Canon a590 - quality (1 Viewer)

I note (from googling) that the Canon a590 is quite widely used for Digiscoping, and is considered something of a bargain.

Given that my (fairly beloved) Canon a630 had acquired some dirt inside its lens (no, I don't know how). I purchased a a590, and used it to take some holiday shots.

I was pretty disappointed.

This morning I took the same shot, in the same circumstances, with both my a630 and a590.

Here is a zoom down, and a 100% crop from both images; both are saved at 95% quality in Gimp, and the zoom down was bicubic.

(I TRIED to get these inline but VB codes seem not to work here)

whole frame, a630:

http://i48.photobucket.com/albums/f234/bugbear33/photo_tech/6302.jpg

100% Crop, a640:

http://i48.photobucket.com/albums/f234/bugbear33/photo_tech/6302crop.jpg

whole frame, a590:

http://i48.photobucket.com/albums/f234/bugbear33/photo_tech/5902.jpg

100% Crop, a590:

http://i48.photobucket.com/albums/f234/bugbear33/photo_tech/5902crop.jpg

Now, I can't quite put a technical description to what's happened, but at the observational level, the a590 shots are a good deal softer, verging on blurred, and the colours (especially in the roof tiles in the 100% crop) are less well shown.

My particular a590 is clearly less good than my particular a630. What I need to know is:

Do I have a duff a590 (which needs returning to the retailer), or is my a630 an unfair basis for comparison?

I don't have multiple spare a590 for comparison - but I'm hoping denizens here can help me out.

Comments keenly appreciated.

BugBear

P.S. I have tried my a590 with my Nikon Sprint Binoculars!

the wife has a 590 and daughter has a 620 which should be close to your 630 except for the .9 megapixel,,

have to really enlarge (200X) them to see much difference in the photos,, 620 has a tad better shadow detail but both are very close,, they both over saturate colors more than I care for though,,

would head back to the store and try you card in another camera shooting at the store and then shoot the same items on your camera,, then see how the two compare when viewed,, could be a faulty unit,,

Derry

Derry said:

the wife has a 590 and daughter has a 620 which should be close to your 630 except for the .9 megapixel,,

Click to expand...

Thanks for that - the 620 is actually the "big boy" from the previous generation (where the low-res/high-res pair was A610/A620). The next generation was the A630/A640 pair.

I got the A630 following rave reviews of the A620, especially the flip out viewfinder (which is great for getting shots in interesting ways). I also considered the 8Mp of the A630 "enough" and didn't want to pay the hefty premium for the (at the time) market leading 10 Mp of the A640.

Thanks again for your great information.

How do the A590 digiscopers out there find the quality?

My image (IMHO) shows numerous issues, in JPEG quantisation, colour definition in shadows, and possibly focus (hard to tell with the JPEG issues).

BugBear

used the 590 for digascoping but the screen is sure lacking in detail and can be tough to focus with,, now have a P5000 which is much nicer to use,,

the 590 can do some very good work but it makes ya work hard to obtain compared to the newer cameras,,

Derry

Derry said:

used the 590 for digascoping but the screen is sure lacking in detail and can be tough to focus with,, now have a P5000 which is much nicer to use,,

the 590 can do some very good work but it makes ya work hard to obtain compared to the newer cameras,,

Derry

Click to expand...

It's the end result (captured images) that I'm presently worried about, although other factors (e.g. poor display) may affect me as I go on.

BugBear

I think the A590 was recommended is because it was one of the few digi cameras left that still has lens adapter threads. It also has good manual control and user interface. In short, it is digiscoping friendly.

Did you only shoot the default JPEG picture settings? If so, you might try experimenting with the Contrast, Sharpness, and Saturation settings under Custom Colors menu.

cheers,
Rick

RJM said:

I think the A590 was recommended is because it was one of the few digi cameras left that still has lens adapter threads. It also has good manual control and user interface. In short, it is digiscoping friendly.

Click to expand...

I though the way the lens focused (what moves, what stays still) was also suitable - IIRC my A630 is NOT liked for digiscoping, due to the lens (in ways I do not understand)

Did you only shoot the default JPEG picture settings? If so, you might try experimenting with the Contrast, Sharpness, and Saturation settings under Custom Colors menu.

cheers,
Rick

Click to expand...

That may be worth a try - I was just using the same settings as the A630 (Large size, "superfine" compression).

I wasn't using a "custom colour" on either camera (which both support it)

BugBear

I agree with Derry. A590 has poor LCD and thus focusing is tricky, especially in sun. IMO now there are better options than this camera, although Canon is realy user friendly (except focusing) and can produce quite good results when you can focus it properly.
Yesterday I tried to digiscope with light directly on the screen and I was really disapointed with results (huge majority was out off focus...) - the best one is included - also not sharp enough (although taken with almost full zoom)

I've finally found something I can put my finger on, although I'm still at a loss for the (exact) cause-and-cure

http://i48.photobucket.com/albums/f234/bugbear33/photo_tech/tiles_hist.png

That's a histogram of the RGB channels for the largest area of roof(tiles) I could cut out, with the 590 on the left and the 630 on the right.

Note that the overall tonal range of the a630 is higher (making for more contrast) and that the R-G-B values differ from each other more strongly, leading to more saturated colours.

So now, at least, I have something "concrete" to chase.

BugBear

BugBear,
You A630 will take better photos than the A590IS. The A620/630/640 had a great lens and some of the best images out of a digicam in their day. Let down by a low rez screen . People who complain about the A590IS screen should try the earlier A series screen - the worst I've seen on a digicam. The A590IS won't handle long distance digiscoping very well, unless in excellent light. Ok for short stuff though ( under 50 metres ). As suggested bump up the camera settings for contrast and sharpening.
Neil.

Some examples of A590is digiscoping are on this thread

http://www.birdforum.net/showthread.php?t=119008