>, Stuart Moore
>> <stjm2@cam.ac.uk.remove> writes
>> >kAnO wrote:
>> >
>> >> Just got a Canon Ixus 430 and the 40m rated waterproof housing to go
>with
>> >> it. I'm planning on taking a load of underwater pictures in the
>Maldives
>> >> next week but I have a question about resolution. The camera is 4Mp and
>will
>> >> go upto 2272 x 1704, but at this resolution the picture quality appears
>to
>> >> drop off - it seems much better at 1600 x 1200. Is that an acceptable
>> >> resolution to get decent results if I want to get any of the pictures
>> >> printed as "proper" photos (i.e. by Boots) when I get back?
>> >> Any advice gratefully received.
>> >>
>> >
>> >http://www.photobox.co.uk/quality.html suggests yes, by a long way, and
>> >you'll probably be fine up to A4
>>
>> How do you judge "..appears to drop off.."
>
>The picture is somewhat grainy.
>
>> If its on a monitor, you are looking at about 96 Pixels per inch, so a
>> full screen display will only show a small part of the picture - or the
>> viewer is down sampling the image. It could be that the fall off in
>> quality you see is an artefact of the down sampling.
>
>No, it's at full resolution, so I have to scroll around to see it. My
>monitor resolution is 1280 x 960.
>
>> I would expect to use a minimum of 200+ pixels/inch in a reasonable
>> print. So 2275X1704 should give 10X8 prints FROM THE WHOLE FRAME.
>> 1600X1200 should give reasonable 8x6 prints.
>>
>> Unless you are "sure" that the print quality is better at 1600x1200 I
>> would keep all the detail you can. Best bet is to take a few shots of
>> the same subject at each resolution - get them "processed" and then
>> choose.
>
>Might be the only way to tell for sure I guess.
>
>Thanks.
>
I think the "graininess" you are seeing is the fact that the image on
screen is that much bigger, so detail looks blockier - because you have
magnified it by 50%.(1600x1200 is fairly close to the size of the
screen) I suspect the only way you will really tell the difference is to
get some big (A4) prints made, or small prints from sections of the
picture.

[Its probably a good idea to get a decent photo printer about now £100
will get you a decent A4 unit from Epson or Canon]

I would stick to the maximum pixel count you can store. Unless you are
seeing distortion in the lens - and I doubt that in a Canon, You will
get always better prints from more pixels - subject to decent processing
software. It will also give you the opportunity to crop the pictures to
get rid of stuff at the edges you didn't notice at the time.

On the other hand if you only ever want standard 7x5 type postcards from
the whole frame of each picture, then 1600X1200 will let you take and
store twice as many frames on whatever storage media you are taking with
you.

Hope you got a strobe to go with the housing. Even in tropical water
below 3M the colour balance goes to hell in a handbasket. Have a great
time.

Regards
--
Peter R Cook